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Search Results: 1 - 10 of 462059 matches for " A. Breskin "
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Advances in Gaseous Photomultipliers
R. Chechik,A. Breskin
Physics , 2008, DOI: 10.1016/j.nima.2008.07.035
Abstract: We review latest progress in gaseous photomultipliers (GPM) combining solid photocathodes and various types of novel electron multipliers. Cascaded gaseous electron multipliers (GEM) coated with CsI photocathodes can efficiently replace UVsensitive wire chambers for single-photon recording in Cherenkov and other detectors. Other hole-multipliers with patterned electrodes (Micro-Hole and Strip Plates) and improved ion-blocking properties are discussed; these permit reducing considerably photon- and ion-induced secondary effects. Photon detectors with other electron-multiplier techniques are briefly described, among them GPMs based on Micromegas, capillary-plates, Thick-GEMs and resistive Thick GEMs. The two latter techniques, robust and economically produced, are particularly suited for large-area GPM applications, e.g. in RICH. Cascaded hole-multipliers with very high ion-blocking performance permitted the development and the first demonstration of DC-operated visible-sensitive gaseous photomultipliers with bialkali photocathodes and single-photon sensitivity. Recent progress is described in GPMs operated at cryogenic temperatures for rare-event noble-liquid detectors and medical imaging.
Gain limits of a Thick GEM in high-purity Ne, Ar and Xe
J. Miyamoto,A. Breskin,V. Peskov
Physics , 2010, DOI: 10.1088/1748-0221/5/05/P05008
Abstract: The dependence of the avalanche charge gain in Thick Gas Electron Multipliers (THGEM) on the purity of Ne, Ar and Xe filling gases was investigated. The gain, measured with alpha-particles in standard conditions (atmospheric pressure, room temperature), was found to considerably drop in gases purified by non-evaporable getters. On the other hand, small N2 admixtures to noble gases resulted in high reachable gains. The results are of general relevance in the operation of gas-avalanche detectors in noble gases, particularly that of two-phase cryogenic detectors for rare events.
Thick GEM-like multipliers - a simple solution for large area UV-RICH detectors
R. Chechik,A. Breskin,C. Shalem
Physics , 2005, DOI: 10.1016/j.nima.2005.08.003
Abstract: We report on the properties of thick GEM-like (THGEM) electron multipliers made of 0.4 mm thick double-sided Cu-clad G-10 plates, perforated with a dense hexagonal array of 0.3 mm diameter drilled holes. Photon detectors comprising THGEMs coupled to semi-transparent CsI photocathodes or reflective ones deposited on the THGEM surface were studied with Ar/CO2 (70:30), Ar/CH4 (95:5), CH4 and CF4. Gains of ~100000 or exceeding 1000000 were reached with single- or double-THGEM, respectively; the signals have 5-10 ns rise times. The electric field configurations at the THGEM electrodes result in an efficient extraction of photoelectrons and their focusing into the holes; this occurs already at rather low gains, below 100. These detectors, with single-photon sensitivity and with expected sub-millimeter localization, can operate at MHz/mm2 rates. We discuss their prospects for large-area UV-photon imaging for RICH.
Further evaluation of a THGEM UV-photon detector for RICH - comparison with MWPC
V. Peskov,M. Cortesi,R. Chechik,A. Breskin
Physics , 2010, DOI: 10.1088/1748-0221/5/11/P11004
Abstract: The operation of single-, double- and triple-THGEM UV-detectors with reflective CsI photocathodes (CsI-THGEM) in Ne/CH4 and Ne/CF4 mixtures was investigated in view of their potential applications in RICH. The studies were carried out with UV, x-rays and {\beta}-electrons and focused on the maximum achievable gain, discharge probability, cathode excitation effects and long-term gain stability. Comparative studies under similar conditions were made in CH4, CF4 and Ne/CF4, with a MWPC coupled to a reflective CsI photocathode (CsI-MWPC). It was found that at counting rates <= 10 Hz/mm^2 the maximum achievable gain of CsI-THGEMs is determined by the Raether limit; at counting rates > 10 Hz/mm^2 it dropped with rate. In all cases investigated the attainable CsI-THGEM gain was significantly higher than that of the CsI-MWPC, under similar conditions. Furthermore, the CsI-THGEM UV-detector suffered fewer cathode-excitation induced effects as compared to CsI-MWPC and had better stability at high counting rates.
Thick GEM-like hole multipliers: properties and possible applications
R. Chechik,A. Breskin,C. Shalem,D. Moermann
Physics , 2004, DOI: 10.1016/j.nima.2004.07.138
Abstract: The properties of thick GEM-like (TGEM) gaseous electron multipliers, operated at 1-740 Torr are presented. They are made of a G-10 plate, perforated with millimeter-scale diameter holes. In single-multiplier elements, effective gains of about 104, 106, and 105 were reached at respective pressures of 1, 10 Torr isobutane and 740 Torr Ar/5%CH4, with pulse rise-times in the few nanosecond scale. The high effective gain at atmospheric pressure was measured with a TGEM coated with a CsI photocathode. The detector was operated in single and cascaded modes. Potential applications in ion and photon detection are discussed.
Advances in Thick GEM-like gaseous electron multipliers. Part I: atmospheric pressure operation
C. Shalem,R. Chechik,A. Breskin,K. Michaeli
Physics , 2006, DOI: 10.1016/j.nima.2005.12.241
Abstract: Thick GEM-like (THGEM) gaseous electron multipliers are made of standard printed-circuit board perforated with sub-millimeter diameter holes, etched at their rims. Effective gas multiplication factors of 100000 and 10000000 and fast pulses in the few nanosecond rise-time scale were reached in single- and cascaded double-THGEM elements, in atmospheric-pressure standard gas mixtures with single photoelectrons. High single-electron detection efficiency is obtained in photon detectors combining THGEMs and semitransparent UV-sensitive CsI photocathodes or reflective ones deposited on the top THGEM face; the latter benefits of a reduced sensitivity to ionizing background radiation. Stable operation was recorded with photoelectron fluxes exceeding MHz/mm2. The properties and some potential applications of these simple and robust multipliers are discussed.
Liquid Hole-Multipliers: A potential concept for large single-phase noble-liquid TPCs of rare events
Amos Breskin
Physics , 2013, DOI: 10.1088/1742-6596/460/1/012020
Abstract: A novel concept is proposed for large-volume single-phase noble-liquid TPC detectors for rare events. Both radiation-induced scintillation-light and ionization-charge are detected by Liquid Hole-Multipliers, LHM, immersed in the noble liquid. The latter may consist of cascaded Gas Electron Multipliers (GEM), Thick Gas Electron Multiplier (THGEM) electrodes or others, coated with CsI UV-photocathodes. Electrons, photo-induced on CsI by primary scintillation in the noble liquid, and event-correlated drifting ionization electrons are amplified in the cascaded elements primarily through electroluminescence, and possibly through additional moderate avalanche, occurring within the holes. The resulting charge-signals or light-pulses are recorded on anode pads or with photosensors, e.g. gaseous photomultipliers (GPM), respectively. Potential affordable solutions are proposed for multi-ton dark-matter detectors; open questions are formulated for validating this dream.
First demonstration of THGEM/GAPD-matrix optical readout in two-phase Cryogenic Avalanche Detector in Ar
A. Bondar,A. Buzulutskov,A. Dolgov,A. Grebenuk,E. Shemyakina,A. Sokolov,A. Breskin,D. Thers
Physics , 2013, DOI: 10.1016/j.nima.2013.07.089
Abstract: The multi-channel optical readout of a THGEM multiplier coupled to a matrix of 3x3 Geiger-mode APDs (GAPDs) was demonstrated in a two-phase Cryogenic Avalanche Detector (CRAD) in Ar. The GAPDs recorded THGEM-hole avalanches in the Near Infrared (NIR). At an avalanche charge gain of 160, the yield of the combined THGEM/GAPD-matrix multiplier amounted at ~80 photoelectrons per 20 keV X-ray absorbed in the liquid phase. A spatial resolution of 2.5 mm (FWHM) has been measured for the impinging X-rays. This technique has potential applications in coherent neutrino-nucleus scattering and dark matter search experiments.
Direct observation of avalanche scintillations in a THGEM-based two-phase Ar avalanche detector using Geiger-mode APD
A. Bondar,A. Buzulutskov,A. Grebenuk,A. Sokolov,D. Akimov,I. Alexandrov,A. Breskin
Physics , 2010, DOI: 10.1088/1748-0221/5/08/P08002
Abstract: A novel concept of optical signal recording in two-phase avalanche detectors, with Geiger-mode Avalanche Photodiodes (G-APD) is described. Avalanche-scintillation photons were measured in a thick Gas Electron Multiplier (THGEM) in view of potential applications in rare-event experiments. The effective detection of avalanche scintillations in THGEM holes has been demonstrated in two-phase Ar with a bare G-APD without wavelength shifter, i.e. insensitive to VUV emission of Ar. At gas-avalanche gain of 400 and under \pm 70^\circ viewing-angle, the G-APD yielded 640 photoelectrons (pe) per 60 keV X-ray converted in liquid Ar; this corresponds to 0.7 pe per initial (prior to multiplication) electron. The avalanche-scintillation light yield measured by the G-APD was about 0.7 pe per avalanche electron, extrapolated to 4pi acceptance. The avalanche scintillations observed occurred presumably in the near infrared (NIR) where G-APDs may have high sensitivity. The measured scintillation yield is similar to that observed by others in the VUV. Other related topics discussed in this work are the G-APD's single-pixel and quenching resistor characteristics at cryogenic temperatures.
Geiger Mode APD performance in a cryogenic two-phase Ar avalanche detector based on THGEMs
A. Bondar,A. Buzulutskov,A. Grebenuk,A. Sokolov,D. Akimov,I. Alexandrov,A. Breskin
Physics , 2010, DOI: 10.1016/j.nima.2010.07.002
Abstract: Characteristic properties of a Geiger Mode APD (G-APD) in a THGEM-based cryogenic two-phase Ar avalanche detector were studied in view of potential applications in rare-event experiments. G-APD signal amplitude and noise characteristics at cryogenic temperatures turned out to be superior to those at room temperature. The effective detection of avalanche scintillations from THGEM-multiplier holes in two-phase Ar has been demonstrated using a G-APD without wavelength shifter. At an avalanche gain of 60, the avalanche scintillation yield measured by the G-APD was as high as 0.9 photoelectrons per avalanche electron, extrapolated to 4pi acceptance.
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