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Low temperature characteristics of SiPMs after very high neutron irradiation
摘要： The design of the CMS phase II upgrade for the HL-LHC uses SiPMs for the Barrel Timing Layer (BTL) and the Behind HCAL detector (BH or CEH). In both sub-detectors the SiPMs will see a 1 MeV equivalent dose of around 1014 n/cm2. To lower the noise in the SiPMs the design is to keep the SiPMs at a low temperature of ?30 ?C. Different samples from two manufactures of SiPMs were irradiated to a total dose of resp. 2 × 1012, 5 × 1013 at the TRIGA reactor at the JSI in Slovenia. The noise in SiPMs is dominated by trap assisted tunneling which is a result of the high internal electric field in SiPMs. We therefore studied the noise behavior from +10 ?C to ?40 ?C from standard high internal field and specially designed low field SiPMs from FBK-irst and Hamamatsu. After the initial characterization before annealing the noise decrease in SiPMs was also studied using accelerated annealing.
关键词： Silicon photomultiplier,MPPC,CMS,GAPD,Radiation damage
更新于2025-09-23 15:23:52
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Fast neutron detectors with silicon photomultiplier readouts
摘要： This work summarizes a fast neutron detection performance of two different silicon photomultipliers from two manufacturers. The first SiPM (MAPD-3NK) from Zecotek Photonics consists of deeply buried cells with the active area 3.7x3.7 mm2. The second one (MPPC-S12572-010P) from Hamamatsu, however, consists of surface cell structure which the active area is 3x3 mm2. Both SiPMs have the same pixel density of 10000 mm-2. Both SiPMs coupled to Stilbene (5*5*5 mm3) and p-terphenyl (5*5*5 mm3) plastic scintillators were evaluated for detection ability of fast neutrons using a PuBe neutron source. Charge comparison and zero crossing neutron/gamma discrimination techniques were performed for these detectors and the results were compared. The obtained results prove a good fast neutron detection performance of the SiPMs which makes it possible to use these types of neutron detectors in fast neutron detection applications.
关键词： Pulse shape discrimination,Micropixel avalanche photodiode,Charge comparison,SiPM,MAPD,PSD,Zero crossing,Silicon photomultiplier
更新于2025-09-23 15:21:21
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Use of YAP(Ce) in the development of high spatial resolution radiation imaging detectors
摘要： A scintillator with a high light output is considered to be required for the development of high spatial resolution radiation imaging detectors. In contrast to this scientific consensus, we found that high spatial resolution images can be obtained using a medium light output scintillator comprising cerium-doped yttrium aluminum perovskite, YA1O3 (YAP(Ce)). We evaluated the performance of a radiation imaging detector comprising a 0.5 mm thick YAP(Ce) plate, which was optically coupled to a 25.4 mm (1-inch) square position-sensitive photomultiplier. The Anger principle was used to calculate the radiation positions. The spatial resolution and energy resolution for the imaging detector with 5.5 MeV alpha particles were 0.2 mm full width at half-maximum (FWHM) and 7.4% FWHM, respectively. The spatial resolutions for 60 keV gamma photons and ~32 keV X-rays were ~ 0.6 mm FWHM and ~ 0.8 mm FWHM, respectively. The spatial resolution of the detector when imaging beta particles at a maximum energy of 254 keV was less than 0.6 mm FWHM. We conclude that YAP(Ce) is a promising scintillator for developing high spatial resolution and high energy resolution radiation detectors for imaging alpha particles, beta particles, and gamma photons.
关键词： YAP(Ce),energy resolution,position-sensitive photomultiplier,spatial resolution
更新于2025-09-23 15:21:21
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Portable Instrument for Monitoring Environmental Toxins Using Immobilized Quantum Dots as the Sensing Material
摘要： A portable instrumental system was designed for the routine environmental monitoring of toxic volatile organic compounds (VOCs) in atmospheric conditions based on changes in the photoluminescence emission of semiconductor nanoparticles (quantum dots) entrapped in a sol-gel matrix as the solid sensing material. The sol-gel sensing material displayed a long-lived phosphorescent emission, which is quenched in the presence of trace levels of a volatile organic compound (acetone) in gaseous atmospheres. The developed instrument could measure and process the changes in the photoluminescence of the sensing material after exposure to gaseous acetone. The developed prototype device consists of a deep-ultraviolet light-emitting diode (UV LED), which excites the chemical sensing material; an optical filter to remove scattered light and other non-desirable wavelengths; a photomultiplier tube (PMT) to convert the phosphorescence emission of the sensor phase to an electrical signal; and a microcontroller to correlate the signal with the analyte concentration. The developed prototype was evaluated for its ability to measure low levels of gaseous acetone in contaminated atmospheres with high sensitivity (detection limit: 9 ppm). The obtained results show the feasibility of this type of instrument for environmental analytical control purposes.
关键词： quantum dots (QDs),photomultiplier,UV LED,instrumentation,nanoparticles,room temperature phosphorescence (RTP)
更新于2025-09-23 15:21:01
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0.16 μm–BCD Silicon Photomultipliers with Sharp Timing Response and Reduced Correlated Noise
摘要： Silicon photomultipliers (SiPMs) have improved significantly over the last years and now are widely employed in many different applications. However, the custom fabrication technologies exploited for commercial SiPMs do not allow the integration of any additional electronics, e.g., on-chip readout and analog (or digital) processing circuitry. In this paper, we present the design and characterization of two microelectronics-compatible SiPMs fabricated in a 0.16 μm–BCD (Bipolar-CMOS-DMOS) technology, with 0.67 mm × 0.67 mm total area, 10 × 10 square pixels and 53% fill-factor (FF). The photon detection efficiency (PDE) surpasses 33% (FF included), with a dark-count rate (DCR) of 330 kcps. Although DCR density is worse than that of state-of-the-art SiPMs, the proposed fabrication technology enables the development of cost-effective systems-on-chip (SoC) based on SiPM detectors. Furthermore, correlated noise components, i.e., afterpulsing and optical crosstalk, and photon timing response are comparable to those of best-in-class commercial SiPMs.
关键词： Silicon photomultiplier (SiPM),photon counting,photon number resolution,optical crosstalk,time-correlated single-photon counting (TCSPC),afterpulsing
更新于2025-09-23 15:21:01
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A normally-distributed crosstalk model for silicon photomultipliers
摘要： Optical crosstalk (OCT) in silicon photomultipliers (SiPM) occurs when photon detection in a microcell leads to the production of further photons that are also detected. Various models have been considered to predict experimental data with varying degrees of success. In this paper, we introduce the Normally-Distributed Crosstalk Model (NDCM), where the probability of triggering additional microcells is given by a 2-d normal distribution with a standard deviation of ??: a device-specific parameter representing OCT photon propagation path length in terms of microcell pitch. Monte Carlo (MC) simulations of NDCM are compared to existing models and experimental data from the CHEC-S camera developed for the Cherenkov Telescope Array, which suggests that OCT occurs with a ?? ≈ 5 microcells in this device.
关键词： SiPM,Silicon photomultiplier,Optical crosstalk
更新于2025-09-23 15:21:01
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CMOS-coupled NaI scintillation detector for gamma decay measurements
摘要： We report an all-solid-state gamma-ray scintillation detector comprised of a NaI(Tl) crystal and a scientific-grade CMOS camera. After calibration, this detector exhibits excellent linearity over more than three decades of activity levels ranging from 10 mCi to 400 nCi. Because the detector is not counting pulses, dead-time correction is not required. Compared to systems that use a photomultiplier tube, this detector has similar sensitivity and noise characteristics on short time scales. On longer time scales, we measure drifts of a few percent over several days, which can be accommodated through regular calibration. Using this detector, we observe that when high activity sources are brought into close proximity to the NaI crystal, several minutes are required for the measured signal to achieve a steady state.
关键词： gamma-ray scintillation detector,dead-time correction,photomultiplier tube,NaI(Tl) crystal,CMOS camera
更新于2025-09-23 15:19:57
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Silicon photomultipliers with area up to 9 mm2 in a 0.35 μm CMOS process
摘要： Silicon photomultipliers produced using standard complementary metal oxide semiconductor (CMOS) processes are at the basis of modern applications of sensors for weak photon fluxes. They allow in fact to integrate transistor-based electronic components within sensors and provide intelligent read-out strategies. In this paper we investigate the scalability of a 0.35 μm CMOS process to large area devices. We report the design and characterization of SiPMs with a total area of 1 mm2, 4 mm2 and 9 mm2. Cross talk, photon detection efficiency at 420 nm, gain at 2.5 V overvoltage and breakdown voltage temperature coefficient do not depend on the total area of the sensor and are 10%, 35%, 2.5 × 106 and 35 mV/K respectively. The dark count rate scales with the total area of the device as 180 kHz/mm2. The total output capacitance, the decay time of the single photon signal and the single photon time resolution depend on the area of the device. We obtain a capacitance of 66.9 pF, 270.2 pF and 554.0 pF, a decay time of (27.1 ± 0.1) ns, (50.8 ± 0.1) ns and (78.2 ± 0.1) ns and a single photon time resolution of (77.97 ± 0.51) ps, (201.67 ± 0.98) ps and (282.28 ± 0.86) ps for the 1 mm2, 4 mm2 and 9 mm2 SiPMs respectively.
关键词： CMOS,Silicon photomultiplier (SiPM),avalanche breakdown structures,Sensors for Brain Positron Emission Tomography
更新于2025-09-19 17:15:36
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[IEEE 2018 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) - Sydney, Australia (2018.11.10-2018.11.17)] 2018 IEEE Nuclear Science Symposium and Medical Imaging Conference Proceedings (NSS/MIC) - Comparison of NaI coupled to photomultiplier tube and silicon photomultiplier
摘要： The NaI scintillator has been widely used for decades. In recent years, the silicon photomultiplier (SiPM), a new photosensor based on semiconductor technologies, has attracted a great deal of attention and has started replacing the conventional photomultiplier tube (PMT) in some applications. This work compares the performance of two NaI detectors with the same size crystals in which one is coupled to a PMT and the other is coupled to a SiPM array. The response of both detectors is fairly linear although the NaI-SiPM detector shows signs of saturation for high energy gammas. The waveform and the energy resolution of the detectors are studied for temperatures between –20 and 50°C. Because of the capacitance of the SiPMs, the decay constant of the waveform for the NaI-SiPM detector is signi?cantly longer than that for the NaI-PMT detector. The energy resolution for both detectors changes with temperatures for a ?xed shaping time. However, with a proper choice of the shaping time according to the temperature, the energy resolution for the NaI-SiPM detector is as good as the NaI-PMT detector.
关键词： NaI scintillator,silicon photomultiplier (SiPM),energy resolution,photomultiplier tube (PMT),temperature dependence
更新于2025-09-16 10:30:52
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Scanning a Silicon Photomultiplier with a Laser Beam
摘要： The Silicon Photomultiplier (SiPM) is a novel semiconducting photodetector which can detect single photons. It consists of many microcells (pixels) operating in the so-called Geiger mode. At present, there are two principal designs among such devices: surface pixel and deeply buried pixel (microwell) structures. The cellular structure decreases the device’s effective photosensitive area, expressed in terms of the geometrical fill factor. It is very important to take it into account when developing new constructions with high pixel densities that are necessary for increasing the dynamic range. It is believed that the fill factor of deep microwell SiPMs is close to unity. In this work, the technique and results of studying the zonal response of different SiPMs by scanning (moving) with micron laser spot are presented. It is shown that the geometrical fill factor of the deep microwell SiPM is less than 100% when detecting the red light (λ = 632 nm).
关键词： Silicon Photomultiplier,Geiger mode,geometrical fill factor,laser scanning,deep microwell SiPM,SiPM
更新于2025-09-16 10:30:52