A high-gain, low ion-backflow double micro-mesh gaseous structure for single electron detection

Application of micro-pattern gaseous detectors to gaseous photomultiplier tubes has been widely investigated over the past two decades. In this paper, we present a double micro-mesh gaseous structure that has been designed and fabricated for this application. Tests with X-rays and UV laser light indicate that this structure exhibits an excellent gas gain of $>7\times 10^4$ and good energy resolution of 19% (full width at half maximum) for 5.9 keV X-rays. The gas gain can reach up to $10^6$ for single electrons while maintaining a very low ion-backflow ratio down to 0.0005. This structure has good potential for other applications requiring a very low level of ion backflow.