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

To predict the neutron influence on various 6LiF 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=Rn/Rg×100%. Where Rn and Rg 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 6LiF concentration for TLD-700 is 0.007%, the magnitude of the neutron flux is ∼1×109 n/cm2/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%.