Neutron response of Geiger-Mueller photon dosemeters for neutron energies between 100 keV and 19 MeV

The energy compensated GM counter is a useful photon dosemeter for mixed neutron-photon dosimetry because of its low fast neutron response. For accurate measurements the ratio of the prompt neutron response to the photon response, the Ksub(u) value, and the neutron activation effects in the GM counter must be known. The measured ksub(u) values for two commercially available GM counters for neutron energies between 100 keV and 19 MeV are presented. Activation effects at 15.5 MeV are studied. An activation of the walls of the counter tube due to the 56Fe(n,p)56Mn reaction with a half life of 2.57 hr and some other activations with shorter half lives were found. (author)