Use of SSNTDs in neutron beam dosimetry

Abstract

A new Biological Irradiation Facility (BIF) has been constructed at the Budapest Research Reactor Center. The 10 cm diameter beam is led through a variable filter and collimator system, providing different neutron spectra from the nearly pure fission one to a well moderated, 1/E spectrum. To use the irradiator for biological irradiation and for investigating the response of neutron detector materials one must know the neutron spectrum, the beam intensity and profile in advance, and moreover, each irradiation should be adequately monitored to be able to correct the dose conversion factors against the burnup of the fuel, change in the reactor thermal power etc. For the purpose, a set of track detectors were developed. All the detectors are chemically etched and evaluated by a new image analyzer system called VIRGINIA (also presented on this conference). Detectors developed are: CR-39 (TASTRAK) track detectors with proton converter (polyethylene, PE) turning this combination into a threshold detector when applying thin gold foils as proton energy degraders; fission track detectors using depleted uranium and thorium with LEXAN polycarbonate and CR-39 using the 6Li and 10B contents of commercially available TLD materials as alpha converters. We present the basic fundamentals of the proton recoil detector, including the response calculation model.