Development of a New Method for Measurement of Neutron Detector Efficiency up to 20 MeV

摘要

A new approach to neutron detector efficiency detemination has been taken. A neutron detector has been calibrated with a ~(252)Cf source at low energy. The calibration can be extended to energies above 8 MeV with accelerator-based neutron sources. This techniques uses the fact that the cross section for a symmetric reaction with nucleus of atomic number A yielding a final nucleus with atomic number (2A - 1) and a neutron A + A → (2A - 1) + n, This reaction must be symmetric about 90° in the center-of-mass system. The laboratory energies for the neutrons at the paired energies differ substantially. Thus, an efficiency known at one of the two angles can be used to determine the efficiency to higher energies or, for a negative Q, to lower neutron energies.