Determination of Neutron Spectrum in D-T Fusion Field by Foil Activation Technique

Neutron spectrum measurement based on the foil activation technique was carried out as a part of the JAERI/USDOE collaborative program on fusion blanket neutronics. The adequacy of the foil activation technique and the current dosimetry nuclear data for the D-T fusion neutron field were examined through the analysis of the spectrum in a Li₂O blanket system enclosed with the Li₂CO³. A method using a pair of activation indices (MPI) is newly proposed to evaluate the neutron flux around the MeV region of interest in a qualitative way. The multi-foil activation technique (MFA) with proper detector cross section data are promising to determine neutron spectra over a wide energy range.