Search results for " photomultiplier"

Detector blockbased on arrays of 144 SiPMs and monolithic scintillators: A performane study

2015

[EN] We have developed a detector block composed by a monolithic LYSO scintillator coupled to a custom made 12 12 SiPMs array. The design is mainly focused to applications such as Positron Emission Tomography. The readout electronics is based on 3 identical and scalable Application Specific Integrated Circuits (ASIC). We have determined the main performance of the detector block namely spatial, energy, and time resolution but also the system capability to determine the photon depth of interaction, for different crystal surface treatments. Intrinsic detector spatial resolution values as good as 1.7 mm FWHM and energies of 15% for black painted crystals were measured. & 2014 Elsevier B.V. All…

Comparison of Silicon Photomultiplier Characteristics using Automated Test Setups

2016

Silicon Photomultipliers (SiPM) are photo-sensors consisting of an array of hundreds to thousands pixels with a typical pitch of 10-100 μm. They exhibit an excellent photon counting and time resolution. Therefore applications of SiPMs are emerging in many fields. In order to characterize SiPMs, the PRISMA Detector Lab at Mainz has established three automated test setups. Setup-A is dedicated to measure the gain, the dark count rate and the optical crosstalk probability. The temperature dependencies are characterized by operating the setup in a climate chamber. Setup-B is an optical system to measure the photon detection efficiency. Setup-C addresses the most challenging aspect of comparing …

Proof-of-principle measurements with a liquid-scintillator detector using wavelength-shifting optical modules

2018

Based on test-beam measurements, we study the response of a liquid-scintillator detector equipped with wavelength-shifting optical modules, that are proposed e.g. for the IceCube experiment and the SHiP experiment, and adiabatic light guides that are viewed either by a photomultiplier tube or by an array of silicon photomultipliers. We report on the efficiency, the time resolution and the detector response to different particle types and point out potential ways to improve the detector performance.

A tracking fiber detector based on silicon photomultipliers for the KAOS spectrometer

2011

A tracking detector based on two meters long scintillating fibers read out by silicon photomultipliers (SiPM) is being developed for the Kaos spectrometer at the Mainz Microtron MAMI. Results from a prototype setup using 2 mm square fibers and large area SiPM readout are presented. The detection efficiency of such a combination was measured to be between 83 and 100% depending on the threshold on the SiPM amplitude. A Monte Carlo simulation based on a physical model was employed in order to extract the photon detection efficiency of the SiPM devices.

SNR measurements of silicon photomultipliers in the continuous wave regime

2014

We report on our Signal-to-Noise Ratio (SNR) measurements carried out, in the continuous wave regime, at different frequencies and at various temperatures, on a novel class of silicon photomultipliers (SiPMs) fabricated in planar technology on silicon p-type substrate. SNR of SiPMs is given by the ratio of the photogenerated current, filtered and averaged by a lock-in amplifier, and the Root Mean Square (RMS) deviation of the same current. In our measurements, we have employed a 10 Hz equivalent noise bandwidth, around the lock-in amplifier reference frequency. The measured noise takes into account the shot noise, resulting from the photocurrent and the dark current, while background light …

First Compton imaging tests with i-TED

2019

The objective of this work is to demonstrate the Compton imaging capabilities of a novel gamma-ray Total-Energy Detector called i-TED. The latter is intended for neutron-capture cross-sections measurements of astrophysical interest, thereby enhancing detection sensitivity by means of the simultaneous combination of Time-of-Flight with Compton-imaging techniques. The developed i-TED demonstrator comprises five position-sensitive radiation detection modules of high energy resolution, which feature an overall position-sensitive field-of-view of 125 cm2, and thus a high efficiency. Each detector module is based on 50x50 mm2 large LaCl 3 (Ce) monolithic crystals optically coupled to 8x8 pixels s…

Silicon photomultiplier properties at cryogenic temperatures

2015

Abstract The properties of different types of silicon photomultipliers (SiPMs) were studied at cryogenic temperatures. In liquid nitrogen at 77 K, problems with quenching in Hamamatsu SiPMs and with the protective epoxy layer, covering Zecotek SiPMs, were observed. Tests with one Zecotek SiPM were successful after removal of the epoxy layer. In liquid helium at 4 K, fast signals with pulse lengths shorter than 50 ns were observed, the dark count rate was below 10 Hz and no after-pulses were detected. The gain, as a function of over-voltage, was comparable to room temperature. The SiPM׳s response to photons was found to be linear with intensity for low light levels and single-photon detectio…

Next generation of the Albira small animal PET based on high density SiPM arrays

2015

A new design of the small animal PET Albira system which detectors are based on arrays of SiPMs and monolithic LYSO scintillator is presented here. The system is made out of 3 rings of 8 detectors each, resulting on an axial and transaxial FOVs of 148 and 80 mm, respectively. The scanner is thermally stabilized using air-cooling. Working temperatures around 22–25°C are reached with individual detector variations around 0.2°C minimizing dark count rates and gain drifts. One of the most significant improvements of the current system is the accurate photon impact determination within the crystal volume, specially its depth of interaction. This allows the calculation of the true line of respons…

Position sensitive photosensors based on SiPM arrays

2014

High-resolution multichannel Time-to-Digital Converter core implemented in FPGA for ToF measurements in SiPM-PET

2013

In this contribution, Coincidence Resolving Time (CRT) results with the developed multichannel FPGA-TDC are showed as a function of different configurations for both, the sensor bias voltage and the digitizer threshold. The dependence of the CRT with the sensor matrix temperature, the amount of SiPM active area and the crystal type are also analyzed. Preliminary measurements carried out with a crystal array of 2 mm pixel size and 10 mm height have shown time resolutions for the entire 144 SiPM two-detectors ensemble as good as 800 ps.