Efficient ion blocking in gaseous detectors and its application to gas-avalanche photomultipliers sensitive in the visible-light range - Physics > Instrumentation and DetectorsReportar como inadecuado




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Abstract: A novel concept for ion blocking in gas-avalanche detectors was developed,comprising cascaded micro-hole electron multipliers with patterned electrodesfor ion defocusing. This leads to ion blocking at the 10^{-4} level, in DCmode, in operation conditions adequate for TPCs and for gaseousphotomultipliers. The concept was validated in a cascaded visible-sensitive gasavalanche photomultiplier operating at atmospheric pressure of Ar-CH {4} 95-5with a bi-alkali photocathode. While in previous works high gain, in excess of10^{5}, was reached only in a pulse-gated cascaded-GEM gaseous photomultiplier,the present device yielded, for the first time, similar gain in DC mode. Wedescribe shortly the physical processes involved in the charge transport withingaseous photomultipliers and the ion blocking method. We present results of ionbackflow fraction and of electron multiplication in cascadedpatterned-electrode gaseous photomultiplier with K-Cs-Sb, Na-K-Sb and Cs-Sbvisible-sensitive photocathodes, operated in DC mode.



Autor: A. V. Lyashenko, A. Breskin, R. Chechik, J. M. F. Dos Santos, F. D. Amaro, J. F. C. A. Veloso

Fuente: https://arxiv.org/







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