CALOR 2024, the 20th International Conference on Calorimetry in Particle Physics, will be held at the Tsukuba International Congress Center on May 20-24, 2024, in Tsukuba City, Japan, co-hosted by the University of Tokyo and the University of Tsukuba. This continues the series of calorimetry conferences which have brought together experts on calorimetry and its applications for nearly 30 years.
Key Topics
This conference will be held in person.
The Hadron Calorimeter (HCAL) in the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC) was recently upgraded for Run 3 to introduce depth segmentation and online timing measurements, expanding the physics capabilities. In particular, the augmentation of the calorimeter information at the hardware trigger level enables quick identification and recording of long-lived particle decays using lower thresholds on HT and other energy-based event quantities. With increased segmentation and readout channels, the HCAL provides new timing capabilities for jets and hadronic tau decays with nearly $4\pi$ coverage, and sensitivity to highly displaced decays that occur within the calorimeter volume. In addition, online timing is utilized for detector alignment based on positioning the pulse rising edge, achieving an alignment accuracy of 0.5ns, considerably higher than previous energy-weighting based approaches. Both the depth segmentation and online timing capabilities are utilized in novel HCAL-based hardware-level triggers to identify displaced and delayed long-lived particles (LLPs), either decaying inside the calorimeter volume or arriving at a delayed time. This allows for sensitivity to LLP decays occurring up to almost 6m from the collision point. These triggers were deployed for Run 3 of the LHC, beginning data-taking in 2022. Long-lived particles are a compelling direction to search for physics beyond the Standard Model, and implementing dedicated LLP triggers provides an excellent avenue to expand experimental coverage into this challenging parameter space. This two-pronged calorimeter trigger approach leverages the new capabilities of the CMS HCAL to expand the phase space accessible in ongoing LLP searches.
The CMS electromagnetic calorimeter (ECAL) is a high resolution crystal calorimeter operating at the CERN LHC. The ECAL trigger system employs fast digital signal processing algorithms to measure the energy and timing of ECAL energy deposits recorded during LHC collisions. These trigger primitives are transmitted to the Level-1 trigger system at the collision rate of 40 MHz, and are combined with information from other CMS sub-detectors to determine whether the event should trigger the readout of the data from CMS to permanent storage.
This presentation will summarise the ECAL trigger performance achieved during LHC Run 3 (2022+). It will describe the improved methods that are used to calibrate the ECAL trigger primitives during LHC operation. In particular, we will describe the commissioning of a new automated procedure to derive, validate and deploy up-to-date time-dependent response corrections to the ECAL trigger primitives using in-situ measurements from a dedicated laser monitoring system.
The rejection of large unwanted signals (termed “spikes”), caused by the direct interaction of particles from LHC collisions with the APD photodetectors used in the barrel region (|eta|<1.48) of ECAL, has been an important issue for the Level-1 trigger since the first LHC collisions in 2009. We will describe how the rejection of spikes performed in the ECAL on-detector and off-detector electronics has evolved with changing LHC and detector conditions, and illustrate the potential of additional, currently unused, features of the ECAL on-detector electronics to improve the spike killer performance.
The CMS Electromagnetic Calorimeter (ECAL) is the largest calorimeter operating in a high energy physics experiment. During the course of the LHC Run 1, Run 2, and Run 3, ECAL has made essential contributions to the CMS physics program by precisely measuring the energy, position, and time of arrival of photons and electrons, and of hadronic jets. Among the masterpieces of physics results achieved with its excellent energy resolution is the observation of the Higgs boson in its two photon decay, in 2012, and the precise measurement of its properties.
Operating a lead-tungstate scintillating calorimeter to such high precision and in a harsh radiation environment requires full control of the environmental conditions, such as temperature and bias voltages of the photodetectors, and a continuous correction of the crystal response changes. The latter is achieved via a dedicated laser-based system, monitoring the response on a timescale of one hour, and via a series of calibration techniques that allow to fine tune residual corrections using physics candles on a timescale of few days, depending on the candle and on the machine luminosity. This talk focuses on the challenges faced over the recent Run 3 years - experiencing the largest increase in LHC luminosity - and describes the techniques developed and the achieved results, also including the evolution of the monitoring system in preparation of the High Luminosity phase of the LHC.
The CMS experiment at LHC has a 15 year experience with the energy measurement of electrons and photons produced in collisions of high-luminosity high-energy colliders with a homogeneous electromagnetic calorimeter. The PbWO$_4$ crystal calorimeter must operate at high rate in a harsh radiation environment: changes in detector response need to be corrected for and dedicated techniques are used to mitigate the large number of overlapping interactions (pileup). It also measures the arrival time of the particles, with a precision ranging from 150 to 200 ps. This information is exploited in physics searches, such as for long-lived particles. After the upgrade of the electronics foreseen for the Phase 2 of the LHC, the time resolution will reach 30 ps for energies higher than about 50 GeV. With this level of precision, ECAL can help discriminate overlapping collisions of protons coming from the same crossing bunches by exploiting the difference in time of flight due to the different position of the vertex along the beam axis the particle is coming from. This will be particularly important with the average levels of pile-up foreseen for the LHC Phase2, that will reach 150 in Run 4 and 200 in Run 5. The talk will present a summary of the performance of the CMS ECAL during the Run3 and the performance measured with the upgraded electronics at recent beam tests.
Unprecedented precision is needed to address the Higgs physics with detectors at future e+e- colliders. Linear colliders (such as ILC and C^3) offer conditions, such as low duty cycles and low backgrounds, that can achieve these goals. The SiD Collaboration is developing an application of Monolithic Active Pixel Sensor (MAPS) technology for tracking and electromagnetic calorimetry (ECal). This technology offers high granularity, thin sensors, fast responses ($<$nsec), and small dead areas. The low collider duty cycle enables gaseous cooling for tracking and passive heat removal for calorimetry.
The first MAPS prototype (NAPA-p1), designed by SLAC in CMOS imaging 65 nm technology, is under test. Simulations predict a pixel jitter of <~400 ps-rms and an equivalent noise charge of 13 $e^{-}$rms with an average power consumption of 1.15 mW/cm$^2$ assuming 1\% duty cycle. The prototype is 1.5 × 1.5 mm$^2$, with a 25 $\mu$m pixel pitch. The long-term objective is a wafer-scale sensor of area $\sim$ 5 $\times$ 20 cm$^2$. Application of large area MAPS eliminates delicate and expensive bump-bonding, provides possibilities for better timing, and uses a CMOS foundry process.
Small pixels significantly improve shower separation in the ECal. Detailed simulation of ECal performance confirms previous results, indicating electromagnetic energy resolution based on digital hit cluster counting provides better performance than the 13 mm$^2$ pixels SiD TDR analog design. Furthermore, two particle separation in the ECal is excellent down to the millimeter scale. Geant4 simulation results with optimized analysis based on machine learning has been studied to optimize these expectations.
Several future Higgs factories are planned for the precision Higgs physics to search for the new physics. The highly granular calorimeters play a crucial role on the precision Higgs measurement. The highly granular Sc-ECAL is based on a scintillator strip readout by a SiPM to realize the 5 mm × 5 mm cell size by aligning the strips orthogonally in x-y configuration. In order to demonstrate the performance of the Sc-ECAL and the scalability to the full-scale detector, the technological prototype has been developed with full 32 layers. In 2022 and 2023, the combined beam test of the Sc-ECAL and the CEPC-AHCAL, which is the scintillator based HCAL designed for the Circular Electron Positron Collider, is conducted at CERN SPS and PS beam lines to demonstrate the full calorimeter performance and the per-channel calibrations and performance demonstration are successfully done. This presentation describes the status the Sc-ECAL analysis of the combined beam test.
The current technological prototype of the SiW ECAL comprises 15 layers equivalent to 15360 readout cells. Each layer has a dimension of about 18x18x0.5 cm3.
In 2021 and 2022 the prototype has been tested in beam tests at DESY and at CERN. We will report on the commissioning and calibration of the prototype (around 450000 parameters in total). Further, a simulation model of the beam test setup has been developed yielding a successful data-Monte Carlo comparison for electrons of 10 GeV. The analysis was complicated by acceptance problems of the prototype caused by the partial delamination of silicon sensors off the interface boards to which they are glued. Since the end of 2022 we are investigating the problem and two alternative solutions will be presented at the conference. The sensors will be mounted on new interface boards that will improve several shortcomings observed with earlier versions and that will facilitate the construction of real size layers.
Future collider experiments and the upgrade of the existing large-scale experiments impose unprecedented radiation conditions for the calorimeter systems, particularly in the forward region. The calorimeters envisaged for these operating conditions must be sufficiently radiation-hard and robust in order to perform as expected for the entire lifetime of the experiments. In this context, a novel calorimeter design utilizing quartz-Cherenkov calorimetry, termed Q-Wall has been developed. The Q-Wall concept is a sampling calorimeter that alternates between plates of absorber (Fe, Pb, W, etc.) and active planes. The active planes comprise compact arrays of PMTs with either very thick quartz windows or fused silica pads optically coupled to traditional PMT windows. In these active elements, charged particles with β > 0.685 produce Cherenkov radiation which impinges directly onto the photocathode of the PMT. The Q-Wall concept holds the promise of a very fast and highly granular tracking calorimeter suitable for high radiation environments.
A prototype module of Q-Wall was constructed and tested at CERN test beam. The prototype consisted of three photodetector setups: multianode PMTs directly coupled to ultraviolet-transmitting (UVT) plexiglass in a 2 x 2 and 3 x 3 configuration, an 8 x 8 array of SiPMs coupled to a 5 x 5 array of borosilicate glass cubes, and a 3 x 3 array of SiPMs connected to a 3 x 3 array of borosilicate glass cubes. Here we report on the results of these tests and compare them with electromagnetic shower development simulations with GEANT4.
The precision of clinical treatment planning systems for particle therapy is reduced by the absence of measurements on the differential fragmentation cross sections generated during interactions between light ions (such as C and O) and hydrogen-enriched targets. To address this issue, the FOOT experiment has been designed to take data for beam energies up to 400 MeV/u using an inverse kinematics approach. By extending the energy range to 800 MeV/u, FOOT will also collect valuable data to optimize the design of spacecraft shielding [1]. The experiment aims at identifying fragments by measuring their momentum, kinetic energy, and time of flight with high resolution: 5%, 2% and <100 ps respectively. A calorimeter detector made of 320 BGO crystals coupled to SiPM photodetectors, covering a dynamic range from tens of MeVs to about 10 GeV, measures the kinetic energy. A series of data taking campaigns aiming at characterizing, optimizing and equalizing the crystals response have been conducted at HIT (Heidelberg, Germany) and CNAO (Pavia, Italy). The measurements confirm an integral energy resolution well below the goal of 2%. The modified Birks-energy-response-function shows an excellent agreement with the response of the crystals between 50 and 430 MeV/u for all the ions, although a dependence of the parameters on Z is observed. In this work, the equalization strategy needed to properly measure the fragments kinetic energy and masses in combination with the ToF detectors will be presented.
The LUXE experiment is designed to explore the strong-field QED regime in interactions of high-energy electrons from the European XFEL in a powerful laser field. One of the crucial aims of this experiment is to measure the production of electron-positron pairs as a function of the laser field strength, where non-perturbative effects are expected to kick in above the Schwinger limit.
For the measurements of positron energy and multiplicity spectra, a tracker and an electromagnetic calorimeter are foreseen. Since the expected number of positrons varies over five orders of magnitude, and has to be measured over a widely spread low energy background, the calorimeter must be compact and finely segmented. The concept of a sandwich calorimeter made of tungsten absorber plates interspersed with thin sensor planes is developed. The sensor planes comprise a silicon pad sensor, flexible Kapton printed circuit planes for bias voltage supply and signal transport to the sensor edge, all embedded in a carbon fibre support. The thickness of a sensor plane is less than 1 mm. A dedicated readout is developed comprising front-end ASICs in 130 nm technology and FPGAs to orchestrate the ASICs and perform data pre-processing. As an alternative, GaAs are considered with integrated readout strips on the sensor. Prototypes of both sensor planes are studied in an electron beam of 5 GeV. Results will be presented on the homogeneity of the response, edge effects and cross talk between channels.
DarkSHINE, a fixed-target experiment leveraging the SHINE facility for light dark matter (LDM) detection, utilizes an 8 GeV electron beam with a 1-10 MHz repetition rate. Dark SHINE ECAL plays a crucial role in the precise measurement of recoil electron energies. This ECAL, featuring a homogeneous LYSO crystal scintillator structure, is designed for exceptional energy resolution, rapid response, and high radiation tolerance. Radiation background within the ECAL has been estimated using Geant4 simulations, revealing an equivalent 1MeV neutron flux of approximately 10^13 for the most irradiated cell. Many laboratory experiments have been conducted to evaluate the light yield, uniformity, and dynamic range of the crystal units. Moreover, a LYSO ECAL prototype has been developed and subjected to a beam test with a 4-channel LYSO unit to assess its high-energy beam response. Future efforts will focus on constructing a larger-scale detector prototype to thoroughly validate the proposed design.
In the field of Medical Physics, calorimeters are often used to obtain an absolute dose measurement in standards labs as part of the chain of calibrations for radiation therapy treatment machines in hospitals and cancer centers. Currently, every calorimeter designed for this purpose is 1-dimensional, despite the radiation dose deposited not always being homogeneous across the entire irradiated area. Therefore, a 2-dimensional calorimeter array is being designed to provide information on the dose both on the central axis of the radiation beam as well as the dose fall off away from center.
The device is composed of 9 voxels in a 3x3 configuration. Each voxel contains a cylindrical core made of high-purity aluminum which is the volume of interest for heating measurements and therefore dose determination. Each core is surrounded by alternating shells of solid Aerogel insulation and additional high-purity aluminum. The outer aluminum shell is operated isothermally with a set temperature above what the ambient air could reach. This provides a buffer for each core from both air temperature fluctuations and heat flow between voxels during measurements. The inner aluminum shell and the core maintain a quasi-adiabatic state to prevent heat flow into or out of the core except from the energy deposited from the radiation. Both temperature measurements and necessary heating for the quasi-adiabatic or isothermal conditions are accomplished using embedded thermistors connected to a LabJack T7 DAQ device operated by a purpose-built Python control code.
The calorimeter array is currently being constructed for testing later this year.
This talk outlines the design and validation of a pointing ECAL facilitating the precise reconstruction of $X \rightarrow \gamma \gamma$ decays in beam dump FIP experiments. The design study primarily employs GEANT4 simulations to evaluate the performance of the proposed ECAL design, emphasizing its pointing capability crucial for $X \rightarrow \gamma \gamma$ vertex reconstruction. Key aspects of the design include the choice of scintillator granularity, optimized for spatial measurements. The Monte Carlo simulation results are presented alongside test beam data to validate the performance of the design.
Motivated by the physics programs of precision measurements of the Higgs, W/Z bosons, and the top quark, future lepton colliders, e.g. the Circular Electron Positron Collider (CEPC), have to meet stringent requirements on the calorimetry systems to achieve unprecedented jet energy resolutions. As part of CEPC’s “4th detector concept”, a novel high-granularity crystal electromagnetic calorimeter (ECAL) has been proposed, with an optimal EM resolution of $2-3\%/\sqrt{E(GeV)}$ and sufficiently low detection limit of photons. By utilizing the Particle Flow Algorithm (PFA) with other optimized sub-detectors, the new ECAL design concept is expected to improve the Boson Mass Resolution (BMR) from 4% in the CEPC CDR to 3% level.
Significant R&D efforts have been made in the design of this crystal ECAL. Geant4 full simulations have been conducted to assess the impact of light yield and time response of the crystal. Laboratory measurements with characterizations of crystal, silicon photo-multipliers (SiPMs), and readout electronics have been carried out to validate the simulations and demonstrate the feasibility of the hardware. A small-scale crystal module has been developed and tested under beam conditions for performance studies and system-level investigations.
This report introduces the design of the novel high-granularity crystal ECAL, outlines its physics potential, and presents the latest progress on module-level tests and PFA performance studies.
Future electron-positron collider experiments necessitate an exceptional jet energy resolution to enable precise measurements of the Standard Model particles and searching for new physics. The Particle Flow Approach (PFA) is regarded as a promising solution to achieve an unprecedented jet energy resolution. The Particle Flow oriented calorimeter requires an impact shower and high granularity readout channels.
A novel electromagnetic calorimeter (ECAL) with orthogonally arranged crystal bar has been proposed to achieve high intrinsic energy resolution and reduce the number of readout channels by approximately an order of magnitude compared to high granularity calorimeters. The primary challenges of this new design include the ambiguity problem arising from the perpendicular arrangement of crystal bars when multiple particles are injected simultaneously, and the shower overlap resulting from the larger Moliere radius of the crystal.
This report will present recent progress for feasibility analysis of this ECAL design. A new PFA with several sub-algorithms has been developed to address aforementioned issues. The ambiguity problem has been resolved through the implementation of multiple optimized pattern recognition approaches, while the issue of shower overlap has been mitigated by an energy splitting module. Performance validations have yielded promising results in the Circular Electron Positron Collider (CEPC) experiment. These results indicate that the proposed ECAL design and the novel PFA approach will broaden detector options and reconstruction methods for Future electron-positron collider experiments.
High-density, high-light-output inorganic scintillators are extensively utilized in the detection of ionizing radiation across various fields, including high-energy physics, space exploration, advanced medical imaging, and industrial applications. The Glass Scintillator Hadronic Calorimeter (GSHCAL) is an important part of calorimeter system in the Circular Electron Positron Collider (CEPC). The Institute of High Energy Physics proposed a design of glass scintillator coupled with SiPM as a new solution for the next generation calorimeter to explore the oapplication of glass scintillators in high energy physics and nuclear radiation detection. The Large Area Glass Scintillator Collaboration Group (GS) was established to research and develop scintillation glass. The response of Gd-doped scintillation glass to gamma rays and neutrons is investigated here. In addition, we performed the corresponding comparison experiments using Gd3Al2Ga3O12 (GAGG:Ce) scintillation crystals. The neutron response of the GAGG:Ce and Gd-doped scintillation glass coupled with silicon photomultiplier (SiPM) has been measured, and two distinct strong low-energy neutron indication peaks can be clearly identified below 100 keV. Although the Gd-doped scintillation glass is not as good as the GAGG scintillator in terms of energy resolution, the response to thermal neutrons is more sensitive, and two strong low-energy neutron peaks are clearly recognized below 100 keV.
For future e-e+ Higgs factories, such as the Circular Electron Positron Collider (CEPC), precision measurements of properties of the Higgs, W and Z bosons are the key scientific goals. A main challenge for these goals is to fulfill an unprecedented jet energy resolution, and the design of the hadronic calorimeter (HCAL) is found to be one of the most important factors. Then, a novel design of the particle flow oriented hadronic calorimeter based on glass scintillators (GSHCAL) was proposed recently. By using high-performance glass scintillators featuring high density, high light yield and short decay time, the GSHCAL can be beneficial for a better jet energy resolution and more compact structure in a cost-effective way. In this contribution, the optimizations for several key design parameters of the GSHCAL are discussed and the performances in different GSHCAL designs are compared, in order to balance the key physics performance and the cost, as well as the engineering complexity.
As an upgrade of the ALICE experiment at the LHC, the Forward Calorimeter (FoCal) with a unique capability to measure direct photon production at the forward rapidity has reached the final stage of the development. FoCal consists of the Si+W electromagnetic calorimeter with longitudinal segmentation (FoCal-E) and Cu+Scintilation-fiber hadronic calorimeter (FoCal-H), and each FoCal-E module has 20 low-granularity layers with silicon pad sensors and 2 high-granularity layers with silicon pixel sensors. 22 FoCal-E modules for covering the pseudo-rapidity of 3.2 < η < 5.8 will be installed at a place of 7 meters seen from the interaction point during Long-Shutdown 3 and the data taking will start in the period of 2029-2032. We developed the FoCal-E pad module prototype and put it to some beam tests at the ELPH and CERN PS/SPS complexes. We also carried out the irradiation tests of the silicon pad sensors at Riken RANS equipment including some electronic components because it is important to estimate a change of characteristics of the sensors in long-term operation in the ALICE cavern. Sensors got the 1MeV neutron beam up to 6 x 10^13 neutron equivalent / cm^2 at the maximum in two days, and we continuously measured the I-V characteristics of the irradiated sensors for two months. In this talk, we would like to report the test beam results of the FoCal-E pad module prototype and irradiation test results of the silicon pad sensors including the MIP measurement, the temperature dependence and bias voltage dependence.
The Zero Degree Calorimeters (ZDC) of the ALICE experiment at LHC were designed to characterize the event and monitor the luminosity in heavy-ion measurement.
In order to fully exploit the potential offered by the LHC increased luminosity in Run 3, while preserving the time and charge resolution performance, the ZDC readout system was upgraded to allow the acquisition of all collisions in self-triggered mode without dead time.
The presence of ElectroMagnetic Dissociation (EMD) processes makes the ZDC running conditions extremely challenging, raising the readout rate for the channels of the most exposed calorimeters up to ~ 1.4 Mevents/s, compared to an hadronic rate of about 50 Kevents/s sustained by all other detectors.
The new acquisition chain is based on a commercial 12 bit digitizer with a sampling rate of ~ 1 GSps, assembled on an FPGA Mezzanine Card.
The signals produced by the ZDC channels are digitized, the samples are processed through an FPGA that, thanks to a custom trigger algorithm, flags for readout the relevant portion of the waveform and extracts information such as timing, baseline average and event rate.
The system is fully integrated with the ALICE data taking infrastructure and acquired physics data in global runs during the 2023 LHC heavy-ion data taking.
The architecture of the new readout system, the auto trigger strategy and the ZDC performance during the 2023 Pb-Pb collisions are presented.
The sPHENIX hadronic calorimeter (HCal) was successfully commissioned in 2023, which marks the very first sampling hadronic calorimeter with large acceptance coverage at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory. The HCal consists of two sections (called Outer and Inner HCal) which sandwiches a super conducting magnet of 1.4T ($\sim \! 0.4 \lambda_0$). The Outer HCal ($\sim 4\lambda_0$) is made of tapered stainless steel plates interleaved with plastic scintillating sheets of 12 $\eta$-dependent shapes. Each scintillating sheet is carved with a groove on one side with a unique pattern for embedding a wavelength shifting fiber for light collecting efficiency and uniformity. The same design idea is for the Inner HCal ($\sim 0.25\lambda_0$) but in smaller size and with aluminum plates. The HCal is read out in units of towers which consist of 5 scintillator tiles for the Outer and 4 for the Inner. The towers are arranged projectively toward the collision vertex in a $\phi$ and $\eta$ grid for a total of 1,536 towers each for the Outer and the Inner HCal. The HCal provides an unprecedented study in high precision of jet production in Au+Au collisions at $\sqrt{s_{NN}} = 200$ GeV for characterizing the properties of quark-gluon plasma, which is one of the major scientific objectives of the sPHENIX experiment. A brief summary of the HCal design, beam tests, construction, installation, calibration, and the detailed GEANT4 simulation will be presented in this talk. The emphasis of this presentation includes the most recent HCal performance results.
The Electron-Ion Collider (EIC) is a Nuclear Physics facility being built at Brookhaven National Laboratory, USA. It will address the fundamental questions in science regarding the visible world, such as the origin of the nucleon mass, the nucleon spin, and the emergent properties of a dense system of gluons.
Realizing the ambitious EIC physics program requires an extremely capable detector to measure the variety of probes in wide momentum range with full geometrical coverage. Asymmetric nature of collisions at the EIC with wide range of beam energies and variety of hadron beam species, leads to unique detector requirements in different kinematical regions.
In this talk we will discuss the requirements for electromagnetic calorimetry (EMCal) in different regions of the ePIC detector, the selected technologies to satisfy the requirements, and expected performance, based on comprehensive simulation and beam tests with module prototypes. We will overview the progress in EMCal design and present the timeline for its construction.
PANDA is the main hadron physics addressing experiment of the future FAIR (Facility for Antiproton and Ion Research) center at Darmstadt, Germany. Located at the HESR antiproton storage ring the PANDA detector is optimized for physics of the weak and strong interactions in the charm sector: Search for new and exotic states of matter, precise determination of quantum numbers, masses and widths of hadronic resonances and deeper insights in the structure of hadrons.
The detector consists of a target spectrometer built around the interaction region of antiprotons carrying momenta of 1.5-15 GeV/c with a fixed hydrogen target and a forward spectrometer. Its design is based on compactness and cost saving while enabling to achieve high resolution, rate capability and physics selectivity.
In the PANDA target spectrometer the electromagnetic calorimeter is composed of three subdetectors based on lead tungstate crystals operated at -25 degrees C. A barrel structure build from 11360 crystals will be closed in up- and downstream direction by two endcaps containing 524 and 3856 crystals, respectively.
The upstream located forward endcap has been completed with vacuum photo tetrode read-out crystal submodules and was operated at two beam times in 2023 at the Jülich Cooler Synchrotron COSY with a 2.5 GeV/c proton beam.
Besides the detector setup, the cooling concept, and beam test results will be presented.
The CMS-HF Calorimeter is designed to detect the forward going particles. Discovery type events are believed to produce high energy particles going at forward angles. Hence, it is important to determine the particle energies accurately by making sure that the detectors have the right calibration all the time. The CMS-HF calorimeters have quartz fibers as the active element. Particle showers caused by the high energy particles travelling through the calorimeter produce the Cherenkov light in the quartz fibers. Particle energies are determined from the signals produced in the PMTs by the Cherenkov light reaching them. Damage in the fibers caused by the radiation during the collisions increases the attenuation in the fibers resulting in less light reaching the PMTs for the same energy. The HF Online radiation monitoring system is designed to measure the attenuation of the light in the fibers independently and to provide the correction factors for the energy calibration as a function of the luminosity during the run period. The system was upgraded and commissioned at the end of the Run II. The correction factors for the 2022 run period were obtained both in terms of time and luminosity. The results were normalized to those at the lowest eta values so that the measurements could be compared with the values obtained from the collision data. The recovery effect in the fibers is also observed in the measurements done by the online system. The same measurements were done for the 2023 run period.
The Tile Calorimeter (TileCal) is a sampling hadronic calorimeter covering the central region of the ATLAS experiment, with steel as absorber and plastic scintillators as active medium. The scintillators are read-out by the wavelength shifting fibers coupled to the photomultiplier tubes (PMTs). The analogue signals from the PMTs are amplified, shaped, digitised by sampling the signal every 25 ns and stored on detector until a trigger decision is received. The TileCal front-end electronics reads out the signals produced by about 10000 channels measuring energies ranging from about 30MeV to about 2 TeV. Each stage of the signal production from scintillation light to the signal reconstruction is monitored and calibrated. A summary of recent performance results and its High Luminosity LHC upgrade project will be presented.
To cope with the increase of the LHC instantaneous luminosity, new trigger readout electronics were installed on the ATLAS Liquid Argon Calorimeters.
On the detector, 124 new electronic boards digitise at high speed 10 times more signals than the legacy system. Downstream, large FPGAs are processing up to 20 Tbps of data to compute the deposited energies. Moreover, a new control and monitoring infrastructure has been developed. This contribution will present the challenges of the commissioning, the first steps in operation, and the milestones still to be completed towards the full operation of both the legacy and the new trigger readout paths for the LHC Run-3.
In order to withstand the high expected radiation doses at the High-Luminosity LHC, the ATLAS Liquid Argon Calorimeter readout electronics will be upgraded.
This includes the development of custom preamplifiers and shapers meeting low noise and excellent linearity in 65 nm and 130 nm CMOS technologies to meet these requirements, a new ADC chip with two gains over a dynamic range of 16 bits and 11 bit precision and new calibration boards with excellent non-linearity and non-uniformity between all of the 182468 calorimeter channels are developed.
New ATCA compliant signal processing boards equipped with FPGAs and high-speed links receiving the total of 345 Tbps of detector data at 40 MHz and performing energy and time reconstruction as well as a new timing and control system connecting to it are also being developed.
Test results of the latest versions of the aforementioned on- and off-detector components as well as the latest firmware development will be presented.
The aim of the LHCb Upgrade II is to operate at a luminosity of up to 1.5 x 10$^{34}$ cm$^{-2}$ s$^{-1}$ to collect a data set of 300 fb$^{-1}$. The required substantial modifications of the current LHCb electromagnetic calorimeter due to high radiation doses in the central region and increased particle densities are referred to as PicoCal. An enhancement of the ECAL already during LS3 will reduce the occupancy and mitigate substantial ageing effects in the central region after Run 3.
Several scintillating sampling ECAL technologies are currently being investigated in an ongoing R&D campaign: Spaghetti Calorimeter (SpaCal) with garnet scintillating crystals and tungsten absorber, SpaCal with scintillating plastic fibres and tungsten or lead absorber, and Shashlik with polystyrene tiles, lead absorber and fast WLS fibres.
Timing capabilities with tens of picoseconds precision for neutral electromagnetic particles and increased granularity with denser absorber in the central region are needed for pile-up mitigation. Time resolutions of better than 20 ps at high energy were observed in test beam measurements of prototype SpaCal and Shashlik modules. Energy resolutions with sampling contributions of about 10%/sqrt(E) in line with the requirements were measured. The presentation will also cover results from detailed simulations to optimise the design and physics performance of the PicoCal.
Secondary electron emission is the primary signal formation and/or amplification technique utilized in accelerator beam monitors and photomultiplier tubes where incident energetic particles cause ejection of additional electrons from a secondary emission surface. The materials employed as surfaces for secondary electron emission have demonstrated exceptional resistance to radiation, making them suitable for serving as the active media in radiation-hard calorimeters. With this motivation, we developed dedicated secondary electron emission sensor modules, tested them with particle beams and developed Monte Carlo simulations to predict the performance of large-scale calorimeters. Here, the details of the sensor modules and the results of the beam tests and simulations will be discussed.
Recently, we have applied high secondary emission yield materials, Al$_2$O$_3$ and TiO$_2$, as surface coatings on the anode plates of one-glass resistive plate chambers developing the so-called hybrid resistive plate chambers. The beam test results manifestly show the contribution of the secondary emission layer on the overall electron multiplication in the gas gap. The measurements also enable preliminary assessment of the secondary emission principle in thin Al$_2$O$_3$ and TiO$_2$ layers in a particle shower/avalanche environment and the development of Monte Carlo simulations. Here we describe the details of the direct utilization of the secondary electron emission surfaces and the impact of the findings on future implementations.
Although inorganic scintillators are widely used in the design of electromagnetic calorimeters for high-energy physics and astrophysics, their crystalline nature and, hence, their lattice orientation are generally neglected in the detector design. However, in general, the features of the electromagnetic field experienced by the particles impinging on a crystal at a small angle with respect to a lattice axis affect their interaction mechanisms. In particular, in case of electrons/photons of $\mathcal{O}(10~\mathrm{GeV})$ or higher impinging on a high-$Z$ crystal at an angle of $\lesssim 1~\mathrm{mrad}$, the so-called strong field regime is attained: the bremsstrahlung and pair production cross sections are enhanced with respect to the case of amorphous or randomly oriented materials. Overall, the increase of these processes leads to an acceleration of the electromagnetic shower development. These effects are thoroughly investigated by the OREO (ORiEnted calOrimeter) team, and pave the way to the development of innovative calorimeters with a higher energy resolution, a higher efficiency in photon detection and an improved particle identification capabilities due to the relative boost of the electromagnetic interactions with respect to the hadronic ones. Moreover, a detector with the same resolution as the current state of the art and reduced thickness could be developed. An overview of the lattice effects at the foundation of the shower boost and of the current status of the development of an operational calorimeter prototype are presented. This concept could prove pivotal for both accelerator fixed-target experiments and satellite-borne $\gamma$-ray observatories.
The design of next-generation calorimeters for accelerator-borne experiments at the intensity frontier poses unprecedented challenges with regard to timing performance and radiation resistance, while rivaling the current state of the art in terms of energy resolution. A significant role may be played by quantum dots, i.e., light-emitting semiconductor nanocrystals with high quantum yield and rather easy to manufacture. Quantum dots can be cast into an optically transparent polymer matrix to obtain nanocomposite scintillators, which are functionally similar to conventional plastic scintillators and can feature O($100~\mathrm{ps}$) emission times and O($1~\mathrm{MGy}$) radiation resistance. Moreover, they are rather economical, thus suiting large-volume applications. The NanoCal project is evaluating the potential for the use of perovskite-based nanocomposite scintillators in sampling calorimeters, which is nowadays yet to be extensively explored; it aims at developing an operational full-scale sampling calorimeter prototype with NC tiles, an absolute novelty, by 2025. We are performing comparative tests of innovative scintillators, both fully organic and nanocomposite, as standalone samples and integrated in fine-sampling shashlik calorimeter prototypes. Measurements are performed using both cosmic rays and electron and MIP beams in a wide energy range (at the CERN and INFN LNF beamtest facilities), allowing the performance gains obtained from the different scintillators to be directly characterized.
The Calvision project seeks to develop high resolution calorimetry for the Future Circular Collider (FCC) with state-of-the-art performance for both electromagnetic (EM) and hadronic signatures using the dual-readout technique. We seek to improve the hadronic energy resolution of homogenous scintillating-crystal calorimeters through the measurement and separation of the scintillation and Cherenkov light in hadronic showers. The research program considers materials, sensors, light-collection techniques, readout and signal analysis, accelerated simulation techniques, as well as reconstruction algorithms to improve measurments in data collected at a Higgs factory. This talk will introduce the goals of the research program and review our test beam efforts and proof-of-principle measurements aimed at studying the collection of Cherenkov and scintillation signals in homogenous crystals applicable to an EM layer with dual-readout capability.
The future circular electron-positron collider (FCC-ee) will be a unique precision instrument designed to offer great direct and indirect sensitivity to new physics. Its primary purpose will be to study the heaviest known particles (Z, W, and H bosons and the top quark) with unprecedented precision, a goal that introduces multiple challenges in the detector design. Key requirements for the detector include excellent energy and angular resolution coupled with strong particle identification capabilities.
One of the proposed experiments for FCC-ee is ALLEGRO, a general-purpose detector concept that is currently in its design and optimization phase. This contribution aims to introduce ALLEGRO’s calorimeter system, offering a comprehensive overview of the baseline technologies planned for its two calorimeter systems: a highly granular noble-liquid electromagnetic calorimeter and a hadronic calorimeter with scintillating-light readout using wavelength shifting fibers.
To assess the calorimeters’ performance, test different detector geometries, and fine-tune reconstruction algorithms such as topological clustering, we employ Monte Carlo simulations of single particles. Preliminary results from performance studies with the standalone HCal and combined ECal+HCal calorimeters are presented, thus shedding light on the promising capabilities of this newly introduced detector concept for FCC-ee. In addition to these design-focused analyses, we briefly introduce our inquiries into the potential use of machine-learning approaches for particle identification and detector calibration.
The Crilin calorimeter is a semi-homogeneous calorimetric system that uses Lead Fluoride (PbF2) crystals with UV-extended Silicon Photomultipliers (SiPMs). Proposed for the Muon Collider, it requires high granularity to distinguish signal particles and address substructures for jet identification.
Anticipating substantial occupancy due to beam-induced backgrounds, simulations indicate a photon flux with an average energy of 1.7 MeV and approximately 4.5 MHz/cm$^2$ fluence. Prioritizing time-of-arrival measurements within the calorimeter is crucial for associating clusters with interaction vertices. The calorimeter's energy resolution is vital for determining jet kinematics.
Operating in a challenging radiation environment, with exposure up to 1 Mrad/year total ionizing dose (TID) and a neutron fluence equivalent to 10^14 neutrons 1 MeV/cm$^2$/year, extensive radiation hardness studies confirm the system's effectiveness.
Prototype (Proto-1), with two layers of 3x3 PbF2 crystals, achieved a timing resolution below 50 ps for energy deposits exceeding 1 GeV during 2023 tests. A comprehensive overview, including mechanics and electronics, along with test beam outcomes, is presented.
Construction is underway for a larger 5x5 crystal matrix prototype with 5 layers, to be completed in 2024. Testing is scheduled for the summer of 2025.
A new type of SiW electromagnetic calorimeter is being developed using digital pixel sensors. The R&D is performed in the context of the FoCal upgrade within the ALICE experiment and is related to studies of imaging in proton CT; it is applicable to other future collider projects such as EIC, ILC, CLIC or FCC. Based on a proof of principle with a first digital calorimeter prototype, we have constructed an advanced second prototype, EPICAL-2, using ALPIDE MAPS sensors. Binary readout is possible due to the pixel size of $\approx 30 \times 30 \, \mu \mathrm{m}^2$. The prototype consists of alternating W absorber and Si sensor layers, with a total thickness of ~20$X_0$, an area of $\mathrm{30mm\times30mm}$, and ~25 million pixels. It has been successfully tested with cosmic muons and with test beams at DESY and the CERN SPS. First results have been published in [1], showing good energy resolution and linearity.
We will report on recent updates of performance results and comparisons to detailed MC simulations. The spatial precision of event-by-event measurements of the showers allows unprecedented studies of the shower shape, providing unique feedback to GEANT developers. The detector also features two-shower separation capabilities at extremely small distances. Further studies include a three-dimensional parameterisation of showers and electron/photon discrimination from hadrons. We will also discuss the limitations of the currently used sensor technology and perspectives for future development of digital calorimetry.
[1] J.Alme et al 2023 JINST 18 P01038
Precision measurement of hadronic final states presents complex experimental challenges. The study explores the concept of a gaseous digital hadronic calorimeter (DHCAL) and discusses the potential benefits of employing Graph Neural Network (GNN) methods for future collider experiments. In particular, we use GNN to describe calorimeter clusters as point clouds or a collection of data points representing a three-dimensional object in space. Combined with AttentionTransformers and DeepSets algorithms, this results in significant improvement over existing baseline techniques for particle identification and energy resolution.
We discuss the challenges encountered in implementing GNN methods for energy measurement in digital calorimeters, e.g., the need for large training datasets, the large variety of hadronic shower shapes and the hyper-parameter optimization. We also discuss the dependency of the measured performance on the incoming particle angle and on the detector granularity. Finally, we highlight potential future directions and applications of these techniques.
Electron-positron Higgs factories such as ILC or FCCee aim to reveal properties of Higgs and other particles much more precise than current knowledge. One of the key concepts of detectors for Higgs factories is Particle Flow, which utilizes highly-segmented calorimeter cells to separate each particle inside hadronic jets, giving much better jet energy resolution by replacing energies of clusters by charged particles to track momenta.
We are working on improving the particle flow algorithm for Higgs factories by utilizing modern machine-learning technologies. We start from Graph Neural Network (GNN)-based algorithm developed in the context of CMS HGCAL clustering. It utilizes GravNet as the GNN architechture and Object Condensation loss function for training. Since the HGCAL algorithm only performs clustering at the calorimeter, we developed track-cluster matching feature inside the network to realize full PFA with this algorithm. Details of initial implementation of the track-cluster matching algorithm as well as performance evaluation with multiple tau events and jet events will be shown in the presentation.
The fluctuations in energy loss to processes that do not generate measurable signals, such as binding energy losses, set the limit on achievable hadronic energy resolution in traditional energy reconstruction techniques. The correlation between the number of hadronic interaction vertices in a shower and invisible energy is found to be strong and is used to estimate invisible energy fraction in highly granular calorimeters in short time intervals (<5 ns). We simulated images of hadronic showers using GEANT4 and deployed a neural network to analyze the images for energy regression. The neural network-based approach results in significant improvement in energy resolution, from 13% to 4% in the case of a Cherenkov calorimeter and from 7% to 4% for an ionization calorimeter for 100 GeV pion showers. We discuss the significance of the phenomena responsible for this improvement and the plans for experimental verification of these results.
The Geant4 Team at CERN is leading a long-term validation program based on detailed reproduction of calorimeter test-beam simulations and results in geant-val, the Geant4 validation and testing suite. This program focused so far on the ATLAS Hadronic Endcap and Tile Calorimeter, the CMS High-Granularity Calorimeter, the CALICE SiW Calorimeter and the optical-fiber Dual-Readout Calorimeter. New results including Geant4 regression testing and physics list comparison will be presented. Moreover, the chart for Geant4 development will be discussed.
Plastic scintillator detectors with 3D granularity and sub-ns time resolution are capable of simultaneous particle tracking, identification and calorimetry. Enhancing the performance of future detectors will necessitate larger volumes, possibly combined with even finer segmentation, making the manufacturing and the assembly processing prohibitive, time consuming, expensive and hard to control with the desired precision. The 3DET R&D collaboration recently developed the additive manufacturing technology that opens the door to large-scale production of 3D-segmented scintillating detectors. A novel technique was developed to additive manufacture a monolithic geometry consisting of 3D granular scintillator without the need for additional production steps. A 5x5x5 matrix of optically-isolated scintillating sub-structures made of highly transparent polystyrene, white reflector, and orthogonal 1 mm diameter holes to accommodate wavelength shifting fibers was produced. This talk presents the fabrication of the additive manufactured prototype. The evaluation of the response with data collected by exposing it to both cosmic rays and test beam at CERN will also be reported. This work paves the way towards a new feasible, time and cost-effective process for the production of future scintillator detectors, regardless their size and difficulty in geometry, with a performance comparable to the current state of the art of plastic scintillator detectors.
Lead tungstate (PbWO4) is an exceptional material for high-energy physics detectors, particularly in the construction of electromagnetic calorimeters. The combination of high density, fast decay time, good energy resolution, and radiation hardness makes lead tungstate an ideal material for electromagnetic calorimeters used in high-energy physics experiments.
We report a novel readout circuit tailored primarily for PbWO4 scintillation detectors in high-energy experiments. The design integrates a 4x4 SiPM array directly coupled to a preamplification stage, housed within a compact electronics module. The readout circuit is design to work with independent number of the SiPMs without affecting the timing output. This module incorporates bias control for SiPMs and adjustable gain and offset controls via USB/RS485 interfaces. The optimization efforts for the readout circuit aimed to achieve the following objectives: high spectral resolution, rapid response, compactness, and low energy consumption. Key features include a fixed bias voltage, externally adjustable preamplifier settings stored on EEPROM and output signal compatibility up to 1V/50Ω. We fabricated a prototype with a 3x3 array of 20 mm x 20 mm x 200 mm PbWO4 crystals coupled to individual sensor arrays and readouts, subjected to thorough testing in energy range 50MeV to 5GeV. Comprehensive characterization measurements will be presented.
The original dual-readout calorimeter prototype (DREAM), constructed two decades ago, has proven instrumental in advancing our understanding of calorimetry. It has facilitated a multitude of breakthroughs by leveraging signals from complementary media (Cherenkov and scintillation) to capture fluctuations in electromagnetic energy fraction within hadronic showers. Over the years, extensive studies have shed light on the performance characteristics of this module, rendering it exceptionally well-understood. Drawing on this wealth of experience, we have embarked on enhancing the detectors’ capabilities further by integrating fast Silicon Photomultipliers (SiPMs) with transverse segmentation approaching 1 cm2, as well as longitudinal segmentation by timing measuring less than 10 cm. This configuration allows us to image hadronic showers with high granularity (HG-DREAM). The spatial information provided by such a granular detector in a short time window (~5 ns) leads to a substantial enhancement in energy resolution when advanced neural networks are employed in energy reconstruction. We discuss the design criteria, construction techniques, electronics readout methodology, expectations from simulations, and the results obtained from bench and cosmic tests, along with preparations for beam tests.
Calorimetry is a fundamental technique in particle physics. It entails precisely measuring the energy of particles deposited during their interaction with detector materials, furnishing crucial insights into their properties and behavior. Recent breakthroughs in materials science,in achieving tunable and narrow emission bandwidths (∼20 nm) in nano-material scintillators containing quantum dots have paved the way for a novel particle physics method known as chromatic calorimetry. This method allows for tracking the progression of electromagnetic or hadronic showers within a calorimeter module, offering the potential to obtain a detailed view of the shower profile. The concept involves strategically layering scintillators with various emission wavelengths. Specifically the nanomaterial scintillators, with those emitting the longest wavelengths positioned at the beginning and the shortest wavelengths placed towards the end of the module. This allows for fine-grained measurements of shower developments and aims to enhance the detector’s particle identification and energy resolution capability. Building upon this foundation, this presented study serves as a proof of concept to validate the relevance of the method by utilizing standard inorganic scintillators with various emission wavelengths. We begin with employing a stack of different inorganic bulk scintillators with different emission spectra strategically positioned in decreasing wavelength maxima, to enable one-directional transparency as per chromatic calorimetry requirement. The stack was excited using pions & electrons with 100 GeV energy. The findings shed light on longitudinal shower measurement and analytical discrimination between electrons and pions. This study highlights the potential to refine and optimize the functionalities of chromatic calorimetry for broader applications.
The Mu2e experiment will search for the CLFV conversion of muons into electrons in the field of an Al nucleus, planning to reach a single event sensitivity of about 3x10−17, four orders of magnitude beyond the current best limit.
The conversion electron has a monoenergetic signature at 105 MeV and will be identified by a high-resolution straw tracker and an electromagnetic calorimeter (EMC). The EMC is composed of 1348 pure CsI crystals, each one read by two custom SiPMs, arranged in two annular disks. It should achieve a 10% energy resolution and 500 ps timing resolution for 100 MeV electrons, while maintaining high levels of reliability in a harsh operating environment with high vacuum, 1 T B-field and radiation exposures up to 100 krad and 10^12 n1MeVeq/cm2.
The calorimeter technological choice and the design were validated through an electron beam test on a large-scale prototype and extensive test campaigns that characterised and verified the performance of crystals, photodetectors, analogue and digital electronics. This included hardware stress tests and irradiation campaigns to test for DD, TID and SEE.
The two disks have been fully assembled, with a full integration and test of all the analogic sensors and electronics. We are now progressing on the insertion of the digital electronics. We will summarise the construction and assembly phases, the QC and the calibration tests performed in the assembly area as well as the installation and commissioning plans of the final disks in the Mu2e hall.
The MEG II experiment in a search of $\mu\to\mathrm{e}\gamma$ started taking physics data in 2021. A liquid xenon calorimeter with 4760 photosensors measures photon position, time, and energy of 52.8 MeV. The precise energy reconstruction to distinguish signal and background events requires the calibration of photosensors and an energy scale of the calorimeter. The energy resolution of 1.8% was achieved and the uncertainty of the energy scale was suppressed to 0.4% in 2021. In addition, pileup elimination algorithms have been developed since a high-intensity muon beam of $3-5 \times 10^{7}\,\mathrm{Hz}$ is stopped at the muon stopping target. A single photon energy is reconstructed by the algorithms. Currently, the analysis of the 2022 data is in progress. This presentation describes the reconstruction algorithm, the calibration, and the achieved performance with the 2021 and 2022 combined datasets.
The MUon proton Scattering Experiment (MUSE) at the PiM1 beam line of the Paul Scherrer Institute is simultaneously measuring the elastic scattering of electrons and muons from a liquid hydrogen target to extract the charge radius of the proton with both positive and negative beam polarities. In addition to providing precise data for addressing the proton radius puzzle, by comparing the four scattering cross sections the experiment will directly test lepton universality, radiative corrections, and two-photon exchange effects for electrons and muons. In order to study radiative correction and get more precise incident beam energy for the cross section measurements, MUSE uses a lead-glass calorimeter located downstream in the beam. In this presentation, the specification and calibration process of the calorimeter detector will be discussed. Latest data and comparison to simulation will be shown to demonstrate the performance of the detector.
The T2K long-baseline neutrino oscillation experiment showed the strongest constraint on the CP violating phase that governs the matter/antimatter symmetry breaking in neutrino oscillation. For further improvement of the experimental sensitivity, T2K installed a novel high granular scintillator detector, called SuperFGD, to reduce systematics. It consists of about 2 millions of 1 cm$^3$ optically-isolated plastic scintillator cubes as a fully-active target. Scintillation light in the cubes is read out by about 56,000 channels in the three orthogonal directions with wave-length shifting fibers coupled to MPPCs. In addition to excellent tracking capability, this novel structure of SuperFGD allows us to perform calorimetry such as EM shower and detection of proton bragg peak. We report the detector design, construction, detection of first neutrino candidates and initial evaluation of detector performance toward the calorimetric analysis.
The Belle II at SuperKEKB electron-positron collider is the new generation B-factory experiment and calorimetry plays an important role to detect neutral particles and reconstruct missing energy/momentum. The CsI(Tl) crystals with the PIN-Photodiode readout are inherited from Belle experiment and readout electronics and data acquisition system are replaced to cope with the high event rate provided by the high luminosity of SuperKEKB accelerator. After accumulating the data corresponding to 428/fb by 2022 summer, we replaced the data acquisition system backend by the PCIe40 based system to receive the data flow from the frontend, updated luminosity monitor firmware and relevant systems, and resumed physics run from 2024 February. Recent operation status and performance at current physics runs are to be reported.
SuperKEKB electron-positron collider utilizes continuous injection to get the world highest luminosity for the Belle II experiment. The injected bunch becomes the source of extra background for 10-20 ms duration and crosses the interaction point (IP) every 10 microsec. To reconstruct energy deposition and timing of the incident particle, the Belle II calorimeter uses the waveform sampling readout during about 17 microsec and the injection background hits can deteriorate the energy resolution. We performed the simulation of the injection background effects and developed the algorithm modification which makes the energy reconstruction immune for high injection background. We present the simulation results and test of the algorithm with experimental data.
The high-granularity homogeneous electromagnetic calorimeters (ECALs), designed for future lepton colliders, demonstrate outstanding electromagnetic energy resolution and maintain sufficient low-energy photon detection capability. This demands an excellent electronic system for the readout of silicon photomultipliers (SiPMs), capable of covering a wide dynamic range from single photons to $10^5$ photons. The novel 32-channel large dynamic range Application-Specific Integrated Circuit (ASIC) MPT2321-B developed by MicroParity is considered to be a promising candidate for the front-end readout of the high-granularity homogeneous ECALs.
Comprehensive measurements were made using the charge injection method and laser calibration of SiPMs in the laboratory. The first high-energy electron beamtest of the chip with crystals and SiPMs has been conducted, demonstrating excellent signal-to-noise for single photon calibration and a large dynamic range.
The development of next-generation calorimeter technology for future accelerator experiments is being advanced. As elemental technologies, it aim to integrate two promising calorimeter technologies, “dual readout calorimeter” and “high-granularity calorimeter,” and to realize calorimeter technology with high time resolution. Dual readout technology is realized by stacking layers of Cherenkov light detector and scintillation light detector and reading out each signal. Furthermore, we achieve readout granularity on the order of cm for each detector and high time resolution on the order of 10 ps for the Cerenkov detector. A scintillator detector is coupled SiPM to readout signal. We use strip to realize a high-granularity scintillator detector. By using this means, high granularity and a small number of readout channels can be achieved.
This time, we optimized the design of a strip scintillator assuming a hadron calorimeter. The performance of the detector has light yield and position dependence, so in order to maximize it, we considered the design of the scintillator material, the size, position of SiPM, and readout method , and reported the results of measurements using prototypes.
Dual-readout calorimeters utilize two distinct readouts from scintillation and Cerenkov fibers to measure energy, yielding high hadronic energy resolution. While these calorimeters can reconstruct the energy, position, and particle type of detected showers, conventional methods are limited to distinguishing between electromagnetic and hadronic particles. To overcome this limitation, we explore deep learning algorithms to optimize particle reconstruction across different regions of the calorimeter and to extend the identification of particle types. This study evaluates of the performance of particle reconstruction using deep learning-based algorithms which is optimized for dual-readout calorimeters.
The HKROC ASIC was originally designed to readout the photomultiplier tubes (PMTs) for the Hyper-Kamiokande (HK) experiment. HKROC is a very innovative ASIC capable of readout a large number of channels satisfying stringent requirements in terms of noise, speed and dynamic range. Each HKROC channel features a low-noise preamplifier and shapers, a 10-bit successive approximation Analog-to-Digital Converter (SAR-ADC) for the charge measurement (up to 2500 pC) and a Time-to-Digital Converter (TDC) for the Time-of-Arrival (ToA) measurement with 25 ps binning. HKROC is auto-triggered and includes all necessary ancillary services as bandgap circuit, PLL (Phase-locked loop) and threshold DACs (Digital to Analog Converters). This presentation will describe the ASIC architecture and the experimental results of the last prototype received in January 2022.
This research focuses on the development of next-generation calorimeter technology that opens access to a '5D calorimeter,' which measures not only energy but also the precise hit position and timing. This technology integrates two key techniques: the 'high-granularity calorimeter' and the 'dual-readout calorimeter,' while also incorporating picosecond-level timing resolution. Within this framework, a new detector type is being developed to read out Cherenkov light generated by charged particles. Cherenkov photons are converted into photoelectrons by a photocathode and subsequently amplified by a Resistive Plate Chamber (RPC). Notably, the amplification layer utilizes an RPC with a Diamond-like Carbon (DLC) electrode, providing high-rate capability for applications in demanding environments. This poster will describe the time resolution estimation of the Cherenkov detection layer and the operational testing of the first prototype, aiming to demonstrate the principle of this innovative detector.
Large Hadron Collider (LHC) produces many energetic mesons with energies of several TeV in the very forward region of the collisions. The LHC forward (LHCf) experiment measures $\pi^0$, $\eta$, $K^0_s$ as well as single photons and neutrons with two detectors called as LHCf-Arm1 and Arm2, which were installed 140 m away from the ATLAS interaction point and cover the pseudorapidity region of η > 8.4. Each detector has two compact sampling and positioning calorimeters with the acceptances of $20\times20$ mm$^2$ and $40 \times 40$ mm$^2$ for Arm1 and $25 \times 25$ mm$^2$ and $32 \times 32$ mm$^2$ for Arm2. The calorimeter consists of tungsten, 16 GSO scintillator layers and 4 position sensitive layers of X-Y GSO-bar hodoscopes in Arm1 and silicon strip detectors in Arm2.
The LHCf conducted operation in 2015 and 2022 with pp collision at $\sqrt{s}$ = 13 and 13.6 TeV. In the obtained data, many photon pair events were found, and many of them were from decays of pi0 and eta with energies of > 0.6 TeV and > 3 TeV, respectively. In this presentation, we report the performance of $\pi^0$ and $\eta$ measurement as well as some results of their production cross-section. Additionally we discuss about possibility of $K^0_s$ measurement detecting four photon events from $K^0_s$ decay of $K^0_s \rightarrow 2\,\pi^0 \rightarrw 4 \gamma.
Quarks and gluons, which are normally confined within hadrons by strong interactions, are released from the confinement at high temperatures and densities, which is called quark-gluon plasma (QGP). To understand QGP, high-energy heavy ion collision experiment has been produced in laboratory and research has been carried out to investigate this property. One of unknowns about the QGP is that it reaches thermal equilibrium much earlier than theoretically expected, and color glass condensation (CGC) is a strong candidate to explain this. The FoCal detector, which consists of an electromagnetic calorimeter and a hadron calorimeter, has been built to detect the CGC experimentally.
Since FoCal will be installed in the forward region where it will be exposed to large neutron dose during the experiment, it is necessary to investigate the radiation tolerance of the p-type silicon sensor.
To evaluate the radiation tolerance, neutron irradiation experiment was conducted at the RIKEN (RANS) in July 2023. In the experiment, indium foil with sensitivity to the amount of neutron irradiation was placed around the p-type silicon sensor and irradiated with neutron beam of about $10^{14} /cm^{2}$, which is assumed in the ALICE experiment. Since the neutron dose depends on the distance from the beam, it is necessary to estimate the dose of the silicon sensor by analyzing the dose of the indium foil. In this poster, an overview of this experiment and the status of dose analysis using indium foil will be presented.
We propose the concept of Jet Origin Identification that aims to identify from which colored SM particle an objective jet originated.
Using full simulated CEPC 2-jet events data, we realize this concept using Arbor and ParticleNet.
In this context, jet origin identification could simultaneously identify 11 different origins of a jet, corresponding to 5 quarks (UDSBC), 5 anti-quarks, and gluon.
It typically exhibits a flavor tagging efficiency of 90/80/70% for b/c/s jets, ~60% for gluon jets, and ~40% for U and D jets.
In addition, it controls the error rates for jet charge measurements ranging from 10-20% for all quark jets.
The impact on the physics program and detector design/requirements are also discussed.
To achieve the physics goal of precisely measure the Higgs, Z, W bosons and the top quark, future electron-positron colliders require that their detector system has excellent jet energy resolution. One feasible technical option is the high granular calorimetery based on the particle flow algorithm (PFA). A new high-granularity hadronic calorimeter with glass scintillator tiles (GSHCAL) has been proposed, focusing on the significant improvement of hadronic energy resolution with a notable increase of the energy sampling fraction by using high-density glass scintillator tiles. The Glass Scintillator R&D Collaboration group is dedicated to developing high-performance glass scintillators to meet the requirements of high-energy physics experiments. The minimum ionizing particle (MIP) response of a glass scintillator tile is crucial to the hadronic calorimeter, so a dedicated beamtest setup was developed for testing the large-size glass scintillator samples. Two beam tests on large glass scintillator tiles at CERN and DESY have been carried out, and the MIP response of glass scintillator tiles can reach ~100 p.e./MIP, which essentially meets the design requirements of the GSHCAL. An optical simulation model of a single scintillator tile has been established, and the simulation results are consistent with the beamtest results. Additionally, the uniformity of glass scintillator tiles was also studied by beamtests and simulation.
A HGCROC1 is an integrated circuit with low noise and wide dynamic range readout for the real detectors to be installed in the experiments.
However, during the R&D phases of silicon detectors, we usually just need a much simpler preamplifier to evaluate a silicon sensor. In this case a sophisticated preamplifier system, like HGCROC is not needed.
Therefore, we developed a highly versatile readout circuit that can be used with a simple setup in a test beam and a laboratory. We focused on the frequency band, noise reduction, and adjusting the impedance matching for silicon pad senser. The fabricated circuit consists of three main circuit blocks: charge sensitive amplifier, primary shaper, and inverting amplifier.
The output of the circuit was confirmed in the case of an LED with high light intensity.
In this poster, we will summarize the current status and results of our custom-made preamplifier tuned for a silicon pad sensor with 320 um thickness ,and discuss a future plan.
1 ASIC chip is plant to be used for data readout of CMS HGCAL and the FoCal-E pad detector in ALICE.
1 Thienpont, Damien; de la Taille, C, "Performance study of HGCROC-v2: the front-end electronics for the CMS High Granularity Calorimeter", JINST 15 (2020) C04055
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The Forward Calorimeter (FoCal) detector is scheduled for installing in the ALICE experiment for the LHC-Run4 upgrade (2029-2032).
The FoCal consists of the FoCal-E (Electromagnetic Calorimeter) and the FoCal-H (Hadronic Calorimeter). The FoCal-E is a detector based on a Si sensor and tungsten to measure direct photons at forward rapidity.
For the readout, each Si pad hosts the HGCROC2 Application-Specific Integrated Circuit (ASIC) originally developed by the OMEGA group for the CMS High Granularity Calorimeter (HGCal).
The FoCal-E has two subsystems, pad and pixel. The FoCal-E pad detector plans to use about 2,000 PCBs containing Si pads and HGCROC chips.
Therefore, it's very important to evaluate the performance of a large number of HGCROC chips and to understand their variability.
This poster summaries the performance variability of about 100 HGCROC v2 chips and the data collected with them in test beam experiments.
Furthermore, we will discuss the perspective of HGCROC v3 chip for the final FoCal-E pad production and readout scheme.
For the CMS High-Granularity Calorimeter (HGCAL) for HL-LHC, scintillator tiles, readout with individual on-tile silicon photomultipliers (SiPMs), will be used where the radiation levels are expected to be less than 5 x $10^{13}$ n/cm$^2$. The scintillator tiles will be mounted on highly-integrated "tileboards" (typical area 30 x 30 cm$^2$) that host up to 108 tiles and their SiPMs, as well as front-end electronics, control and powering components. A dedicated LED system will be implemented to monitor stability effects. We present recent developments for the HGCAL scintillator material and SiPMs, including quantification of the scintillator and SiPM radiation-damage impact, modeling of SiPM noise and its evolution with time, SiPM production testing and quality control plans, and tests of tileboards in laboratories and beam-tests.
The Hadron Calorimeter (HCAL) of the CMS experiment comprises two different technologies. The barrel and endcap regions of the HCAL are composed of layers of brass absorber plates interleaved with plastic scintillator tiles, and the barrel is augmented by an additional layer of scintillators beyond the CMS magnet. These subdetectors are read out by silicon photomultipliers (SiPMs) present on the detector. The HCAL also comprises a Cherenkov detector in the forward region made of steel absorber with quartz fibres read out by photomultiplier tubes (PMTs).
The irradiation of the HCAL subdetectors results in decreased signal output from the active materials as well as increased noise in the SiPMs and PMTs. The HCAL has a dedicated calibration system used to monitor and correct for these effects and to help synchronise the timing of the subdetectors.
This talk will describe the HCAL calibration system, in particular detailing the upgrades to the laser system which has undergone significant changes since the end of Run 2 of the LHC in 2018. A new solid state laser has been installed and commissioned, also allowing for a simplification of the optical setup for light distribution. An upgrade to the laser trigger board has reduced the laser trigger jitter by an order of magnitude. A new system has also been developed to fire the laser, based on existing HCAL electronics. The talk concludes with a discussion of further possible improvements, including ongoing work on extending the system to include real-time remote monitoring capabilities.
Many neutrons with high energies of several TeV are produced in the zero-degree region of LHC collisions, and a precise measurement of these neutrons is important to study several soft-QCD processes like one-pion exchange. A joint operation of the LHCf and ATLAS experiments including the ZDC detectors has been performed with proton-proton collisions at $\sqrt{s}$ = 13.6 TeV in September 2022. Three hadronic modules of the ZDC detectors were installed behind each LHCf detector, and approximately 300 M events were corrected successfully.
In this presentation, we report about a performance study of the LHCf and ZDC joint operation evaluated using 350 GeV/c proton beams at CERN-SPS in 2021. The detectors were aligned to the beam line similar to the operation configuration at LHC. A proton induced a hadronic shower in the LHCf detector, and a part of shower particles leaked out from LHCf were detected by the ZDC modules. The summation of energy deposit in both the detectors after some corrections was used as an energy estimator for hadronic showers, and we confirmed the energy resolution of 19%, which is much better than that of the LHCf-standalone measurement, 40%.
The High Luminosity upgrade of the LHC (HL-LHC) at CERN will provide unprecedented instantaneous and integrated luminosities of around 5 x 10^34 /cm2 /s and 3000/fb respectively from 2029 onwards. Particular challenges at the HL-LHC are the harsh radiation environment, the increasing data rates, and the extreme level of pileup events, with up to 200 simultaneous proton-proton collisions expected. In the barrel region of the CMS electromagnetic calorimeter (ECAL), the lead tungstate crystals and avalanche photodiodes (APDs) will continue to perform well, while the readout and trigger electronics need to be replaced.
The upgraded on-detector readout will use new, faster analog electronics and an increased pulse sampling rate to provide better time resolution, which will improve pileup mitigation and the rejection of large unwanted signals in the APDs, termed “spikes”. The new electronics allow more sophisticated trigger algorithms.
We present the most recent test beam results of the new on-detector and off-detector readout electronics obtained using the H4 beamline at the CERN SPS. During these tests, signals from high energy electrons were read out from the crystals and APD photodetectors, via the new on-detector readout, and finally to the off-detector processor boards, and precise measurements of the energy and timing resolution were obtained. This presentation will provide an overview of the scope of the ECAL barrel upgrade, will describe the current status, and will highlight the key results from these latest integration tests.
To precisely measure the properties of the Higgs, W, Z bosons and explore new physics beyond the Standard Model, fast timing performance is crucial for the calorimetry of future electron-positron colliders. High-precision time-of-flight (ToF) measurements can complement dE/dx measurements and significantly improve the particle identification performance with a required TOF resolution of around 50 ps. In addition, timing measurements with a resolution at nanosecond-level can also enhance the hadronic energy resolution by approximately 3% to 4% through the local software compensation for the CALICE AHCAL.
Using 55 nm CMOS technology, a pico-second timing (PIST) front-end electronic chip with a power consumption of 15 mW (per channel) has been developed for future electron-positron collider experiments. Extensive tests have been performed to evaluate the timing performance of a dedicated SiPM-readout system equipped with a PIST chip. The results show that the system timing resolution can achieve 45 ps (24 ps) for the HPK(NDL) SiPM signals at the minimum-ionizing particle (MIP) level 200 p.e. and can reach sub 10 ps for energy depositions six times higher or more, while the PIST intrinsic timing resolution is better than 5 ps. The PIST dynamic range has been further extended using the time-over-threshold (ToT) technique, which can cover the SiPM response spanning from 900 p.e. to 40000 p.e. This low-power PIST chip can be can be a promising candidate in applications of SiPM-based detectors for fast timing at future Higgs factories.
Hui Wang is a postdoctoral researcher at Rutgers University, working for the CMS experiment at the LHC. He is currently a level-2 convener of the CMS Hadron Calorimeter (HCAL) and leads six groups (reconstruction, calibration, trigger, etc) of over a hundred people.
In this talk, he will give a review of energy reconstruction algorithms in the CMS HCAL, based on his recent published paper (JINST 18 (2023) P11017). In addition, he will also introduce a machine learning approach of energy reconstruction, which will significantly improve the HCAL resolution and benefit almost all CMS physics analyses.
The High-Luminosity phase of LHC, starting in 2029, will bring unprecedented challenges to data acquisition and event reconstruction. The Compact Muon Solenoid (CMS) Experiment will address these challenges with substantial upgrades to the detector and software. The High Granularity Calorimeter (HGCAL) will replace the current calorimeters in the Endcaps. HGCAL will provide excellent spatial resolution and precise time measurements for high-energy deposits, enabling a 5D reconstruction. The front-end electronics will measure the time of arrival of pulses above a charge threshold, achieving a resolution as fine as 25 ps for high individual energy deposits.
This study focuses on leveraging timing information in HGCAL, starting from reconstructed hits up to the final particle flow candidates. This information can be also used in later stages of the reconstruction, e.g. in the linking with tracks and for pileup mitigation, to enhance the global event interpretation.
Particle Identification (PID) plays a central role in associating the energy depositions in calorimeter cells with the type of primary particle in a particle flow oriented detector system. In this talk, we hope to present novel PID methods based on the Residual Network (ResNet) architecture, which enable the training of very deep networks, bypass the need to reconstruct feature variables, and ensure the generalization ability among various geometries of detectors, to classify electromagnetic showers and hadronic showers. Using Geant4 simulation samples with energy ranging from 5 GeV to 120 GeV, the efficacy of Residual Connections is validated and the performance of our model is compared with Boosted Decision Trees (BDT) and other pioneering Artificial Neural Network (ANN) approaches. In shower classification, we observe an improvement in background rejection over a wide range of high signal efficiency ($95\%$). These findings highlight the prospects of ANN with Residual Blocks for imaging detectors in the PID task of particle physics experiments and our methods have already been applied to solving beam contamination issues met during the beam test at CERN for the CEPC AHCAL prototype in 2022 and 2023.
A particle flow oriented high granularity Analog Hadronic Calorimeter (AHCAL) has been designed for the Circular Electron Positron Collider (CEPC). An AHCAL prototype consisting of 40 longitudinal layers with a transverse granularity of $ 40 \times 40~cm^{2} $, using scintillator tiles as active material and stainless steel as absorber, has been constructed and tested at the CERN SPS H2 beam line. About 30 millions of test-beam data corresponding to muon, electron, and charged pion events are collected.
We developed a pattern recognition algorithm based on fractal dimension and average hit energy. The FD serves as a characteristic property of a fractal, providing a quantitative descriptor of the complexity of the shower shape, and is designed for high granularity calorimeters with good separation power. Using this algorithm, we quantified the PID efficiency with Monte Carlo samples. The noise, MIP, EM, hadronic components and other interesting events in the data are observed and separated by artificial cuts. The fractions of these components as a function of beam energy are estimated. This algorithm performed a good purity analysis of the test beam data.
Online monitoring of data quality is essential for experiments with complex detectors like the ones at the LHC. Such online monitoring allows prompt actions in case of issues that degrade the data quality. Shifters scrutinize histograms and plots automatically produced while acquiring data. Machine learning techniques can be used to help in the detection of anomalies. We will present a real-time autoencoder-based anomaly detection system that uses semi-supervised neural network developed for the CMS electromagnetic calorimeter. This anomaly detection system uses a novel method that exploits the time-dependent evolution of anomalies as well as spatial variations in the ECAL detector response. After having been validated with CMS data taking in 2018 and 2022, the system was deployed in 2023 during the LHC Run 3. The presentation will cover the description of the used techniques, the validation, and the performance observed during Run 3.
Due to its continuously adjustable composition and low cost, glass scintillator (GS) has become a new choice for solid scintillation materials. Compared to scintillation crystals, glass can achieve a similar density (approximately 6 g/cm3) at a lower cost, making it the preferred luminescent device for scintillation detectors. However, research on glass scintillator has mainly focused on composition adjustment and performance optimization, with relatively little research on high-density, large-sized glass scintillator and the scintillation detectors composed of photodetectors. Since 2021, the Glass Scintillator Collaboration Group (GS Group) has been developing large-size, high-density(~6 g/cm3), high-light-yield(>1000 ph/MeV), fast-decay(<300 ns), and radiation-resistant scintillation glass for glass scintillator hadron calorimeter (GSHCAL) of Circular Electron-Positron Collider(CEPC), and has achieved certain results. In order to explore the differences between scintillation crystals and glass scintillator in different sizes and detection methods, we have selected the standard scintillation crystal Bi4Ge3O12 (BGO) for comparison, hoping to make a contribution to the application of large glass scintillator detectors.
The Electron-Ion Collider (EIC) under construction at Brookhaven National Laboratory in the USA, will be a unique particle accelerator where electrons will collide with protons or nuclei to scan the internal structure of nucleons. Electromagnetic Calorimeter (EmCal) based on lead tungstate (PbWO4) crystals is proposed to be a key element of particle identification system at EIC.
A quality assurance of crystals produced by CRYTUR, the light yield and transmission of crystals have been measured at A.I. Alikhanyan National Science Laboratory (AANL). Measurements showed that the crystals have an average light output of ~16 pe/MeV, and that within error, the light output of crystal at two different points located at a distance of ~14 cm from each other is almost the same (within 3 − 5 %). A prototype of EmCal is designed, constructed and tested with cosmic muons. It consists of 16 PbWO4 crystals arranged in a 4 × 4 matrix.
The results obtained are compared with results from other groups of the EIC EmCal collaboration, Selection of final design of the EIC calorimeter and requirements to the characteristics of crystals will be based on combined analysis of the results from different groups of collaboration.
We are planning to continue these studies, as well as to study radiation hardness and low energy resolution of EmCal using electron beam with energy of 10 - 75 MeV from linear accelerator LINAC-75 and proton beam with energy of 18 MeV from C18/18 cyclotron at AANL.
Future lepton collider experiments (FCC-ee and CEPC) require excellent hadronic energy resolution to exploit their advantages. The dual-readout calorimeter can satisfy the requirement by using two types of calorimeter signals, which have complimentary information about the shower development. The calorimeter design takes into account a range of different absorbers. We investigated the performance, such as energy resolution of EM, hadronic particles, or shower developments, of the dual-readout calorimeter for different absorbers such as Fe, Brass, Cu, Pb, and W. In this talk, we will present the performance comparison for these absorbers derived from the GEANT4 simulation studies.
The Korean dual-readout calorimeter collaboration fabricated dual-readout calorimeter modules using several Cu forming prototypes such as 3D printing and Skiving.
All prototype modules were assembled to form an electromagnetic calorimeter whose depth was 25 $X_{0}$ and 2.5 Moliere radii.
This electromagnetic calorimeter was exposed to low-energy positrons ranging from 0.5 GeV to 5 GeV at T9, CERN East Area.
We performed test beam programs to scrutinize the electromagnetic performance of the dual-readout calorimeter below 5 GeV.
We will discuss the results of the test beam conducted in 2023 in the presentation.
This work will present the full simulation and reconstruction development of a segmented crystal ECAL option for the IDEA detector, building upon previous 'proto-PFA' work previously simulated in Geant4 by M. Lucchini. The simulation has been implemented with the IDEA dual-readout and tracker packages within the latest key4hep framework, enabling a unified detector description and centralized data schemas for the first time in the era of PFA-oriented detector development. New AI/ML clustering and reconstruction algorithms leveraging the full granularity and longitudinal segmentation of the crystals and timing layer will be presented. The physics case for the detector in the context of probing the Higgs tri-linear self-coupling will also be discussed with a focus on detector-specific characteristics that we advocate as the basis for performance benchmarks for the next generation of colliders, including the FCC-ee.
In calorimetry, the poor hadronic energy resolution of non-compensating calorimeters is caused mainly by the non-Gaussian fluctuation of the electromagnetic component and that in binding energy loss. To remedy this situation, the dual-readout method was proposed and proved with beam tests for the last 20 years. The dual-readout calorimeter, a significant advancement in the field of calorimetry and particle physics, has become the calorimeter component of a 4π detector concept, IDEA, for future Lepton collider experiments such as FCC-ee and CEPC. A primary goal of the dual-readout calorimeter is to achieve high-quality jet energy measurement by exploiting two types of calorimeter signals produced by scintillation and Cerenkov photons. GEANT4 simulation studies suggest a potential precise jet energy measurement. In this talk, we will present the high-precision jet energy measurement of the dual-readout calorimeter predicted by GEANT4 simulations.
to be added
The SND@LHC experiment, situated 480 m downstream of the ATLAS interaction point, is a compact standalone experiment at the Large Hadron Collider (LHC). It is designed to perform measurements with neutrinos produced at the LHC, focusing on the hadronic calorimeter and muon system. The hadronic calorimeter, integral to this experiment, serves to measure the energy of hadronic jets, crucial for identifying neutrino interactions. Comprising eight layers of scintillating planes and iron slabs, it provides comprehensive coverage for hadronic showers. The 2023 Test beam played a pivotal role in evaluating the hadronic calorimeter’s performance. Data from this campaign were essential for calibrating the energy measurement capabilities and assessing the system’s overall functionality. These recent measurements are significant as they contribute to fine-tuning the experiment’s performance, enhancing the precision of neutrino interaction studies and probing physics in the forward region of the LHC. The successful commissioning and testing of the hadronic calorimeter thus mark a critical step in advancing the SND@LHC experiment’s objectives and its potential to uncover new insights in particle physics
Physics program of the symmetric electron-positron collider VEPP-2000 includes high-
precision measurements of the e+ e−− > hadrons cross-sections in the energy range
from the production threshold to 2 GeV. These precise data are highly demanded for a
calculation of the hadronic contribution to the muon anomalous magnetic moment (g−2)μ
in the frame of the Standard Model as well as for the verification of various thoretical
models of light hadrons interactions. One of the key detector subsystem to achieve these
goals is high quality electromagnetic calorimeter. The CMD-3 detector under operation
now at VEPP-2000 combines properties of the magnetic spectrometry with high resolution electromagnetic calorimeter. The barrel calorimeter of this detector consists of a coaxially arranged liquid xenon (LXe) on the inner layer and CsI crystals on the outer layer. This combined structure of the calorimeter provides a high photon coordinate measurement as well as a good energy resolution. However, this combined structure requires special sophisticated procedures for the energy calibration, photon reconstruction and quality monitoring, which are discussed in this report.
The FASER experiment at the Large Hadron Collider (LHC) aims to detect new, long-lived fundamental particles and to study neutrino interactions. To enhance its discovery potential, a W-Si preshower detector is being built, targeting surface commissioning and then installation during the second half of 2024. The new preshower will enable the identification and reconstruction of electromagnetic showers produced by high-energy photon pairs with separations as fine as 200 µm. The detector incorporates a cutting-edge monolithic ASIC with hexagonal pixels measuring 100 µm in pitch, designed to achieve an extended dynamic range for charge measurement and capable of storing charge information for thousands of pixels per event. The ASIC integrates fast front-end electronics based on SiGe heterojunction bipolar transistor technology, providing a O(100) ps time resolution. Analog memories embedded within the pixel array facilitate frame-based event readout, minimizing dead areas. In this presentation, we detail the design and expected performance of the preshower detector, along with the results from lab characterisation of pre-production ASIC prototypes, and of the first module prototypes.
The FASER calorimeter system has been upgraded to improve the dynamic range. The upgrade is based on the original calorimeter with only changes to the Photomultiplier Type ,PMT, system. The basic concept is to introduce a light splitter between the calorimeter and the PMT: A few percent of the light is guided to one PMT (high range) while the majority of the light is guided to another PMT (low range). The splitting is selected such that the range of the PMTs has a significant overlap for cross calibration. The low range PMT is then calibrated with MIPs, while the high range PMT is cross calibrated to the low range PMT. This allows for significant dynamic range extension with a static system.
A new electromagnetic calorimeter (ECAL) consisting of 1596 lead tungstate PbWO$_{\rm 4}$ scintillating crystals has been fabricated and installed in the experimental Hall-D at Jefferson Lab (JLab). The high-granularity, high-resolution calorimeter is required by the JLab Eta Factory experiment, whose main physics goal is to study rare decays of eta mesons. The ECAL replaced the inner part of the forward lead glass calorimeter of the GlueX detector. Prior to the ECAL construction, we built a large-scale prototype, which was used to study performance of ECAL modules and light monitoring system, and to optimize the design of the front-end electronics for JEF operating conditions. The prototype was successfully used in the PrimEx-eta experiment in Hall D. The ECAL is integrated into the trigger system of the GlueX detector using electronics modules designed at JLab. Signals from the detector will be digitized using a twelve-bit flash analog-to-digital converters operated at a sampling rate of 250 MHz. The ECAL is currently at the commissioning stage and should be ready for the physics run in the early fall of the 2024. I will give an overview of the JEF experiment, the performance of the calorimeter prototype, the design and construction of the ECAL, and the integration of the detector and its infrastructure into the Hall D experimental setup.
Development of high-precision electromagnetic calorimeter prototype featuring the record timing resolution is presented in the report. Significant improvement of timing resolution, compared with electromagnetic calorimeters of the current high-energy experiment, is essential for particle identification. The prototype, based on the ALICE PHOS calorimeter design, is build of PbWO$_4$ scintillating crystals of $22\times 22\times 180$ mm$^3$ size equipped with a dual-channel photodetector Hamamatsu MPPC S14160-6015PS and S14160-6010PS. In addition to signal amplitude measurements, the SiPM readout channel is also used for the time measurements. The time resolution ($\sigma_t$) of the prototype, measured at the secondary electron beam at PS, results in $\sigma_t < 200$ ps for electrons of energies $E \geq 1$ GeV. The energy resolution of the prototype in the range from 0.5 GeV to 10 GeV is also presented in this report.
This presentation proposes a novel design of stereo crystal ECal, with the goal of creating a truly homogeneous calorimeter with 2D readout on the outer side of the long crystal bar, and obtaining the third position dimension information by allowing the adjacent layers to have opposite pointing angles with respect to the radius of the cylinder of the detector system, similar to human left/right eyes. A simulation using the CEPC software (CEPCSW) framework was conducted to assess the 3D position resolution, intrinsic energy resolution, as well as the separation of two particles using traditional clustering algorithms. Additionally, an end-to-end neural network was employed to resolve the shower information, similar to the human brain.
The RADiCAL Collaboration is conducting R&D on precision-timing electromagnetic (EM) calorimetry to address the challenges expected in future collider experiments under conditions of high luminosity and/or high irradiation such as those expected at the FCC-ee and FCC-hh colliding beam facilities. Under development are sampling calorimeter structures known as RADiCAL modules, based on scintillation and wavelength-shifting (WLS) technologies, and read out by SiPM photosensors. The current module under test consists of alternating layers of very dense tungsten (W) absorber and scintillating crystal (LYSO:Ce) plates, assembled to a depth of 25 radiation lengths (Xo). The scintillation signals produced by the EM showers in the region of EM shower maximum (shower max) are transmitted to SiPM located at the upstream and downstream ends of the module via quartz capillaries which penetrate the full length of the module and which contain either organic DSB1 WLS filaments or ceramic LuAG:Ce WLS filaments positioned within the region of shower max, where the shower energy deposition is greatest. The remaining volume within the capillaries, upstream and downstream of the WLS filaments is filled and fused with quartz rod to form solid quartz waveguides. Studies will be presented of the timing resolution of the RADiCAL module over the energy range 25 GeV ≤ E ≤ 150 GeV, which were conducted using beam electrons in the H2 beamline at CERN.
The Circular Electron Positron Collider (CEPC) is a next-generation electron–positron collider proposed for precision measurement of the properties of the Higgs boson. A major challenge for the CEPC detector is achieving a boson mass resolution (BMR) of 4%, which is required to separate the Higgs, Z, and W bosons in their hadronic decays. The baseline design of the CEPC detector was guided by the particle flow algorithm (PFA) concept to satisfy the BMR requirements. The BMR performance obtained by the PFA approach is primarily determined by the shower separation capability and energy resolution of the calorimeters of the detector system. A hadronic calorimeter with high granularity is crucial for providing the required separation power and energy resolution for the desired BMR. In this context, the analogue hadron calorimeter (AHCAL), a scintillator hadronic calorimeter with analogue readout, is a potential hadronic calorimeter option for the CEPC detector. In this talk, We will introduce the performance and validation of AHCAL based on MC and the beam test results, including the energy response to high energy electrons (1-100 GeV/c) .
The future Circular Electron-Positron Collider (CEPC) is a large-scale experimental facility, which aims to accurately measure the Higgs boson, electroweak physics and the top quark. For the detector system in CEPC, a highly granular crystal electromagnetic calorimeter is proposed to achieve an EM energy resolution of less than 3%. It is a homogenous structure with long crystal scintillator bar as active material, and SiPM as the preferred photon sensor. There is a high requirement on the dynamic range of SiPM. since more than ten thousand photons can be detected for one channel. However, the response calibration for SiPMs with such a large dynamic range is challenging, mainly because of the limitation of scaler.
We have developed an experiment which used laser and PMT as light source and scaler respectively. In this experiment, we measured the response curves of SiPMs with very large pixel number up to 244k, and small pixel size down to 6μm. A toy Monte Carlo was also built for comparison, which introduced almost all of the SiPM's characteristics, like PDE, crosstalk, afterpulse and recovery time.
Following the priority research directions for calorimetry documented in the DOE HEP basic research needs for instruments the Caltech HEP Crystal Lab has been actively investigating novel inorganic scintillators along the following three directions. Fast and radiation hard inorganic scintillators to face the challenge of severe radiation environment expected by future HEP experiments at hadron colliders, such as the HL‐LHC and a 10 TeV pCM collider, where radiation damage is induced by ionization dose, protons and neutrons. Ultrafast inorganic scintillators to face the challenge of unprecedented event rate expected by future HEP experiments searching for rare decays, such as Mu2e‐II, and ultrafast time of flight (TOF) system at colliders. Cost‐effective inorganic scintillators for the homogeneous hadron calorimeter (HHCAL) concept to face the challenge of both electromagnetic and jet mass resolutions required by the proposed Higgs factory. We report recent progress in all these directions, such as LuAG:Ce ceramic fibers for the RADiCAL proposal, Lu2O3:Yb ceramics for TOF and ABS:Ce and DSB:Ce glass scintillators for HHCAL and the CalVision proposal. The result of this investigation may also benefit nuclear physics experiments, GHz hard X‐ray imaging, medical imaging and homeland security applications.
We will present a sampling calorimeter to measure the photons' incident angle. A three-dimensional fine-segmented calorimeter will measure the profiles of generated shower particles along the photon’s direction, which indicates the incident angle. A toy detector is designed for a feasibility study by simulation based on the GEANT4, a block consisting of alternating layers of a 1-mm-thick lead absorber and a 5-mm-thick plastic scintillator. The plastic scintillator is segmented into 15-mm-wide strips, alternately oriented in the vertical and horizontal directions. The energy deposits of each strip are used to train the machine learning algorithm (XGboost) to deduce the given angle. The obtained angular resolution is 1.3 degrees for 1 GeV photon.
We fabricate a small-size sampling calorimeter to confirm the simulation results. We use 0.15-mm-thick tungsten strips instead of lead plates and 1mm-square scintillating fibers instead of plastic scintillators for better energy resolution. The simulation study for the updated version indicates no significant difference in the angular resolution. The detector is made of 24 layers, each of which contains 16 modules. We completed the detector fabrication and performed a beam test in January this year.
In this talk, we will report on the sampling calorimeter for the angle measurement, including its design and fabrication and the performance test result using the positron beam.
High-precision detectors are crucial for the exploration of new physics. This research aims to develop a new excellent resolution and high granular calorimetry by integrating Dual-Readout and High-Granularity techniques, along with picosec timing resolution. Dual-Readout is to measure hadronic showers by Cherenkov light addition to scintillation light to simultaneously read two types of signals. By distinguishing between the electromagnetic and non-electromagnetic components in the hadron showers, energy can be reconstructed more accurately when using additional Cherenkov information. Moreover, High-Granularity with picosec timing resolution improves the identification of individual particles and reconstructs more accurate energy with best suited detectors depending on particle types. This study evaluates the overall resolution improvement of this detector equipped with these three technologies by simulation. This presentation will discuss the current state of optimizing detectors that combine Dual-Readout and High-Granularity.
We propose a new type of fully active total absorption
calorimeter with fine splitting capability. The calorimeter consists of a sandwich structure consisting of layers of scintillator glass and lead glass, which are further divided into small tiles. This configuration provides a finely segmented 3D calorimeter compatible with PFA. This article provides a description of the calorimeter and results from simulations. The critical performances of linearity and energy resolution are shown to be very close to those of homogeneous calorimeters. The simulated calorimeter has an energy resolution of about 9%/sqrt(E).
Calorimetry at the HL-LHC faces two enormous challenges, particularly in the forward direction: radiation tolerance and unprecedented in-time event pileup. Therefore, the CMS Collaboration is preparing to replace its current endcap calorimeters for the HL-LHC era with a high-granularity calorimeter (HGCAL), featuring a previously unrealized transverse and longitudinal segmentation, with 5D information (space-time-energy) read out. This design uses silicon sensors for the electromagnetic section and high-irradiation regions (with fluences above 10¹⁴neq/cm²) of the hadronic section, while in the low-irradiation regions of the hadronic section plastic scintillator tiles with on-tile silicon photomultipliers are used. The active layers include copper cooling plates embedded with thin pipes carrying biphase CO2 coolant, front-end electronics and electrical/optical services. The scale and density of the calorimeter poses many engineering challenges, including: the design and production of 600 tonnes of stainless steel absorber plates to very high tolerances; the development of the CO2 cooling system to maintain each 220-tonne endcap at -35oC with electronics dissipating up to 140kW; the need to cantilever the calorimeters from the existing CMS endcap disks, using titanium supports; the production of a thin but strong inner cylinder to take the full weight while minimising impact on physics performance; the integration of on-detector services in a restricted height of only a few millimetres. In this talk we present the ideas behind the HGCAL, the current status of the project, and the lessons that have been learnt while creating this first calorimeter of its type at a hadron collider.
The endcap calorimeters of CMS will be upgraded a single High Granularity Calorimeter (HGCAL) for the HL-LHC, including both silicon sensors and scintillator tiles with on-tile SiPMs as active elements. Both. The readout of the active elements is performed by an ASIC (HGCROC in 130nm CMOS technology) that measures the amplitude and arrival time of the signals. The amplitude is measured over a large dynamic range to allow calibration with single particles and the measurement of TeV showers. The time of arrival of high-energy showers will be measured with a precision of around 30 ps. A second pair of “concentrator” ASICs – ECON-D and ECON-T – takes the data from the HGCROC channels and packages them for transmission via optical links to the off-detector electronics. The ECON-D transmits concentrated data packets at up to 1 MHz, upon reception of a level-1 trigger signal. The ECON-D transmits trigger data at 40 MHz, to form part of the level-1 trigger. In addition to these ASICs HGCAL will use modified versions of common HL-LHC electronics developments, for the power chain and the optical control/readout. The dense nature of the HGCAL provides additional challenges for the electronic boards and cabling. In this talk the overall HGCAL front electronics scheme, including the latest performance of the HGCROC and ECON ASICs will be presented.
In preparation for the High-Luminosity era of the LHC, the CMS experiment will replace the existing calorimeter endcaps with a novel device - the High Granularity Calorimeter (HGCAL), having around six million readout channels. The back-end readout system is based on a common CMS-wide development: ATCA boards called "Serenity", featuring optical inputs and FPGA-based processing. The electronics system for this upgrade project is highly specialized and complex, involving multiple layers of data transfer, so the testing must be carefully planned. The strategy has been to split the efforts between vertical (start-to-end) and horizontal (parallelization) test systems. An important milestone for the former has been the development and operation of test systems to prototype one vertical slice of the future endcap electronics system. This talk will provide an overview of the HGCAL backend system design and development of vertically integrated test systems what were used as the readout element in beam tests in September, 2023.
The High Granularity Calorimeter (HGCAL) being prepared by the CMS Collaboration for the Phase 2 of the LHC features previously unrealized transverse and longitudinal fine-grained readout of both the electromagnetic and hadronic compartments. The high granularity of the calorimeter, associated with measurements of energy and time of arrival, provides unique inputs for advanced reconstruction techniques beyond those that have been used so far in present experiments.
Recently, significant progress has been made in developing reconstruction algorithms capable of identifying and reconstructing electromagnetic and hadronic showers in the harsh conditions expected in Phase 2 where up to 200 proton-proton collisions may occur in each bunch crossing.
The progress reported in this presentation emphasizes algorithms which can run efficiently at trigger level and provide a performance for physics as close as possible to that expected after an offline reconstruction. We report on the status of the reconstruction and clustering algorithms and on their performance for particle identification and energy/position resolution. Other aspects of simulation of the calorimeter, calibration strategies and leveraging timing information in HGCAL for reconstruction are also covered.