Mixed field dosimetry with CaSO₄:Dy

The thermal neutron response and gamma -ray sensitivity of CaSO 4 :Dy as a function of Dy concentration were studied in detail. CaSO 4 with 0.2% Dy has maximum gamma -ray sensitivity. The thermal neutron response of CaSO 4 :Dy increases rapidly with concentration beyond 0.1% Dy. CaSO 4 :0.05% Dy (or Tm) has high gamma -ray sensitivity coupled with low thermal neutron response and hence is useful for gamma -ray dosimetry in mixed fields. A mixture of LiF TLD-100 and TLD-700 was arrived at for rem equivalent dosimetric purposes in a mixed field consisting of thermal and intermediate energy neutrons and gamma -rays. Mixtures of CaSO 4 :Dy with various lithium based materials were also selected for the same purpose. The thermal neutron response and glow peak temperature of CaSO 4 :(Dy, 6 Li) were studied as a function of 6 Li concentration.