Response of LiF: Mg, Cu, P TL Detector Simulated with Geant4

Abstract

The Geant4 simulation code was developed to study the H p (10) energy response of the LiF:Mg,Cu,P (TLD-100H). Initial study chose the simulation conditions similar to the work reported by Obryk et al. in year 2011, in which a TLD-100H chip without filter was used. The work went further to simulate the H p (10) results obtained experimentally at SSDL Malaysia. The experiment used a TLD-100H chip embedded in a TLD card and the card was enclosed in a badge complete with PTFE filter. Irradiation with eleven photon energies in the range of 24-1250 keV was applied. The simulation code therefore took into accounts the details of the badge (the materials type and the dimensions of the chip, the card, the badge and the filters) and the setup of the experiment (the source distance and the energies). In comparison with Obryk's work, the simulation code yielded the mean deviation of 0.59%. For the experimental work, the simulated H p (10) curves obtained were quite similar and comparable and a mean deviation of 13.96% was obtained. As both 0.59% and 13.96% deviations are within the acceptable limit of ±25%, it was concluded that a satisfactory level of accuracy has been achieved by the developed simulation code and the selection materials and physics processes that have been adapted in the code were correct. Sources of uncertainty that has contributed to this deviation are discussed.

Geant4 Simulation of Number of Event Effect on the TLD LiF: Mg, Cu, P Energy Response

“…The lowest deviation value with a minimum computational time was yielded when 2×10 9 number of events were selected. From this number upwards, both the deviation value and the computational time keep increasing until the maximum number of events that can be handled by the CPU (2×10 12 ).…”

“…However, based on previous studies, it was reported that a flat energy response, especially for TLD: LiF: Mg, Cu, P can only be achieved at high energy (> 500 keV). Whereas at low energy (<500 keV), this has not been materialized [10][11] [12].…”