Uncertainty analysis of Hp(10)meas/Hp(10)del ratio for TLD-100H at energy 24-1250 keV

Abstract

The Hp(10) of an ideal TLD is independent of photon energy. This is to say that at any photon energy, the ratio R of the measured dose Hp(10)meas to the delivered dose Hp(10)del is always 1. In practice however the Hp(10) is dependent on the energy and R is not equal to 1. For this reason, ICRP has set the lower limit LL and upper limit UL for R as 0.55≤R≤1.63 for detection limit of 0.1 mSv and Hp(10)del=1 mSv. As R is the quantity arises from the measurement processes, the existence of uncertainty of R, i.e. {increment}R is inevitable. In the boundary cases, such as when R is slightly lower than LL or slightly larger than UL, {increment}R would serve a useful quantity in decision making either to accept or to reject the value of R. The purpose of the present work is to estimate {increment}R for the TLD-100H for photon energy of 24-1250 keV. The estimation of {increment}R is based on the error propagation method. For the eleven photon energies, this work obtained (a) R in the range of 0.77 to 1.16, (b) {increment}R in the range of ± 0.02 to ± 0.04. The values of R were satisfactory as they complied the ICRP limit. The determined {increment}R is considered very small as it is in the order of 3% in comparison of R.