Dosimetric Performance of the Fast Neutron Dosemeter for ENEA Personal Dosimetry Service

The Institute for Radiation Protection of ENEA has employed for many years a solid state nuclear track detector CR-39 as a fast neutron personal dosemeter with good results. The 1990 recommendations of ICRP 60 has introduced new parameters to neutron dosimetry that require harmonisation of the dosemeters' response within international recommendations. This paper reports the results of an experimental study performed at ENEA in order to investigate the dosimetric performance of two kinds of CR-39 produced in UK and Italy. Sensitivity, lowest detectable dose, background, linearity, energy and angular responses are compared between the two CR-39 materials. Irradiation tests have been performed with monoenergetic neutron beams in the range from 100 keV to 20 MeV, as well as with 252 Cf and 241 Am-Be sources. The Italian CR-39 material, used elsewhere for heavy ions detection in scientific applications, has here been comprehensively tested for neutron dosimetry purposes. Results were very satisfactory and it has therefore been introduced in the ENEA Personal Dosimetry Service.