We present a Photon-Assisted Cascaded Electron Multipliers (PACEM) which has a potential for ion back-flow blocking in gaseous radiation detectors: the avalanche from a first multiplication stage propagates to the successive one via its photons, which in turn induce photoelectron emission from a photocathode deposited on the second multiplier stage; the multiplication process may further continue via electron-avalanche propagation. The photon-mediated stage allows, by a proper choice of geometry and fields, complete blocking of the ion back-flow into the first element; thus, only ions from the latter will flow back to the drift region. The PACEM concept was validated in a double-MHSP (Micro-Hole & Strip Plate) cascaded multiplier operated in xenon, where the intermediate scintillation stage provided optical gain of ~60. The double-MHSP detector had a total gain above 10^4 and energy resolution of 18% FWHM for 5.9 keV x-rays.
@article{arxiv.physics/0606209,
title = {The Photon-Assisted Cascaded Electron Multiplier: a Concept for Potential Avalanche-Ion Blocking},
author = {J. F. C. A. Veloso and F. D. Amaro and J. M. F. dos Santos and A. Breskin and A. Lyashenko and R. Chechik},
journal= {arXiv preprint arXiv:physics/0606209},
year = {2009}
}
Comments
13 pages, 5 figures. Submitted to JINST - electronic Journal of Instrumentation, June 25, 2006