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Evaluation of the optical cross talk level in the SiPMs adopted in ASTRI SST-2M Cherenkov Camera using EASIROC front-end electronics
摘要： ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana), is a flagship project of the Italian Ministry of Education, University and Research whose main goal is the design and construction of an end-to-end prototype of the Small Size of Telescopes of the Cherenkov Telescope Array. The prototype, named ASTRI SST-2M, will adopt a wide field dual mirror optical system in a Schwarzschild-Couder configuration to explore the VHE range of the electromagnetic spectrum. The camera at the focal plane is based on Silicon Photo-Multipliers detectors which is an innovative solution for the detection astronomical Cherenkov light. This contribution reports some preliminary results on the evaluation of the optical cross talk level among the SiPM pixels foreseen for the ASTRI SST-2M camera.
关键词： Front-end electronics for detector readout,Gamma detectors,Cherenkov detectors,Gamma telescopes
更新于2025-09-23 15:23:52
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Characterization and performance of PADME’s Cherenkov-based small-angle calorimeter
摘要： The PADME experiment, at the Laboratori Nazionali di Frascati (LNF), in Italy, will search for invisible decays of the hypothetical dark photon via the process e+e? → γA′, where the A′ escapes detection. The dark photon mass range sensitivity in a first phase will be 1 to 24 MeV. We report here on performance measurements and simulation studies of a prototype of the Small-Angle Calorimeter, a component of PADME’s detector dedicated to rejecting 2- and 3-gamma backgrounds. The crucial requirement is a timing resolution of less than 200 ps, which is satisfied by the choice of PbF2 crystals and the newly released Hamamatsu R13478UV photomultiplier tubes (PMTs). We find a timing resolution of 81 ps (with double-peak separation resolution of 1.8 ns) and a single-crystal energy resolution of 10% at 550 MeV with light yield of 2.05 photo-electrons per MeV, using 100 to 400 MeV electrons at the Beam Test Facility of LNF. We also propose the investigation of a two-PMT solution coupled to a single PbF2 crystal for higher-energy applications, which has potentially attractive features.
关键词： Ultra fast calorimeter,Dark matter,PbF2 crystals,Cherenkov detectors,Dark photon
更新于2025-09-23 15:22:29
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First experience with Belle II Aerogel RICH detector
摘要： The Aerogel Ring-Imaging Cherenkov (ARICH) detector provides particle identification information in the forward endcap part of Belle II. It efficiently separates charged kaons from pions for momenta between 0.5 GeV/c and 4.0 GeV/c. Optical photons are emitted in a double layer aerogel radiator and detected by Hybrid Avalanche PhotoDetectors. ARICH was installed in Belle II at the end of 2017, the first phase of a complex detector calibration of electronic signals and preparation for physics signals calibration has been successfully concluded. Cherenkov rings, created by cosmic rays as well as by charged particles from beam collisions, have been observed. The kaon identification efficiency using D±? decays has been studied and its calibration is expected by the end of the commissioning phase when sufficient data is available.
关键词： Cherenkov detectors,Calibration,Particle identification,Optical photons,Beam collisions
更新于2025-09-23 15:21:01
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Progress on next generation gamma-ray Cherenkov detectors for the National Ignition Facility
摘要： Fusion reaction history and ablator areal density measurements for Inertial Con?nement Fusion experiments at the National Ignition Facility are currently conducted using the Gamma Reaction History diagnostic (GRH 6m). Future Gas Cherenkov Detectors (GCDs) will ultimately provide ～100x more sensitivity, reduce the effective temporal response from ～100 to ～10 ps, and lower the energy threshold from 2.9 to 1.8 MeV, relative to GRH 6m. The ?rst phase toward next generation GCDs consisted of inserting the existing coaxial GCD-3 detector into a reentrant well which puts it within 4 m of the implosion. Reaction history and ablator gamma measurement results from this Phase I are discussed here. These results demonstrate viability for the follow-on Phases of (II) the use of a revolutionary new pulse-dilation photomultiplier tube to improve the effective measurement bandwidth by >10x relative to current PMT technology; and (III) the design of a NIF-speci?c “Super” GCD which will be informed by the assessment of the radiation background environment within the well described here.
关键词： pulse-dilation photomultiplier tube,Gas Cherenkov Detectors,Gamma-ray Cherenkov detectors,Inertial Con?nement Fusion,National Ignition Facility
更新于2025-09-10 09:29:36
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<i>Ab initio</i> response functions for Cherenkov-based neutron detectors
摘要： Neutron time-of-?ight diagnostics at the NIF were recently out?tted with Cherenkov detectors. A fused silica radiator delivers sub-nanosecond response time and is optically coupled to a microchannel plate photomultiplier tube with gain from ～1 to 104. Capitalizing on fast time response and gamma-ray sensitivity, these systems can provide better than 30 ps precision for measuring ?rst moments of neutron distributions. Generation of ab initio instrument response functions (IRFs) is critical to meet the <1% uncertainty needed. A combination of Monte Carlo modeling, benchtop characterization, and in situ comparison is employed. Close agreement is shown between the modeled IRFs and in situ measurements using the NIF’s short-pulse advanced radiographic capability beams. First and second moments of neutron spectra calculated using ab initio IRFs agree well with established scintillator measurements. Next-step designs offer increased sensitivity and time-response.
关键词： instrument response functions,neutron time-of-flight,NIF,Cherenkov detectors,Geant4 modeling
更新于2025-09-10 09:29:36
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Pulse dilation gas Cherenkov detector for ultra-fast gamma reaction history at the NIF (invited)
摘要： The Cherenkov mechanism used in Gas Cherenkov Detectors (GCDs) is exceptionally fast. However, the temporal resolution of GCDs, such as the Gamma Reaction History diagnostic at the National Ignition Facility (NIF), has been limited by the current state-of-the-art photomultiplier tube technology to ～100 ps. The soon-to-be deployed Pulse Dilation Photomultiplier Tube (PD-PMT) at NIF will allow for temporal resolution comparable to that of the gas cell or ～10 ps. Enhanced resolution will contribute to the quest for ignition in a crucial way through precision measurements of reaction history and ablator areal density (ρR) history, leading to better constrained models. Features such as onset of alpha heating, shock reverberations, and burn truncation due to dynamically evolving failure modes may become visible for the ?rst time. Test measurements of the PD-PMT at Atomic Weapons Establishment con?rmed that design goals have been met. The PD-PMT provides dilation factors of 2 to 40× in 6 increments. The GCD-3 recently deployed at the NIF has been modi?ed for coupling to a PD-PMT and will soon be making ultrafast measurements.
关键词： Gas Cherenkov Detectors,Pulse Dilation Photomultiplier Tube,National Ignition Facility,temporal resolution,Cherenkov mechanism
更新于2025-09-09 09:28:46
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Development of an ultra-fast photomultiplier tube for gamma-ray Cherenkov detectors at the National Ignition Facility (PD-PMT)
摘要： A new ultra-fast photomultiplier tube and associated drivers have been developed for use in the next generation of gamma-ray high pressure gas Cherenkov detectors for inertial con?nement fusion experiments at the National Ignition Facility. Pulse-dilation technology has been applied to a standard micro-channel-plate-based photomultiplier tube to improve the temporal response by about 10×. The tube has been packaged suitably for deployment on the National Ignition Facility, and remote electronics have been designed to deliver the required non-linear waveforms to the pulse dilation electrode. This is achieved with an avalanche pulse generator system capable of generating fast arbitrary waveforms over the useful parameter space. The pulse is delivered via fast impedance-matching transformers and isolators, allowing the cathode to be ramped on a sub-nanosecond time scale between two high voltages in a controlled non-linear manner. This results in near linear pulse dilation over several ns. The device has a built-in ?ducial system that allows easy calibration and testing with ?ber optic laser sources. Results are presented demonstrating the greatly improved response time and other parameters of the device.
关键词： inertial con?nement fusion,gamma-ray Cherenkov detectors,National Ignition Facility,ultra-fast photomultiplier tube,pulse-dilation technology
更新于2025-09-09 09:28:46
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Cherenkov light imaging in astroparticle physics
摘要： Cherenkov light induced by fast charged particles in transparent dielectric media such as air or water is exploited by a variety of experimental techniques to detect and measure extraterrestrial particles impinging on Earth. A selection of detection principles is discussed and corresponding experiments are presented together with breakthrough-results they achieved. Some future developments are highlighted.
关键词： cosmic-ray detectors,gamma-ray telescopes,Cherenkov detectors,neutrino telescopes,Astroparticle physics
更新于2025-09-04 15:30:14