Identification of neutrons from the cooling water of a GeV electron accelerator

Abstract

Measurements were made on delayed neutrons emitted by the cooling water of a beam dump for GeV electrons produced by the accelerator at the Stanford Linear Accelerator Center. A ³He spectrometer was used to measure the energy spectrum and a BF₃ counter was used to measure the half-life of the neutron activity. The spectrum showed neutron groups at 383, 1170 and 1700 keV and the possibility of another group at 2070 keV. The three lower groups, in combination with the measured half-life of 4.4±0.2 s, indicate that most of the delayed neutrons were emitted by ¹⁷N produced by the ¹⁸O(gg, p)¹⁷N reaction.