The Use of a Helium-3 Filled Proportional Counter as a Sensitive Dose or Dose Equivalent Meter

When properly processed, the pulses resulting from fast neutron interaction in a high pressure, helium-3 proportional counter can be used to form the basis for a sensitive dose or dose equivalent meter. Such a system has been constructed from commercially available NIM modules. The system has been tested using neutrons having energies in the range 0.2 to 18 MeV. The counting rate is such that 1 microrad of 1 MeV neutrons can be measured with a precision of 0.1 microrad. The background counting rate is of the order of 1 microrad/hr.