Pulse shape discrimination in hydrogen-filled proportional counters by digital methods

A fast digital sampler has been employed in place of conventional analogue electronics to measure the rise times and amplitudes of pulses from a hydrogen-filled spherical proportional counter of the SP2 type. The rise-time information was used to distinguish neutron events from gammas, and separated neutron events were recorded at energies below those that would have been possible with amplitude measurements alone. The electronics were considerably simpler than those required for an equivalent analogue system.