Geiger counter backgrounds

Abstract

An extensive study of counting backgrounds in ten essentially identical Geiger counters is reported. Important long-term time variations were found; their rate is generally less than ½% per day, they change direction frequently and their total magnitude averages about 6%. They could not be correlated with counter efficiency, and were not, in general, correlated among the different counters. Consecutive day differences were generally less than 1%, although about 20% of the time there were non-statistical variations in the same direction in all counters, averaging 2.3% in magnitude. No day-night variations were detected within an accuracy of one part in 300. Temperature effects were found to be extremely important. An experience with an area-wide air contamination is discussed.