Characterization of the neutron field from the 241Am-Be isotopic source of the IPHC irradiator

A measurement campaign has been carried out recently to provide the source intensity and the reference spectra around a neutron irradiation facility based on 241Am-Be radionuclide source, using the UAB Bonner Sphere Spectrometer. This facility, which consists of a bunker, a container/shielding for the source and an irradiation device that uses an automated remote-controlled system for the source positioning and rotating during the dosimeter irradiation, is intended to be routinely used to check the response of passive dosimeters, namely those based on photo-stimulated imaging plates and solid-state nuclear track detectors. The measurement results, in terms of neutron spectra and global dosimetric quantities (i.e., fluence and ambient dose equivalent rates) at different distances with respect to the 241Am-Be source, were compared with Monte Carlo simulations using the MCNPX code and a good agreement was observed. An estimation of the un-scattered neutron spectrum directly emitted from the 241Am-Be source is given as well.

► We describe a neutron irradiation facility based on 241Am-Be radioactive source.
► The neutron field was characterized with a Bonner sphere spectrometer (BSS).
► Monte Carlo simulations using the MCNPX code were in good agreement with BSS.
► The un-scattered neutron spectrum is provided and compared to that given by the ISO-8529 standard.
► The neutron intensity of the 241Am-Be source is also estimated.