Research and development of gaseous photomultiplier tubes for practical use

通过组装GEM和Micromegas等微图案气体探测器，我们研制出了一种能够将光子信号转换为电信号的气体光电倍增管。在这个研发项目的过程中，离子反馈现象是一个关键问题。在气体放大过程中，产生了大量的离子，在电场的引导下，离子被转移到光阴极上。然后，可能会产生新的电子，或者光电阴极本身可能会被这种离子轰击破坏。我们继续进行这个研发计划，目的是在获得高增益的同时有效地抑制离子反馈。最后，我们研制了一种接近实际应用的气体光电倍增管，其增益为105，离子反馈速率为10-3。

By assembling Micro Pattern Gas Detectors(MPGD) such as GEM and Micromegas, we developed a gaseous photomultipliers which can transform photon signals to electric signals. In the course of this R & D program, one of critical issues was ion-feedback phenomena. During the gas amplification process a lot of ions are created and they are moved to the photocathode guided by the electric field. Then new electrons may be created or photocathode itself may be damaged by this ion bombardment. We proceeded to this R & D program aiming to get high gain while effectively suppressing ion-feedbacks. Finally we have developed a gaseous photomultipliers having a 105 gain and a 10-3 ion-feedback rate, which is close to a practical use.