The research on neutron dose equivalent meter for pulse neutron radiation field

Abstract

This paper introduces a new type of real-time neutron dosimeter that can reduce the counting loss of a general neutron dosimeter in a pulsed neutron field or strong neutron field, such as in the area of high-energy physics equipment, accelerator, and light source. In a general neutron dosimeter, signal is transmitted from the BF3 proportional counter tube, via the charge-sensitive pre-amplifier, the main amplifier, and the discriminator that filtering γ background and noise, and finally to the counter, and the counting will be converted to Sv or Sv/h. Based on general neutron dosimeter, by using the proportional relationship of the electric charge and the energy loss of the particle in the tube, when several neutrons are recorded simultaneously, the amplitude of the output impulse rises. Several Regions of Interest (ROIs) can be set in the pulse amplitude spectrum measured by multi-channel pulse amplitude analyzer (MCA) for one-neutron pulse, two-neutron-overlapping pulse and three-neutron-overlapping pulse. By individually integrating the count in these ROIs and multiplying with proper coefficient, the actual neutron influence can be obtained. The influence represents the neutron dose equivalent. The pulse amplitude spectrum obtained by multi-channel analyzer (MCA) in a pulsed neutron field shows that the peaks in the spectrum correspond to the energy of one neutron reaction, and two or three neutrons reacting simultaneously. The ROIs are set according to corresponding peaks. The experiment shows that the method can reduce the counting loss of a neutron dosimeter in a strong neutron field.