THE RESPONSE OF A MOVING GEIGER PROBE TO DISCRETE SOURCES OF BETA RADIATION

摘要

Recent experiments at Harwell, reported in AERE-R 4264, have shown that the efficiency with which the average person detects contamination on his clothing with a contamination monitor is considerably less than was hitherto supposed. As a further contribution to this problem the present paper investigates the response of a standard instrument when its geiger probe is moved over radioactive sources at different distances and velocities. The results are compared with a simple theory which is applicable if the time constant of the ratemeter is greater than the time during which the moving probe records counts from the source.nThe peak response is found to be inversely proportional to velocity and not strongly dependent on distance. Detection thresholds in terms of source strength are in the range 0.01 to 0.1μc.