Speaker
Description
The GEM detector is useful for various fields, not only high energy physics. But, one uncomfortable feature is to be broken due to a large discharge. One large charge deposit makes a trigger to lead the large discharge and to carbonize inside the GEM hole. In order to avoid such a bad situation, we are developing new GEM foil without carbon. One good solution is to apply ceramic as an insulator instead of Polyamide and Liquid Crystal Polymer (LCP). New ceramic GEM was manufactured with 100 mm × 100 mm size and 100 m thickness. Also, a neutron detector was constructed with a hybrid cathode to detect both thermal (or cold) neutron and MeV neutron. The hybrid cathode consists 0.5mm PET (Polyethylene Terephthalate) plate with 1 m boron layer. Thermal neutron can be absorbed in the boron layer and can produce alpha particle (and Li nuclei). The cross section of boron for the MeV neutron is too small. It is better to select another material to detect the MeV neutron. The MeV neutron can easily hit the hydron inside of material and can produce the proton. On good candidate is PET, which contents large amount of hydrogen. The cathode was fabricated by ourself and installed in the chamber with single GEM structure. The chamber is work fine. Now, we are trying to make boron coated GEM to get higher efficiency for the thermal neutron. It will be available near future.
