SiPM Array Research Articles

Performance evaluation of a GAGG-SiPM based compton camera for gamma-ray astronomy

We fabricated and calibrated a GAGG-SiPM based Compton camera which can provide directional information of radiation sources for gamma-ray astronomy. The proposed Compton camera consists of two layers of 8 × 8 GAGG scintillator detectors, directly read out by an 8 × 8 SiPM (MicroFC-60035) array. Each GAGG crystal in the scatterer layer measures 6 × 6 × 8 mm3 in 7.2 mm pitches, while that in the absorber layer measures 6 × 6 × 12 mm3 in 7.2 mm pitches. A reconstruction software running on multiple GPUs based on the list mode MLEM algorithm for the Compton camera has also been developed. Point source imaging studies demonstrated an angular resolution (Full width at half maximum, FWHM) of 13.5°, and a measured intrinsic efficiency of 0.85% when a137Cs point source is placed 52 mm away from the scatterer with a scatterer-to-absorber distance of 57 mm. The camera's capability to simultaneously image point sources of different energies was assessed by imaging two distinct point sources, 22Na and 137Cs. The phantom imaging study was carried out with a U-shaped tube injected with 18F solution to verify the imaging capability of the system.

Production of the DarkSide-20k photo-detectors

DarkSide-20k is a 50t dual phase liquid argon time projection chamber currently under construction in Hall-C of LNGS. DarkSide-20k is projected to lead the search for WIMP like dark matter, probing down to WIMP-nucleon cross sections of 10−48cm2 for a WIMP mass of 0.1TeV. In order to achieve this goal DarkSide-20k employs novel techniques and technologies including: the use of underground argon depleted in the radioisotope 39Ar; a neutron veto integrated into the TPC mechanical structure; large-area cryogenic SiPM array photodetectors. These bespoke SiPMs, assembled into photodetector modules, instrument both the veto and TPC detectors. The design and ongoing production of these photodetector modules will be reported.

Development of an ultrahigh resolution 1 mm Si-PM array based GGAG alpha particle imaging detector with gamma or X-ray separation capability

For precise distribution measurements of alpha particles, as required in alpha radionuclide therapy research, a high-resolution alpha particle imaging detector is desirable. While combining a thin scintillator with a photodetector array, such as a position-sensitive photomultiplier (PSPMT), is a potential method to develop an event-by-event-based alpha particle imaging detector, the spatial resolution is currently limited to around 0.8 mm FWHM. To overcome this limitation, we utilized a small-sized Si-PM array combined with a thin GGAG plate to create an alpha particle imaging detector and evaluated its performance. In the developed alpha particle imaging detector, a Si-PM array with a channel size of 1 mm × 1 mm arranged in an 8 × 8 configuration was optically coupled to a 1 mm thick GGAG plate, with a 1-mm-thick light guide between them. Since the decay times of GGAG differ between alpha particles and gamma photons or X-rays, we were able to separately measure the distributions of alpha particles and gamma photons using pulse shape discrimination. The spatial resolution of the developed alpha particle imaging detector was 0.19 mm FWHM, and the energy resolution was 11% FWHM for 5.5 MeV alpha particles. Additionally, we were able to separately measure the distributions of alpha particles and gamma photons for simultaneously irradiated phantoms using pulse shape discrimination. The developed imaging detector shows promise for distribution measurements of alpha particles, as well as gamma photons or X-rays, where high spatial resolution and separation of gamma photons or X-rays are required.

A study on “position-energy” response correction method based on monolithic crystal coupled SiPM array

A study on “position-energy” response correction method based on monolithic crystal coupled SiPM array

Development of a plastic scintillator based and SiPM readout detector for high-precision fast-timing measurements at rosphere array

We report on the development of a custom particle detection system that aims to improve the detection capabilities of the ROSPHERE array. The detector is designed specifically for lifetime measurements using the in-beam Fast-timing method for nuclear states in nuclides produced in nuclear transfer reactions. An 80 x 3.6 mm disc of BC400 plastic scintillator was coupled to a sparse SiPM array readout connected to a dedicated Front End Electronics board. The detector was tested versus a conical LaBr3(Ce) coupled to a Hamamatsu PMT readout. The timing measurements resulted in a resolution of 896(5) ps. The detector design, characteristics, and performances are presented in this paper along with future improvements.

A novel method for accurate and real-time quantification of radiopharmaceutical activity in automated dose dispensers

In recent years, there has been a rapid growth in new technologies within nuclear medicine and PET diagnostics, particularly in the field of radiopharmaceutical dose preparation. These advancements are driven by the integration of automatic algorithms into the process. This evolution has brought about significant improvements in the efficiency and accuracy of radiopharmaceutical dose preparation. These automatic algorithms utilize state-of-the-art technologies to streamline the process and ensure precise and tailored doses for patients. The integration of these advanced technologies has revolutionized the field, allowing for more effective and personalized treatment options in nuclear medicine and PET diagnostics. By employing automatic radiopharmaceutical dose dispensers (ARDDs), radiation exposure to technologists is minimized while also mitigating the risk of potential infections for patients. Ionization chambers are currently the most used detectors to measure the activity of radiopharmaceuticals in ARDDs. However, they present certain limitations, including size constraints. This study is part of an international endeavor to develop a new approach for evaluating radiopharmaceutical activity in an ARDD named KARl 100. A new approach was used to develop a scintillation detector by linking a PVT detector to a SiPMs array consisting of four elements, each having an active surface of 6 × 6 mm with a bias voltage of 30 V. The detection system's amplified output was then fed to a single-channel analyzer called Enviro, developed by Tema Sinergie S.p.A in Italy. The counts per second (CPS) detected by the detector were studied using WinTAM software allowing for the radionuclide’s activity concentration to be read out at run-time. Three widely used medical radioisotopes, 18F, 11C and 68Ga, were used to evaluate the performance of the detector in terms of linearity and repeatability of the measurements. Half-life and linear response were evaluated over a wide range of activities with different decay schemes. Data analysis was conducted, resulting in half-lives of the 18F, 11C and 68Ga radioisotopes of 109.75 ± 0.35, 20.62 ± 0.34 and 67.82 ± 0.25 min, respectively, with calculated deviations of 0.0167%, 1.00% and 0.29% from expected values. The linear response of the detector over the entire range of desired activity concentrations was confirmed after data correction for the detector dead time. Calibration of the detector combined with the dispenser system was carried out in parallel investigations to provide the required device properties for reference applications in nuclear medicine. Furthermore, Monte Carlo simulations using FLUKA code were performed to investigate the contribution of beta particles in addition to gamma radiations to assess the influence of beta particles on the calibration factors. For better accuracy, a shielding was designed to prevent any beta particles from reaching the detector.

Reactor neutrino physics potentials of cryogenic pure-CsI crystal

AbstractThis paper presents a world-leading scintillation light yield among inorganic crystals measured from a 0.5 kg pure-CsI detector operated at 77 Kelvin. Scintillation photons were detected by two 2-inch Hamamatsu SiPM arrays equipped with cryogenic front-end electronics. Benefiting the light yield enhancement of pure-CsI at low temperatures and the high photon detection efficiency of SiPM, a light yield of 30.1 photoelectrons per keV energy deposit was obtained for X-rays and $$\gamma $$ γ -rays with energies from 5.9 to 59.6 keV. Instrumental and physical effects in the light yield measurement are carefully analyzed. This is the first stable cryogenic operation of kg-scale pure-CsI crystal readout by SiPM arrays at liquid nitrogen temperatures for several days. The world-leading light yield opens a door for the usage of pure-CsI crystal in several fields, particularly in detecting the coherent elastic neutrino-nucleus scattering of reactor neutrinos. The potential of using pure-CsI crystals in neutrino physics is discussed in the paper.

Design and performance evaluation of a compact thermal and fast neutron spectrometer

Measurement of the space neutron radiation environment has put forward new requirements for the miniaturization and lightweight design of neutron spectrometers. In this paper, a compact broad-spectrum neutron spectrometer was designed, in which the fast neutron detector was based on the EJ-254 scintillator-coupled with SiPMs array, and the thermal and epithermal neutron detectors were based on the NaI(Tl + Li) (NaIL) scintillator coupled with SiPMs array encapsulated in Al and Cd shells, respectively. The overall weight of the neutron spectrometer was only 2.4 kg, and its dimensions were 154 mm × 123 mm × 115 mm. The fast neutron energy spectrum was obtained based on the capture-gated method and the Maximum Likelihood Expectation Maximization (MLEM) unfolding algorithm; the counts of thermal and epithermal neutrons were obtained based on the optimized frequency-domain Pulse Shape Discrimination (PSD) method and cadmium difference method. The proposed neutron spectrometer with all applied methods was tested as a whole system with a252Cf and a241Am–Be source. The spectrum result was compared to an ISO standard source. The accuracy of fast part of 0.5–10 MeV was 5.9% in definition of Relative Root Mean Squared Error (RRMSE). The thermal and epithermal neutron counts were far higher than standard spectrum, and we proved it being effected by laboratory introduced neutron scattering through a simulation, thus the thermal and epithermal flux measurements was believed to be decent. The Figure of Merit (FoM) of the NaIL's PSD neutron gamma discrimination were 2.57 and 2.90 respectively.

Performance Comparison of DOI-Encoding PET Detectors Based on 1.1-mm Pitch BGO Arrays With Different Reflectors.

Bismuth germanate (BGO)-based positron emission tomography (PET) detectors are potential candidates for low-dose imaging PET scanners, owing to the high stopping power and low background radiation of BGO. In this paper, we compared the performance of two dual-ended readout PET detectors based on 15 × 15 BGO arrays. Both arrays had the same 1.1 mm pitch but utilized different reflectors - barium sulfate (BaSO4) and enhanced specular reflector film (ESR) - for high-resolution PET applications. The detectors were constructed with Hamamatsu 13361-2050-08 SiPM arrays. Each BGO element had dimensions of 1.02 × 1.02 × 20 mm3. The lateral surfaces of the BGO elements were unpolished (saw-cut), while the two ends were polished. Flood histograms showed that the detector based on the BGO array with BaSO4 reflector had much better crystal identification and depth-of-interaction (DOI) resolution. Specifically, the energy, DOI, and timing resolutions for the detector using the BGO array with BaSO4 reflector were 19.8 ± 1.5%, 4.13 ± 0.48 mm, and 2.80 ± 0.23 ns, respectively. In contrast, the values obtained using the BGO array with ESR reflector were 20.9 ± 2.1%, 7.69 ± 1.92 mm, and 2.93 ± 0.20 ns, respectively.

Optimization of pulse shape discrimination based on frequency domain for SiPM-based NaIL scintillator detector

Frequency gradient analysis (FGA) neutron-gamma pulse shape discrimination (PSD) based on Fourier transform has proved to be an effective method for discrimination between two types of pulses by simply constructing a discrimination parameter by subtracting the amplitude of the 1st frequency component from the 0th frequency component. However, the discrimination parameter constructed by the above method could not meet the requirements at some lower sample rates, and the dark noise caused using optoelectronic devices such as miniaturized SiPMs array further erodes the difference between the two frequency components. This paper proposes a new discrimination parameter construction method based on FGA for neutron-gamma discrimination, which is referred as mFGA (modified FGA). This discrimination parameter uses the 0th frequency component and other frequency components to enhance the discrimination performance. A neutron detector module consisting of a 25.4 mm× 25.4 mm× 50.8 mm NaI:Tl,6Li (NaIL) scintillator and an array of 8 × 8 SiPMs was established to verify the method of mFGA. The module measured a 252Cf neutron source under three shielding conditions: no shield, 5 cm high-density polyethylene (HDPE), and 10 cm lead brick. The proposed mFGA method was used to calculate the figure of merit (FoM) under each shielding condition and compared to the traditional frequency gradient method (FGA) and the traditional charge comparison method (CCM). The results show that the discrimination performance with the mFGA method is significantly improved. Taking the HDPE shielding group as an example, the performances of the three methods are FoM-FGA =1.14, FoM-mFGA =2.75, FoM-CCM =0.92. At the same time, with the increase of energy, due to the neutron gamma pulse becoming similar, and the discrimination performance of FGA and CCM decrease significantly. The discrimination performance of the mFGA method is relatively stable in all energy regions. Therefore, the proposed method is superior to the traditional FGA of the 0th frequency minus the 1st frequency and has a good application prospect for neutron-gamma discrimination with detectors of poor signal quality.

The DarkSide-20k experiment

The DarkSide-20k experiment represents the present goal of the Global Argon Dark Matter Collaboration program. Bringing together the experience from previous argon-based detectors, as well as the knowledge gained on large volume membrane cryostats developed within the DUNE program, the community is now building a dual-phase LAr-TPC equipped with SiPM arrays for light readout. The main goal of the experiment is to discover or to extend the current sensitivity limits on the search for dark matter WIMP-like particles. Currently, the experiment has entered the construction phase and the external cryostat is being put in place at Laboratori Nazionali del Gran Sasso (LNGS), Italy. Detector construction will follow, and data taking is expected to start in late 2026. This contribution will introduce the DarkSide detector and goals, and it will report on the ongoing construction of the underground infrastructure at LNGS. Finally, it will concentrate on the current activities on large arrays of silicon light detectors, that are at the base of the construction of the detector light readout system.

The Performance of the New KETEK Low-Noise SiPM Array Series: Characterization in a Compton Camera Study

The Performance of the New KETEK Low-Noise SiPM Array Series: Characterization in a Compton Camera Study

X-Arapuca long term test

The photon detection system of the DUNE experiment is based on the X-ARAPUCA light trap. The basic elements of the X-ARAPUCA are the dichroic filters coated with wavelength shifter (para-Therphenyl), a waveshifting plate and an array of SiPMs which detects the trapped photons. A small scale prototype of the X-ARAPUCA has been installed in liquid argon in a dedicated facility at INFN-Napoli and exposed to alpha particles from a source. In order to test the stability of the overall device response the X-ARAPUCA was kept for 10 days in continuously purified liquid argon. The performed tests allowed for a preliminary estimation of the X-ARAPUCA absolute photon detection efficiency.

Comparative study of SiPM arrays performances for neutron detectors

Comparative study of SiPM arrays performances for neutron detectors

Improving the Time Resolution of Large-Area LaBr3:Ce Detectors with SiPM Array Readout

LaBr3:Ce crystals have good scintillation properties for X-ray spectroscopy. Initially, they were introduced for radiation imaging in medical physics with either a photomultiplier or SiPM readout, and they found extensive applications in homeland security and gamma-ray astronomy. We used 1″ round LaBr3:Ce crystals to realize compact detectors with the SiPM array readout. The aim was a good energy resolution and a fast time response to detect low-energy X-rays around 100 keV. A natural application was found inside the FAMU experiment, at RIKEN RAL. Its aim is a precise measurement of the proton Zemach radius with impinging muons, to contribute to the solution to the so-called “proton radius puzzle”. Signals to be detected are characteristic X-rays around 130 KeV. A limit for this type of detector, as compared to the ones with a photomultiplier readout, is its poorer timing characteristics due to the large capacity of the SiPM arrays used. In particular, long signal falltimes are a problem in experiments such as FAMU, where a “prompt” background component must be separated from a “delayed” one (after 600 ns) in the signal X-rays to be detected. Dedicated studies were pursued to improve the timing characteristics of the used detectors, starting from hybrid ganging of SiPM cells; then developing a suitable zero pole circuit with a parallel ganging, where an increased overvoltage for the SiPM array was used to compensate for the signal decrease; and finally designing ad hoc electronics to split the 1″ detector’s SiPM array into four quadrants, thus reducing the involved capacitances. The aim was to improve the detectors’ timing characteristics, especially falltime, while keeping a good FWHM energy resolution for low-energy X-ray detection.

A Compact Particle Detector for Space-Based Applications: Development of a Low-Energy Module (LEM) for the NUSES Space Mission

NUSES is a planned space mission aiming to test new observational and technological approaches related to the study of relatively low-energy cosmic rays, gamma rays, and high-energy astrophysical neutrinos. Two scientific payloads will be hosted onboard the NUSES space mission: Terzina and Zirè. Terzina will be an optical telescope readout by SiPM arrays, for the detection and study of Cerenkov light emitted by Extensive Air Showers generated by high-energy cosmic rays and neutrinos in the atmosphere. Zirè will focus on the detection of protons and electrons up to a few hundred MeV and to 0.1–10 MeV photons and will include the Low Energy Module (LEM). The LEM will be a particle spectrometer devoted to the observation of fluxes of relatively low-energy electrons in the 0.1–7-MeV range and protons in the 3–50 MeV range along the Low Earth Orbit (LEO) followed by the hosting platform. The detection of Particle Bursts (PBs) in this Physics channel of interest could give new insight into the understanding of complex phenomena such as eventual correlations between seismic events or volcanic activity with the collective motion of particles in the plasma populating van Allen belts. With its compact sizes and limited acceptance, the LEM will allow the exploration of hostile environments such as the South Atlantic Anomaly (SAA) and the inner Van Allen Belt, in which the anticipated electron fluxes are on the order of 106 to 107 electrons per square centimeter per steradian per second. Concerning the vast literature of space-based particle spectrometers, the innovative aspect of the LEM resides in its compactness, within 10 × 10 × 10 cm3, and in its “active collimation” approach dealing with the problem of multiple scattering at these very relatively low energies. In this work, the geometry of the detector, its detection concept, its operation modes, and the hardware adopted will be presented. Some preliminary results from the Monte Carlo simulation (Geant4) will be shown.

Front-End Electronics and Optimal Ganging Schemes for Single Photon Detection With Large Arrays of SiPMs in Liquid Argon

Front-End Electronics and Optimal Ganging Schemes for Single Photon Detection With Large Arrays of SiPMs in Liquid Argon

Characterization of Hamamatsu S13161-3050AE-08 SiPM (8 × 8) array at different temperatures with CAEN DT5202

Silicon PhotoMultipliers, SiPMs, constitute the enabling technology for a diverse and rapidly growing range of applications: medical imaging, experimental physics, and commercial applications are only a few examples. In this work, a characterization protocol for SiPM qualification has been applied to Hamamatsu S13161-3050AE-08 SiPM (8 × 8) array in the (−40 ÷ ＋30) °C temperature range. The protocol foresees to measure several parameters: breakdown voltage, quenching resistance, gain, dark count rate and probability of cross-talk. Methods to extract them and their dependence on temperature at fixed overvoltage are shown and the results are discussed.

Timing, Energy, and Spatial Characterization of Highly Sampled Monolithic PET Detectors with Different Thicknesses.

The HyPET project proposes a hybrid dedicated TOF-PET for prostate imaging, with pixelated detector blocks in the front layer and monolithic blocks in the back layer. In this work, four detector configurations have been experimentally evaluated for the rear detector layer. The detector configuration consists of LYSO monolithic blocks with the same size (25.4 mm × 25.4 mm) but different thicknesses (5, 7.5, 10, and 15 mm) coupled to the same SiPM array. Each detector configuration has been experimentally characterized in terms of time, energy and spatial resolution by scanning the crystal surface using a fan beam in steps of 0.25 mm. Regarding spatial resolution, the interaction position was estimated using a Neural Network technique. All resolutions except energy, which remains nearly constant at 17% for all cases, show better values for the 5 mm detector thickness. We have achieved spatial resolution values of FWHM of 1.02 ± 0.10, 1.19 ± 0.13, 1.53 ± 0.17, 2.33 ± 0.55 mm, for the 5, 7.5, 10, and 15 mm blocks, respectively. The detector time resolution obtained was 275 ± 26, 291 ± 21, 344 ± 48, and 433 ± 45 ps respectively, using the energy weighted average method for the time stamps.

Integration of thermo-electric coolers into the CMS MTD SiPM arrays for operation under high neutron fluence

Abstract The barrel section of the novel MIP Timing Detector (MTD) will be constructed as part of the upgrade of the CMS experiment to provide a time resolution for single charged tracks in the range of 30–60 ps using LYSO:Ce crystal arrays read out with Silicon Photomultipliers (SiPMs). A major challenge for the operation of such a detector is the extremely high radiation level, of about 2 × 1014 1 MeV(Si) Eqv. n/cm2, that will be integrated over a decade of operation of the High Luminosity Large Hadron Collider (HL-LHC). Silicon Photomultipliers exposed to this level of radiation have shown a strong increase in dark count rate and radiation damage effects that also impact their gain and photon detection efficiency. For this reason during operations the whole detector is cooled down to about -35°C. In this paper we illustrate an innovative and cost-effective solution to mitigate the impact of radiation damage on the timing performance of the detector, by integrating small thermo-electric coolers (TECs) on the back of the SiPM package. This additional feature, fully integrated as part of the SiPM array, enables a further decrease in operating temperature down to about -45°C. This leads to a reduction by a factor of about two in the dark count rate without requiring additional power budget, since the power required by the TEC is almost entirely offset by a decrease in the power required for the SiPM operation due to leakage current. In addition, the operation of the TECs with reversed polarity during technical stops of the accelerator can raise the temperature of the SiPMs up to 60°C (about 50°C higher than the rest of the detector), thus accelerating the annealing of radiation damage effects and partly recovering the SiPM performance.