Several types of commercially available ceramic Be0 are evaluated for thermoluminescence and combined thermolurninescence-exoelectron dosimetry (TLD-TSEE) . The ceramic Thermalox 995 is superior in nearly all respects. Physical and chemical treatments which enhance or reduce sensitivity and stability of TSEE exert often similar influences on the TL. A thin surface region, which is rich in impurities, suppresses spurious emissions of both light and electrons and allows combined TL and TSEE measurements to be made on the same B e 0 disk. The luminescence is a maximum at 260 nm requiring a reader with a u.v.-sensitive photomultiplier tube. The characteristics important for TLD are as follows: a lower exposure limit of 1 mR with supralinearity starting at 10 R; only 10 % fading after 3 months at 3OoC and 90 % relative humidity, but rapid bleaching in laboratory fluorescent lighting of 50 % in 30 min; and an energy dependence of response similar to that of LiF TLD.

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Enewetak Atoll is one of the Pacific atolls used for atmospheric testing of U.S. nuclear weapons. Beta dose and gamma-ray exposure measurements were made on two islands of the Enewetak Atoll during July-August 1976 to determine the beta and low energy gamma-contribution to the total external radiation doses to the returning Marshallese. Measurements were made at numerous locations with thermoluminescent dosimeters (TLD), pressurized ionization chambers, portable NaI detectors, and thin-window pancake GM probes. Results of the TLD measurements with and without a beta-attenuator indicate that approx. 29% of the total dose rate at 1 m in air is due to beta- or low energy gamma-contribution. The contribution at any particular site, however, is somewhat dependent on ground cover, since a minimal amount of vegetation will reduce it significantly from that over bare soil, but thick stands of vegetation have little effect on any further reductions. Integral 30-yr external shallow dose estimates for future inhabitants were made and compared with external dose estimates of a previous large scale radiological survey (En73). Integral 30-yr shallow external dose estimates are 25-50% higher than whole body estimates. Due to the low penetrating ability of the beta's or low energy gamma's, however, several remedial actions can be taken to reduce the shallow dose contribution to the total external dose.

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