crystal of se"'um iodide, thallhhum iodide activated, The TH-7-A uses the same phosphor and circuit as the Top Hat radiatic ‘ector meter and has a nearly air-equivalent energy .esponse. The unit has a logarithmic scale, calibrated from 1 mr/hr to 10 r/hr. 4 inches in The circuits meter section is calibrated in seven ranges from 100 The standard high-sensitivity scintameter, TH-3-B to 100,600 counts/sec. The base line may be seiected as 3, 1.5, or 0.75 Mevfull scale and swept automati- uses a sodium iodide detector that has an energydependent dose-rate response (Figure B.2). It has a logarithmic scale, calibrated from 0.01 to 100 mr/hr. cally from 1 minute to 4 hours for the full-energy scan. Data is displaved on a Mosely Autograf 2, X-Y recorder. B.6 GAMMA SPECTROMETER, HASL TM-10-A The unit operates on 115-volt, 60-cps current. The gamma spectrometer is a single-channel, automatic-sweep pulse-height analyzer. neter and 4 inches fugh. are designed to handle high pulse rates, and the rute- Its detector is a For helicopter use, external inverters must be supplied to invert the 28-volt current of the aircraft. DOE ARCHIVES 65 (, | so er Teper eee FORRES me em SOR SO AE AN, CRE ETS Me RE em ,