Design of a Positionally Sensitive Laser-heated Thermoluminescent Detector System

Abstract

The design and performance of a positionally sensitive system for the laser read-out of dosimetric information contained in LiF chips and a specially designed composite detector having a thin LiF layer is reported. A 2 cm X 3 cm X 0.254 mm LiF layer was successfully manufactured with a glass backing; however, this was subject to thermal cracking at high temperatures encountered with laser heating. Multiple spot heating of this plate resulted in dosimetric images having a spatial resolution of approximately 2.5 mm, limited primarily by the laser beam radius, a homogeneity of better than 10%, a reproducibility of less than 7%, and a minimum detectable dose of approximately 3.12 X 10(-4) C kg-1 (1.21 R). Observed glow curves were consistent with those predicted theoretically using a first-order kinetic model and assuming rapid heating conditions. Several images of positional radiation dose produced using an x-ray machine are presented.