Advances in ion back-flow reduction in cascaded gaseous electron multipliers incorporating R-MHSP elements
A V Lyashenko; A Breskin; R Chechik; J F C A Veloso; J M F Dos Santos; F D Amaro
Журнал:
Journal of Instrumentation
Дата:
2006-10-01
Аннотация:
We present and discuss in details a concept for the reduction of ion back-flow in GEM-based cascaded gaseous electron multipliers, by incorporating Micro-Hole & Strip Plate (MHSP) elements operating in reversed-bias mode (R-MHSP). About an order of magnitude reduction in ion back-flow is achieved by diverting back-drifting ions from their original path. A R-MHSP/2GEM/MHSP cascaded multiplier operated at total gain of ∼ 1.5 × 10<sup>5</sup> yielded ion back-flow fractions of 1.5 × 10<sup>-3</sup> and 4 × 10<sup>-4</sup>, at drift fields of 0.5 and 0.1 kV/cm, respectively. A 2R-MHSP/MHSP cascaded multiplier operated at a total gain of ∼ 10<sup>5</sup>, yielded an ion back-flow fraction of 3 × 10<sup>-3</sup>. We discuss the concept for trapping back-flowing ions in these cascaded multipliers and the relevance to gaseous photomultiplier and TPC applications; directions for future developments are outlined.
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