A new GEM based neutron diagnostic concept fo high flux neutron beams

Fusion-fission hybrid reactors will need high flux neutron detectors to diagnose the deuterium-tritium fusion plasmas as well as the fission reactions. A candidate detection technique is the Gas Electron Multiplier (GEM). New GEM based detectors are being developed for application to a neutral deuterium beam test facility. The proposed detection system is called Close-contact Neutron Emission Surface Mapping (CNESM). The diagnostic aims at providing the map of the neutron emission due to interaction of the deterium beam with the deuterons implanted in the beam dump surface. This is done by placing a detector in close contact, right behind the dump. CNESM uses nGEM detectors, i.e. GEM detectors equipped with a cathode that also serves as neutron-proton converter foil. A small size prototype of nGEM detector has been built and is ready to be tested.