1987 Neutron and gamma personnel dosimeter intercomparison study using a D/sub 2/O-moderated /sup 252/Cf source

Abstract

The thirteenth Personnel Dosimetry Intercomparison Study (i.e., PDIS 13) was conducted during April 1987 as a joint effort by Oak Ridge National Laboratory's (ORNL) Dosimetry Applications Research Group and the Southwest Radiation Calibration Center at the University of Arkansas. A total of 48 organizations (34 from the US and 14 from abroad) participated in PDIS 13. Participants submitted a total of 1,113 neutron and gamma dosimeters for this mixed field study. The dosimeters were transferred by mail and were handled by experimental personnel at ORNL and the University of Arkansas. The type of neutron dosimeter and the percentage of participants submitting that type are as follows: TLD-albedo (49%), direct interaction TLD (31%), CR-39 (17%), film (3%). The type of gamma dosimeter and the percentage of participants submitting that type are as follows: Li/sub 2/B/sub 4/O/sub 7/, alone or in combination with CaSO/sub 4/, (69%), /sup 7/LiF (28%), natural LiF (3%). Radiation exposures in PDIS 13 were limited to 0.5 and 1.5 mSv from /sup 252/Cf moderated by 15-cm of D/sub 2/O. Traditional exposures using the Health Physics Research Reactor (HPRR) were not possible due to the fact that all reactors at ORNL, including the HPRR, were shutdown by order of the Department of Energy at the time the intercomparison was performed. Planned exposures using a /sup 238/PuBe source were negated by a faulty timing mechanism. Based on accuracy and precision, direct interaction TLD dosimeters exhibited the best performance in PDIS 13 neutron measurements. They were followed, in order of best performance, by CR-39, TLD albedo, and film. The Li/sub 2/B/sub 4/O/sub 7/ type TLD dosimeters exhibited the best performance in PDIS 13 gamma measurements. They were followed by natural LiF, /sup 7/LiF, and film. 12 refs., 1 fig., 5 tabs.