A GEM-based thermal neutron detector for high counting rate applications

Among other neutron detector systems proposed as a possible substitute for He-3 tubes, GEM-based ones have shown appealing characteristics, when coupled with suitable neutron-converter cathodes. In this paper, we present the results of a GEM-based neutron detector in a high-flux environment (the ORPHEE reactor in Saclay), especially in terms of maximum rate capability and linearity. Recorded data show that the detector can manage neutron counting rates in the order of 50 x 10(6) counts/sec cm(2) while maintaining a reasonable linearity and with no sign of instability.