A. D. Zych

Spark chamber and time-of-flight detector for 15-150 MeV neutrons from an extended source

Abstract A new detection method for 15–150 MeV neutrons from an extended source utilizes a spark chamber time-of-flight technique. Both secondary particles in an n-p scatter are measured - the recoil proton in a spark chamber and the scattered neutron in a time-of-flight hodoscope, enabling the direction and energy of the incident neutron to be determined uniquely. Carbon events in the CH 2 radiator are separated from n-p scatters by the 90° kinamatical rewquirement between the secondary particles. The detection efficiency is 1x10 −4 at 70 MeV, the acceptance cone 40°, the angular resolution 3.0° and the energy resolution 10%. The detector has been used on high altitude ballon flights to measure the flux of atmospheric neutrons and to search for solar neutrons.