Identification of Abnormal Curves in Thermoluminescent Personnel Dosimetry

The personal Dosimetry Service Seibersdorf analyses monthly a large number of thermoluminescent dosemeters. These dosemeters consist of LiF:Ti, Mg chips mounted between teflon foils on aluminium cards. These cards are wrapped and heat sealed in thin aluminised plastic bags and are worn in plastic badges with one open window and an aluminium filter. The readout is carried out with an automated Harshaw reader system. In rare cases the luminescent glow curves of the routine analyse do not have the expected form. They have an abnormal shape as a result of external chemical contamination, hardware problems, poor heat transfer, etc. It is therefore interesting to investigate the reasons for the irregularity of these curves.