Optimization of the Photon Response for a LiF Thermoluminescent Dosimeter
NAVAL ACADEMY ANNAPOLIS MD
Pagination or Media Count:
A Harshaw LiF TLD card holder was optimized for maximum discrimination between different energies of irradiating photons in order to improve the dosimetric response. Since dose is proportional energy deposited, a theoretical model was created to estimate the TLD response by calculating the energy deposition. These results correlated with experimental data from NIST to within 20. In order to increase the accuracy of the model, energy deposition calculations were made using the MCNP particle transport program. MCNP improved the correlation of the modeled data with the experimental data. Next, Harshaws 8825 card holder was optimized for photon energy determination by analyzing the card holders response with different filter materials and thickness. This analysis showed that increasing the copper filter thickness by 20 times and doubling the tin filter thickness compared to the original 8825 design improved the TLDs photon energy determination response. The improved 8825 card holder was constructed and experiments were conducted at Armstrong Laboratories. The MCNP model predicted the experimental response of the card holder to within two standard deviations for all beams except M60. Finally, recommendations for a new card holder were made by Naval Dosimetry Center which included a modified filter for improved dose determination.
- Nuclear Instrumentation