The LHCb RICH system, with the ability to provide hadron identification over a wide momentum range (2-100 GeV/c), is one of the big strengths of the LHCb experiment in the search for New Physics in decays of hadrons containing the charm and bottom quarks. Extensive maintenance took place during the Long Shutdown 1 of the LHC. A significant number of photon detectors (HPDs) were refurbished...
The High Momentum Particle IDentification (HMPID) detector installed in the ALICE experiment on the LHC at CERN consists of seven Ring Imaging Cherenkov (RICH) modules, 1.3x1.3 m2 each, having proximity focusing geometry. The Cherenkov photon detection is achieved by means of pad segmented photocathodes coated with 300 nm thick Caesium Iodide layer and installed in multiwire proportional...
The NA62 experiment at CERN has been constructed to measure the ultra rare charged Kaon decay into a charged pion and two neutrinos with a 10% uncertainty. The main background is made by the charged kaon decay into a muon and a neutrino which is suppressed by kinematic tools using a magnetic spectrometer and by the different stopping power of muons and pions in the calorimeters. A RICH...
High precision flavor physics measurements are an essential complement to the direct searches for
new physics at the LHC. Such measurements will be performed using the upgraded Belle II detector
that will take data at the SuperKEKB accelerator. With 40x the luminosity of KEKB, the detector
systems must operate effciently at much higher rates than the original Belle detector. A central
element...
In the forward end-cap of the Belle II spectrometer, a proximity focusing Ring Imaging Cherenkov counter with an aerogel radiator will be installed. The detector will occupy a limited space inside solenoidal magnet with longitudinal field of 1.5 T. It consists of a double layer aerogel radiator, an expansion volume and a photon detector. 420 Hamamatsu hybrid avalanche photo detectors with 144...
The PANDA detector at the international accelerator Facility for Antiproton and Ion
Research in Europe (FAIR) near GSI, Darmstadt, Germany will address fundamental questions
of hadron physics.
Excellent Particle Identification (PID) over a large range of solid angles and
particle momenta will be essential to meet the objectives of the rich physics program,
which includes charmonium...
A focusing DIRC (FDIRC) detector is being developed to upgrade the particle identification capabilities in the forward region of the GlueX experiment at Jefferson Lab. The GlueX FDIRC will utilize four existing decommissioned BaBar DIRC bar boxes, which will be oriented to form a plane roughly 4 m from the fixed target of the experiment. A new photon camera has been designed that is based on...
A large area Ring-Imaging Cherenkov detector has been designed to provide clean
hadron identification capability in the momentum range from 3 GeV/c up to 8 GeV/c for the CLAS12 experiments at the upgraded 12 GeV continuous electron beam
accelerator facility of Jefferson Lab, to study the 3D nucleon structure in the yet poorly explored valence region by deep-inelastic scattering, and to...
The LHCb experiment is devoted to high-precision measurements of CP violation and search for New Physics by studying the decays of beauty and charmed hadrons produced at the Large Hadron Collider (LHC).
Two RICH detectors are currently installed and operating successfully, providing a crucial role in the particle identification system of the LHCb experiment.
Starting from 2019, the LHCb...
The Compressed Baryonic Matter (CBM) experiment at the future Facility for Antiproton and Ion Research (FAIR) complex will investigate the phase diagram of strongly interacting matter at high baryon density and moderate temperatures in nucleus-nucleus collisions. The beam energy will range from 2 up to 11 AGeV for the heaviest nuclei at the SIS 100 accelerator setup.
One of the key detector...
The Aerogel Ring Imaging Cherenkov (ARICH) counter takes the role in particle identification at the endcap region of the Belle II detector. ARICH discriminates charged pions from kaons using the difference in radiation angle of Cherenkov light. ARICH is composed of aerogel tiles and Hybrid Avalanche Photo-Detectors (HAPDs). To keep high photon detection efficiency of HAPDs, periodical check of...
The CBM experiment at the future FAIR facility will investigate strongly interacting matter at high net-baryon densities but moderate temperatures in heavy-ion collisions with beam energies up to 11 AGeV (SIS 100). Electromagnetic radiation from the fireball is among the most sensitive probes for the created matter. In order to identify di-electrons in a momentum range up to 8 GeV/c, a RICH...
The Compressed Baryonic Matter (CBM) experiment at the future FAIR facility will investigate the QCD phase diagram at high net baryon densities and moderate temperatures in A+A collisions from 2-11 AGeV (SIS100). Electron identification in CBM will be performed by a Ring Imaging Cherenkov (RICH) detector and Transition Radiation Detectors (TRD).
A real size prototype of the RICH detector was...
We report on measurements of 511 keV annihilation photons with ultimate timing resolution via detection of Cherenkov radiation in
PbF2 crystals attached to an ultra-fast single-channel Micro-Channel PhotoMultiplier Tube (MCP-PMT). We have measured back-to-back timing resolution using a pair of such detectors, and compare the results with a Monte Carlo simulation. The study would provide useful...
The performance of the photon detectors in the upgraded LHCb RICH counters will be critical to the charged particle identification efficiency and to the physics goals of the LHCb experiment. Quantum Efficiency (QE) and the closely related the Photon Detection Efficiency (PDE) are the most important properties for single photon counting detectors. In vacuum photon tubes, the PDE generally is...
We present the performance of a novel neutron detection technique based on a
Water Cherenkov Detector (WCD) employing pure water, an inner coating material
acting as a light reflector and diffuser, and a single photomultiplier tube
(PMT). The detector employed in this work is part of the Latin American Giant
Observatory (LAGO) collaboration, that measures the low energy component of
cosmic...
Abstract submitted by Aldo PENZO
Due to extremely high rates near the intense LHC interacting beams, forward regions of LHC experiments are challenging for most detectors, that need to have superior time resolution and radiation resistance. Detectors based on Cherenkov light produced in quartz elements meet these requirements and are ideal components for forward calorimeters.
For instance...
An array of $8 \times 8$ silicon photomultipliers (SiPMs) was characterised as a position sensitive single photon sensor for Ring Imaging Cherenkov (RICH) counter. To improve the geometric efficiency of the array, light concentrators were designed in a form of truncated pyramids and machined from borosilicate glass. A very high number of photons per Cherenkov ring, approximately 35, was...
The detector architecture consists in a hybrid MPGD combination:
two layers of Thick-GEMs (THGEM), the first of which also acts
as a reflective photocathode thanks to a CsI film is deposited
on its top face, are coupled to a bulk MICROMEGAS with pad
segmented anode kept at positive high voltage (HV), while the
micromesh is grounded; the signals are read-out via capacitive
coupling from a...
The TOP detector of the Belle II Experiment at KEK is a particle
identification detector, devoted mainly to the separation of charged pions
and kaons.
Principle of operation of the TOP is the total internal reflection of
Cherenkov photons emitted by charged particles while crossing a quartz
radiator. The Cherenkov photons are then detected by an array of micro-cannel plate
photomultipliers,...
The RICH detector of the HADES experiment is designed for efficient electron identification (electron momenta up to few hundred MeV/c) in relativistic heavy ion collisions, and successfully in operation since 1999 at the SIS18 accelerator facility, GSI, Darmstadt, Germany. It is based on a gaseous photon detector with a reflective CsI cathode deposited on the MWPC pad plane.
The CBM experiment...
The two RICH detectors in LHCb have successfully collected data corresponding to 3.3 /fb of integrated luminosity since 2010 and have been essential for most of the physics programme of LHCb. From 2021 onwards LHCb plans to collect data corresponding to 5 /fb of integrated luminosity per year in order to improve the statistical precision of the physics measurements and to search for very rare...
TORCH (Timing Of internally Reflected CHerenkov photons) is a time-of-flight detector for particle identification at low momentum. It has been originally proposed for the LHCb experiment to complement its particle identification capabilities provided by two gaseous ring-imaging Cherenkov detectors. TORCH is using 10mm-thick planes of quartz radiator in a modular design. A fraction of the...
CBM is a future heavy-ion experiment at the FAIR facility. It will explore the intermediate region of the QCD phase diagram with beam energies of up to 11 AGeV for the heaviest nucleus at SIS100. In CBM electrons with momenta of up to 8 GeV/c will be mainly identified with a RICH detector. It consists of a CO2 gaseous radiator, a spherical mirror system, and Multianode Photomultiplier Tubes...
A 2 cm thick fused silica plate is the central part of the Endcap Disc DIRC, that has been designed to identify traversing pions, kaons and protons in the future PANDA experiment. The detector has a dodecagonal structure with a diameter of about 2 m. The radiator is segmented into 4 identical quadrants. Its acceptance covers the PANDA forward range of 5° to 22°. Cherenkov light produced by...
A large area ring-imaging Cherenkov detector will be operated at the CLAS12 experiment at the upgraded continuous electron beam accelerator facility of Jefferson Lab for hadron identification.
With the new beam energy, the momentum range under study will range between 3 GeV/c and 8 GeV/c. The detector consist of areogel radiator, composite mirrors and photon detector and will be built with a...
Gamma ray induced air showers can be observed by particle detector arrays at high altitudes. The water-Cherekov detection technique has proven to result in robust observations of the gamma-ray sky around TeV energies and has been applied in observatories like Milagro and more recently in HAWC. The biggest challenge for these kind of observatories is to effectively reject background events from...
The Aerogel Ring Imaging Cherenkov (ARICH) counter is the particle identification device covering the endcap region in the Belle II detector. As a Cherenkov photon sensor a position-sensitive Hybrid Avalanche Photo-Detector (HAPD) will be used. In total 420 HAPDs will be arranged to cover the endocarp area. To operate HAPD six power lines with different voltages are needed. Negative voltage of...
In 2019 the LHCb RICH detector will be upgraded to increase the read out rate
from 1MHz to 40MHz. As a consequence, the current Hybrid Photon Detectors
(HPDs) will have to be replaced. Multianode Photomultiplier Tubes (MaPMT)
from Hamamatsu with 64-channels will be used: the 1-inch R13742 and the
2-inch R13743 MaPMTs (custom modifications of the MaPMTs R11625 and
H12699). Quality assurance...
The Latin American Giant Observatory (LAGO) is an extended cosmic ray observatory composed by a network of water-Cherenkov detectors (WCD) spanning over different sites located at significantly different altitudes (from sea level up to more than $5000$\,m a.s.l.) and latitudes across Latin America, covering a huge range of geomagnetic rigidity cut-offs and atmospheric absorption/reaction...
Micropattern Gaseous Detectors opened a novel way for
photon detection for RICH applications;
mostly using hole-type amplifiers like GEM and ThickGEM,
and hybrid structures based on the formers.
The main features are low ion backflow, high gain,
and possibility for suppressing the MIP signal.
Latter can enhance the dynamic range, and allow for high gain operation,
while using cost effective...
TORCH is a large-area precision time-of-flight detector based on the DIRC principle, proposed to provide positive particle identification of low momentum kaons for the LHCb experiment at CERN. The DIRC bar boxes of the BaBar experiment at SLAC could possibly be reused to form a part of the TORCH detector time-of-flight wall area.
For the implementation of the BaBar bars, new imaging and...
The increase in luminosity planned for the next LHC experiments upgrade is such that even detectors far from the interaction region will be exposed to considerable amount of radiation. The LHCb experiment at CERN is preparing for an important upgrade to be achieved in the years 2019-2020 in order to sustain higher instantaneous luminosities and read out the detectors at 40 MHz. The LHCb...
The CBM experiment at FAIR, Darmstadt, has recently bought 1100 HAMAMATSU H12700 photon sensors to equip the photon detection plane of the CBM RICH detector.
Delivery of these MAPMTs just started, and will continue until mid 2017.
This MAPMT features a clear single photon peak (PV $>1.5:1$) at high efficiency (peak quantum efficiency (QE) $\geq 30$\%) whilst having relatively low noise...
One of the biggest challenges for the upgrade of the LHCb RICH detectors from 2020 is to readout the photon detectors at the full 40 MHz rate of the LHC proton-proton collisions. A test facility has been setup at CERN with the purpose to investigate the behaviour of the Multi Anode PMTs, which have been proposed for the upgrade, and their readout electronics at high trigger rates.
The MaPMTs...
In the forward end-cap of the Belle II spectrometer, the proximity focusing RICH with aerogel radiator will be installed for charged particle identification. At the back side of the Hybrid Avalanche Photo Detector (HAPD), a low power front end electronics board will be mounted. The board consists of a 11 layer PCB with four custom ASICs on the HAPD side and a FPGA on the other side. The front...
Very precise timing below the 100ps-mark is gaining importance in modern detector designs. Many technology demonstrators achieving this goal were based on the Cherenkov effect exploiting its prompt light emission. One common requirement is the necessity to compensate inherent walk effects to reach the sub-100ps timing precison.
In traditional approaches either the amplitude is measured in...
Silicon photomultiplier (SiPM) photodetectors perform well in many particle and medical physics applications, especially where good efficiency, insensitivity to magnetic field and precise timing are required. Recent developments in available devices and research which improved the understanding of SiPM response enable further improvement in the time resolution that can be achieved. We report...
The PANDA detector at the international accelerator Facility for Antiproton and Ion
Research in Europe (FAIR) in Darmstadt, Germany will address fundamental questions
of hadron physics. The PANDA Forward RICH (FRICH) is intended for identification of charged particles produced in antiproton collisions with a fixed hydrogen target that fly in the forward direction below 5°–10° of polar angle...
The Stony Brook University group has been involved with Cherenkov detector work for many years and our accomplishments include the RICH detector in PHENIX (photo-tube RICH) and the Hadron-Blind Detector (HBD), a windowless Cherenkov detector based upon CsI photocathodes directly placed upon the top surface a Gas Electron Multiplier (GEM). More recently, we have extended the work on CsI GEM...
We have previously built and tested a full scale prototype of a Focusing DIRC (FDIRC) detector [1]. This device was based on the BaBar radiators and bar box enclosures attached to a new cylindrically focused camera, and intended for the upgrade of the BaBar detector for the SUPERB factory. Similar optical concepts are now being considered for the GLUEX experiment at JLAB, and possibly, the...
The two RICH detectors of the LHCb experiment have been operational since 2008 and the data provided by them have been crucial for the physics program of LHCb. They have achieved an impressive performance for such complex detectors, one for all, its Cherenkov angle resolution of 0.67 mrad for single photons. The current system is expected to continue to take data until 2019, when a two year...
PANDA will be one of the pillar experiments at the new FAIR facility at GSI. With a high intensity antiproton beam its objectives will be, among others, charmonium spectroscopy and the search for gluonic excitations. These scientific goals require a high performance PID system which will consist of DIRC detectors residing inside a magnetic field of 2 Tesla.
Microchannel-plate (MCP) PMTs are...
A micro-channel-plate photomultiplier tube (MCP-PMT) has the best timing resolution
for single photon detection, which enabled us to realize the novel RICH detector,
the TOP counter, for particle identification in Belle II. A major concern about using MCP-PMTs under a high background environment like Belle II is a short lifetime of the photocathode because the quantum efficiency drops...
Planar microchannel plate photomultipliers (MCP-PMTs) with bialkali photocathodes are able to achieve single photon detection with excellent time (picosecond) and spatial (millimeter) resolution. They have recently drawn great interests in experiments requiring time of flight (TOF) measurement and/or Cherenkov imaging. Current MCP-PMTs have a response range of 300 nm – 600 nm, limited by the...
The Argonne MCP-based photo detector is an offshoot of the Large Area Pico-second Photo Detector (LAPPD) project, wherein
6 cm x 6 cm sized detectors are made at Argonne National Laboratory. We investigated these devices, which have pico-second timing and millimetre spatial resolution, in the laboratory. We will present measurements of the properties of these detectors, including gain, time...
The RICH-1 Detector of the COMPASS Experiment at CERN SPS is undergoing an important
upgrade for the physics run 2016 starting in April 2016: four new Photon Detectors, based on MPGD technology and
covering a total active area larger than 1.2 square meters will replace the actual MWPC-based
photon detectors in order to cope with the challenging efficiency and stability requirements
of the new...
The Aerogel Ring-Imaging Cherenkov detector (ARICH) is being installed in the endcap region of Belle II spectrometer to identify particles from $B$ meson decays by detecting the Cherenkov ring image from an aerogel radiator. To detect the single photons, a high-sensitive photon detector which has wide effective area ($\sim$70 mm $\times$ 70mm), a Hybrid Avalanche Photo Detector (HAPD), has...
The Ring Imaging Cherenkov (RICH) detectors of the LHCb experiment provide particle identification (PID) of charged particles in the momentum range of 2-100 GeV. This is essential for the LHCb core physics program. As the center-of-mass energy of the LHC has been increased from 8 TeV to 13 TeV, and the LHCb experiment will upgrade from 2021 and run at a 4-times higher luminosity than the...
In rare decays experiments an effective online selection is mandatory for the data acquisition system in order to reduce data bandwidth and save storage resources. The NA62 experiment at CERN studies ultra-rare kaon decays and makes use of a three-levels trigger system to reduce the 10 MHz incoming events rate of about three orders of magnitude before storage. The first trigger stage (L0) is a...
The ALICE apparatus is dedicated to collect data coming from pp, p-Pb and Pb-Pb collisions provided by LHC, to study the properties of strongly interacting matter under extremely high temperature and energy density conditions. For such a task, enhanced particle identification capabilities are requested. Among the other PID ALICE detectors, the ALICE-HMPID (High Momentum Particle Identification...
For the Belle II spectrometer a proximity focusing RICH counter with an aerogel radiator (ARICH) will be employed as a PID system in the forward end-cap region of the spectrometer. The detector will provide about 4$\sigma$ separation of pions and kaons up to momenta of 3.5 GeV/$c$, at the kinematic limits of the experiment. We present the up-to-date status of the ARICH simulation and...
AMS-02 is a high-energy particle physics magnetic spectrometer installed
on the International Space Station since May 2011, and operating continuously
since then. By means of the simultaneous use of the Silicon Tracker,
the AMS-02 RICH is able to investigate the isotopic composition of cosmic
rays (CRs) in the kinetic energy range from few GeV/n to ~10 GeV/n
for elements with charge |Z| up...
The nature and the sources of the cosmic rays of ultra-high energy are not yet elucidated. The cutoff of the spectrum around 50 EeV is now clearly established, but its interpretation is still ambiguous: it can be interpreted as the so-called GZK effect on a flux dominated by protons, or by an upper bound on the acceleration in the sources, or through a complex scenario implying a mixture of...
We review Cherenkov experiments in the Tunka Valley. The experiments span nearly a quarter of a century. They started with a small “toy” array and are being presently evolved into a large scale experiment with a wide range of physics goals covering primary cosmic ray studies in the energy range of 1014-1018 eV and very high energy gamma-ray astronomy. We discuss future perspectives of the...
Recent discoveries of new materials, combined with modern nanofabrication techniques, have revealed novel ways of manipulating and confining light on the nanoscale. These developments offer opportunities to control a variety of light-matter interactions, and in particular, manipulate radiation emission from charged particles. My talk will discuss novel phenomena that occur when charged...
Experimental results obtained with a prototype of a Focused Internal Reflection Cherenkov, equipped with 16 high-granularity arrays of NUV-SiPM and tested at CERN SPS in March 2015, are discussed. The detector was exposed to relativistic ions of 13 and 30 GeV/n obtained from fragmentation of a primary Ar beam. The FDIRC included a single Fused Silica radiator bar optically connected to a...
The High-Altitude Water Cherenkov (HAWC) observatory was completed and began full operation on March 2015, collecting more than one year of data in its full configuration. The detector consists of an array of 300 water tanks, each containing 200 tons of purified water and instrumented with 4 PMTs. Located at an elevation of 4100 m a.s.l. near the Sierra Negra volcano in central Mexico, HAWC...
The IceCube Neutrino Observatory is a cubic-kilometer neutrino telescope located at the Geographic South Pole. Buried deep under the Antarctic glacial, an array of 5160 Digital Optical Modules (DOMs) is used to capture the Cherenkov light emitted by relativistic particles generated from neutrino interactions. The main goal of IceCube is the detection of astrophysical neutrinos, and the...
The SNO experiment was a highly successful experiment that ran from 1999 until 2006. The use of heavy water as a neutrino detection material allowed for the measurement of solar neutrinos in both a charged current channel and a unique neutral current channel. Simultaneous measurements in both channels allowed SNO to demonstrate neutrino flavour change as the solution to the solar neutrino...
When a high energetic particle or gamma-ray interacts with the atmosphere, it induces an air shower. Secondary particles of such showers emit dim and short duration flashes of Cherenkov light that can be measured with Imaging Atmospheric Cherenkov Telescopes (IACTs). For this task, very fast and sensitive photosensors are necessary. To be able to statistically distinguish between showers...
Jon Lapington for the CTA Consortium
The Gamma Cherenkov Telescope (GCT) is one of the designs proposed for the Small Sized Telescope (SST) section of the Cherenkov Telescope Array (CTA). The GCT uses dual-mirror optics, resulting in a compact telescope with good image quality and a large field of view with a smaller, more economical, camera than is achievable with conventional single mirror...
Neutrino astronomy plays a key role in the exploration of the high-energy sky, due to excellent source pointing capabilities and an unrivaled field of view. Indeed, neutrinos can escape much denser celestial environments than light, thus behaving as tracers of the innermost processes occurring in astrophysical sources, hidden to traditional astronomy, without being deflected by the presence of...
Hyper-Kamiokande is proposed as a next-generation underground water Cherenkov detector having an enormous potential to discover proton decays and leptonic CP violation in neutrino oscillations. Two cylindrical tanks, each with a height of 60m and a diameter of 74m, will be filled with 520,000 metric tons of ultrapure water, a volume approximately 10 times larger than that of predecessor...
The KM3NeT collaboration is building a km3-scale neutrino telescope in the Mediterranean Sea. The current phase of construction comprises the deep-sea and onshore infrastructures at two installation sites and the installation of the first detection units for the ARCA and ORCA detector. At the KM3NeT-It site, 100 km offshore Capo Passero, Italy, the first 32 detection units for the ARCA...
The gamma ray observatory Cherenkov Telescope Array (CTA) is planned to significantly improve upon the sensitivity and precision of the current generation of Cherenkov telescopes. The observatory will consist of several dozens of telescopes with varying sizes and different types of cameras. Of these, the FlashCam camera system is the first to implement a fully digital signal processing chain...
The observation and study of faint signals at very high energy (E > 100 GeV) associated with cosmic phenomena constantly requires the development of advanced technologies and instruments to improve the sensitivity. Imaging Atmospheric Cherenkov Telescopes (IACTs) represent a class of instruments dedicated to the ground-based detection of cosmic VHE gamma ray emission based on the detection of...
The RICH detectors of the LHCb experiment provide particle identification, especially for hadrons, in high energy proton-proton collisions at the LHC at CERN over a wide momentum range (2 to 100 GeV/c). The Cherenkov light is collected on 2D photon detector planes sensitive to single photons. In order to make the detector capable to operate at 40 MHz event readout speed, matching the bunch...
Novel Cherenkov detector upgrades favour GEM and THick-GEM (THGEM)
based MPGD systems. These detectors have reduced ion backflow,
fast signal formation, high gain, and could suppress the MIP signals as well.
Sources of concern are the possible inefficiencies of the photo-electron
collection from the top of the THGEM and the local variation of the gain related to geometrical non-uniformity.
The...
The Belle II experiment will start up the detector commissioning from early 2017 and will carry out various physic programs from 2018, where good particle identification is demanded. The Time-of-Propagation (TOP) detector is responsible for π±/K± separation in the barrel region of the Belle II spectrometer. It has 16 detector modules cylindrically arranged around the beam line at a radius of...
We have developed a RICH counter as a new forward particle identification device for the Belle II experiment. In this RICH counter, the Cherenkov radiator consists of dual silica aerogel layers with different refractive indices in upstream and downstream. After intensive R&D on silica aerogel production and optical improvements, a refractive index combination of 1.045 and 1.055 was chosen for...
The work is devoted to the development of aerogel radiators for RICH detectors. The aerogel tiles with refractive index 1.05 and thickness of 30 mm were tested with RICH prototype on electrons beam at VEPP-4M collider.
The tile with cracks inside has been investigated. The experimental
data show that the Cherenkov angle resolution for tracks in the crack
area and for tracks in the normal...
A large area ring-imaging Cherenkov detector has been designed for the CLAS12 experiment, to achieve a pion vs kaon rejection power of 500:1 in the momentum range 3 - 8 GeV/c. The adopted solution foresees a novel hybrid optics design based on aerogel radiator, composite mirrors and multi-anode photon detectors. To minimize the instrumented area, a proximity imaging method will be used for...
Imaging Atmospheric Cherenkov Telescopes (IACT) are dedicated to the very high energy Astrophysics. An IACT consists of an optical system formed by high reflectivity mirrors that focus the Cherenkov light onto a multi-pixel focal camera with fast read-out electronics. IACT telescopes image the very short flash of Cherenkov radiation generated by the cascade of relativistic charged particles...
Despite its success in the SLD CRID at the SLAC Linear Collider, ultrasonic measurement of Cherenkov radiator refractive index has been less fully exploited in more recent Cherenkov detectors employing gaseous radiators. This is surprising, since it is ideally suited to monitoring hydrostatic variations in refractive index as well as its evolution during the replacement of a light radiator...
