Abstract
CaSO4:Dy phosphor prepared by a new recipe (denoted as N) is nearly 50% more sensitive than the presently used one (denoted as P). N consists of needle shaped crystals while P is mostly quadrilateral. In P most of the grains in as-grown condition are >75 μm in size while in N most of the grains are <75 μm. While the sensitivity of P increases with grain size, an exactly opposite trend is seen with N since higher sized grains (>105 μm) in N are agglomerates of particles and hence are opaque. The detection threshold of N (14.4 μGy) is nearly 4 times lower than that of P (54.2 μGy). The major glow peak(s) in both the phosphors occur in the 460-490 K (187-217°C) region. But the low temperature peak near 390 K (117°C) is very prominent in P while its presence is insignificant in N. The post-irradiation storage stability of N at -30°C was tested up to a period of 25 d and found to be better than that of P. The emission spectra of P and N are characteristic of Dy3+:. In P, the 480 nm to 570 nm emission intensity ratio varies slightly with glow peak temperature, unlike that of N. The Dy concentration quenching effect in N is less serious than that in P. The intrinsic UV sensitivity of N is nearly a factor of 20 times lower than that of P.
Original language | English |
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Pages (from-to) | 235-238 |
Number of pages | 4 |
Journal | Radiation Protection Dosimetry |
Volume | 100 |
Issue number | 1-4 |
DOIs | |
State | Published - 1 Jan 2002 |
Externally published | Yes |
ASJC Scopus subject areas
- Radiation
- Radiological and Ultrasound Technology
- Radiology Nuclear Medicine and imaging
- Public Health, Environmental and Occupational Health