Silicon Photomultiplier Sensors Research Articles

A study for gamma attenuation behavior of polyimide (PI) film by MPPC

Although lead is a very good radiation shielding material, its toxicity has led researchers to find alternative materials instead of it. Moreover, as the use of Kapton polyimide (PI) film in nuclear power plants and space exploration increases, the need to reveal the radiation degradation properties of this material has come along. In this regard, in the present study, it is aimed to determine the mass and linear attenuation coefficients, half value layer, tenth value layer, mean free path and radiation protection efficiency attenuation parameters for this material, experimentally and theoretically, by using the gammas of the 133Ba radioisotope. Experimental gamma attenuation measurements were made by a spectrometer using a Hamamatsu multi pixel photon counter device with a silicon photomultiplier sensor. The constant fraction discrimination timing method was used to reduce the electronic noise of the spectrometer. The attenuation parameters determined experimentally by following two ways were compared with the theoretical ones obtained from the XCOM program.

Mini-EUSO on Board the International Space Station: Mission Status and Results

The telescope Mini-EUSO has been observing, since 2019, the Earth in the ultraviolet band (290–430 nm) through a nadir-facing UV-transparent window in the Russian Zvezda module of the International Space Station. The instrument has a square field of view of 44°, a spatial resolution on the Earth surface of 6.3 km and a temporal sampling rate of 2.5 microseconds. The optics is composed of two 25 cm diameter Fresnel lenses and a focal surface consisting of 36 multi-anode photomultiplier tubes, 64 pixels each, for a total of 2304 channels. In addition to the main camera, Mini-EUSO also contains two cameras in the near infrared and visible ranges, a series of silicon photomultiplier sensors and UV sensors to manage night-day transitions. Its triggering and on-board processing allow the telescope to detect UV emissions of cosmic, atmospheric and terrestrial origin on different time scales, from a few microseconds up to tens of milliseconds. This makes it possible to investigate a wide variety of events: the study of atmospheric phenomena (lightning, transient luminous events (TLEs) such as ELVES and sprites), meteors and meteoroids; the search for nuclearites and strange quark matter; and the observation of artificial satellites and space debris. Mini-EUSO is also potentially capable of observing extensive air showers generated by ultra-high-energy cosmic rays with an energy above 1021 eV and can detect artificial flashing events and showers generated with lasers from the ground. The instrument was integrated and qualified in 2019 in Rome, with additional tests in Moscow and final, pre-launch tests in Baikonur. Operations involve periodic installation in the Zvezda module of the station with observations during the crew night time, with periodic downlink of data samples, and the full dataset being sent to the ground via pouches containing the data disks. In this work, the mission status and the main scientific results obtained so far are presented, in light of future observations with similar instruments.

Optical photon transport simulations for SiPM based PET scanner

Positrons emitted from radioisotope quickly annihilates to two collinear photons that are captured by the array of scintillator detectors to infer about the origin of radioactivity. Coincidence collection of pair of points from the detector modules makes a line of response, their large number reveals a radioactive region of interest. Most of the medical diagnostic research is conducted with position sensitive imaging device whose performance strongly depends on the optical light collection efficiency. A versatile Lutetium–Yttrium Oxyorthosilicate (LYSO) scintillator is used to mimic the optical photon production and transport processes followed by the light collection with Silicon PhotoMultiplier sensor. Charge spectrum from a 2 × 2 × 10 mm3 single LYSO bar is obtained in GEANT4, and reproduces well the scintillation characteristics of LYSO along with photons incidence angle distribution with a single SiPM pad. This excercise is followed by the simulation performance of two PET modules comprises of 12 × 12 SiPM tile coupled with mesh of LYSO bars. The preliminarly results shows the transverse position resolution (FWHM) as 7.82 mm for a point source. Objective of this study is to search for a cheaper detector solution which will have equivalent imaging performance.

Measurements of the Cherenkov effect in direct detection of charged particles with SiPMs

In this paper, different Silicon PhotoMultiplier (SiPM) sensors have been tested with charged particles to characterize the Cherenkov light produced in the sensor protection layer. A careful position scan of the SiPM response has been performed with different prototypes, confirming the large number of firing cells and proving almost full efficiency, with the SiPM filling factor essentially negligible. This study also allowed us to study the time resolution of such devices as a function of the number of firing cells, reaching values below 20 ps. These measurements provide significant insight into the capabilities of SiPM sensors in direct detection of charged particles and their potential for several applications.

Study of radiation effects on SiPM for an optical readout system for the EIC dual-radiator RICH

Silicon photomultipliers (SiPM) are the potential candidate photodetector technology selected for the dual-radiator Ring-Imaging Cherenkov (dRICH) detector of the future Electron-Ion Collider (EIC). SiPM are inexpensive devices, with high detection efficiency and insensitive to the high magnetic field experienced at the expected location of the sensors in the experiment. On the other hand, SiPM are susceptible to radiation damage. The integrated radiation level at the location of the sensors in the experiment is expected to be moderate, nonetheless it should be tested whether the capabilities for single photon-counting can be maintained to ensure the optimal dRICH detector performance across the years keeping the dark count rates under control as well. In this paper, the current status of the research studies performed for the EIC dRICH application and the first results on a sample of commercial and prototype SiPM sensors are presented.

A SiPM-based optical readout system for the EIC dual-radiator RICH

Silicon photomultipliers (SiPM) are candidates selected as the potential photodetector technology for the dual-radiator Ring-Imaging Cherenkov (dRICH) detector at the future Electron-Ion Collider (EIC). SiPM are cheap devices, highly efficient and insensitive to the high magnetic field at the expected location of the sensors in the experiment. On the other hand, SiPM are not radiation tolerant. Despite the integrated radiation level is expected to be moderate it should be tested whether single photon-counting capabilities and the increase in dark count rate can be kept under control to maintain the optimal dRICH detector performance across the years. The current status of the research for the EIC dRICH application and the first results on studies performed on a sample of commercial and prototype SiPM sensors are presented.

Extensive air shower tracker using Cherenkov detection

Cosmic rays continuously bombard Earth’s atmosphere triggering cascades of secondary particles. Many constituents progress to reach the surface and capturing these events can intrigue and awe young curious minds, opening them to the amazing world of physics. Cloud chambers are an established method of revealing the subatomic world; frequently used by universities to introduce cosmic rays to visitors and prospective students, they provide a fascinating real-time display of the ‘ghostly’ particles showering upon those viewing.Using the Cherenkov radiation detection technique, we have developed a novel, compact, Extensive Air Shower (EAS) particle tracking method that enhances the cloud chamber visualisation of cosmic ray interactions towards a digital audience. Once digital, live event interaction can be streamed to multiple display devices presenting an immediate illustration of the event that showered in that location.Our instrument hardware is built around Cherenkov-optimised silicon photomultiplier sensors. Each single detection unit monitors particle event rate and tracks incident angle by measuring Cherenkov intensity. By operating multiple detection units in one location, we can record time correlated air shower events to monitor and collate information on the primary cosmic rays.We introduce first results, illustrating instrument response and EAS rate variations, compiled from the initial running period of our development instruments. We present intensity spectra, compare with simulation, and describe the instrument response due to sensor location, Cherenkov intensity, mean muon energy and detector acceptance angle.With further development towards low-cost readout electronics, we aim to build a networked array of trackers, located around the campus, to expand data gathering ability and scientific potential.

Data Compression in the NEXT-100 Data Acquisition System.

NEXT collaboration detectors are based on energy measured by an array of photomultipliers (PMT) and topological event filtering based on an array of silicon photomultipliers (SiPMs). The readout of the PMT sensors for low-frequency noise effects and detector safety issues requires a grounded cathode connection that makes the readout AC-couple with variations in the signal baseline. Strict detector requirements of energy resolution better than 1% FWHM require a precise baseline reconstruction that is performed offline for data analysis and detector performance characterization. Baseline variations make it inefficient to apply traditional lossy data compression techniques, such as zero-suppression, that help to minimize data throughput and, therefore, the dead time of the system. However, for the readout of the SiPM sensors with less demanding requirements in terms of accuracy, a traditional zero-suppression is currently applied with a configuration that allows for a compression ratio of around 71%. The third stage in the NEXT detectors program, the NEXT-100 detector, is a 100 kg detector that instruments approximately five times more PMT sensors and twice the number of SiPM sensors than its predecessor, the NEXT-White detector, putting more pressure in the DAQ throughput, expected to be over 900 MB/s with the current configuration, which will worsen the dead time of the acquisition data system. This paper describes the data compression techniques applied to the sensor data in the NEXT-100 detector, which reduces data throughput and minimizes dead time while maintaining the event rate to the level of its predecessor, around 50 Hz.

Characterization of a Mass-Produced SiPM at Liquid Nitrogen Temperature for CsI Neutrino Coherent Detectors.

Silicon Photomultiplier (SiPM) is a sensor that can detect low-light signals lower than the single-photon level. In order to study the properties of neutrinos at a low detection threshold and low radioactivity experimental background, a low-temperature CsI neutrino coherent scattering detector is designed to be read by the SiPM sensor. Less thermal noise of SiPM and more light yield of CsI crystals can be obtained at the working temperature of liquid nitrogen. The breakdown voltage (Vbd) and dark count rate (DCR) of SiPM at liquid nitrogen temperature are two key parameters for coherent scattering detection. In this paper, a low-temperature test is conducted on the mass-produced ON Semiconductor J-Series SiPM. We design a cryogenic system for cooling SiPM at liquid nitrogen temperature and the changes of operating voltage and dark noise from room to liquid nitrogen temperature are measured in detail. The results show that SiPM works at the liquid nitrogen temperature, and the dark count rate drops by six orders of magnitude from room temperature (120 kHz/mm2) to liquid nitrogen temperature (0.1 Hz/mm2).

Design, upgrade and characterization of the silicon photomultiplier front-end for the AMIGA detector at the Pierre Auger Observatory

AMIGA (Auger Muons and Infill for the Ground Array) is an upgrade of the Pierre Auger Observatory to complement the study of ultra-high-energy cosmic rays (UHECR) by measuring the muon content of extensive air showers (EAS). It consists of an array of 61 water Cherenkov detectors on a denser spacing in combination with underground scintillation detectors used for muon density measurement. Each detector is composed of three scintillation modules, with 10 m2 detection area per module, buried at 2.3 m depth, resulting in a total detection area of 30 m2. Silicon photomultiplier sensors (SiPM) measure the amount of scintillation light generated by charged particles traversing the modules. In this paper, the design of the front-end electronics to process the signals of those SiPMs and test results from the laboratory and from the Pierre Auger Observatory are described. Compared to our previous prototype, the new electronics shows a higher performance, higher efficiency and lower power consumption, and it has a new acquisition system with increased dynamic range that allows measurements closer to the shower core. The new acquisition system is based on the measurement of the total charge signal that the muonic component of the cosmic ray shower generates in the detector.

Diseño, mejora y caracterización del front-end con fotomultiplicadores de silicio para los detectores de AMIGA del Observatorio Pierre Auger

AMIGA (Auger Muons and Infill for the Ground Array) es una mejora del Observatorio Pierre Auger con el objetivo de complementar el estudio de los rayos cósmicos de ultra alta energía (UHECR) mediante la medición del contenido muónico de las cascadas atmosféricas extensas (EAS). Éste consiste en un arreglo de 61 detectores de agua de efecto Cherenkov ubicado en un espacio más denso en combinación con detectores de centelleo enterrados bajo tierra utilizados para la medición de densidad de muones. Cada detector esta compuesto por tres módulos centelladores, con un área de detección de 10 m2 por módulo, enterrados a 2.3 m de profundidad, resultando un área total de detección de 30 m2. Fotomultiplicadores de silicio (SiPM) miden la cantidad de luz de centelleo generada por las partículas cargadas que atraviesan los módulos. En este trabajo, el diseño de la electrónica del front-end para procesar las señales de esos SiPMs, y los resultados de pruebas realizadas en el laboratorio como también en el sitio del Observatorio Pierre Auger son descriptos. Comparado con el diseño anterior, esta nueva electrónica muestra un mayor rendimiento, una mayor eficiencia y un menor consumo de potencia, e incluye además, un nuevo sistema de adquisición con un rango dinámico ampliado que permite realizar mediciones cercanas al núcleo de la lluvia. El nuevo sistema de adquisición esta basado en la medición de la carga total que la componente muónica de la lluvia cósmica genera en el detector.

Retrofitting an environmental monitor with a silicon photomultiplier sensor

We report on the retrofitting of a standard DP2 environmental radiation monitor replacing the photomultiplier tube with a silicon photomultiplier (SiPM). The use of a SiPM has several advantages for a hand-held radiation monitor, including convenient low-voltage operation and physical robustness. We report the detection efficiency and alpha/beta discrimination performance of the modified probe compared with an unmodified version.

Design and Assessment of External Insulation for Critical Components in a Medium Voltage SiC-Based Converter via Optical Method

Exposed metal or insulator to air interfaces widely exists in medium voltage SiC-based converters. To effectively address external insulation along such interfaces, a large insulation distance in the air is applied. However, such insulation tends to significantly impair converter power densities and performances. Targeting the external discharge free design approaches that reflect the relationship between insulation structures and square wave excitation parameters is highly demanded. Moreover, due to possible fabrication issues and insulation degradation, massive external discharges may still occur, even that they should be eliminated by the design. Therefore, insulation assessment for the entire system, or at least for critical components, is necessary. In this article, silicon photomultiplier (SiPM)-based external discharge detection solutions are introduced. Then, for a self-designed SiC-based medium voltage converter, the SiPM sensors enable both its external insulation design and assessment. By using SiPM sensors, two types of external discharges are characterized under square wave excitation, and thus, general design suggestions are developed. Moreover, as shown by two examples, SiPM sensors can be used to assess the external insulation for converter applications. Based on the experimental data, analysis, and real examples, the results of this study can be used to design and assess the external insulation for future medium voltage, high-power density SiC-based converters.

Precision timing with LYSO:Ce crystals and SiPM sensors in the CMS MTD barrel timing layer

The Compact Muon Solenoid (CMS) detector at the CERN Large Hadron Collider (LHC) is undergoing an extensive Phase II upgrade program to prepare for the challenging conditions of the High-Luminosity LHC (HL-LHC). In particular, a new timing detector will measure minimum ionizing particles (MIPs) with a time resolution of ∼30-40 ps and hermetic coverage up to a pseudo-rapidity of |η|=3. The precision time information from this MIP Timing Detector (MTD) will reduce the effects of the high levels of pileup expected at the HL-LHC and will bring new and unique capabilities to the CMS detector. The central Barrel Timing Layer (BTL) will be based on LYSO:Ce crystals read out with silicon photomultipliers (SiPMs). The BTL will use elongated crystal bars, with double-sided read-out, with a SiPM on each end of the crystal, in order to maximize detector performance within the constraints of space, cost, and channel count. This unusual geometry enables the instrumentation of large surfaces while minimizing the active area of the photodetectors, and thus noise and power consumption. We will present an overview of the MTD BTL design and will detail the extensive R&D studies carried out to optimize the MTD BTL crystal-based technology and test beam results in which the goal of 30 ps timing resolution has been achieved.

Use of the Peak-Detector mode for gain calibration of SiPM sensors with ASIC CITIROC read-out

The ASIC CITIROC is a 32-channel fully analogue front-end ASIC dedicated to the read-out of silicon photo-multiplier (SiPM) sensors that can be used in a variety of experiments with different applications: nuclear physics, medical imaging, astrophysics, etc. For each channel, two parallel AC coupled voltage preamplifiers, one for the high gain and one for the low gain, ensure the read-out of the charge from 160 fC to 320 pC (i.e. from 1 to 2000 photo-electrons with SiPM gain = 106, with a photo-electron to noise ratio of 10). The signal in each of the two preamplifier chains is shaped and the maximum value is captured by activating the peak detector for an adjustable time interval. In this work, we illustrate the peak detector operation mode and, in particular, how this can be used to calibrate the SiPM gain without the need of external light sources. To demonstrate the validity of the method, we also present and discuss some laboratory measurements.

Monitoring of Microfluidics Systems for PET Radiopharmaceutical Synthesis Using Integrated Silicon Photomultipliers

Silicon photomultipliers (SiPM) can be used to sense the position and movement of the radioactive reagents involved in the synthesis of radiopharmaceuticals, while providing information on the evolution through the different steps of this synthesis. An SiPM array can be placed next to a lab-on-chip substrate made of PDMS and is able to detect particles emitted by <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">18</sup> F, the radioisotope used in fluorine-based positron-emission tomography (PET) imaging. In this paper, an array of 16 SiPM sensors is used to monitor the synthesis of [ <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">18</sup> F]-based radiopharmaceuticals. Results prove that it is possible to measure the position of the radioactive sample with adequate spatial and temporal resolution.

The ASTRI Camera control software of the ASTRI SST-2M prototype for the Cherenkov Telescope Array

Within the framework of the Cherenkov Telescope Array (CTA) observatory, the Italian National Institute for Astrophysics (INAF) is leading the “Astrofisica con Specchi a Tecnologia Replicante Italiana” (ASTRI) Project mainly devoted to the definition and development of a set of small-size class telescopes with dual-mirror optical design (SST-2M) for the CTA southern site. The prototype of such telescopes, named ASTRI SST-2M, is installed in Italy at the INAF “M.C. Fracastoro” observing station located in Serra La Nave, Mount Etna, Sicily. In addition to the dual-mirror optical design based on the Schwarzschild-Couder configuration, the ASTRI SST-2M telescope adopts a focal plane camera formed by an array of monolithic silicon photomultiplier sensors coupled with a specifically designed front-end electronics and back-end electronics that represent a further innovative solution for the detection of atmospheric Cherenkov light. The ASTRI SST-2M prototype is currently under completion of the overall commissioning phase: structure, mirrors, camera, control software, data archiving and analysis pipeline. This contribution focuses the attention on the software devoted to the control and monitoring operations of the ASTRI camera. We will provide a brief description of the electronic assemblies and of the software architecture designed, according to software engineering modularization, in terms of functional blocks and how they are deployed in the back-end electronics. Then, we will show how all these functionalities are accessible by the user through the graphical user interface developed and currently used for the engineering tests performed on site.

Electronic Interface for Lidar System and Smart Cities Applications

This work deals with the design of a new readoutelectronics for silicon photomultipliers sensors. The so-calledSiPMs sensors are an emerging technology currentlydiffusing in many applications and, among them, in thedefinition of a new generation of LIDAR systems. Thelatter, nowadays have a primary role in the evolutionprocess that is involving Smart Cities, being an enablingtechnology in different fields. The solution here proposed isrealized at electronic level with a 150 nm technology processfrom LFoundry and results provide a feasibledemonstration of the capability of the proposed designapproach to be employed in practical application.

Study of the light response of an arch-shaped scintillator with direct coupling to a Silicon Photomultiplier readout

We report about a study of the light response of a solid polystyrene-based scintillator with an arch shaped geometry, directly coupled to Silicon Photo Multiplier sensors for the light readout. This geometry is relevant for the design of a novel borehole detector for “muography” applications in Civil Engineering, Geology or Archaeology. The scintillator response has been investigated using a dedicated experimental set-up based on the detection of cosmic ray muons. Configurations that use reflecting and diffusive materials have been tested, as well as configurations with a cover specifically designed to enclose and protect the scintillator. The results found a good compromise between the light response and an easy solution for the detector assembly.

A Sensor Network Architecture for Digital SiPM-Based PET Systems

Digital silicon photo-multipliers (SiPMs) have emerged in the recent past as a viable low cost alternative to photomultiplier tubes in positron emission tomography systems, providing multiple timestamps, energy and scintillation coordinates at high spatial granularity as well as MRI compatibility. The rich but large datasets generated by digital SiPM sensors have posed a data preprocessing and acquisition challenge, at the sensor, module and system level when a multitude of such sensors are to be used. In this paper, we present a sensor network-based approach for data acquisition, scalable to multiring configurations, whereby each module acts as an autonomous sensing and computing unit, capable of determining in real time basic information for each scintillation event and communicating it to its peers. The proposed architecture is equally applicable to modules based on analog SiPMs with local digitization. Coincidence detection can then take place in the ring itself, in a deferred and distributed manner to ensure scalability and allow to fully process only the fraction of the total events which corresponds to true coincidences. Simulations and experimental results show that it is indeed possible to handle the system level challenges associated with digital SiPMs at data rates compatible with realistic configurations, including event packet transfers and real-time coincidence detection, using Gb/s serial communication links for internode communication. The downside of the proposed architecture is represented by the need, at module level, for additional connectivity and processing power. We also address possible solutions for network-based clock synchronization, in particular a hybrid scheme, combining a hard-wired ring clock distribution network with a network-based clock offset estimator. The latter was tested in an 8-node system, performing synchronization in real time with a worst-case phase estimator stability (standard deviation of the clock phase offset estimation between two nodes) of about 160 ps, and substantial room for improvement (at least $5\boldsymbol \times $ according to simulations).