Long-term sensitivity with an automatic TL personnel dosimetry system

Since the response of thermoluminescent dosimeters are highly affected by systemdependent parameters, any variation in the reader conditions, in the thermal treatment or in the readout parameters may cause significant changes of the relative sensitivity of the system. For this reason the essential parameters determining satisfactory operation of the dosimetry system must be regularly monitored. For most commercially available systems a certain number of controls, like the control of the preheating and heating temperatures or the control of the power supply voltage of the photomultiplier, are carried out automatically. In the daily routine work of a personnel monitoring laboratory these controls have to be complemented by specific measurements which check the general behaviour of the measurement circuit and which make part of the dose evaluation procedure. The analysis of these measurements over a long period permit an estimation of the practical long-term stability of the sensitivity of an automatic radiothermoluminescent dosimetry system. The authors report on the experience gained in the field with the use of a standard Harshaw system of a Swiss personnel monitoring laboratory. 1 ref., 2 figs. (Author)