A fully automated and fast pneumatic transport system for short-time activation analysis was recently developed. It is suitable for small nuclear research reactors or laboratories that are using neutron generators and other neutron sources. It is equipped with a programmable logic controller, software package, and 12 devices to facilitate optimal analytical procedures. 550 ms were only necessary to transfer the irradiated capsule (diameter: 15 mm, length: 50 mm, weight: 4 gram) to the counting chamber at a distance of 20 meters using pressurized air (4 bars) as a transport gas.
Accidents resulting in widespread dispersal of radioactive materials have given rise to a need for materials that are convenient in allowing individual dose assessment. The present study examines natural Dead Sea salt adopted as a model thermoluminescence dosimetry system. Samples were prepared in two different forms, loose-raw and loose-ground, subsequently exposed to 60 Co gamma-rays, delivering doses in the range 2-10 Gy. Key thermoluminescence (TL) properties were examined, including glow curves, dose response, sensitivity, reproducibility and fading. Glow curves shapes were found to be independent of given dose, prominent TL peaks for the raw and ground samples appearing in the temperature ranges 361-385 ºC and 366-401 ºC, respectively. The deconvolution of glow curves has been undertaken using GlowFit, resulting in ten overlapping first-order kinetic glow peaks. For both sample forms, the integrated TL yield displays linearity of response with dose, the loose-raw salt showing some 2.5 × the sensitivity of the ground salt. The samples showed similar degrees of fading, with respective residual signals 28 days post-irradiation of 66% and 62% for the ground and raw forms respectively; conversely, confronted by light-induced fading the respective signal losses were 62% and 80%. The effective atomic number of the Dead Sea salt of 16.3 is comparable to that of TLD-200 (Z eff 16.3), suitable as an environmental radiation monitor in accident situations but requiring careful calibration in the reconstruction of soft tissue dose (soft tissue Z eff 7.2). Sample luminescence studies were carried out via Raman and Photoluminescence spectroscopy as well as X-ray diffraction, ionizing radiation dependent variation in lattice structure being found to influence TL response.
The level of 137Cs in 28 species of mushroom collected and analyzed between 1986 and 1992, after the Chernobyl accident, are reported. Xerocomus badius was found to accumulate 137Cs (the median value of 58 samples is 3667 Bq/kg). The 137Cs content of Rozites caperata, Scleroderma vulgare, and Tylopilus felleus exceeded 600 Bq/kg. Some of these samples collected in August 1992 were investigated for their 134Cs and 137Cs content as well as their Na, K, Rb, and Cs levels by applying instrumental neutron activation analysis (INAA). The results show a high correlation coefficient (0.80) between the contents of 137Cs and Na, but none between 137Cs and K.
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