Neutron-gamma mixed field dosimetry using a 6LiF:Mg,Cu,P thermoluminescent dosimeter

Abstract

Satisfactory discrimination between the neutron and gamma components in a mixed neutron-gamma field is one of the most important objectives of neutron dosimetry. One of the common techniques for estimating gamma and neutron dose components in mixed neutron-gamma fields is the two peak method. This method has been applied using dosimeters such as LiF:Mg,Ti, but in the present work, a 6LiF:Mg,Cu,P dosimeter has been used, whose thermoluminescence sensitivity is much higher than the LiF:Mg,Ti dosimeter, and therefore, if appropriate results are achieved, it can drastically reduce the dose estimation threshold. Applicability of 6LiF:Mg,Cu,P for estimation of the gamma dose using the two peak method in a mixed thermal neutron-gamma radiation field was studied. The ratio of the area underneath the high temperature thermoluminescence glow peak to dosimetry peak of this phosphor in an Am-Be neutron field is 0.127, while this ratio in a pure gamma ray field of 137Cs is 0.039. The calibration curves were obtained by separately irradiating 6LiF:Mg,Cu,P chips with known gamma and neutron doses. Results show that 6LiF:Mg,Cu,P can be used to estimate the contributions of neutron and gamma doses in a mixed neutron-gamma field by using the two peak method.