MEASUREMENT OF THE NEUTRON SENSITIVITY OF TLD-300 IRRADIATED IN A TISSUE-EQUIVALENT PHANTOM BY D(48.5)+BE NEUTRONS

The neutron sensitivities of the total response (k(T)) as well as of s eparate peaks 3 (k(3)) and 5 (k(5)) on the glow curve were measured fo r CaF2:Tm (TLD-300) thermoluminescent dosimeters, The TLD-300 were enc apsulated in A-150 TE plastic and located at different depths in the w ater phantom. The phantom was irradiated with neutrons produced by the d(48.5) + Be reaction at the superconducting cyclotron of the Gershen son Radiation Oncology Center at Harper Hospital. A set of measurement s, based on the use of a TE ionization chamber and Geiger-Muller (GM) counter was used to measure the neutron (D-n) and gamma (D-gamma) dose at these locations. The neutron sensitivities of the TLDs were thus d erived by comparison with the results obtained with the twin detector method. The average neutron sensitivities relative to gamma of the tot al response and the responses of single peaks 3 or 5 are 0.215+/-0.016 , 0.126+/-0.010, and 0.357+/-0.014, respectively. A linear relationshi p was found between the ratio of the areas under peak 3 to that under peak 5 and the ratio of the gamma dose to the total dose. (C) 1998 Ame rican Association of Physicists in Medicine. [S0094-2405(98)01704-0].