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تسجيل مستخدم جديدLarge-Area MPPC with Enhanced VUV Sensitivity for Liquid Xenon Scintillation Detector
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A large-area Multi-Pixel Photon Counter (MPPC) sensitive to vacuum ultra violet (VUV) light has been developed for the liquid xenon (LXe) scintillation detector of the MEG II experiment. The LXe detector is designed to detect the 52.8,MeV photon from the lepton flavour violating decay $mu^+ to mathrm{e}^+ gamma$ and is based on $900,ell$ LXe with a highly granular scintillation readout by 4092 VUV-MPPCs with an active area of $139,mathrm{mm}^2$ each, totalling $0.57,mathrm{m}^2$. The VUV-MPPC shows an excellent performance in LXe, which includes a high photon detection efficiency (PDE) up to 21% for the LXe scintillation light in the VUV range, a high gain, a low probability of the optical cross-talk and the after-pulsing, a low dark count rate and a good single photoelectron resolution. The large active area of the VUV-MPPC is formed by connecting four independent small VUV-MPPC chips in series to avoid the increase of the sensor capacitance and thus, to have a short pulse-decay-time, which is crucial for high rate experiments. Performance tests of 4180 VUV-MPPCs produced for the LXe detector were also carried out at room temperature prior to the installation to the detector and all of them with only a few exceptions were found to work properly. The design and performance of the VUV-MPPC are described in detail as well as the results from the performance tests at room temperature.
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A new type of the Multi-Pixel Photon Counter (MPPC), sensitive to Vacuum Ultra-Violet (VUV) light (wavelength {lambda} < 150 nm), is recently developed and produced by Hamamatsu Photonics K.K. The basic properties of the new MPPC are measured at cryo
genic facility of Waseda university using liquid nitrogen. Temperature dependence of breakdown voltage, capacitance, and dark count rate of the MPPC are also evaluated. In addition, the absolute photon detection efficiency (PDE) for liquid argon (LAr) scintillation light ({lambda} = 128 nm) is estimated to be about 7% with uncertainty of 2% by using 241 Am {alpha}-ray source. Based on these basic measurements a possible application of the new MPPC to LAr detector for dark matter search is discussed.
Scintillation light is used in liquid argon (LAr) neutrino detectors to provide a trigger signal, veto information against cosmic rays, and absolute event timing. In this work, we discuss additional opportunities offered by detectors with enhanced se
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An 800L liquid xenon scintillation $gamma$ ray detector is being developed for the MEG experiment which will search for $mu^+tomathrm{e}^+gamma$ decay at the Paul Scherrer Institut. Absorption of scintillation light of xenon by impurities might possi
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Scintillation from noble gases is an important technique in particle physics including neutrino beam experiments, neutrino-less double beta-decay and dark matter searches. In liquid argon, the possibility of enhancing the light yield by the addition
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