No Arabic abstract
PIXELATED geiger-mode avalanche photodiodes(PPDs), often called silicon photomultipliers (SiPMs) are emerging as an excellent replacement for traditional photomultiplier tubes (PMTs) in a variety of detectors, especially those for subatomic physics experiments, which requires extensive test and operation procedures in order to achieve uniform responses from all the devices. In this paper, we show for two PPD brands, Hamamatsu MPPC and SensL SPM, that the dark noise rate, breakdown voltage and rate of correlated avalanches can be inferred from the sole measure of dark current as a function of operating voltage, hence greatly simplifying the characterization procedure. We introduce a custom electronics system that allows measurement for many devices concurrently, hence allowing rapid testing and monitoring of many devices at low cost. Finally, we show that the dark current of Hamamastu Multi-Pixel Photon Counter (MPPC) is rather independent of temperature at constant operating voltage, hence the current measure cannot be used to probe temperature variations. On the other hand, the MPPC current can be used to monitor light source conditions in DC mode without requiring strong temperature stability, as long as the integrated source brightness is comparable to the dark noise rate.
This paper presents the physical concept and test results of sample data of the high-speed hardware true random number generator design based on typically used for High Energy Physics hardware. Main features of this concept are the high speed of the true random numbers generation (tens of Mbt/s), miniature size and estimated lower production cost. This allows the use of such a device not only in large companies and government offices but for the end-user data cryptography, in classrooms, in scientific Monte-Carlo simulations, computer games and any other place where large number of true random numbers is required. The physics of the operations principle of using a Geiger-mode avalanche photo detector is discussed and the high quality of the data collected is demonstrated.
Silicon-based photosensors (SiPMs) working in the Geiger-mode represent an elegant solution for the readout of particle detectors working at low-light levels like Cherenkov detectors. Especially the insensitivity to magnetic fields makes this kind of sensors suitable for modern detector systems in subatomic physics which are usually employing magnets for momentum resolution. In our institute we are characterizing SiPMs of different manufacturers for selecting sensors and finding optimum operating conditions for given applications. Recently we designed and built a light concentrator prototype with 8x8 cells to increase the active photon detection area of an 8x8 SiPM (Hamamatsu MPPC S10931-100P) array. Monte Carlo studies, measurements of the collection efficiency, and tests with the MPPC were carried out. The status of these developments are presented.
A successfull application of Geiger-mode multipixel avalanche diodes (GMAPDs) for pulse-shape discrimination in alpha-beta spectrometry using organic liquid scintillator is described in this paper. Efficient discrimination of alpha and beta components in the emission of radioactive isotopes is achieved for alpha energies above 0.3 MeV. The ultra-compact design of the scintillating detector helps to efficiently suppress cosmic-ray and ambient radiation background. This approach allows construction of hand-held robust devices for monitoring of radioactive contamination in various environmental conditions.
The results of a development of a scintillator counter with wavelength shifting (WLS) fibre and a multi-pixel Geiger-mode avalanche photodiode readout are presented. The photodiode has a metal-resistor-semiconductor layered structure and operates in the limited Geiger mode. The scintillator counter has been developed for the EMMA underground cosmic ray experiment.
Silicon Photo-Multipliers (SiPMs) are detectors sensitive to single photons that are used to detect scintillation and Cherenkov light in a variety of physics and medical-imaging applications. SiPMs measure single photons by amplifying the photo-generated carriers (electrons or holes) via a Geiger-mode avalanche. The Photon Detection Efficiency (PDE) is the combined probability that a photon is absorbed in the active volume of the device with a subsequently triggered avalanche. Absorption and avalanche triggering probabilities are correlated since the latter probability depends on where the photon is absorbed. In this paper, we introduce a physics motivated parameterization of the avalanche triggering probability that describes the PDE of a SiPM as a function of its reverse bias voltage, at different wavelengths. This parameterization is based on the fact that in p-on-n SiPMs the induced avalanches are electron-driven in the ultra-violet and near-ultra-violet ranges, while they become increasingly hole-driven towards the near-infra-red range. The model has been successfully applied to characterize two Hamamatsu MPPCs and one FBK SiPM, and it can be extended to other SiPMs. Furthermore, this model provides key insight on the electric field structure within SiPMs, which can explain the limitation of existing devices and be used to optimize the performance of future SiPMs.