Measurement of Low-Yield Pulse Neutron by Dy Activation

A polyethylene moderator was designed for moderating d-T and d-D neutrons from neutron generator. The cross-section of ¹⁶⁴Dy(n,γ)¹⁶⁵Dy^m is very large for the thermal neutron, so that lots of ¹⁶⁵Dy^m are produced in the moderator. The half life of ¹⁶⁵Dy^m is 75 s, and it emits ample gamma rays. The gamma rays were measured by HPGe detector. The amount of γ-ray is proportional to the neutron yield, hence the yield of pulse neutron source can be measured.