Volume 3, Issue 3 (May 1975)
Dosimetry Related to Controlled Thermonuclear Research
Controlled thermonuclear research (CTR) dosimetry is presently concerned with measurements of neutron flux, fluence, and neutron spectra. This information is being used to (1) correlate radiation effects data, (2) evaluate and describe the irradiation environment of currently available neutron sources, and (3) provide diagnostics for plasma physics studies. Current radiation effects studies are emphasising surface phenonena such as sputtering, and are utilising (d,t) and Be(d,n) reactions as the sources of neutrons. The energy region of 8 to 15 MeV is of most interest for CTR purposes. Experimental constraints necessitate use of the foil activation technique for dosimetry measurements. For the cases of monoenergetic neutron sources (RTNS), accuracies of about 7.5% are being obtained. Cross section uncertainties are limiting the accuracy for broad spectrum measurements, such as from Be-d sources. Because no present neutron source adequately represents the type of radiation environment expected to be encountered in future CTR devices, emphasis must be placed on carefully documenting and standardizing the dosimetry measurements so that the radiation effects data can ultimately be extrapolated to anticipated CTR conditions. Future efforts in CTR dosimetry must develop methods for characterizing charged and neutral particle radiation.