Hamamatsu Photonics introduced a new generation of their Multi-Pixel Photon Counters in 2013 with significantly reduced after-pulsing rate. In this paper, we investigate the causes of after-pulsing by testing pre-2013 and post-2013 devices using laser light ranging from 405 to 820nm. Doing so we investigate the possibility that afterpulsing is also due to optical photons produced in the avalanche rather than to impurities trapping charged carriers produced in the avalanches and releasing them at a later time. For pre-2013 devices, we observe avalanches delayed by ns to several 100~ns at 637, 777nm and 820 nm demonstrating that holes created in the zero field region of the silicon bulk can diffuse back to the high field region triggering delayed avalanches. On the other hand post-2013 exhibit no delayed avalanches beyond 100~ns at 777nm. We also confirm that post-2013 devices exhibit about 25 times lower after-pulsing. Taken together, our measurements show that the absorption of photons from the avalanche in the bulk of the silicon and the subsequent hole diffusion back to the junction was a significant source of after-pulse for the pre-2013 devices. Hamamatsu appears to have fixed this problem in 2013 following the preliminary release of our results. We also show that even at short wavelength the timing distribution exhibit tails in the sub-nanosecond range that may impair the MPPC timing performances.
Development of Parallel Plate Avalanche Counter PPAC for BigRIPS fragment separator
我们已经开发出一种位置敏感的平行板雪崩计数器（PPAC），它已被用作BigRIPS碎片分离器和随后的RI束输送线在RIKEN Nishina中心RI束工厂的焦平面探测器。PPAC探测器不仅在分离器和传输线的调谐中起着重要的作用，而且在稀有同位素（RI）束的粒子识别中也起着重要的作用。PPAC探测器的灵敏面积为240 mm x 150 mm，位置信息通过延迟线读出方法获得。被称为双PPAC，它是由两个完整的PPAC，每个测量粒子轨迹的二维。通过使用双PPAC检测器的双重测量，使得高检测效率成为可能。灵敏度均匀性也被发现是优秀的。使用阿尔法源测得均方根位置分辨率为0.25 mm，而对于240 mm的探测器尺寸，位置线性度高达+/-0.1mm。介绍了PPAC探测器的特点、工作原理、规格、性能和问题，包括其使用光纤电缆的信号传输系统。
We describe a novel gaseous detector concept for heavy-ion tracking and imaging: the Optical Parallel-Plate Avalanche Counter (O-PPAC). The detector consists of two thin parallel-plate electrodes separated by a small (typically 3 mm) gap filled with low-pressure scintillating gas (i.e. CF4). The localization of the impinging particles is achieved by recording the secondary scintillation, created during the avalanche processes within the gas gap, with dedicated position-sensitive optical readouts. The latter may comprise arrays of collimated photo-sensors (e.g. SiPMs) that surround the PPAC eff…
Beta-delayed neutron emission plays a fundamental role in the explosive nucleosynthesis of elements heavier than iron by the rapid neutron capture (r-process). The most ambitious project related to beta-delayed neutron detection of very exotic nuclei is carried out by the BRIKEN collaboration at RIKEN Nishima Center. In this work, a brief description of the BRIKEN project is presented. A methodology for the precise characterization of the BRIKEN neutron counter efficiency, for fast neutrons, using an uncalibrated 252Cf neutron source is described. The method relies on the well-known neutron mu…
An integrated readout system for parallel-plate avalanche counter and multi-wire drift chamber at HIAF-HIRIBL
Institute of Modern Physics, Chinese Academy of Sciences（中国科学院近代物理研究所）；School of Nuclear Science and Technology, University of Chinese Academy of Sciences（中国科学院大学核科学与技术学院）
Recoil Proton Telescopes and Parallel Plate Avalanche Counters for the $^{235}$U(n,f) cross section measurement relative to H(n,n)H between 10 and 450 MeV neutron energy
Physics-Informed Self-Supervised Learning for Joint Wire Calibration and Interaction Position Reconstruction in Multi-Wire Parallel Plate Avalanche Counters
The information theoretic security promised by quantum key distribution (QKD) holds as long as the assumptions in the theoretical model match the parameters in the physical implementation. The superlinear behaviour of sensitive single-photon detectors represents one such mismatch and can pave the way to powerful attacks hindering the security of QKD systems, a prominent example being the after-gate attack. A longstanding tenet is that trapped carriers causing delayed detection can help mitigate this attack, but despite intensive scrutiny, it remains largely unproven. Here we approach this prob…
Many choices are available in order to evaluate large radioactive decay networks. %multi-particle decay data. There are many parameters that influence the calculated $β$-decay delayed single and multi-neutron emission branching fractions. We describe assumptions about the decay model, background, and other parameters and their influence on $β$-decay delayed multi-neutron emission analysis. An analysis technique, the ORNL BRIKEN analysis procedure, for determining $β$-delayed multi-neutron branching ratios in $β$-neutron precursors produced by means of heavy-ion fragmentation is presented. The …
