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Lee S, Park J, Lee JS, Seo H, Ko GB, Seo JM, Kim SM. Comparative study on gamma-ray detectors for in-situ ocean radiation monitoring system. Appl Radiat Isot 2023; 197:110826. [PMID: 37094496 DOI: 10.1016/j.apradiso.2023.110826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 03/07/2023] [Accepted: 04/14/2023] [Indexed: 04/26/2023]
Abstract
Large-sized crystals and state-of-the-art photosensors are desirable to cope with low environmental radioactivity (e.g., 1-2 Bq∙m-3137Cs in surface seawater) for homeland security purposes. We compared the performances of two different gamma-ray detector assemblies, GAGG crystal + silicon photomultiplier (SiPM) and NaI(Tl) crystal + photomultiplier tube, for our mobile in-situ ocean radiation monitoring system. We performed energy calibration, followed by water tank experiments with varying the depth of a137Cs point source. Experimental energy spectra were compared with MCNP-simulated spectra with identical setup and the consistency was validated. We finally assessed the detection efficiency and minimum detectable activity (MDA) of the detectors. Both GAGG and NaI detectors exhibited favorable energy resolutions (7.98 ± 0.13% and 7.01 ± 0.58% at 662 keV, respectively) and MDAs (33.1 ± 0.0645 and 13.5 ± 0.0327 Bq∙m-3 for 24-h 137Cs measurement, respectively). Matching the geometry of the GAGG crystal with that of the NaI crystal, the GAGG detector outperformed the NaI detector. The results demonstrated that the GAGG detector is potentially advantageous over the NaI detector in detection efficiency and compactness.
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Affiliation(s)
- Seungeun Lee
- Department of Biomedical Sciences, Seoul National University, 103 Daehak-Ro, Jongno-Gu, Seoul, 03080, Republic of Korea
| | - Junsung Park
- Department of Quantum System Engineering, Jeonbuk National University, 567 Baekje-Daero, Deokjin-Gu, Jeonju-Si, Jeollabuk-Do, 54896, Republic of Korea
| | - Jae Sung Lee
- Department of Biomedical Sciences, Seoul National University, 103 Daehak-Ro, Jongno-Gu, Seoul, 03080, Republic of Korea; Brightonix Imaging Inc., 25 Yeonmujang 5ga-Gil, Seongdong-Gu, Seoul, 04782, Republic of Korea
| | - Hee Seo
- Department of Quantum System Engineering, Jeonbuk National University, 567 Baekje-Daero, Deokjin-Gu, Jeonju-Si, Jeollabuk-Do, 54896, Republic of Korea
| | - Guen Bae Ko
- Brightonix Imaging Inc., 25 Yeonmujang 5ga-Gil, Seongdong-Gu, Seoul, 04782, Republic of Korea
| | - Jung-Min Seo
- Maritime ICT & Mobility Research Department, Korea Institute of Ocean Science and Technology, 385 Haeyang-Ro, Yeongdo-Gu, Busan, 49111, Republic of Korea
| | - Soo Mee Kim
- Maritime ICT & Mobility Research Department, Korea Institute of Ocean Science and Technology, 385 Haeyang-Ro, Yeongdo-Gu, Busan, 49111, Republic of Korea.
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Sanusi MSM, Hassan WMSW, Hashim S, Ramli AT. Tabulation of organ dose conversion factors for terrestrial radioactivity monitoring program. Appl Radiat Isot 2021; 174:109791. [PMID: 34062400 DOI: 10.1016/j.apradiso.2021.109791] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 05/07/2021] [Accepted: 05/21/2021] [Indexed: 12/01/2022]
Abstract
Terrestrial radioactivity monitoring of 238U and 232Th series, and 40K in soil is an essential practice for radioactivity and radiation measurement of a place. In conventional practice, only basic data can be in-situ measured using a survey instrument, for example radioactivity concentration in soil and ambient dose equivalent rate. For other physical quantities, for example organ absorbed dose and organ equivalent dose, the measurement is impossible to be performed and can only be computed using Monte Carlo radiation transport simulations. In the past, most of the works only focused on calculating air-kerma-to-effective dose conversion factors. However, the information on organ dose conversion factors is scarcely documented and reported. This study was conducted to calculate organ absorbed and tissue-weighted equivalent dose conversion factors as a result of exposure from terrestrial gamma radiation. Series of organ dose conversion factors is produced based on computations from Monte Carlo MCNP5 simulations using modelled gamma irradiation geometry and established adult MIRD phantom. The study found out that most of the radiation exposed organs absorb energy at comparable rates, except for dense and superficial tissues i.e., skeleton and skin, which indicated slightly higher values. The good agreement between this work and previous studies demonstrated that our gamma irradiation geometry and modelling of gamma radiation sources are adequate. Therefore, the proposed organ dose conversion factors from this study are reasonably acceptable for dose estimation in environmental radioactivity monitoring practices.
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Affiliation(s)
- M S M Sanusi
- Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310, Skudai, Joho Bahru, Johor, Malaysia.
| | - W M S W Hassan
- Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310, Skudai, Joho Bahru, Johor, Malaysia
| | - S Hashim
- Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310, Skudai, Joho Bahru, Johor, Malaysia
| | - A T Ramli
- Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310, Skudai, Joho Bahru, Johor, Malaysia
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Selivanova A, Hůlka J, Vrba T, Češpírová I. Efficiency calibration of a CZT detector and MDA determination for post accidental unmanned aerial vehicle dosimetry. Appl Radiat Isot 2019; 154:108879. [PMID: 31479820 DOI: 10.1016/j.apradiso.2019.108879] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 08/16/2019] [Accepted: 08/23/2019] [Indexed: 11/20/2022]
Affiliation(s)
- Anna Selivanova
- National Radiation Protection Institute, Bartoškova 28, 140 00, Prague, Czech Republic; Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Břehová 7, 115 19, Prague, Czech Republic.
| | - Jiří Hůlka
- National Radiation Protection Institute, Bartoškova 28, 140 00, Prague, Czech Republic.
| | - Tomáš Vrba
- Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Břehová 7, 115 19, Prague, Czech Republic.
| | - Irena Češpírová
- National Radiation Protection Institute, Bartoškova 28, 140 00, Prague, Czech Republic.
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Landsberger S, Sharp A, Wang S, Pontikes Y, Tkaczyk AH. Characterization of bauxite residue (red mud) for 235U, 238U, 232Th and 40K using neutron activation analysis and the radiation dose levels as modeled by MCNP. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2017; 173:97-101. [PMID: 28049554 DOI: 10.1016/j.jenvrad.2016.12.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Revised: 12/22/2016] [Accepted: 12/22/2016] [Indexed: 06/06/2023]
Abstract
This study employs thermal and epithermal neutron activation analysis (NAA) to quantitatively and specifically determine absorption dose rates to various body parts from uranium, thorium and potassium. Specifically, a case study of bauxite residue (red mud) from an industrial facility was used to demonstrate the feasibility of the NAA approach for radiological safety assessment, using small sample sizes to ascertain the activities of 235U, 238U, 232Th and 40K. This proof-of-concept was shown to produce reliable results and a similar approach could be used for quantitative assessment of other samples with possible radiological significance. 238U and 232Th were determined by epithermal and thermal neutron activation analysis, respectively. 235U was determined based on the known isotopic ratio of 238U/235U. 40K was also determined using epithermal neutron activation analysis to measure total potassium content and then subtracting its isotopic contribution. Furthermore, the work demonstrates the application of Monte Carlo Neutral-Particle (MCNP) simulations to estimate the radiation dose from large quantities of red mud, to assure the safety of humans and the surrounding environment. Phantoms were employed to observe the dose distribution throughout the human body demonstrating radiation effects on each individual organ.
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Affiliation(s)
- S Landsberger
- Nuclear and Radiation Engineering Program, University of Texas, Pickle Research Campus, R-9000, Austin, TX 78712, USA.
| | - A Sharp
- Nuclear and Radiation Engineering Program, University of Texas, Pickle Research Campus, R-9000, Austin, TX 78712, USA
| | - S Wang
- Nuclear and Radiation Engineering Program, University of Texas, Pickle Research Campus, R-9000, Austin, TX 78712, USA
| | - Y Pontikes
- KU Leuven, Department of Materials Engineering, Kasteelpark Arenberg 44, 3001 Leuven, Belgium
| | - A H Tkaczyk
- Institute of Physics, University of Tartu, Ostwaldi 1, 50411 Tartu, Estonia
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Wallace J. Establishing a NORM based radiation calibration facility. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2016; 155-156:84-88. [PMID: 26921707 DOI: 10.1016/j.jenvrad.2016.02.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 02/03/2016] [Accepted: 02/04/2016] [Indexed: 06/05/2023]
Abstract
An environmental radiation calibration facility has been constructed by the Radiation and Nuclear Sciences unit of Queensland Health at the Forensic and Scientific Services Coopers Plains campus in Brisbane. This facility consists of five low density concrete pads, spiked with a NORM source, to simulate soil and effectively provide a number of semi-infinite uniformly distributed sources for improved energy response calibrations of radiation equipment used in NORM measurements. The pads have been sealed with an environmental epoxy compound to restrict radon loss and so enhance the quality of secular equilibrium achieved. Monte Carlo models (MCNP),used to establish suitable design parameters and identify appropriate geometric correction factors linking the air kerma measured above these calibration pads to that predicted for an infinite plane using adjusted ICRU53 data, are discussed. Use of these correction factors as well as adjustments for cosmic radiation and the impact of surrounding low levels of NORM in the soil, allows for good agreement between the radiation fields predicted and measured above the pads at both 0.15 m and 1 m.
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Affiliation(s)
- J Wallace
- Radiation & Nuclear Science Unit, Queensland Health, Australia.
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Kleinschmidt R, Watson D. Terrestrial gamma radiation baseline mapping using ultra low density sampling methods. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2016; 151 Pt 3:609-622. [PMID: 26063584 DOI: 10.1016/j.jenvrad.2015.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 05/05/2015] [Accepted: 05/08/2015] [Indexed: 06/04/2023]
Abstract
Baseline terrestrial gamma radiation maps are indispensable for providing basic reference information that may be used in assessing the impact of a radiation related incident, performing epidemiological studies, remediating land contaminated with radioactive materials, assessment of land use applications and resource prospectivity. For a large land mass, such as Queensland, Australia (over 1.7 million km(2)), it is prohibitively expensive and practically difficult to undertake detailed in-situ radiometric surveys of this scale. It is proposed that an existing, ultra-low density sampling program already undertaken for the purpose of a nationwide soil survey project be utilised to develop a baseline terrestrial gamma radiation map. Geoelement data derived from the National Geochemistry Survey of Australia (NGSA) was used to construct a baseline terrestrial gamma air kerma rate map, delineated by major drainage catchments, for Queensland. Three drainage catchments (sampled at the catchment outlet) spanning low, medium and high radioelement concentrations were selected for validation of the methodology using radiometric techniques including in-situ measurements and soil sampling for high resolution gamma spectrometry, and comparative non-radiometric analysis. A Queensland mean terrestrial air kerma rate, as calculated from the NGSA outlet sediment uranium, thorium and potassium concentrations, of 49 ± 69 nGy h(-1) (n = 311, 3σ 99% confidence level) is proposed as being suitable for use as a generic terrestrial air kerma rate background range. Validation results indicate that catchment outlet measurements are representative of the range of results obtained across the catchment and that the NGSA geoelement data is suitable for calculation and mapping of terrestrial air kerma rate.
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Affiliation(s)
- R Kleinschmidt
- Radiation and Nuclear Sciences, Forensic and Scientific Services, Queensland Department of Health, PO Box 594, Archerfield, Queensland 4108, Australia.
| | - D Watson
- Radiation and Nuclear Sciences, Forensic and Scientific Services, Queensland Department of Health, PO Box 594, Archerfield, Queensland 4108, Australia
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