The TH-7-A uses the same phosphor and circuit as
the Top Hut radiation detector meter art bis a nearly
air-equivalent energy response. The unit has a loga-
erystal of sodium iodide, thallium iodide activ
rithmic scale, calibrated from 1 mr/hr to 10 r/hr.
meter section is calibrated in seven ranges from 10C
to 100,000 counts/sec. The base line maybe selected
as 3, 1.5, or 0.75 Mev full scale and swept autor iat:-
The standard high-sensitivity scintameter, TH-3-B
uses a sodium indice detector that has an energy
dependent dost -rate response (Figure B.2). It has a
logarithmic scale, calibrated from 0.01 to 100 mr,’/hr.
B.6 GAMMA SPECTROMETER,
HASL TM-10-A
4 inches in diameter and 4 inches high.
tet,
The circuits
are designed to handle high pulse rates, are the rate
eally from 1 minut? ta 4 hours for the full-energy scan
Data is displayer} on a Mosely Autograf 2, X-¥Y
recorder.
The unit operates on 115-volt, 60-cps current.
The gamma spectrometeris a single-channel, automatic-sweep pulse-height analyzer. Its detector isa
65
For
helicopter use, external inverters must be supplied to
invert the 28-volt current of the aircraft.