Improvements to the Leake neutron detector III: Increased sensitivity and compliance with ANSI and IEC standards

We report on an improved design, HSREM(IEC) of a spherical polyethylene moderator neutron detector with an internal shield of boron that is based on the NGREM. This has nearly three times the neutron sensitivity of the NGREM and complies with the energy requirements of the recently published third edition of IEC 61005. A second detector, HSREM, has a slightly higher sensitivity and is compliant with ANSI N42.17A:2003. We also report on a modified version of the NGREM, NGREM(IEC), that is fully compliant with IEC 61005:2014 and has a similar sensitivity to the existing model. Finally, we show that the present NGREM can comply with the ANSI spec.