| Autor: |
V. P. Ramzaev, A. N. Barkovsky, C. Bernhardsson, S. Mattsson |
| Jazyk: |
English<br />Russian |
| Rok vydání: |
2017 |
| Předmět: |
|
| Zdroj: |
Радиационная гигиена, Vol 10, Iss 1, Pp 18-29 (2017) |
| Druh dokumentu: |
article |
| ISSN: |
1998-426X |
| DOI: |
10.21514/1998-426X-2017-10-1-18-29 |
| Popis: |
A commercially available NaI(Tl) based spectrometer-dosimeter has been used to separate contributions of the terrestrial radionuclides (238U series, 232Th series and 40K) and 137Cs to the total ambient dose equivalent rate (ADER), Ḣ*(10) , outdoors. The device had been initially calibrated by the manufacturer to measure: 1) the total ADER; 2) activity concentrations of 226Ra, 232Th, 40K and ‘effective’ activity concentration of the terrestrial radionuclides, ACeff, in soil, agricultural raw materials, forestry products and construction materials; and 3) ground contamination density by 137Cs. In order to derive a conversion coefficient from ACeff to the ADER stipulated by the terrestrial radionuclides (ADERTRN), two series of additional calibration measurements were performed. The calibration measurements were conducted at 27 outdoor locations in the center of St.-Petersburg and in the Leningradskaya region (background areas). The conversion coefficient from ACeff to ADERTRN of 0.51 (nSv h–1)/(Bq kg–1) has been obtained using a regression analysis of experimental data. The intrinsic noise of the spectrometer and its response to cosmic radiation at sea level has been estimated to 7 nSv h–1. The calibration factors must be used with caution and only for detectors similar to the one employed in this study (assembly based on a NaI(Tl) single crystal, 63 mm in diameter and 63 mm in length). The spectrometer-dosimeter and experimentally derived calibration coefficients have been tested in field at seven sites in the south-western districts of the Bryansk region that had been heavily contaminated by Chernobyl fallout. The contribution of 137Cs to the total ADER varies between 40% and 95%. The preliminary results of the measurements confirm the potential of in situ gamma-ray spectrometry for assaying natural and artificial components of the ambient dose equivalent rate outdoors. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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