Charge recombination lifetime in a silicon wafer is directly proportional to the high energy particle (HEP) irradiation dose of a device. It is widely recognized that the dose of irradiation can be directly related to the density of defects. However, the microscopic picture of defects is highly inhomogeneous with several kinds of defects clustered along the path of HEPs. Electron and hole...
There are presented the simulation of electron mobility dependence on concentration of different defects (ionized and neutral impurities, dipoles, clusters) according the known models and by TCAD Synopsys program (in the neutron irradiated Si).
The known and new experimental data compared with the simulation results.
This project focuses on the investigation of radiation damage of epitaxial P type silicon.
Various test structures consisting of Schottky diodes and p junctions of different size and flavors are being fabricated at different facilities, including RAL, Carleton University and CNM.
The structures are fabricated on a 6 inch wafer of various doping (1e13, 1e14, 1e15, 1e16, and 1e17 B cm-3)...
We will report on the electrically active defects induced by hadron irradiation in p-type diodes processed on different materials (EPI and CZ) and of different resistivities. The generation of the defects and their electrical parameters (activation energy and capture cross sections) have been investigated by DLTS technique, in the framework of the RD50- Acceptor removal project. The defects'...
Radiation hardness of detector sensors and components is a major challenge for the success of the scheduled High Luminosity upgrade of the CERN Large Hadron Collider, and a world-wide campaign for sensor characterisation and qualification has been undertaken. By convention, effects of irradiation with beams of different particle species and energy, aiming to assess displacement damage in...
In this contribution, we present an analysis of the flunece profile at the JSI TRIGA neutron reactor facility in Ljubljana.
For the study, 5$\times$5 array LGAD sensors are used, with 1.3$\times$1.3 mm$^2$ pad area. The gain layer active doping has been extracted via C-V measurements for each pad before and after irradiation at 1.5$\cdot$10$^{15}$ n$_{eq}$/cm$^2$, providing a precise...
The charge collection of two $\text{n}^{+}\text{p}\text{p}^+$ pad diodes for light with a wavelength of $660$ nm from a sub-nanosecond laser and $\alpha$-particles with energies, $E_{\alpha}$, between $1.5$ and $2.8$ MeV injected from the $\text{n}^{+}\text{p}$ side, has been measured. The diodes had an area of $25$ $\text{mm}^{2}$, a thickness of $150$ $\mu$m and a doping concentration of...
We report the measurements of time resolution for double-sided 3D pixel sensor with a single cell of 50 $\mu$m x 50 $\mu$m fabricated at IMB-CNM. Measurements were conducted using a radioactive source at -20 and 20 degrees °C in a bias voltage range of 50-200 V.
Temporal resolution measurements are reported before and after irradiation of 8x10$^{14}$ N$_{eq}$/cm$^{2}$ (1 Mev equivalent...
During edge-TCT studies on irradiated p-type sensors, a significant change on signal amplitude and shape from subsequent laser pulses has been observed, even with pulse repetition time of several microseconds.
We observed in particular a strong reduction of the collected signal, which can be due to a recombination with the previously trapped charge or to a significant change of the electric...
The Transient Current Technique (TCT) has become a very important tool for characterization of unirradiated and irradiated silicon detectors. In recent years a novel method, the Two Photon Absorption - Transient Current Technique (TPA-TCT), based on the charge carrier generation by absorption of two photons, was developed. TPA-TCT proved to be very useful in 3D characterization of silicon...
The Two Photon Absorption - Transient Current Technique, TPA-TCT is a powerful tool for spatially resolved inspection of semiconductor detectors. The nonlinear absorption of light is excited by femtosecond lasers that deliver photons of energy lower than the band-gap energy of the semiconductor material. Simultaneous absorption of 2 photons (the sum of their energies being higher than the...
Silicon sensor leakage currents are often used as a diagnostic tool for monitoring the bulk damage caused by non-ionizing energy loss. One of the key inputs to interpreting leakage current data is the effective band gap energy, which is used to correct for temperature variations in the current. Using dedicated temperature scans in 2017 and 2018, the effective band gap energy is measured for...
A TCAD simulation of radiation damage for Low Gain Avalanche Detector (LGAD) by using various deep energy level models and acceptor removal has been performed. The simulation illustrates the influence of initial gain layer acceptor density and sensor structure. Other radiation damage characteristics could also be reproduced qualitatively: gain reduction, electric field distribution, and...
The High Luminosity of the Large Hadron Collider (HL-LHC) is scheduled to be in operation around 2027, where the instantaneous luminosity will reach up to 7.5e34cm-2s-1. To mitigate the high luminosity induced pile-up, both ATLAS and CMS has proposed to use LGAD as the key sensor for timing measurement in the irradiation region. On the other hand, radiation hardness study on detectors will...
The parameter space of silicon detectors can be large. For this reason, simulations can be useful tool to simplify the system to get a better understanding of the impact of different parameters .
The study to be presented aims to build a fundamental understanding of what affects time resolution of a detector. The focus of the presentation will be on how thickness influences time resolution....
The results presented in this contribution are the results of the joint research of the Extreme Light Infrastructure (ELI) – Beamline The first measurements were devoted to understanding the potential of ELI ultrafast spectroscopy for LGAD studies (timing with SPA/TPA) and building up an infrastructure for future LGAD tests. As it will be shown, the preliminary results opened new...
A set of LGADs from HPK was irradiated with different neutron fluxes to the equivalent fluence of $4\cdot10^{14}$ cm$^{-2}$ . The fluxes covered range from $10^{10}$ cm$^{-2}$ s$^{-1}$ to close to $10^{13}$ cm$-2$ s$^{-1}$. The gain layer and bulk depletion voltage as well as charge collection and timing performance were measured after 80 min at 60$^\circ$C annealing point. No dependence of...
Several thin Low Gain Avalanche Detectors from Hamamatsu Photonics were irradiated with neutrons to different equivalent fluences up to $\Phi_{eq}=3\cdot10^{15}$ cm$^{-2}$. After the irradiation they were
annealed at 60$^\circ$C in steps to times $>20000$ minutes. Their properties, mainly full depletion voltage, gain layer depletion voltage, generation and leakage current, as well as their...
This contribution describes the first measurements of a resistive AC-coupled Low Gain Avalanche Diode (AC-LGAD) strip detector using $120$ GeV protons. AC-LGADs combine the precise time resolution of standard LGAD silicon sensors with precise spatial resolution, and make excellent candidates for future 4-dimensional tracking detectors. The sensor studied in this result has a strip pitch of...
In this contribution we present the latest results on spatial and timing resolution of Resistive AC-Coupled Silicon Detectors (RSD), produced by FBK in 2019. RSD are a new type of silicon detectors specifically designed for high precision 4D tracking. They are based on the LGAD technology, benefiting from its excellent timing performances, and can achieve a spatial resolution a factor 10...
RSDs (Resistive AC-Coupled Silicon Detectors) are n-in-p silicon sensors based on LGAD (Low-Gain Avalanche Diode) technology, featuring a continuous gain layer over the whole sensor area. The innovative feature of these sensors is that the signal induced by an ionizing particle spreads among several pixels, allowing position reconstruction techniques that combine the information of many...
Using electrical characterization, acceptor removal coefficients are estimated and compared for Boron, Gallium and Boron with Carbon diffused gain layer LGADs. Effective implant is computed as a function of fluence for up to 6e15 neutron and proton irradiated sensors in different processes. Results are compared to gain reduction calculations aand relent coefficients are derived. The two...
Low Gain Avalanche Detectors (LGADs) are silicon detectors with modest internal gain (up to ~50) that allows the sensor to be very thin (20-50 um). LGADs are characterized by an extremely good time resolution (down to 17ps), a fast rise time (~500ps) and a very high repetition rate (~1ns full charge collection). In a broad array of fields, including particle physics (4-D tracking) and photon...
The performance of Ultra-Fast Silicon Detectors (UFSD) is compromised by hadronic irradiation which removes the acceptors in the thin layer below the junction responsible for the gain. This effect is measured in several different UFSD after irradiation with protons with energy of 70 MeV (CYRIC), 800 MeV (LANL) and 24 GeV (CERN) and compared to the same sensors irradiated with neutrons at IJS....
LGAD Discussion
Abstract:
Future particle trackers require formidable position (~5 microns) and time (~ 10 ps) resolutions. In traditional silicon sensors, better position resolution implies smaller pixels and, consequently, much higher channel count and smaller area available for the electronics. This combination is at odd with the requirement of also measuring accurately the timing information, a request...
With the HL-LHC upgrade of the ATLAS detector, the surface of the ATLAS pixel detector will increase from 2 m² to approximately 13 m² . Therefore, commercial CMOS processing lines offering high production throughput at comparatively low costs represent an attractive option for such large-area detectors. Further benefits originate from multiple metal layers, metal–insulator–metal capacitors,...
This contribution will be focused on the lab performance evaluation of the electrical parameters before irradiation of three different blocks of the RD50-MPW2 device, the 8 by 8 matrix of depleted monolithic active pixel sensors, the bandgap voltage reference and the SEU (Single Event Upset) tolerant memory array. The RD50-MPW2 was developed in the framework of the RD50 collaboration and...
Digital calorimetry relies on a highly granular detector where the cell size is sufficiently small so that only a single particle in a shower enters each cell within a single readout cycle. The DECAL sensor, a depleted monolithic active pixel sensor (DMAPS), has been proposed as a possible technology for future digital calorimeters. A DECAL sensor prototype has been designed and fabricated in...
The data acquisition (DAQ) system used to read out and characterize the two versions of RD50 HV-CMOS prototype chips (MPW1 and MPW2) is based on the CaRIBOu (Control and Readout Inner tracking Board) system. CaRIBOu is a widely used versatile DAQ platform to characterize pixel detectors and ASICs, such as CLICpix2, C3PD and others. It consists of a system-on-chip board (e.g. Xilinx ZC706), a...
We had p-type HV-silicon JFETs, fabricated at Brookhaven National Laboratory, irradiated with neutrons at the Triga reactor in JSI, up to a fluence of 1.5e15 neq/cm2. Most notably, output characteristics show a dramatic increase of the drain saturation voltage with the irradiation. By means of TCAD simulations, which used the Perugia radiation damage model, we are explaining this effect as due...
