55 research outputs found
Attempt to estimate the background pulse height spectrum of the CeBr3 scintillation spectrometer due to terrestrial gamma ray components: Application in environmental radiation monitoring
No full textThis article describes an attempt to estimate the background (BG) pulse height spectrum (PHS) of the CeBr3 scintillation spectrometer due to terrestrial gamma ray components. In radiological emergencies, there are some cases which the prior measurement of the background components can't be made. By subtracting the BG components from the measured gross PHS, timely and accurate information about the artificial radionuclides involved in the emergencies would be effectively drawn to protect the member of the public and first responders. A Monte Carlo calculation was conducted to simulate the PHS by gamma rays from natural radionuclides uniformly distributed in the ground. The calculated PHS were verified to be consistent with measured PHS. Derived dose equivalent rate from the calculated PHS were compared with reference value and found to be in good agreement with each other. The study revealed that applying the calculated PHS to the in-situ gamma ray spectrometry components hardly affected the determination of surface deposition density on soil for radioactive cesium.journal articl
Study on Method for Simultaneous Determination of Ambient Dose Equivalent Rates and Activity Concentration in Air for Environmental Radiation Monitoring
No full textAPPLICABILITY OF A COMMERCIALLY AVAILABLE ACTIVE EXTREMITY DOSE-RATE METER TO EYE LENS DOSE MONITORING
No full text
Study on Method for Simultaneous Determination of Ambient Dose Equivalent Rates and Activity Concentration in Air for Environmental Radiation Monitoring
No full textFor proper environmental radiation monitoring, a method to simultaneously determine ambient dose equivalent rate and radioactivity concentration in the air by using a newly developed scintillation spectrometer,
namely a CeBr3 spectrometer was investigated. The performance of the proposed method, including energy
dependence, angular dependence and the linearity of the spectrometer (i.e. the dose rate dependence of its response), was verified by a series of measurements, conducted according to the procedure of inter-comparison of
detectors used for early warning network performed by the European Radiation Dosimetry Group (EURADOS).
Measurement results show that the proposed method is suitable for environmental radiation monitoring purposes. After thorough tests, the investigation on obtaining activity concentration in air from the pulse height
spectrum of γ-ray was demonstrated in the laboratory by using a point-like sealed 133Ba source to simulate an
artificial increase of ambient dose equivalent rate due to a radioactive cloud containing 131I and 133Xe. The
photon fluence rate was obtained from the pulse height spectrum by using the unfolding method, and the activity concentration in air for radionuclides of interest could be estimated from the obtained photon fluence rate
by applying the conversion coefficient evaluated via a Monte Carlo calculation.journal articl
Rapid measurement of actinides in urine by mass and alpha spectrometric methods
No full textTo provide timely information for prompt decision-making in emergency radiation therapy, we developed simple and rapid mass and alpha spectrometric methods for urinary bioassays to determine ultra-trace actinide isotopes. For the mass spectrometric method, after organic matter decomposition, LaF3/CaF2 coprecipitation, and chromatographic purification using 2 mL of AG MP-1M anion exchange resin, U and Pu isotopes were measured in a 20-mL urine sample by ICP-MS. In the alpha spectrometric method, after organic matter decomposition, iron hydroxide coprecipitation, and chromatographic purification using 2 mL of TEVA and 2 mL of DGA resin cartridges, Pu, U, and Am/Cm isotopes were measured in a 500-mL urine sample by alpha spectrometry. These alpha and mass spectrometric methods were then applied for participation in the 2020 intercomparison organized by the Association for the PROmotion of Quality COntrol in RADiotoxicological Analysis (PROCORAD), France, for method validations.journal articl
Actinide analysis in?urine during?participating PROCORAD intercomparison
No full textThe National Institutes for Quantum Science and Technology (QST), Japan, has been engaged in international comparisons organized by the French organization PROCORAD (Association for the PROmotion of Quality Control in RADiotoxicological Analysis) since 2016. To improve the quality control of urinary bioassay for actinides, we developed and modified radiometric and mass spectrometric methods, and improved lab manuals and lab specifications, during PROCORAD comparisons. Based on the performance criteria including Z-score, bias, and En value, our lab qualified as TOP LABO for these comparisons: DTPA-actinides urine (2022), Actinides in urine (2023), and DTPA-actinides urine (2023).journal articl
APPLICABILITY OF A COMMERCIALLY AVAILABLE ACTIVE EXTREMITY DOSE-RATE METER TO EYE LENS DOSE MONITORING
No full textA commercially available active extremity dosemeter is a promising candidate for medical staff aid individual monitoring of the
eye lens. We investigated the applicability of the newly developed active extremity dosemeter, which uses a low-energy photon
probe, to eye lens dose monitoring by performing a complete characterization of the dosemeters. Performance tests revealed
that the active extremity dosemeter would overestimate personal dose equivalent, Hp(3), when the probe is worn close to the
lens of the eye of a medial worker without any improvement in the response. Introducing an appropriate filter into the probe for
low-energy photon has proven to improve the response. The dosemeter then satisfies the criteria of the personal dosemeter for
eye lens dosimetry and can be applicable to individual monitoring of eye lens dose. This article also discusses the applicability of
the dosemeter to area monitoring for decision making regarding additional monitoring of the eye lens and the extremities.journal articl
Estimation of inhomogeneous occupational exposure to the lens of the eyes and the extremities of radiation workers in a research accelerator facility
No full textWe performed an experimental investigation on occupational exposure of the eye lens and the extremity of radiation workers engaged in handling of highly activated materials in a small research accelerator facility. Using a simplified physical phantom to simulate the relevant inhomogeneous radiation exposure situations, the personal dose equivalents obtained at the eye lens and the extremities of radiation workers handling heavily radioactive converters were measured together with the dose measured by personal dosemeters worn on their trunk. Results of a mockup experiments and the Monte Carlo calculations suggest that the quantitative estimation of the eye lens doses can be estimated from the trunk dose, while the extremity doses vary considerably from the dose readings from the trunk, depending on the use of simple point-source or volume source geometry.journal articl
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