Thermal neutron fluence measurement in a research reactor using thermoluminescence dosimeter TLD-600.

A thermal neutron fluence in the range between 10(11) and 10(13) n cm(-2) in the reactor core of the Tehran research reactor has been measured using TLD-600 thermoluminescence dosimeters. After a thermal treatment of 1 h at 400 degrees C followed by 20 h cooling down to room temperature of pre-exposed dosimeters in the reactor, the accumulated TL light was measured after periods of storage of 24, 48 and 72 h. The influence of the irradiation-induced damage effect on the response of TLDs and their subsequent readings has been minimized in this manner. The induced TL light due to self-activity in the TLD-600 dosimeters, which is dependent on the neutron fluence, caused a conveniently measurable TL glow curve. The induced TL in the dosimeter due to the Q-value for the beta-decay of tritium Ebeta-max = 18.6 keV has been reproduced separately by a beta source to check the proportions of radionuclides in the chip. A short theoretical treatment is also presented.