DOE personel neutron dosimeter evaluation and upgrade program: Informational statement on DOE activities

The U.S. Department of Energy initiated a research program in FY-81 to evaluate and upgrade neutron dosimetry at DOE facilities. The program involves DOE national laboratories, universities, and private companies. The objectives of the program are to assess current personnel neutron dosimeter capabilities and to develop improved personnel neutron measurement systems. Two types of passive personnel neutron dosimeters have been used at DOE facilites: NTA film and TLD-albedo dosimeters. Each type exhibits an energy-dependent response to neutron exposure. The NTA film dosimeter only responds to neutrons with energies above 400 KeV. In contrast, the TLD-albedo dosimeter responds to all neutron energies, but the response is inversely proportional to neutron energy. As a consequence the dose equivalent per unit of thermoluminescent response can vary by more than one order of magnitude which then requires some knowledge of the neutron energy spectrum to properly interpret dosimeter results. Two new neutron dosimeters are being developed to overcome these problems: combination/track-etch dosimeters and pocket rem-meters. Track-etch methods have been studied for about 20 years. One of the first track-etch neutron dosimeters was developed in 1964. It was used to detect fission fragment damage in plastic. This dosimeter was not widely applied because the dosimeter material itself contained interfering fissionable radioactivity