Micromegas type neutron detector for ADS system

ADS need neutron detectors working on a wide energy range and quite insensitive to X- and gamma-rays. Micromegas technology has been proposed to achieve this goal. The ability of Micromegas to detect neutrons has already been demonstrated and this detector is, under certain conditions, insensitive to gamma-rays. A new Micromegas neutron detector has been designed and it gives the possibility to get integrated neutron fluxes on different energy domains. The configuration of the detector will be presented as well as its functioning and the reasons of its insensitivity to gamma-rays. Moreover, some experiments have been realized on a TRIGA reactor at Casaccia in Italy. It is the first time that a Micromegas is placed in a nuclear reactor. The configuration and results of these tests will be shown and some improvements suggested.