Studies on the Surface Charge Distribution of Radon Exposed Electrets Within an Electret Ionisation Chamber

Abstract

For studying the processes inside an electret ionisation chamber the charge distribution on the electret surface was measured using an automatic scanning device constructed using a non-contacting voltmeter. A series of such measurements of electrets exposed to radon within an electret ionisation chamber shows a changing shape of the charge distribution. The initial shape of the charge distribution depends on the method of electret charging, whereas the discharging processes depends on the chamber design and the electric field. Investigations have also been made in how far small areas charged with opposite sign affect the readings of radon concentration. The data are used to calculate the recombination loss inside the chamber and to optimise the chamber design.