RADIOACTIVITY METHODS 



1001 



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Fig. 616. — (Left) Counting rate meter with three stages of sensitivity. (A) G-M tube, (B) meter, 

 (C) sensitivity switch, (D) phone jack for audio counting. (Right) Quick change plug-in assembly 

 for multi-stage sensitivity counter. (E) subminiature tubes, (F) battery connector, (G) sensitivity 

 switch, (H) R-C coupling. (Courtesy of Precision Radiation Instruments, Inc.) 



Fig. 617. — Radioactivity logging equipment for diamond drill holes: (A) cable; (B) 

 tripod support for guide sheave; (C) reel; (D) recording equipment; (E) sheave wheel; 

 (F) tripod brae?. 



