A Geiger-Mueller detector with a “pancake” probe is being used to monitor workers leaving a radiologically controlled area for contamination.
The probe is sensitive to alpha, beta, and gamma radiation.
The background count rate is 20 cpm.
As one worker’s shoe is scanned, the count rate increases to 1,000 cpm.
Given the following separate actions:
• When a sheet of paper is placed between the probe and the shoe, the count rate decreases to 400 cpm.
• When a sheet of aluminum foil is placed between the probe and the shoe, the count rate decreases to 20 cpm.
The results of the above actions indicate that the radiation from the shoe contamination consists of…
A. beta only.
B. alpha and beta only.
C. beta and gamma only.
D. alpha, beta, and gamma.
Show Answer
Answer: B
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