Mproved Fluoroglass Dosimeter as Personnel Monitoring Dosimeter and Microdosimeter

Abstract

Low pre-dose and low-Z silver-activated phosphate glass was studied. With due regard to measurement errors, a newly-contrived optical system has been employed. This system is insensitive to dirt on glass and its holder, and limits the predose fluorescence due to the holder to a value lower than 8 per cent of that in the prototype. The mechanical accuracy of positioning of the glass is improved. The null detecting method is utilized for the sake of accuracy and sensitivity. Filters for X-and gamma rays have been studied and badge cases and finger ring cases for X-and gamma rays and thermal neutrons have been developed. On account of these new contrivances, reproducibility and sensitivity have been considerably elevated, that is, the 8x8x4.7 mm glass has an accuracy of [plus or minus]15% for 10 mR, [plus or minus]6 per cent for 25 mR and [plus or minus]2 per cent for 50 mR of gamma rays. The newly devised holder for fluorods (1 mm [PHI] X 6 mm) eliminates errors due to uncertainties of positioning and dirt on glass, and the standard deviation for 500 R becomes 1.4%. A gold sheath shielding case for fluorods is described. A method of dose assessment of X-rays and co-existing X- and gamma rays and a very simple method of photon dose assessment from 40 keV to 1.25 MeV are described. The fading of this glass is reported. This improved dosimeter is discussed compared with film dosimetry and as a microdosimeter compared with other microdosimeters.