Abstract: A dual-track counting method and a detector structure for measuring low energy neutrons (energy below 0.5 eV) with a solid state nuclear track detector are described. The detector track density per unit area induced by low energy neutron was analyzed by both Monte Carlo simulation and field experiments. The results showed that the dual-track counting method achieved the response of CR39 to low energy neutrons, suggesting that individual dose induced by low energy neutron could be estimated with this method. The energy response range of CR39 was extended so that low energy neutrons with fluence of less than 104 could be measured. The dual-track counting method can effectively discriminate the background track for monitoring of personal neutron dose, thus the measurement uncertainty is reduced.

Key words: CR39 solid state nuclear track detector, low energy neutron, Monte Carlo simulation, dual-track counting