Charge Collection and Electrical Characterization of Neutron Irradiated Silicon Pad Detectors for the CMS High Granularity Calorimeter
N. Akchurin, P. Almeida, G. Altopp, M. Alyari, T. Bergauer, E. Brondolin, B. Burkle, W. D. Frey, Z. Gecse, U. Heintz, N. Hinton, V. Kuryatkov, R. Lipton, M. Man… 展开作者
N. Akchurin, P. Almeida, G. Altopp, M. Alyari, T. Bergauer, E. Brondolin, B. Burkle, W. D. Frey, Z. Gecse, U. Heintz, N. Hinton, V. Kuryatkov, R. Lipton, M. Mannelli, T. Mengke, P. Paulitsch, T. Peltola, F. Pitters, E. Sicking, E. Spencer, M. Tripathi, M. Vicente Barreto Pinto, J. Voelker, Z. Wang, R. Yohay
The replacement of the existing endcap calorimeter in the Compact Muon Solenoid (CMS) detector for the high-luminosity LHC (HL-LHC), scheduled for 2027, will be a high granularity calorimeter. It will provide detailed position, energy, and timing information on electromagnetic and hadronic showers in the immense pileup of the HL-LHC. The High Granularity Calorimeter (HGCAL) will use 120-, 200-, and 300-$μ\textrm{m}$ thick silicon (Si) pad sensors as the main active material and will sustain 1-MeV neutron equivalent fluences up to about $10^{16}~\textrm{n}_\textrm{eq}\textrm{cm}^{-2}$. In order to address the performance degradation of the Si detectors caused by the intense radiation environment, irradiation campaigns of test diode samples from 8-inch and 6-inch wafers were performed in two reactors. Characterization of the electrical and charge collection properties after irradiation involved both bulk polarities for the three sensor thicknesses. Since the Si sensors will be operated at -30 $^\circ$C to reduce increasing bulk leakage current with fluence, the charge collection investigation of 30 irradiated samples was carried out with the infrared-TCT setup at -30 $^\circ$C. TCAD simulation results at the lower fluences are in close agreement with the experimental results and provide predictions of sensor performance for the lower fluence regions not covered by the experimental study. All investigated sensors display 60$\%$ or higher charge collection efficiency at their respective highest lifetime fluences when operated at 800 V, and display above 90$\%$ at the lowest fluence, at 600 V. The collected charge close to the fluence of $10^{16}~\textrm{n}_\textrm{eq}\textrm{cm}^{-2}$ exceeds 1 fC at voltages beyond 800 V.
A silicon-based fine granularity calorimeter is a potential technology for the future International Linear Collider ILC, the future circular collider CEPC, and is also the chosen technology for the upgraded CMS experiment of the Large Hadron Collider. Active silicon sensing pads are used as MIP counters and the standard calibration of the calorimeter uses weights based on the average energy loss, $dEdx$. In this work, the limitations of the dEdx calibration method in terms of energy linearity, scale and resolution are explored. In the case of a calorimeter with varying passive layer thickness …
Eight PbWO4 crystals produced for the electromagnetic calorimeter of the CMS experiment at LHC have been irradiated in a 20 GeV/c proton beam up to fluences of 5.4 E13 p/cm2. The damage recovery in these crystals, stored in the dark at room temperature, has been followed for over a year. Comparative irradiations with 60Co photons have been performed on seven other crystals using a dose rate of 1 kGy/h. The issue whether hadrons cause a specific damage to the scintillation mechanism has been studied through light output measurements on the irradiated crystals using cosmic rays. The correlation …
High-energy physics detectors, like Low Gain Avalanche Detectors (LGADs) that will be used as fast timing detectors in the High Luminosity LHC experiments, have to exhibit a significant radiation tolerance. Thereby the impact of radiation on the highly boron-doped gain layer that enables the internal charge multiplication, is of special interest, since due to the so-called Acceptor Removal Effect (ARE) a radiation-induced deactivation of active boron dopants takes place. In this paper we present defect-spectroscopy measurements (Deep-Level Transient Spectroscopy and Thermally Stimulated Curren…
In this work, charge collection profiles of non-irradiated and irradiated 150 $μ$m $p$-type pad diodes were measured using a 5.2 GeV electron beam traversing the diode parallel to the readout electrode. Four diodes were irradiated to 1 MeV neutron equivalent fluences of 2, 4, 8, and 12E15 {cm}^{-2} with 23 MeV protons. The Charge Collection Efficiency profiles as a function of depth are extracted by unfolding the data. The results of the measurements are compared to the simulation using three radiation damage models from literature which were tuned to different irradiation types and fluences.
The understanding of the weighting field of irradiated silicon sensors is essential for calculating the response of silicon detectors in the radiation environment at accelerators like at the CERN LHC. Using 1-D calculations of non-irradiated pad sensors and 1-D TCAD simulations of pad sensors before and after irradiation, it is shown that the time-dependence of the weighting field is related to the resistivity of low field regions with ohmic behaviour in the sensor. A simple formula is derived, which relates the time constant of the time-dependent weighting field, $τ$, with the resistivity and…
The PADME apparatus was built at the Frascati National Laboratory of INFN to search for a dark photon ($A'$) produced via the process $e^+ e^- \rightarrow A' γ$. The central component of the PADME detector is an electromagnetic calorimeter composed of 616 BGO crystals dedicated to the measurement of the energy and position of the final state photons. The high beam particle multiplicity over a short bunch duration requires reliable identification and measurement of overlapping signals. A regression machine-learning-based algorithm has been developed to disentangle with high efficiency close-in-…
We present the research and development work of the first version of a 6*6 array of silicon pad detectors, carried out in India, for the proposed forward calorimeter (FOCAL) as part of the ALICE collaboration upgrade program at CERN. The primary motivation is to develop a large area silicon pad array realizing the challenging requirements of high-energy physics experiments such as low leakage current, high breakdown voltage and evaluate its performance as an active layer in the prototype silicon tungsten (Si-W) electromagnetic (EM) calorimeter. Towards these goals, a 36-pad silicon sensor with…
The foreseen upgrade of the LHC to its high luminosity phase (HL-LHC), will maximize the physics potential of the facility. The upgrade is expected to increase the instantaneous luminosity by a factor of 5 and deliver an integrated luminosity of 3000 fb-1 after 10 years of operation. As a result of the corresponding increase in radiation and pileup, the electromagnetic calorimetry in the CMS endcaps will sustain maximum integrated doses of 1.5 MGy and neutron fluences above 1e16 neq/cm2, necessitating their replacement for HL-LHC operation. The CMS collaboration has decided to replace the exis…
High-granularity calorimeters utilizing silicon pad sensors as main active material are being designed for the CMS endcap calorimeter upgrade and have been proposed for the electromagnetic calorimeters at CLIC, ILC and FCC-ee. The silicon sensors in such experiments are foreseen to cover a very large area of O(1000 $\mathrm{m^2}$). They are typically produced from 6- or 8-inch wafers and consist of a few hundred smaller cells, each with an area of O(0.1 to 1.1 $\mathrm{cm^2}$). Currently the CMS endcap calorimeter upgrade is in a prototyping phase with the aim of choosing the final sensor desi…
Eight production quality PbWO4 crystals of CMS have been irradiated in a 20 GeV/c proton beam up to fluences of 5.4E13cm-2. The damage recovery in these crystals has been followed for over a year. Comparative irradiations with 60Co photons have been performed on seven other crystals using a dose rate of 1 kGy/h. In proton irradiated crystals the light transmission band-edge shifts and the induced absorption length is proportional to the inverse of the 4th power of the wavelength. In gamma-irradiated crystals the band-edge does not shift but formation of absorption bands is seen clearly. The ab…
Low Gain Avalanche Detectors (LGADs) are a type of thin silicon detector with a highly doped gain layer. LGADs manufactured by Fondazione Bruno Kessler (FBK) were tested before and after irradiation with neutrons. In this study, the Inter-pad distances (IPDs), defined as the width of the distances between pads, were measured with a TCT laser system. The response of the laser was tuned using $β$-particles from a 90Sr source. These insensitive "dead zones" are created by a protection structure to avoid breakdown, the Junction Termination Extension (JTE), which separates the pads. The effect of n…
As part of its HL-LHC upgrade program, CMS is developing a High Granularity Calorimeter (HGCAL) to replace the existing endcap calorimeters. The HGCAL will be realised as a sampling calorimeter, including an electromagnetic compartment comprising 28 layers of silicon pad detectors with pad areas of 0.5 - 1.0 cm2 interspersed with absorbers. Prototype modules, based on 6-inch hexagonal silicon pad sensors with 128 channels, have been constructed and include many of the features required for this challenging detector. In 2016, beam tests of sampling configurations made from these modules have be…
The PADME experiment, at the Laboratori Nazionali di Frascati (LNF), in Italy, will search for invisible decays of the hypothetical dark photon via the process $e^+e^-\rightarrow γA'$, where the $A'$ escapes detection. The dark photon mass range sensitivity in a first phase will be 1 to 24 MeV. We report here on measurement and simulation studies of the performance of the Small-Angle Calorimeter, a component of PADME's detector dedicated to rejecting 2- and 3-gamma backgrounds. The crucial requirement is a timing resolution of less than 200 ps, which is satisfied by the choice of PbF$_2$ cryst…
Silicon pad sensors are proposed as active material in highly granular sampling calorimeters of future collider experiments such as the Compact Linear Collider (CLIC) or the International Linear Collider (ILC). The electromagnetic section of these designs often include O(1000 m$^2$) of silicon pad sensors. For the luminosity measurement, a dedicated forward calorimeter called LumiCal is foreseen. More recently, the CMS experiment has decided to adopt the same concept in its endcap calorimeter upgrade for the HL-LHC. The sensors are typically produced from 6- or 8-inch wafers and consist of a f…
Kinetics of radiation damage of the PWO crystals under irradiation and recovery were studied. Crystals were irradiated with dose corresponding to average one expected in the electromagnetic calorimeter (working dose irradiation). Radiation damage and recovery were monitored through measurements of PWO optical transmission. An approach is proposed which allows evaluating the influence of the PWO crystals properties on the statistical term in the energy resolution of the electromagnetic calorimeter. The analysis also gives important information about the nature of the radiation damage mechanism …
In this paper the weighting field $E_W$ and the frequency dependence of the admittance Y of n$^+$p pad sensors irradiated by 24 GeV/c protons to equivalent fluences in the range $Φ_{\rm eq} = 3$ to $13\times 10^{15}$ cm$^{-2}$ are investigated. 1-D TCad simulations are used to calculate $E_W$. For $Φ_{\rm eq} < 10^{13}$ cm$^{-2}$ $E_W$ depends on position and time. However, for higher $Φ_{\rm eq}$ the time constant $τ$ is much longer than the typical electronics readout time and $E_W = 1/d$ ($d$ = sensor thickness). It is demonstrated that the increase of the resistivity of the Si bulk with ir…
A Lead Tungstate crystal produced for the electromagnetic calorimeter of the CMS experiment at the LHC was cut into three equal-length sections. The central one was irradiated with 290 MeV/c positive pions up to a fluence of (5.67 +- 0.46)x10^13 /cm^2, while the other two were exposed to a 24 GeV/c proton fluence of (1.17 +- 0.11) x 10^13/ cm^2. The damage recovery in these crystals, stored in the dark at room temperature, has been followed over two years. The comparison of the radiation-induced changes in light transmission for these crystals shows that damage is proportional to the star dens…
The SDHCAL technological prototype is a $1 \times 1 \times 1.3$ m$^3$ high-granularity Semi-Digital Hadronic CALorimeter using Glass Resistive Plate Chambers as sensitive medium. It is one of the two HCAL options considered by the ILD Collaboration to be proposed for the detector of the future International Linear Collider project. The prototype is made of up to 50 GRPC detectors of 1 m$^2$ size and 3 mm thickness each with an embedded semi-digital electronics readout that is autotriggering and power-pulsed. The GRPC readout is finely segmented into pads of 1 cm$^2$. Measured performances of t…
The calorimeter and muon systems are essential components to provide a trigger for the LHCb experiment. The calorimeter system comprises a scintillating pad detector and pre-shower, followed by electromagnetic and hadronic calorimeters. The calorimeter system allows photons, electrons and hadrons to be identified, and their energy to be measured. The muon system consists of five measuring stations equipped with Multi-Wire Proportional Chambers (MWPCs) and triple-Gas Electron Multiplier (GEM) detectors, separated by iron filters. It allows the muons identification and transverse momentum measur…
A silicon-tungsten (Si-W) sampling calorimeter, consisting of 19 alternate layers of silicon pad detectors (individual pad area of 1~cm$^2$) and tungsten absorbers (each of one radiation length), has been constructed for measurement of electromagnetic showers over a large energy range. The signal from each of the silicon pads is readout using an ASIC with a dynamic range from $-300$~fC to $+500$~fC. Another ASIC with a larger dynamic range, $\pm 600$~fC has been used as a test study. The calorimeter was exposed to pion and electron beams at the CERN Super Proton Synchrotron (SPS) to characteri…
The collected charge of two pad diodes is measured along the diode width using a 5:2 GeV electron beam at the DESY II beam test facility. The electron beam enters parallel to the readout electrode plane and perpendicular to the edge of the diode. The position of the electron beam is reconstructed by three planes of an EUDET-type telescope. An in-situ procedure is developed to align the diode surface parallel to the electron beam. The result of these measurements is the charge collection efficiency profile as a function of depth for each diode. For a non-irradiated diode, the charge profile is …
The calorimeter system of LHCb is subdivided into four sub-detectors which ensure its longitudinal segmentation: a Scintillator Pad Detector (SPD) followed by a Preshower (PS) and then an electromagnetic (ECAL) an hadronic (HCAL) calorimeter. After a description of these detectors, procedures developed to calibrate their response are discussed together with the degradation of response observed due to the harsh conditions (hard radiation and high current). First results on the calorimeter performance over the two most productive years of physics data taking, 2011 and 2012 are given.
Within CERN RD50 Collaboration, MCz Si was identified as a best material for the detector used in the high luminosity collider experiments. The n in p Si detectors were utmost radiation hard detectors, which can be used for the phase 2 upgrade plan of the new Compact Muon Solenoid tracker detector in 2026. The choice of n or p-MCz Si material depends upon the high electrical charge collection efficiency performance of these detectors over n or p-FZSi detectors. The bulk radiation damage model for n, p-MCz Si need to develop for the designing, development and optimization of the advanced detect…
A method is presented which allows to obtain the position-dependent electric field and charge density by fits to velocity profiles from edge-TCT data from silicon strip-detectors. The validity and the limitations of the method are investigated by simulations of non-irradiated $n^+p$ pad sensors and by the analysis of edge-TCT data from non-irradiated $n^+p$ strip-detectors. The method is then used to determine the position dependent electric field and charge density in $n^+p$ strip detectors irradiated by reactor neutrons to fluences between 1 and $10 \times 10^{15}$ cm$^{-2}$ for forward-bias…
CEPC (Circular Electron and Positron Collider) is a large experiment facility proposed by Chinese particle physics community. One of its running option is being the Higgs factory. Calorimeter is the main part of this experiment to measure the jet energy. Semi-digital hadron calorimeter (SDHCAL) is one of the options for the hadron measurement. GEM detector with its high position resolution and flexible configuration is one of the candidates for the active layer of the SDHCAL. The main purpose of this paper is to provide a feasible readout method for the GEM-based semi-digital hadron calorimete…
A method is proposed for determining the electric field in highly-irradiated silicon pad diodes using admittance-frequency (Y-f ), and current measurements (I). The method is applied to Y-f and I data from square n+p diodes of 25mm2 area irradiated by 24 GeV/c protons to four 1MeV neutron equivalent fluences between 3E15 cm^2 and 13E15 cm^2. The measurement conditions were: Reverse voltages between 1V and 1000V, frequencies between 100Hz and 2MHz and temperatures of -20°C and -30°C. The position dependence of the electric field is parameterised by a linear dependence at the two sides of the di…
We present measurements of the reduction of light output by plastic scintillators irradiated in the CMS detector during the 8 TeV run of the Large Hadron Collider and show that they indicate a strong dose rate effect. The damage for a given dose is larger for lower dose rate exposures. The results agree with previous measurements of dose rate effects, but are stronger due to the very low dose rates probed. We show that the scaling with dose rate is consistent with that expected from diffusion effects.
The expected increase of total integrated luminosity by a factor of ten at the HL-LHC compared to the design goals for LHC essentially eliminates the safety factor for radiation hardness realized at the current cold amplifiers of the ATLAS Hadronic Endcap Calorimeter (HEC). New more radiation hard technologies have been studied: SiGe bipolar, Si CMOS FET and GaAs FET transistors have been irradiated with neutrons up to an integrated fluence of 2.2 \cdot 10^{16} n/cm2 and with 200 MeV protons up to an integrated fluence of 2.6 \cdot 10^{14} p/cm2. Comparisons of transistor parameters such as th…
The expected increase of total integrated luminosity by a factor ten at the HL-LHC compared to the design goals for LHC essentially eliminates the safety factor for radiation hardness realized at the current cold amplifiers of the ATLAS Hadronic End-cap Calorimeter (HEC). New more radiation hard technologies have been studied: SiGe bipolar, Si CMOS FET and GaAs FET transistors have been irradiated with neutrons up to an integrated fluence of 2.2 x 10^{16} n/cm^2 and with 200 MeV protons up to an integrated fluence of 2.6 x 10^{14} p/cm^2. Comparisons of transistor parameters such as the gain f…
A prototype Silicon-Tungsten electromagnetic calorimeter (ECAL) for an International Linear Collider (ILC) detector was installed and tested during summer and autumn 2006 at CERN. The detector had 6480 silicon pads of dimension 1x1 cm^2. Data were collected with electron beams in the energy range 6 to 45 GeV. The analysis described in this paper focuses on electromagnetic shower reconstruction and characterises the ECAL response to electrons in terms of energy resolution and linearity. The detector is linear to within approximately the 1% level and has a relative energy resolution of (16.6 +- …
A sampling calorimeter equipped with gaseous sensor layers with digital readout is near perfect for "Particle Flow Algorithm" approach, since it is homogeneous over large surfaces, robust, cost efficient, easily segmentable to any readout pad dimension and size and almost insensitive to neutrons. The response of a finely segmented digital calorimeter is characterized by track efficiency and multiplicity. Monte Carlo (MC) programs such as GEANT4 simulate with high precision the energy deposited by particles. The sensor and electronic response associated to a pad are calculated in a separate "di…
The SiD collaboration is developing a Si-W sampling electromagnetic calorimeter, with anticipated application for the International Linear Collider. Assembling the modules for such a detector will involve special bonding technologies for the interconnections, especially for attaching a silicon detector wafer to a flex cable readout bus. We review the interconnect technologies involved, including oxidation removal processes, pad surface preparation, solder ball selection and placement, and bond quality assurance. Our results show that solder ball bonding is a promising technique for the Si-W EC…
A new design of highly granular hadronic calorimeter using Glass Resistive Plate Chambers (GRPCs) with embedded electronics has been proposed for the future International Linear Collider (ILC) experiments. It features a 2-bit threshold semi-digital read-out. Several GRPC prototypes with their electronics have been successfully built and tested in pion beams. The design of these detectors is presented along with the test results on efficiency, pad multiplicity, stability and reproducibility.
New generation high-energy physics experiments demand high precision tracking and accurate measurements of a large number of particles produced in the collisions of lementary particles and heavy-ions. Silicon-tungsten (Si-W) calorimeters provide the most viable technological option to meet the requirements of particle detection in high multiplicity environments. We report a novel Si-W calorimeter design, which is optimized for $γ/π^0$ discrimination up to high momenta. In order to test the feasibility of the calorimeter, a prototype mini-tower was constructed using silicon pad detector arrays …
The Mu2e calorimeter is composed of 1400 un-doped CsI crystals, coupled to large area UV extended Silicon Photomultipliers (SiPMs), arranged in two annular disks. This calorimeter has to provide precise information on energy, timing and position resolutions. It should also be fast enough to handle the high rate background and it must operate and survive in the high radiation environment. Simulation studies estimated that, in the highest irradiated regions, each photo-sensor will absorb a dose of 20 krad and will be exposed to a neutron fluency of 5.5x10^11 n_(1MeV)/cm^2 in three years of runni…
Glass RPC detectors are an attractive candidate for the active part of a highly granular digital hadron calorimeter (DHCAL) at the ILC. A numerical study, based on the GEANT3 simulation package, of the performance of such a calorimeter is presented in this work. A simplified model for the RPC response, tuned on real data, is implemented in the simulation. The reliability of the simulation is demonstrated by comparison to existing data collected with a large volume calorimeter prototype exposed to a pion beam in an energy range from 2 GeV to 10 GeV. In view of an optimization of the readout pit…
The CALICE collaboration is studying the design of high performance electromagnetic and hadronic calorimeters for future International Linear Collider detectors. For the electromagnetic calorimeter, the current baseline choice is a high granularity sampling calorimeter with tungsten as absorber and silicon detectors as sensitive material. A ``physics prototype'' has been constructed, consisting of thirty sensitive layers. Each layer has an active area of 18x18 cm2 and a pad size of 1x1 cm2. The absorber thickness totals 24 radiation lengths. It has been exposed in 2006 and 2007 to electron and…
We report on the measurement of the neutron radiation hardness of silicon photomultipliers (SiPMs) manufactured by Hamamatsu Corporation in Japan and SensL in Ireland. Samples from both companies were irradiated by neutrons created by a 1 GeV electron beam hitting a thin lead target at Jefferson Lab Hall A. More tests regarding the temperature dependence of the neutron radiation damage and self-annealing were performed on Hamamatsu SiPMs using a calibrated Am-Be neutron source from the Jefferson Lab Radiation Control group. As the result of irradiation both dark current and dark rate increase …
A new module concept for future ATLAS pixel detector upgrades is presented, where thin n-in-p silicon sensors are connected to the front-end chip exploiting the novel Solid Liquid Interdiffusion technique (SLID) and the signals are read out via Inter Chip Vias (ICV) etched through the front-end. This should serve as a proof of principle for future four-side buttable pixel assemblies for the ATLAS upgrades, without the cantilever presently needed in the chip for the wire bonding. The SLID interconnection, developed by the Fraunhofer EMFT, is a possible alternative to the standard bump-bonding. …
Radiation Tolerance Characterisation of an Indigenously Developed p-type Silicon Pad Sensor for Forward Calorimetry Applications
Variable Energy Cyclotron Centre（变能回旋加速器中心）；Homi Bhabha National Institute（霍米·巴巴国立研究所）；Jadavpur University（贾达普大学）；Bhabha Atomic Research Centre（巴哈原子研究中心）；Institute for Plasma Research（等离子体研究所）
Silicon PhotoMultipliers (SiPM) are an excellent choice for the scintillator light readout at hadron calorimeters due to their insensitivity to magnetic fields, low operating voltages, low cost, compactness and mechanical endurance. They are already successfully utilized in Projectile Spectator Detector (PSD) of NA61 at CERN, and will be utilized soon in PSD of CBM at FAIR and Forward Hadron CALorimeters (FHCAL) of BM@N at NICA heavy-ion collision experiments. The main issue of SiPM application is their degradation due to high neutron fluence that can reach up to 2E11 neq/cm2 per year of the e…
A high granularity hadronic 1 m3 calorimeter prototype with semi-digital readout has been designed and built. This calorimeter has been made using stainless steel as absorber and Glass Resistive Plates Chambers (GRPC) as active medium, and read out through 1x1 cm2 pads. This prototype aims to demonstrate that this technology fulfills the physics requirements for future linear collider experiments, and also to test the feasibility of building a realistic detector, taking into account design aspects as for instance a fully embedded front-end electronics based on power pulsing system, a compact a…
Detector-plane prototypes of the very forward calorimetry of a future detector at an e+e- collider have been built and their performance was measured in an electron beam. The detector plane comprises silicon or GaAs pad sensors, dedicated front-end and ADC ASICs, and an FPGA for data concentration. Measurements of the signal-to-noise ratio and the response as a function of the position of the sensor are presented. A deconvolution method is successfully applied, and a comparison of the measured shower shape as a function of the absorber depth with a Monte-Carlo simulation is given.
The International Large Detector (ILD) is a proposed detector for the International Linear Collider (ILC). It has been designed to achieve an excellent jet energy resolution by using Particle Flow Algorithms (PFA), which rely on the ability to separate nearby particles within jets. PFA requires calorimeters with high granularity. The ILD Electromagnetic Calorimeter (ECAL) is a sampling calorimeter with thirty tungsten absorber layers. The total thickness of this ECAL is about 24 X$_0$, and it has between 10 and 100 million channels to make high granularity. Silicon sensors are a candidate tech…
For the high-luminosity phase of the Large Hadron Collider (HL-LHC), at the expected position of the innermost pixel detector layer of the CMS and ATLAS experiments, the estimated equivalent neutron fluence after 3000 fb$^{-1}$ is 2$\cdot$10$^{16}$ n$_{eq}$/cm$^2$, and the IEL (Ionizing Energy Loss) dose in the SiO$_2$ 12 MGy. The optimisation of the pixel sensors and the understanding of their performance as a function of fluence and dose makes a radiation damage model for TCAD simulations, which describes the available experimental data, highly desirable. The currently available bulk-damage …
Silicon pad sensors with novel functions of higher timing resolution (LGAD: Low Gain Avalanche Detector) and higher position resolution (PSD: Position Sensitive Detector) are studied for an application to Silicon-Tungsten electromagnetic calorimeter for a detector of the International Linear Collider (ILC). Prototype sensors are fabricated, equipped with dedicated ASICs (Application-Specific Integrated Circuits) and tested with a positron beam as well as a radioisotope. The first results of the measurements of timing resolution with LGADs and position reconstruction with PSDs are reported.
The unique electrical and material properties of 4H-silicon-carbide (4H-SiC) make it a promising candidate material for high rate particle detectors. In contrast to the ubiquitously used silicon (Si), 4H-SiC offers a higher carrier saturation velocity and larger breakdown voltage, enabling a high intrinsic time resolution and mitigating pile-up effects. Additionally, as radiation hardness requirements grow more demanding, wide-bandgap materials such as 4H-SiC could offer better performance. In this work, the detector performance of 50 micron thick 4H-SiC p-in-n planar pad sensors was investiga…
