A precision broad-range dosimeter based on cerium doped yttrium aluminum perovskite (YAP)

Among the properties of YAP relevant for dosimetry are its rapid (∼28 ns) dominant (97%) bright (∼40% of NaI:Tl) decay with neligible afterglow as well as its physical ruggedness and chemical nonreactivity. Our recent success with YAP-based x-ray, γ-ray, and alpha particle detectors encouraged us to use a YAP scintillator in a broad range (20-3,000 keV) portable dosimeter. Its large Compton-to-photoabsorption cross section ration makes YAP response relatively energy insensitive and so it becomes a promising phosphor for accurately measuring exposure, equivalent, and absorbed doses. Its stopping power and speed allow a YAP-based dosimeter to operate over more than five decades of exposure dose (5 μR/h to 1 R/h) using only a single small (25 mm diameter, 15 mm thick) crystal. In a radiation field of (∼10 μR/h) (∼20 counts/s) a statistical precession of ∼15% can be obtained in ∼10 s. In implementing our broad-range YAP-based dosimeter we have used spectrometric signal processing and a measured absorbed energy data correction algorithm which provides the possibility of reducing the measured dose energy dependence to ±10% over the full energy range. We have verified our instrument using usual γ-ray sources. To extend the dosimeter range down to ∼5 keV we are constructing a combination YAP-plastic scintillator