New developments in the thermoluminescent dosimetry

Renata KopeÃ„Â‡

New developments in the thermoluminescent dosimetry

Renata KopeÃ„Â‡

Institute of Nuclear Physics PAN, Poland

: J Diagn Tech Biomed Anal

Abstract

T he standard measurements of thermoluminescence consist of increasing of temperature of TL material in a controlled way with simultaneous measurement of emitted light. Measurements of light intensity were usually based on thermoluminescent (TLD) detectors and were realized almost entirely with use of photomultipliers (PM). Since 2005 at the Institute of Nuclear Physics of the Polish Academy of Sciences, especially 2D thermoluminescent (TL) reader with CCD camera has been developed. The ultrasensitive 12-bit monochromatic CCD camera is applied instead of PM. The results from that system are 2-D images of TL lighting. Two- dimensional (2-D) thermoluminescence (TL) dosimetry system was tested by evaluating 2-D dose distributions around radioactive sources for different purposes e.g.: radiotherapy, radiology and individual dosimetry. The other new developed TL method is dose reassessment based on photo transferred thermoluminescence (PTTL). It demonstrated the possibility of applying PTTL for dose reassessment in MTS-N TL detectors routinely applied in the dosimetric service at IFJ PAN. Readings of TL detectors exposed to relatively high doses by the customers of the dosimetry service can now be reassessed using our automatic readers. A major obstacle in applying the PTTL method at lower exposures is the presence of residual dose accumulated in LiF: Mg, Ti detectors after many field exposure and readout cycles.