Error prediction of LiF-TLD used for gamma dose measurement for BNCT

Abstract

To predict the neutron influence on various (6)LiF concentration in the LiF-TLD, the Monte Carlo code MCNP was adopted to simulate the energy deposition on a TLD chip with dimensions of 3.2×3.2×0.9 mm. By assuming that the TL response is proportional to the energy deposition on it, the percentage error of LiF-TLD used for gamma dose measurement in mixed (n, γ) fields can be written as: %Error=R(n)/R(g)×100%. Where R(n) and R(g) are the TL responses resulted from neutron and gamma, respectively. Taking the water phantom irradiated with the BNCT facility at the Tsing Hua Open-pool Reactor (THOR) as an example, the (6)LiF concentration for TLD-700 is 0.007%, the magnitude of the neutron flux is ~1×10(9) n/cm(2)/s, the neutron energy is ~4×10(-7) MeV (cadmium cut-off energy), the gamma dose rate is ~3 Gy/h, thus the percentage error can be predicted as 38%.