After-pulsing and cross-talk in multi-pixel photon counters Du, Y.; Retière, F.
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2008, Letnik:
596, Številka:
3
Journal Article
Recenzirano
Multi-pixel photon counters (MPPC) are pixelated Geiger-mode photon manufactured by Hamamatsu photonics. They will be used for reading out all the scintillator elements within the near detector of ...the T2K experiment. Their performances photo-detection efficiency, dark noise and gain, and their insensitivity to magnetic field fulfill the ND280 requirements. On the other hand, two known issues, cross-talk and after-pulsing may adversely impact the detector response. In this paper, cross-talk and after-pulsing are precisely measured by recording waveforms and identifying all the avalanche pulses. At an over-voltage of 2
V, an avalanche generates on an average 0.5 additional avalanches due to after-pulsing, whereas it generates 0.13 at 1
V over-voltage. After-pulses follow two independent time constants of 15 and 82
ns. The cross-talk probability is a factor of 3 smaller than the after-puling probability. Simulating the MPPC response, we find that after-pulsing and cross-talk do not degrade the detector performance significantly within the expected operating conditions of the T2K near detector.
Photo-multiplier tubes (PMTs) and silicon photo-multipliers (SiPMs) are detectors sensitive to single photons that are widely used for the detection of scintillation and Cerenkov light in subatomic ...physics and medical imaging. This paper presents a method for characterizing two of the main noise sources that PMTs and SiPMs share: dark noise and correlated noise (after-pulsing). The proposed method allows for a model-independent measurement of the after-pulsing timing distribution and dark noise rate.
The calorimeter, range detector and active target elements of the T2K near detectors rely on the Hamamatsu Photonics Multi-Pixel Photon Counters (MPPCs) to detect scintillation light produced by ...charged particles. Detailed measurements of the MPPC gain, afterpulsing, crosstalk, dark noise, and photon detection efficiency for low light levels are reported. In order to account for the impact of the MPPC behavior on T2K physics observables, a simulation program has been developed based on these measurements. The simulation is used to predict the energy resolution of the detector.
Silicon Photo-Multipliers (SiPMs) have emerged as a compelling photo-sensor solution over the course of the last decade. In contrast to the widely used Photomultiplier Tubes (PMTs), SiPMs are ...low-voltage powered, optimal for operation at cryogenic temperatures, and have low radioactivity lev- els with high gain stability over the time in operational conditions. For these reasons, large-scale low-background cryogenic experiments, such as the next- generation Enriched Xenon Observatory experiment (nEXO), are migrating to a SiPM-based light detection system. In this paper we report on the charac- terization of the Hamamatsu VUV4 (S/N: S13370-6152) Vacuum Ultra-Violet (VUV) sensitive Multi-Pixel Photon Counters (MPPC)s as part of the develop- ment of a solution for the detection of liquid xenon scintillation light for the nEXO experiment.
A full-ring PET insert consisting of 16 PET detector modules was designed and constructed to fit within the 114 mm diameter gradient bore of a Bruker 7 T MRI. The individual detector modules contain ...two silicon photomultiplier (SiPM) arrays, dual-layer offset LYSO crystal arrays, and high-definition multimedia interface (HDMI) cables for both signal and power transmission. Several different RF shielding configurations were assessed prior to construction of a fully assembled PET insert using a combination of carbon fibre and copper foil for RF shielding. MR-compatibility measurements included field mapping of the static magnetic field (B
) and the time-varying excitation field (B
) as well as acquisitions with multiple pulse sequences: spin echo (SE), rapid imaging with refocused echoes (RARE), fast low angle shot (FLASH) gradient echo, and echo planar imaging (EPI). B
field maps revealed a small degradation in the mean homogeneity (+0.1 ppm) when the PET insert was installed and operating. No significant change was observed in the B
field maps or the image homogeneity of various MR images, with a 9% decrease in the signal-to-noise ratio (SNR) observed only in EPI images acquired with the PET insert installed and operating. PET detector flood histograms, photopeak amplitudes, and energy resolutions were unchanged in individual PET detector modules when acquired during MRI operation. There was a small baseline shift on the PET detector signals due to the switching amplifiers used to power MRI gradient pulses. This baseline shift was observable when measured with an oscilloscope and varied as a function of the gradient duty cycle, but had no noticeable effect on the performance of the PET detector modules. Compact front-end electronics and effective RF shielding led to minimal cross-interference between the PET and MRI systems. Both PET detector and MRI performance was excellent, whether operating as a standalone system or a hybrid PET/MRI.
A liquid Xenon detector for micro-PET Retière, F.
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2010, Letnik:
623, Številka:
1
Journal Article
Recenzirano
Liquid Xenon is a very promising technology for the new generation of Positron Emission Tomography detectors. The performance achieved by combining both scintillation light and ionization charge ...readout significantly exceeds the capabilities of conventional crystal based detectors. In these proceedings, we show that we achieved a 9.6% (full width half maximum) for 511keV photons by combining light and charge. Then, we investigate the performance of a liquid Xenon micro-PET detector by running simulations and relying on a Compton reconstruction algorithm. The image quality is far superior to the existing FOCUS 120 micro-PET.
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