Heavy particle dosimetry with high temperature peaks of CaF2:Tm and 7LiF phosphors

The LET dependence of low and high temperature peaks of CaF2:Tm and Li7F thermoluminescent material was studied by irradiation of both materials along the depth dose distribution of a Ne+10 and He+2 beam. The sensitivity of the 140 deg C peak of CaF2:Tm decreases rapidly with increasing LET, while the sensitivity of the high temperature peak at 230 deg C remains constant up to 50 keV.μ-1 and then decreases. In Li7F the main peak sensitivity decreases, whereas the sensitivity of the 260 deg C peak increases with increasing LET. These different LET dependences can be utilised in heavy charged particle and neutron dosimetry. In negative pion fields CaF2:Tm allows one to measure simultaneously dose and average LET. This was confirmed experimentally by measurements of treatment dose distributions at the SIN Piotron. In neutron fields the different LET dependence of low and high temperature peaks can be used to separate gamma and neutron dose. (author)