12–17 Oct 2015
Trieste - Italy
Europe/Rome timezone

Statistical fluctuations of photoelectron emission from CsI photocathodes in Noble gases

13 Oct 2015, 16:25
Oceania (Trieste - Italy)

Oceania

Trieste - Italy

Congress Centre Stazione Marittima Molo Bersaglieri, 3 34123 Trieste Italy
Board: 52
Poster MPGD Detector Physics Poster session & coffee break

Speaker

Prof. João Veloso (University of Aveiro)

Description

CsI photocathodes coupled to Gaseous Photomultipliers have long been used in experiments and applications due to their high gains, fast response and coverage of large areas of detection at reasonable costs [1, 2]. In the future, experiments based on rare event detection, namely Dark Matter [3, 4] and Double Beta Decay [5] research, are faced with the problem of the prohibitive costs of the use of PMTs [6]. High mass pressurized GPMs with noble gases and CsI photocathodes are a promising solution; a note-worthy example is the research on single and double-phase Xenon-based detectors [7]. The drop in extraction efficiency caused by the photoelectron backscattering in gases is a well-known aspect of CsI photocathodes [8], but the way this affects the uncertainty over the number of electrons extracted is still not known. In this work we present the first results of our experimental investigations on the statistical aspects of the photo-electron extraction efficiency of CsI photocathodes. For that purpose, a detection chamber was assembled consisting of a photo converting plane and a thin aluminum layer above so a drift electric field can be applied. The CsI photocathode is irradiated with pulsed UV light and the photo-electrons are collected and measured without electron multiplication in the gas, thus allowing the study of the statistical fluctuations of the photon conversion process itself. Results are presented for different noble gas media at various pressures. [1] CsI photocathodes: history and mistery, A. Breskin, Nucl. Instrum. Meth. A 371 (1996) 116 [2] Advances in gaseous photomultipliers, R. Chechik, A. Breskin, Nucl. Instrum. Meth. A 595.1 (2008): 116-127. [3] The XENON1T Dark Matter Search Experiment, E. Aprile (for the XENON1T collaboration), Proceedings of DM2012, Tenth Symposium on Sources and Detection of Dark Matter and Dark Energy in the Universe; UCLA, California, USA, February 2012 [4] DARWIN dark matter WIMP search with noble liquids, L. Baudis (for the DARWIN consortium), 2012, J. Phys. Conf. Ser. 375 012028; arXiv:1201.2402v1 [5] Double-beta decay: Present status; A. S. Barabash, Phys. Atom. Nucl. 73 (2010), arXiv:1206.6288v1 [6] Liquid Hole-Multipliers: A potential concept for large single-phase noble-liquid TPCs of rare events, A. Breskin, Journal of Physics: Conference Series. Vol. 460. No. 1. IOP Publishing, 2013. [7] Operation of a Thick Gas Electron Multiplier (THGEM) in Ar, Xe and Ar-Xe; R. Alon, J. Miyamoto, M. Cortesi, A. Breskin, R. Chechik et al., Journal of Instrumentation 3.01 (2008): P01005. [8] Photoelectron extraction efficiency from cesium iodide photocathodes in a pressurized atmosphere of argon and xenon up to 10 bar, D.S. Covita, C.D.R. Azevedo, C.C. Caldas, J.F.C.A. Veloso, Physics Letters B 701.2 (2011): 151-154

Primary author

Mr Fábio Pereira (University of Aveiro)

Co-authors

Dr C. D. R. Azevedo (I3N – Department of Physics, University of Aveiro, Portugal) Dr D. S. Covita (I3N – Department of Physics, University of Aveiro, Portugal) Dr J. F. C. A. Veloso (I3N – Department of Physics, University of Aveiro, Portugal)

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