DEVELOPMENT OF A MICRO ARRAY TYPE ELECTRON MULTIPLIER

We are currently developing a micro array type electron multiplier whi ch can be used for a two dimensional photomultiplier tube (PMT). This device consists of dynode plates which have many pixels. Keeping its p osition information, incident electrons are multiplied within each pix el of the array. The micromachining technique was used to fabricate th e dynodes of the detector. Slanting hole and pyramid hole structures w ere investigated as the dynode structure. From the simulation result o f these two types, more than 1000 would be obtained as the signal gain factor with 12 dynodes and 200V/dynode. From the experimental results , the electron multiplication factor similar to 2 of the pyramid type dynode was obtained with 2 dynode stages and 150V/dynode. The signal g ain factor 4.6 of the slanting hole dynode was obtained with 2 dynode stages and 400V/dynode. These were well agreed with the simulation res ults.