Self-powered neutron detectors (SPNDs) with erbium, hafnium, gadolinium, rhodium, silver, and cobalt emitters have been irradiated in several different neutron and gamma spectra obtained by a variety of filters: cadmium, gadolinium, boron, lead, zirconium, aluminum, or light water. The irradiation locations were inside the core or reflector of the MELUSINE (8 MW) and SILOE (35 MW) reactors.

Fast and delayed sensitivities to thermal and epithermal neutron and gamma-ray fluxes have been evaluated. Measurements show that gamma and epithermal neutron currents are of the same order of magnitude. It became possible, however, to drive down to zero the gamma sensitivity by laying one or several shroudings onto the emitter surface. This shrouding may now be optimized in order to reduce the SPND's response time.