Optically stimulated luminescence fluence response of dosimeters exposed to different types of radiation (original) (raw)
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Radiation Measurements, 2008
This work investigates the change in shape of optically stimulated luminescence (OSL) curves from carbon-doped aluminum oxide (Al 2 O 3 : C) dosimeters as a function of ionization density. The dosimeters were exposed to Ne 371.9 MeV/u and Fe 120.4 MeV/u heavy charged particle (HCP) beams, and 90 Sr/ 90 Y beta radiation in the interval of absorbed dose to water from 2 mGy up to 8.5 kGy. The change in the shape of the OSL curves occurs for absorbed doses higher than 10 Gy for beta radiation and higher than 50 Gy for the HCP beams. Based on the HCP fluences corresponding to the absorbed dose of 50 Gy and analytical models of radial dose distribution, we estimated that the dose level in the overlapping track region is comparable to the beta dose in which the OSL curve start to change. This is an indication that track overlap is responsible for changes in shape of the OSL curves of Al 2 O 3 :C Luxelீ dosimeters as the HCP fluence increases.
Proceedings of the Second International Symposium on Radiation Detectors and Their Uses (ISRD2018), 2019
It is expected that optically stimulated luminescence (OSL) dosimeters composed of Al 2 O 3 :C will be used for radiation monitoring of the high dose region in high energy accelerator facilities. The nanoDot, a small type OSL dosimeter, can easily measure absorbed doses and read with a microStar reader, a portable OSL reader. In this study, we evaluated the reliability of nanoDot OSL dosimeters for dose measurements of more than 10 Gy. In the evaluation of the upper dose limit and the uncertainty of measurement, the nanoDot OSL dosimeters were exposed to 60 Co gamma rays of 0.07-2350 Gy. They were read using a microStar with an additional neutral density filter to prevent the saturation of PMT response. Although the response of nanoDot OSL dosimeters was proportional to the absorbed dose below 1 Gy, it showed supra linearity greater than 1 Gy and it saturated approximately at 250 Gy. When the fitting line was made in the dose region of less than 1 Gy, and it was extrapolated up to 250 Gy and large deviations in the response were observed. Therefore, we proposed to use a third-ordered fitting curve, which can reduce the deviations within ± 16.8%. We concluded that the nanoDot OSL dosimeter is capable of measuring absorbed doses of up to 110 Gy by using the proposed fitting curve.
2014
This paper reviews the state of the optically stimulated luminescence (OSL) technique for space dosimetry applications, focusing on the properties of carbon-doped aluminum oxide (Al 2 O 3 :C). New data presented include the most complete and recent values for the relative efficiency HCP, for heavy charged particles as a function of the incident radiation's linear energy transfer (LET), obtained through groundbased experiments at heavy ion accelerators. We also discuss the factors influencing the OSL efficiencies, the LET-dependent properties of Al 2 O 3 :C, and the experience gained from past space experiments using Al 2 O 3 :C. The characterization of the OSL efficiency values as a function of LET allows the use of the OSL of Al 2 O 3 :C in combination with plastic nuclear track detectors for personal dosimetry of astronauts, as proposed by the NCRP Report 142.
Radiation Measurements, 2004
The thermoluminescence (TL) and optically stimulated luminescence (OSL) response of Al2O3 dosimeters to high-energy heavy charged particles (HCP) has been studied using the heavy ion medical accelarator at Chiba, Japan. The samples were Al2O3 single-crystal chips, of the type usually known as TLD-500, and Luxel TM dosimeters (Al2O3:C powder in plastic) from Landauer Inc. The samples were exposed to 4 He (150 MeV=u), 12 C (400 MeV=u), 28 Si (490 MeV=u) and 56 Fe (500 MeV=u) ions, with linear energy transfer values covering the range from 2.26 to 189 keV= m in water and doses from 1 to 100 mGy (to water). A 90 Sr= 90 Y beta source, calibrated against a 60 Co secondary standard, was used for calibration purposes. For OSL, we used both continuous-wave OSL measurements (CW-OSL, using green light stimulation at 525 nm) and pulsed OSL measurements (POSL, using 532 nm stimulation from a Nd:YAG Q-switched laser). The e ciencies (ÁHCP; ) of the di erent HCPs at producing OSL or TL were observed to depend not only upon the linear energy transfer (LET) of the HCP, but also upon the sample type (single crystal chip or Luxel TM ) and the luminescence method used to deÿne the signal-i.e. TL, CW-OSL initial intensity, CW-OSL total area, or POSL. Observed changes in shape of the decay curve lead to potential methods for extracting LET information of unknown radiation ÿelds. A discussion of the results is given, including the potential use of OSL from Al2O3 in the areas of space radiation dosimetry and radiation oncology.
Radiation Measurements, 2004
The thermally and optically stimulated luminescence (TL and OSL) response to high energy heavy-charged particles (HCPs) was investigated for two types of Al2O3:C luminescence dosimeters. The OSL signal was measured in both continuous-wave (CW) and pulsed mode. The e ciencies of the HCPs at producing TL or OSL, relative to gamma radiation, were obtained using four di erent HCPs beams (150 MeV=u 4 He; 400 MeV=u 12 C; 490 MeV=u 28 Si, and 500 MeV=u 56 Fe). The e ciencies were determined as a function of the HCP linear energy transfer (LET). It was observed that the e ciency depends on the type of detector, measurement technique, and the choice of signal. Additionally, it is shown that the shape of the CW-OSL decay curve from Al2O3:C depends on the type of radiation, and, in principle, this can be used to extract information concerning the LET of an unknown radiation ÿeld. The response of the dosimeters to low-LET radiation was also investigated for doses in the range from about 1-1000 Gy. These data were used to explain the di erent e ciency values obtained for the di erent materials and techniques, as well as the LET dependence of the CW-OSL decay curve shape.
High Dose Measurement Using Low Density Aluminum Oxide Element
Proceedings of the Second International Symposium on Radiation Detectors and Their Uses (ISRD2018), 2019
Optically Stimulated Luminescence (OSL) dosimeters using aluminum oxide as a detection material does not require high temperature to stimulate. It is also possible to change the fundamental characteristics of the detector material by mixing other substances with aluminum oxide. A good example would be in neutron dosimetry. The aluminum oxide material is not sensitive to neutrons; however, using several different substances with the aluminum oxide makes it possible to detect neutrons as it gives the detector material sensitivity to neutrons. In this study, it was found that the energy dependence characteristics to photons of the detector material changes depending on the atomic number of the substance to be mixed; the substance to be mixed with the aluminum oxide material should be chosen carefully. It was observed that a mixture of aluminum oxide having a small particle size and a low atomic number material may have energy characteristics equivalent to the human body. Detector materials made of fine powder aluminum oxide and epoxy resin was made, but the energy characteristics for photons did not change. Since this element was very insensitive, experiments on high doses were conducted. It was found that the element containing aluminum oxide at a weight ratio of 1% can measure gamma rays up to 750 Gy.
Recent advances in dosimetry using the optically stimulated luminescence of Al2O3:C
Radiation Protection Dosimetry, 2004
This paper presents an overview of some very recent developments in optically stimulated luminescence (OSL) dosimetry using aluminium oxide (Al 2 O 3 :C), with special emphasis given to the work of the research group at Oklahoma State University. Some of the advances are: (i) the development of a real-time optical ®bre system for in vivo dosimetry applied to radiotherapy; (ii) the development of a ®bre dosimetry system for remote detection of radiological contaminants in soil; (iii) the characterisation of Al 2 O 3 :C in heavy charged particle ®elds and the study of ionisation density dependence of the OSL from Al 2 O 3 :C; and (iv) fast and separate assessment of beta and gamma components of the natural dose rate in natural sediments. These achievements highlight the versatility of the OSL technique associated with the high-sensitivity of Al 2 O 3 :C for the development of new dosimetry applications.
World Journal of Nuclear Science and Technology, 2012
The laboratory of Radiation Dosimetry and Calibration of the Belgian Nuclear Research Centre (SCK·CEN) is using thermoluminescence dosimetry for more than thirty years for routine measurements and for R & D investigations. In 2002, it has developed an experimental device based on the optically stimulated luminescence (OSL) technique. This device is working with AL 2 O 3 :C crystals stimulated by the green line (488 nm) emitted by a 150 mW argon laser. This paper describes this device, its characteristics, some applications in space dosimetry and the R & D works initiated in this field during the next few years.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2007
The prime objective of this study is to investigate if radioluminescence (RL) from carbon-doped aluminum oxide ðAl 2 O 3 :CÞ crystals potentially can be used for absorbed dose-rate measurements during proton radiotherapy. The RL from two separate (2 mg) Al 2 O 3 :C crystals attached to optical-fiber cables were recorded during irradiations in water in a 175 MeV clinical proton beam. The RL response for low-LET protons in the plateau region of the Bragg curve was found to closely resemble that observed for a clinical 6 MV X-ray beam. An identical response was found in the Bragg peak (where the dose-averaged LET is about 4 keV=mmÞ for absorbed doses less than 0.3 Gy. For doses in the range of 0.3-3 Gy, we observed a significant decrease in luminescence efficiency with LET. At 3 Gy, the luminescence efficiency was about 60% in the Bragg-peak region. The study implies that the RL-signal from Al 2 O 3 :C could potentially be suitable for medical proton dosimetry in the 0-0.3 Gy range even without any LET-dependent correction factors. r