scholarly journals Correlation between calculated and measured values of gamma dose rate in air in forests contaminated with 137Cs: the remote period after the Chernobyl accident

2020 ◽  
Vol 12 (4) ◽  
pp. 37-46 ◽  
Author(s):  
Valery P. Ramzaev ◽  
Anatoly N. Barkovsky
Keyword(s):  
Vertical Distribution ◽  
Dose Rate ◽  
Chernobyl Accident ◽  
Gamma Dose ◽  
Dose Equivalent ◽  
Air Kerma ◽  
Equivalent Rate ◽  
Ambient Dose Equivalent ◽  
Air Kerma Rate ◽  
Ambient Dose

In 2015–2016, 13 forest and 7 virgin grassland plots located in the south-western districts of the Bryansk region were surveyed. The aim of the work was to experimentally test the possibility of using a method for calculating the dose rate of gamma radiation in air in radioactively contaminated forests in a remote period after the Chernobyl accident. According to the results of gamma-spectrometric analysis of soil samples obtained at the sites in another study, the values of inventory and vertical distribution of 137Cs in the upper 20 cm layer were established. In this paper, these data were used to calculate the air kerma rate using a method taken from literature. In addition, at the sites of soil sampling, ambient dose equivalent rate in air was measured, and the contribution of 137Cs to the total gamma dose rate was determined with a field gamma spectrometer-dosemeter. The measured values of the ambient dose equivalent rate from 137Cs correlated positively and statistically significantly with the calculated values of the air kerma rate. The Spearman correlation coefficient was 0.989 (P < 0.01) for the location “forest” and 0.893 (P < 0.05) for the location “grassland”. There was no statistically significant difference between the “forest” and “grassland” locations when analyzing the ratio of the measured dose rate values to the calculated dose rate values (the Mann-Whitney U test, P > 0.05). Results of this work show that, when calculating gamma radiation dose rate in air in forests at a remote stage after the Chernobyl accident, it is enough to know the 137Cs inventory in the upper 20 cm soil layer and a detailed picture of vertical distribution of the radionuclide in this layer. The presence of woody biomass can be neglected. This dose rate estimate is conservative. However, a degree of overestimation of the dose rate in air is small, within +10%, which is quite acceptable for determining the external effective dose rate for an individual in the radioactively contaminated forest.

Estimating the terrestrial gamma dose rate by decomposition of the ambient dose equivalent rate

2017 ◽  
Vol 166 ◽  
pp. 296-308 ◽  
Author(s):  
P. Bossew ◽  
G. Cinelli ◽  
M. Hernández-Ceballos ◽  
N. Cernohlawek ◽  
V. Gruber ◽  
...  
Keyword(s):  
Dose Rate ◽  
Gamma Dose ◽  
Gamma Dose Rate ◽  
Dose Equivalent ◽  
Equivalent Rate ◽  
Ambient Dose Equivalent ◽  
Ambient Dose

scholarly journals Calculating radiation dose rate from online real-time environmental -spectrum using NaI(Tl) detector

2021 ◽  
Vol 11 (1) ◽  
pp. 16-25
Author(s):  
Thu Bac Vuong ◽  
Hoang Tuan Truong ◽  
Duc Thang Duong ◽  
Dac Dung Bui ◽  
Duc Viet Cao ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Dose Rate ◽  
Real Time ◽  
Specific Activity ◽  
Radioactive Isotopes ◽  
Dose Equivalent ◽  
Radiation Dose Rate ◽  
Equivalent Rate ◽  
Ambient Dose Equivalent ◽  
Ambient Dose

Calculating gamma radiation dose rate from online real-time environmental gamma spectrum using NaI(Tl) detector has been developed into a software named RADAPROC V.1 in the Center for Operating the National Network of Environmental Radiation Monitoring And Warning (CONNERMAW). Currently, hundreds of online gamma spectra per day from online monitoring stations are processed to calculate the total ambient dose equivalent rate and the ambient dose equivalent rate of typical natural radioactive isotopes such as K-40, Bi-214, Tl-208 according to the method of using the function G(E) and the photo-peak area method. The calculated results have been compared with the results of calculating the dose rate from the specific activity of radioactive isotopes in soil samples collected at the same monitoring location and analyzed in the laboratory. The difference between the methods is less than 25%. The ambient dose equivalent rates of typical natural radioactive isotopes are a bit higher than those calculated with SARA-NMC software. The software will be improved shortly for better results.

ESTABLISHMENT OF A LOW DOSE RATE GAMMA RAY CALIBRATION FIELD FOR ENVIRONMENTAL RADIATION MONITORING DEVICES

2019 ◽  
Vol 187 (1) ◽  
pp. 61-68
Author(s):  
Munehiko Kowatari ◽  
Hiroshi Yoshitomi ◽  
Sho Nishino ◽  
Yoshihiko Tanimura ◽  
Tetsuya Ohishi ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Radiation Monitoring ◽  
Dose Equivalent ◽  
Environmental Radiation ◽  
Air Kerma ◽  
Ambient Dose Equivalent ◽  
Reference Air Kerma Rate ◽  
Monitoring Devices ◽  
Air Kerma Rate ◽  
Ambient Dose

Abstract For routine calibration of dosemeters used for environmental radiation monitoring, a low dose rate 137Cs gamma ray calibration field that fully satisfies the requirement of the ISO 4037 series was established in the Facility of Radiation Standards in Japan Atomic Energy Agency. Two different methods were employed to determine the reference air kerma rate, namely a conventional ionisation chamber and a G(E) function method used a newly developed scintillation spectrometer. To fulfil the requirement of the ISO 4037 and suppress scattering of Cs gamma ray within the room as far as possible, a suitable lead collimator was introduced to limit the irradiation area at test points and placed at the middle height in an irradiation room with a grating floor. From measured results of de-convoluted photon fluence spectrum and the variation of evaluated reference air kerma rates between 1.0 m and 3.0 m from the centre of the source, gamma ray scattering from the room structures was found to be negligible. The reference air kerma rate at distances between1.0 m and 3.0 m could be then interpolated by simply considering the inverse square law of the distance and air attenuation. The resulting Cs gamma ray calibration field could provide ambient dose equivalent rates of 0.7–7.2 μSv h−1 for use with environmental radiation monitoring devices. Finally, we attempted to calibrate a widely used NaI(Tl) scintillation survey metre, obtaining a quite satisfactory calibration factor. These results also imply that such survey metres can be employed to monitor affected areas and assess the progress of decontamination, as they can provide appropriate measurements of the ambient dose equivalent rate.

scholarly journals Study of the screening survey using an ambient dose equivalent rate survey meter in criticality accidents

2019 ◽  
Vol 6 (0) ◽  
pp. 152-155
Author(s):  
Katsuya Hoshi ◽  
Norio Tsujimura ◽  
Tadayoshi Yoshida ◽  
Osamu Kurihara ◽  
Eunjoo Kim ◽  
...  
Keyword(s):  
Dose Equivalent ◽  
Equivalent Rate ◽  
Ambient Dose Equivalent ◽  
Criticality Accidents ◽  
Screening Survey ◽  
Ambient Dose

Correction Coefficients for Measuring the Ambient Dose Equivalent Rate of Neutrons

ANRI ◽  
2021 ◽  
Vol 0 (4) ◽  
pp. 32-40
Author(s):  
Alexander Alexeev ◽  
Vladimir Pikalov ◽  
Pavel Alexeev
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Dose Equivalent ◽  
Equivalent Rate ◽  
Ambient Dose Equivalent ◽  
Ambient Dose

Calculations of the response for the most widely used neutron dosimeters at the Russian nuclear power plant (NPP) have been performed. It is shown that in some cases it is necessary to introduce a correction for the measured value of the ambient dose equivalent rate (AEDR). The experimentally tested values of the correction for measuring AEDR in the containment rooms of NPP with VVER-1200 are given.

scholarly journals Indoor Radon Measurements Using Radon Track Detectors and Electret Ionization Chambers in the Bauxite-Bearing Areas of Southern Adamawa, Cameroon

2020 ◽  
Vol 17 (18) ◽  
pp. 6776
Author(s):  
Saïdou ◽  
Oumar Bobbo Modibo ◽  
Ndjana Nkoulou II Joseph Emmanuel ◽  
Olga German ◽  
Kountchou Noube Michaux ◽  
...  
Keyword(s):  
Indoor Radon ◽  
Geometric Mean ◽  
Reference Level ◽  
Dose Equivalent ◽  
Ionization Chambers ◽  
The Public ◽  
Average Value ◽  
Equivalent Rate ◽  
Ambient Dose Equivalent ◽  
Ambient Dose

The current work deals with indoor radon (222Rn) concentrations and ambient dose-equivalent rate measurements in the bauxite-bearing areas of the Adamawa region in Cameroon before mining from 2022. In total, 90 Electret Ionization Chambers (EIC) (commercially, EPERM) and 175 Radon Track Detectors (commercially, RADTRAK2) were used to measure 222Rn concentrations in dwellings of four localities of the above region. A pocket survey meter (RadEye PRD-ER, Thermo Scientific, Waltham, MA, USA) was used for the ambient dose-equivalent rate measurements. These measurements were followed by calculations of annual doses from inhalation and external exposure. 222Rn concentrations were found to vary between 36 ± 8–687 ± 35 Bq m−3 with a geometric mean (GM) of 175 ± 16 Bq m−3 and 43 ± 12–270 ± 40 Bq m−3 with a geometric mean of 101 ± 21 Bq m−3 by using EPERM and RADTRAK, respectively. According to RADTRAK data, 51% of dwellings have radon concentrations above the reference level of 100 Bq m−3 recommended by the World Health Organization (WHO). The ambient dose equivalent rate ranged between 0.04–0.17 µSv h−1 with the average value of 0.08 µSv h−1. The inhalation dose and annual external effective dose to the public were assessed and found to vary between 0.8–5 mSv with an average value of 2 mSv and 0.3–1.8 mSv with an average value of 0.7 mSv, respectively. Most of the average values in terms of concentration and radiation dose were found to be above the corresponding world averages given by the United Nations Scientific Commission on the Effects of Atomic Radiation (UNSCEAR). Even though the current exposure of members of the public to natural radiation is not critical, the situation could change abruptly when mining starts.

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