Establishing radiation standards in high-technology research fields and their advancement

Utilization of synchrotron radiation as well as development of X-ray sources using laser plasma require standardization of soft X-ray dose measurement near 1 keV, while nuclear fusion research requires standardization of such parameters as reaction cross-section, damage cross-sections toward materials, sensitivity of neutron measurement in the energy range from 5 to 14 MeV. Absolute calorimetric measurements of soft X-rays from synchrotron radiation were verified by ion-chamber method. This method also permits to determine absorption cross-sections of Kr and Xe to soft X-rays. Calibration from air-attenuation density yielded exposure dose calibration. Radon density measurement became possible by in-line ionization chamber method utilized for standardization of radon field. Combination of positron-sensitive proportional counter with Si-detector and multi-channel analyzing system enables one to determine a precise measurement of fast neutron energy and particle intensity with high-energy resolution. Effects of energetic Ar-ion bombardment of multi-layered Fe/Si revealed that AFC characteristics changes resulting from atomic mixing and that magnetization decreased proportionally with ion dose. (S. Ohno)