USE OF SSNTDS IN NEUTRON BEAM DOSIMETRY

A new Biological irradiation Facility (BIF) has been constructed at th e Budapest Research Reactor Center. The 10 cm diameter beam is led thr ough a variable filter and collimator system, providing different neut ron spectra from the nearly pure fission one to a well moderated, 1/E spectrum. To use the irradiator for biological irradiation and for inv estigating the response of neutron detector materials one must know th e neutron spectrum, the beam intensity and profile in advance, and mor eover, each irradiation should be adequately monitored to be able to c orrect the dose conversion factors against the burnup of the fuel, cha nge 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 present ed on this conference). Detectors developed are: CR-39 (TASTRAK) track detectors with proton converter (polyethylene, PE) turning this combi nation into a threshold detector when applying thin gold foils as prot on energy degraders; fission track detectors using depleted uranium an d thorium with LEXAN polycarbonate and CR-39 using the Li-6 and B-10 c ontents of commercially available TLD materials as alpha converters. W e present the basic fundamentals of the proton recoil detector, includ ing the response calculation model.