What is the maximum acceptable background for personnel survey with a Beta-Gamma Pancake Detector?

The maximum acceptable background for personnel surveys with a Beta-Gamma Pancake Detector is set to ensure that any detected radiation is distinguishable from normal environmental levels. In this context, 300 counts per minute (CPM) is considered the maximum acceptable level because it allows for effective monitoring while still accounting for variations in background radiation. The Pancake Detector is designed to measure beta and gamma radiation, and a threshold like 300 CPM is established as a typical cutoff for when further investigation might be warranted or when a detected reading is deemed significant in relation to normal background levels.

Choosing this value helps ensure that personnel are not alarmed unnecessarily by fluctuations in background radiation that can occur in various environments. Other suggested options, being lower than 300 CPM, do not accurately reflect the established threshold used by facilities for monitoring personnel radiation exposure effectively.