A novel technique for the measurement of the avalanche fluctuation of   gaseous detectors
  We have developed a novel technique for the measurement of the avalanche fluctuation of gaseous detectors using a UV laser. The technique is simple and requires a short data-taking time of about ten minutes. Furthermore, it is applicable for relatively low gas gains. Our experimental setup as well as the measurement principle, and the results obtained with a stack of Gas Electron Multipliers (GEMs) operated in several gas mixtures are presented. 
Makoto Kobayashi, Tomohisa Ogawa, Tomohiko Kawaguchi, Keisuke Fujii,   Takahiro Fusayasu, Katsumasa Ikematsu, Yukihiro Kato,...
physics.ins-det hep-ex