Application of the Slowing Down Time method for neutron spectrum measurement in the energy region of eV in various neutron field

The Slowing Down Time (SDT) method was adopted for several fusion benchmark experiments, and neutron spectra below 10 keV were successfully measured in Be, Fe, Cu, SS316 and SS316/water assemblies with experimental errors of around 10%. It was found that the SDT method had a wide applicability and many advantages in comparison with other techniques for neutron spectrum measurement in the energy region below 10 keV. As a result, the techniques of in-situ neutron spectrum measurement in the whole energy were established for D-T fusion environment at FNS with combination of the SDT method and the existing proton-recoil methods for higher energies. (author)