A New Type of Spurious Reading in TL Personnel Monitoring

A particularly serious type of spurious reading in automated TL personnel monitoring has been observed. These readings simulate dose values up to several mSv and can only be detected by glow curve analysis. Characteristic for these events are high artifical dose values and irregular glow curves of a particular shape. Extensive investigations to reproduce this effect purposely failed to produce any results. It can be assumed, however, that it must be some chemical surface contamination, which penetrates the sealed dosemeter bag or which is transferred from the bag to the detector. The effect can be eliminated by manual cleaning of the dosemeter cards. The importance of this observation lies in the fact that only proper glow curve evaluation can prevent the monitoring service from reporting artificial high dose readings creating lots of serious problems. The paper shows how this problem can be avoided for this kind of spurious effect, if glow cuves are available and stored for every dosemeter readout.