Preparation of a liquid nitrogen target for measurement of γ-rays in the 14N( n , γ ) 15N reaction as an intensity standard in energy regions up to 11 MeV

We have developed a liquid nitrogen (N 2) target that allows us to clearly measure γ-rays below 2 MeV and to improve neutron beam availability. The intensity of the prompt 2223 keV γ-ray from the 1H( n , γ ) reaction in the present target could be reduced to about 1 60 in comparison with the one in the commercially available melamine (C 3H 6N 6) target. The statistics of the full-energy-peak counts were improved by factors of 15–30 and about 4 in the energy regions below and above 2 MeV, respectively.