Spectrum–dose conversion operator of NaI(Tl) and CsI(Tl) scintillation detectors for air dose rate measurement in contaminated environments

Tsuda, Shuichi; Saitô, Kimiaki

doi:10.1016/j.jenvrad.2016.02.008

Cited by 39 publications

(19 citation statements)

References 20 publications

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“…As expected, the ( ) ° function, i.e., ( ) function for the angle of incidence of 0°, tended to yield higher values over the entire energy range than those for other directions of photons with respect to the detector axis. Additionally, there were relatively small differences between the values of ( ) functions for energies above 200 keV, showing good agreement with previous results [9,12]. This could be ascribed to the fact that the energy deposition of relatively high energy depends primarily on the volume of the crystal.…”

Section: G(e) Functions For Idealized Irradiation Geometiressupporting

confidence: 90%

“…The total dose rate ( ) in multi-energy radiation conditions can, therefore, be represented as Consequently, the total dose rate can be directly estimated using the G(E) function and a measured spectrum. According to related studies [7][8][9]11], the G(E) function can be expressed as…”

Section: G(e) Functionmentioning

confidence: 99%

“…Intending to minimize the effect of photon energy on dose rate response and to achieve more accurate estimates of the dose rate, the use of scintillation detectors is a way to make the response less sensitive to radiation energy by obtaining an energy spectrum. The G(E) function is a typical example of conversion from the energy spectrum to dose rate [7][8][9][10][11][12]; the measured spectrum is directly converted into dose rate without applying stripping or unfolding methods [13][14][15]. This method is, therefore, often adopted for real-time dose measurement.…”

Section: Introductionmentioning

confidence: 99%

“…However, in a real contaminated environment, the irradiation direction of photons entirely depends on typically unknown source distributions. Although isotropic or rotational geometry approximate certain real irradiation conditions [9,16], these are not the same as the idealized ones [17]. In addition, since the response of dosimetry is normalized to the ambient dose rate under one of the geometric conditions, most errors in dose rate estimation primarily arise from the calculation of the dose conversion operator.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Uncertainty Estimation of the Dose Rate in Real-Time Applications Using Gaussian Process Regression

Kim

Lim

Park

et al. 2020

Sensors

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Major standard organizations have addressed the issue of reporting uncertainties in dose rate estimations. There are, however, challenges in estimating uncertainties when the radiation environment is considered, especially in real-time dosimetry. This study reports on the implementation of Gaussian process regression based on a spectrum-to-dose conversion operator (i.e., G(E) function), the aim of which is to deal with uncertainty in dose rate estimation based on various irradiation geometries. Results show that the proposed approach provides the dose rate estimation as a probability distribution in a single measurement, thereby increasing its real-time applications. In particular, under various irradiation geometries, the mean values of the dose rate were closer to the true values than the point estimates calculated by a G(E) function obtained from the anterior–posterior irradiation geometry that is intended to provide conservative estimates. In most cases, the 95% confidence intervals of uncertainties included those conservative estimates and the true values over the range of 50–3000 keV. The proposed method, therefore, not only conforms to the concept of operational quantities (i.e., conservative estimates) but also provides more reliable results.

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Section: G(e) Functions For Idealized Irradiation Geometiressupporting

confidence: 90%

Section: G(e) Functionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Uncertainty Estimation of the Dose Rate in Real-Time Applications Using Gaussian Process Regression

Kim

Lim

Park

et al. 2020

Sensors

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“…a CsI detector used in the KURAMA-II system was developed [14], and the performance of the KURAMA-II system was verified using standard sources [15]. Also, the KURAMA-II systems were installed in public buses which run fixed routes in Fukushima, and the obtained data are published every week on a specific web site.…”

Section: Jrprmentioning

confidence: 99%

Temporal Change in Radiological Environments on Land after the Fukushima Daiichi Nuclear Power Plant Accident

et al. 2019

Self Cite

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Massive environmental monitoring has been conducted continuously since the Fukushima Daiichi Nuclear Power accident in March of 2011 by different monitoring methods that have different features together with migration studies of radiocesium in diverse environments. These results have clarified the characteristics of radiological environments and their temporal change around the Fukushima site. At three months after the accident, multiple radionuclides including radiostrontium and plutonium were detected in many locations; and it was confirmed that radiocesium was most important from the viewpoint of long-term exposure. Radiation levels around the Fukushima site have decreased greatly over time. The decreasing trend was found to change variously according to local conditions. The air dose rates in environments related to human living have decreased faster than expected from radioactive decay by a factor of 2-3 on average; those in pure forest have decreased more closely to physical decay. The main causes of air dose rate reduction were judged to be radioactive decay, movement of radiocesium in vertical and horizontal directions, and decontamination. Land-use categories and human activities have significantly affected the reduction tendency. Difference in the air dose rate reduction trends can be explained qualitatively according to the knowledge obtained in radiocesium migration studies; whereas, the quantitative explanation for individual sites is an important future challenge. The ecological half-lives of air dose rates have been evaluated by several researchers, and a short-term half-life within 1 year was commonly observed in the studies. An empirical model for predicting air dose rate distribution was developed based on statistical analysis of an extensive car-borne survey dataset, which enabled the prediction with confidence intervals. Different types of contamination maps were integrated to better quantify the spatial data. The obtained data were used for extended studies such as for identifying the main reactor that caused the contamination of arbitrary regions and developing standard procedures for environmental measurement and sampling. Annual external exposure doses for residents who intended to return to their homes were estimated as within a few millisieverts. Different forms of environmental data and knowledge have been provided for wide spectrum of people. Diverse aspects of lessons learned from the Fukushima accident, including practical ones, must be passed on to future generations.

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Advances in Organometallic Perovskites Enabled Radiation Detection Technologies

Gedda

Faber

Petridis

et al. 2023

Metal-Halide Perovskite Semiconductors

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Spectrum–dose conversion operator of NaI(Tl) and CsI(Tl) scintillation detectors for air dose rate measurement in contaminated environments

Cited by 39 publications

References 20 publications

Uncertainty Estimation of the Dose Rate in Real-Time Applications Using Gaussian Process Regression

Uncertainty Estimation of the Dose Rate in Real-Time Applications Using Gaussian Process Regression

Temporal Change in Radiological Environments on Land after the Fukushima Daiichi Nuclear Power Plant Accident

Advances in Organometallic Perovskites Enabled Radiation Detection Technologies

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