Response of a neutron monitor area with TLDs pairs

Abstract

The response of a passive neutron monitor area has been calculated using the Monte Carlo code MCNP5. The response was the amount of n(6Li, T) reactions occurring in a TLD600 located at the center of a cylindrical polyethylene moderator. Fluence, (n, a) and H*(10) responses were calculated for 47 monoenergetic neutron sources. The H*(10) relative response was compared with responses of commercially available neutron monitors being alike. Due to 6Li cross section (n, ) reactions are mainly produced by thermal neutrons, however TLD600 is sensitive to gamma-rays; to eliminate the signal due to photons monitor area was built to hold 2 pairs of TLD600 and 2 pairs of TLD700, thus from the difference between TLD600 and TLD700 readouts the net signal due to neutrons is obtained. The monitor area was calibrated at the Universidad Politecnica de Madrid using a 241AmBe neutron source; net TLD readout was compared with the H*(10) measured with a Berthold LB6411. Performance of the neutron monitor area was determined through two independent experiments, in both cases the H*(10) was statistically equal to H*(10) measured with a Berthold LB6411. Neutron monitor area with TLDs pairs can be used in working areas with intense, mixed and pulsed radiation fields.