Mixed field dosimetry with CaSO₄:Dy

Abstract

The thermal neutron response and gamma -ray sensitivity of CaSO4:Dy as a function of Dy concentration were studied in detail. CaSO4 with 0.2% Dy has maximum gamma -ray sensitivity. The thermal neutron response of CaSO4:Dy increases rapidly with concentration beyond 0.1% Dy. CaSO4:0.05% 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 CaSO4:Dy with various lithium based materials were also selected for the same purpose. The thermal neutron response and glow peak temperature of CaSO4:(Dy, 6Li) were studied as a function of 6Li concentration.

Photoluminescence of F-aggregate centers in thermal neutron irradiated LiF TLD-100 single crystals

“…Our earlier studies [16] have shown that the TL response of the dosimetric peak at 200 "C in LiF TLD-100 is about 30 times more sensitive to thermal neutrons as compared to y-rays on a DE basis. Thus the PL from F t centers in TLD-100 will be nearly 45 times more efficient than that of TL of the 200 "C peak from the point of view of discriminative measurement of radiations of high SID in mixed fields.…”

“…a high y-dose of 1.45 x lo3 Gy and a relatively low thermal neutron fluence of about 10" n cm-2 give nearly the same PL emission. The thermal neutron fluence of 10" n cm-2 is equivalent to a dose equivalent (DE) of 1.07 Sv [16]. For y-rays, 1 Sv 2 1 Gy.…”

Redox reactions, radio-photoluminescence and thermoluminescence in

“…In the case of CaSO 4 :Dy or Tm, impurity concentrations in the range 0.05-0.2 mol% were found to be optimum for TL (Ayyangar et al 1974, Nambi et al 1974, Prokic 1978, Atone et al 1993b. While studying redox reactions and RPL in CaSO 4 :Eu, similar concentrations have been used in previous studies (Bapat 1977, Calvert and Danby 1984, Upadeo et al 1994.…”

Influence of (group IIB) codopants on the thermostimulated luminescence sensitivity of CaSO4:Dy/Tm

“…codopant shows the maximum TSL sensitivity. At concentrations higher than 0.2 mol%, the TSL intensities were reduced due to concentration quenching [10,11]. About a 45% increase in the TSL efficiency is seen in Zn and Cd (each 0.…”