A Geiger-Mueller detector with a “pancake” probe (often called a frisker) is being used to monitor workers leaving a radiologically controlled area for contamination.
The probe is equipped with a mica window.
The background detector count rate is 20 cpm.
As one worker’s shoe is scanned the count rate increases to 200 cpm.
When a sheet of paper is placed between the probe and the shoe, the count rate decreases to 60 cpm.
Which one of the following is indicated by the decrease in the count rate?
A. The contamination contains beta particles.
B. The contamination contains alpha particles.
C. The contamination does not contain beta particles.
D. The contamination does not contain alpha particles.
Show Answer
Answer: B
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