Development of a micro array type electron multiplier

We are currently developing a micro array type electron multiplier which can be used for a two dimensional photomultiplier tube (PMT). This device consists of dynode plates which have many pixels. Keeping its position information, incident electrons are multiplied within each pixel of the array. Since each pixel works as a conventional PMT, this device will be useful for a high counting rate target measurement such as in SR facilities. The micromachining technique was used to fabricate the dynodes of the detector. Slanting hole and pyramid hole structures were investigated as the dynode structure. From the simulation result of these two types, more than 1000 would be obtained as the signal gain factor with 12 dynodes and 200 V/dynode. Based on these results, the pyramid and slanting hole type dynode were fabricated using a silicon technique and a LIGA like process, respectively. From the experimental results, the electron multiplication factor ~2 of the pyramid type dynode was obtained with 2 dynode stages and 150 V/dynode. The signal gain factor 4.6 of the slanting hole dynode was obtained with 2 dynode stages and 400 V/ dynode. These were well agreed with the simulation results