Mixed Field Personnel Dosimetry, Part I: High Temperature Peak Characteristics of the Reader-annealed Tld-600*

~ The high temperature peaks (TL peaks 6-7) of TLD-600 are known to have higher responses to high LET radiation than to low LET radiation. These high temperature peak characteristics were studied for the automatic readerannealed Harshaw albedo neutron TLD. The high temperature peaks response is linear for neutrons over the dose equivalent range tested (0.05-3 mSv of a 252Cf source moderated by a 15 cm radius polyethylene sphere), but is supralinear above 20 mSv of 137Cs photons. The peaks ratio (peaks 6-‘l/peaks 3-5) of TLD-600 is 0.15 for neutrons of any incident energy, 0.01 for 137Cs gammas, and 0.02 for M150 x-rays. Based on the high temperature peak characteristics, a mixed field neutron-photon personnel dosimetry methodology using a single TLD-600 element was developed. The dosimetric method was evaluated in mixed 238PuBe + 137Cs fields with four neutron-gamma dose equivalent ratios, and the neutron, photon and total dose equivalent estimations are better than 20% except in one case. However, it was found that the neutron and photon dose equivalent estimations are sensitive to the neutron and photon peaks ratios, depending on the neutron-photon dose equivalent ratio and the neutron source in the mixed field. Therefore, a successful use of this method requires knowledge of the photon and neutron energies in the mixed field. Contributed to the Eighth International Congress of IRPA, Montreal, Canada, May 17-2.2, 1992. * Work supported by Department of Energy contract DE-AC03-76SF00515.