摘要
The performance of gaseous detectors coupled to photocathodes is often limited by secondary effects. For instance, the ions generated from avalanche mul- tiplication will impact on the photocathode, yielding secondary electrons and generating spurious signals, with discharge eventually possible. They can also gradually damage the photocathode surface, resulting in loss of quantum efficiency. To quantify the ion- induced secondary effects, the notion of ion back flow （IBF） is defined as the fraction of avalanche-generated ions reaching the photocathode. The purpose of this work is to investigate ways to suppress ion back flow in thick gas electron multiplier （THGEM） based de- tectors.
The performance of gaseous detectors coupled to photocathodes is often limited by secondary effects. For instance, the ions generated from avalanche mul- tiplication will impact on the photocathode, yielding secondary electrons and generating spurious signals, with discharge eventually possible. They can also gradually damage the photocathode surface, resulting in loss of quantum efficiency. To quantify the ion- induced secondary effects, the notion of ion back flow （IBF） is defined as the fraction of avalanche-generated ions reaching the photocathode. The purpose of this work is to investigate ways to suppress ion back flow in thick gas electron multiplier （THGEM） based de- tectors.
基金
Supported by the National Natural Science Foundation of China under Grant Nos 11205240 and 11265003, and the China Postdoctoral Science Foundation under Grant No 2012M510587.
