A Scintillation Counter for Cosmic Ray Neutrons

Abstract

Methods of detecting neutrons with scintillation counters are discussed. It is seen that one method using liquid phosphors should make possible the construction of fast neutron detectors of high efficiency which may provide new information on the neutron component of cosmic rays. The detector recognises neutrons by the occurrence of pulses in pairs: one from recoil protons and the second resulting from the capture of the neutron by some element in the solution. The operation of such a detector is examined. A solution scintillation counter containing boron, with which detection of fast neutrons by the observation of pulse pairs was attempted, is described. It is concluded that, because of the poor response of organic phosphors to heavy particles, solutions containing boron are less likely to be satisfactory than solutions containing cadmium or gadolinium and producing the second pulse by radiative capture.