查看更多>>摘要：In recent years, there has been increasing demand for a scintillator showing near-infrared (NIR) luminescence owing to the potential for radiation monitoring applications. In this study, Pr-doped Bi4Ge3O12 (BGO) single crystals were prepared by the floating zone method to explore candidates as a NIR scintillator, and the luminescence and dose-rate response properties of Pr-doped BGO were studied. Both photoluminescence and scintillation peaks appeared at 400-600 nm due to Bi3+, and sharp emission peaks by Pr3+ were also confirmed at 480-1100 nm, with consistent decay times. Further, to investigate performance as a scintillation detector, a linearity of the response to X-ray exposure dose rate was evaluated. Among the samples, the 0.5% Pr-doped BGO showed the highest sensitivity with the lowest detection limit of 0.006 Gy/h.
查看更多>>摘要：We report thermally-assisted optically stimulated luminescence (TA-OSL) of microcline (KAlSi3O8) from Sri Surya Pahar hill in Assam state, North-Eastern India. To study the luminescence associated with deep electron traps, a beta-irradiated sample was first heated to 500 & DEG;C at 1 oCs(-1) to deplete all electron traps accessible up to this temperature. Thereafter, the sample was illuminated by 470 nm blue-or 870 nm infrared light at various temperatures between 30 and 300? and TA-OSL associated with deep electron traps recorded. The intensity of TA-OSL increased with measurement temperature. The TA-OSL decay curves measured under both types of illumination can be described by a sum of two exponential components. Further, the TA-OSL stimulated by blue light is more intense than that corresponding to infrared light. The TA-OSL is consistent with the presence of at least two types of deep electron traps with differing values of the activation energy for thermal assistance. As regards dose response, the TA-OSL intensity increases sublinearly with dose between 100 and 1000 Gy.
查看更多>>摘要：Optically stimulated luminescence (OSL) and thermoluminescence (TL) are well-described phenomena utilized to measure the absorbed dose of crystalline materials. The techniques are used to monitor low linear energy transfer (LET) radiation (beta, gamma) as well as high-LET heavy charged particles (HCPs). Detector efficiency 'I-det, defined as the ratio of the luminescence per unit dose from a non-reference radiation field compared to the identical quantity from the reference field, is particle and energy dependent. The responses of BeO ceramics exposed to low-energy HCPs were investigated in this work. Dosimeters were bombarded with 1, 2, and 4 MeV protons, as well as 2 and 4 MeV carbon ions; these radiation qualities constitute a mean LET range of 37.6 keV/mu m -628 keV/mu m and were realized using the 2 MV tandem Pelletron particle accelerator at East Carolina University. Each dosimeter was calibrated using a dose response constructed with a(90)Sr/Y-90 beta source, which was calibrated against a(137)Cs gamma source. This enabled 'Idet to be calculated. It was observed that optical and thermal signal shape and magnitude depend on the mean LET. Furthermore, thermal efficiencies are significantly higher than optical efficiencies for all ions investigated.
查看更多>>摘要：The new InfraRed PhotoLuminescence (IRPL) signal in feldspar offers a promising alternative to the wellestablished OSL method to recover the absorbed radiation dose for dating purposes. The non-destructive readout using Stokes shifted photoluminescence offers the opportunity to carry out repeat measurements to improve the signal to noise ratio, and the steady state signal enables straightforward spatially and spectrally resolved measurements. However, the exploitation of the IRPL signal has been hampered by a large background signal, making the IRPL emission that is of interest for measuring absorbed dose difficult to discriminate. A new IRPL detection attachment for the Riso luminescence reader has been developed which enables measurement of the IRPL emission with a signal to background at least two orders of magnitude higher than reported previously. These improvements have been achieved through a combination of a bespoke optical design along with careful selection of filters and coatings. Key instrument design details are presented along with some preliminary results from slices of museum specimens of feldspar.
Chandler, J. R.Sholom, S.McKeever, S. W. S.Bakhanova, E....
14页
查看更多>>摘要：An anthropomorphic phantom was equipped with three smartphones and irradiated in five separate exposure geometries in air using a(137)Cs source. The phantom was fitted internally with thermoluminescence dosimeters (TLD-700 chips) to measure the absorbed dose to the individual organs, while the absorbed doses in the phones were evaluated using optically stimulated luminescence (OSL) from the phones' surface mount resistors (SMRs), along with reference dosimeters, namely Luxel OSL films and TLD-700 chips. The results indicate a strong dependence on the phone location with respect to the source due to shielding and scattering from the body. Dose conversion factors were calculated for several plausible exposure scenarios in order to correlate the absorbed doses measured in the phones to the average body dose received by the phantom. The measured conversion factors were compared with calculated factors using MCNP6.2 Monte Carlo simulations and an ADAM voxel phantom. Experiments were conducted to assess how the phone orientation and angle impacts the dose received by the phone components. The overall results indicate that the doses measured can vary significantly depending upon exposure geometry (including phone position and angle). However, in rotational irradiation symmetry, the phone doses lead to an over-estimate of the average whole-body dose by an average of similar to 10%, independent of the phone locations tested in this study. This result, if confirmed in future studies, may be acceptable for triage.
查看更多>>摘要：Translucent ceramics of undoped and Eu-doped NaMgF3 were synthesized by the spark plasma sintering method. Their optical, scintillation, thermally stimulated luminescence (TSL), and optically stimulated luminescence (OSL) properties were examined. In photoluminescence and scintillation spectra, Eu-doped NaMgF3 mainly showed the emission peaks at 360 and 375 nm, ascribed to 4f-4f and 5d-4f transitions of Eu2+, respectively. The TSL glow curve consists of the glow peaks at 94, 132, 166, 203, 249, 316, and 377 degrees C. The OSL signal could be detected by stimulation at 415 nm. The dominant luminescence center in TSL and OSL processes was Eu2+ ions, showing the emission peaks at 360 and 375 nm. The Eu-doped NaMgF3 had linear TSL and OSL responses from an irradiation dose of 0.01 mGy.
查看更多>>摘要：Time build-up properties of a recently developed radiophotoluminscence (RPL) glass made of silver-activated P2O5-Al2O3-Na2O-Ag2O, named "SAPANS" herewith, were examined using Cs-137 source gamma-rays. It was observed that the RPL intensities of SAPANS continuously increased at room temperature and did not reach a stable state even at six months after irradiation. For obtaining stable RPL values corresponding to dose levels, preheating at 160 degrees C for 1 h was judged to be the most suitable. The good weathering resistance of SAPANS was confirmed in a 63-days outdoor weathering test in the summer season; its physical and dosimetric properties were well maintained after the long exposure to the harsh environment. According to these findings, it is expected that SAPANS will be effectively applied to long-term radiation monitoring at various types of working/living places including outdoor fields.
查看更多>>摘要：Measurements of the natural radiation background with different devices and at various conditions are important from a methodological point of view in order to compare and eventually inter-calibrate different experimental sets, also to provide a reliable basis for improving the existing models for assessment of the environmental radiation in the Earth's atmosphere. Here, we report results from methodological measurements with a small portable device, namely mobile dosimetry unit (MDU)-1 Liulin, performed in different conditions in the Arctic region, including the altitude profile of the atmospheric radiation obtained during the flight of the HEMERA-2 zero-pressure balloon. A comparison with a calibrated device is also performed. It was demonstrated that the MDU-1 Liulin can provide reliable measurements of the radiation background in the Arctic atmosphere during a zero-pressure balloon flight.
NSTL
Elsevier