Thermoluminescent properties of some phosphor glasses based on aluminum oxide.

The transparent thermoluminescent aluminum oxide-based glass of 15Al2 O3 -35P2 O5 -25CaO-25Na2 CO3 , abbreviated as APCN (all in mol%) doped with different concentrations of SiO2 from 0.0-500 ppm was prepared using a conventional melt-quenching technique. The TL sensitivities of the prepared glasses were investigated at 3 Gy γ-dose using a 60 Co source and measured at a heating rate 10 C/sec. The highest TL intensity of the material doped with SiO2 was found at a concentration of 500 ppm (APCNSi5 ). Deconvolution of the glow curve from APCNSi5 resulted in four peaks at about 161, 194, 237 and 293 C with a Figure Of Merit (FOM) of 1.28%. The APCNSi5 specimen had the best dosimetric properties when compared with the other samples. Reproducibility, repeatability, dose-response curve and fading effect were checked for peak 3, which appeared at about 237 C. The results displayed that the APCNSi5 glass system was a low-Z material (Zeff ≈ 10), and had good reproducibility and good repeatability. Peak 3 showed good linearity over a dose range up to 20 Gy (R2 = 0.999) and sublinearity behaviour was found. The signal from APCNSi5 faded by about 11% after 2 days post irradiation, therefore it showed almost no significant loss. Such properties make the newly prepared glasses suitable for and highly recommended for use in γ-dosimeters. Copyright © 2016 John Wiley & Sons, Ltd.

Airborne 222Rn concentration in an Egyptian village.

The indoor radon concentration in a typical Egyptian village in Delta was measured in 50 houses during summer 1999 and winter 2000. This survey was done using three different types of charcoal canisters: 4" open-faced, 2.75" open-faced, and 2.75" diffusion barrier. The average winter to summer ratio was 2.1 and 1.2 for open rooms and closed rooms, respectively, in clay buildings, while it was 0.8 and 1.0, respectively, in concrete buildings. The seasonal variations of radon concentration as well as the effect of building materials were discussed.

Temperature and humidity consideration for calculating airborne 222Rn using activated charcoal canisters.

A radon calibration chamber with variable and controlled radon concentration, humidity, and temperature was constructed and used to extend the calibration range of open-faced and diffusion-barrier charcoal canisters for higher temperature and humidity applications. The optimum exposure time to achieve the best detection accuracy and the lowest minimum detectable level was between 2 and 4 d depending on relative humidity for open-faced canister and 4 d for diffusion barrier canister over a range of humidity. The dependence of radon adsorption on the temperature was also studied for both types of canister at different values of relative humidity. The open-faced canisters at 15 degrees C absorb 68% more radon than at 30 degrees C over the range of humidity from 20% to 80%. The diffusion-barrier canister shows insignificant variation in absorption over the same range of temperature and humidity.