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Revisiting external dose rate and ground deposition of Chornobyl fallout in the Gävle region in Sweden : Comparison between estimates from soil sampling vs in situ measurements using a field portable NaI(Tl) gamma spectrometer

Rääf, Christopher LU orcid ; Jönsson, Mattias LU and Bernhardsson, Christian LU orcid (2025) In Radiation Protection Dosimetry 201(13-14). p.941-947
Abstract

A field survey was conducted in Sweden with the purpose to revisit the ground deposition of Chornobyl 137Cs and the associated ambient dose equivalent rate, H∗ (10), at various measuring locations in the Gävle and Älvkarleby municipalities. The specific purpose was to compare the 137Cs deposition values as measured in situ using a field portable gamma spectrometer [3″(Ø) × 3″ NaI(Tl)-crystal] with the ex situ estimates obtained from gamma spectrometry of soil cores taken at the measuring locations. An additional purpose was to re-assess the effective ecological half-times of the Cs-contribution to the H∗ (10) and compare with a previous assessment done for data until 2013. The results show... (More)

A field survey was conducted in Sweden with the purpose to revisit the ground deposition of Chornobyl 137Cs and the associated ambient dose equivalent rate, H∗ (10), at various measuring locations in the Gävle and Älvkarleby municipalities. The specific purpose was to compare the 137Cs deposition values as measured in situ using a field portable gamma spectrometer [3″(Ø) × 3″ NaI(Tl)-crystal] with the ex situ estimates obtained from gamma spectrometry of soil cores taken at the measuring locations. An additional purpose was to re-assess the effective ecological half-times of the Cs-contribution to the H∗ (10) and compare with a previous assessment done for data until 2013. The results show that ex-situ soil sample data exceed the 137Cs deposition values from the field portable NaI(Tl) gamma spectrometer by, on average, 50%. The discrepancy could mainly attributed to the difference between the actual field-of-view seen by the portable device at 1 m above ground compared with the calibration geometry of an infinite planar surface with a Cs ground penetration at 3 g cm-2. The H∗ (10) measurements collected in 2022 could indicate that the effective ecological half-time of 137Cs attributed ambient dose equivalent rate in the area ranges between 10 and 20 y instead of the 6.8 y obtained from the previous assessment of data between 1987 and 2013. The findings demonstrate, however, the usability of the portable field gamma spectrometer when used to characterize the long-term time dynamics of external doses from 137Cs in cases where the 137Cs dose contribution is well below normal background levels.

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author
; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Radiation Protection Dosimetry
volume
201
issue
13-14
pages
7 pages
publisher
Oxford University Press
external identifiers
  • pmid:40875270
  • scopus:105014623795
ISSN
0144-8420
DOI
10.1093/rpd/ncaf040
language
English
LU publication?
yes
id
411510e3-0fe8-4c7e-81cf-4b2b851b581d
date added to LUP
2025-10-16 13:06:25
date last changed
2025-10-30 14:06:03
@article{411510e3-0fe8-4c7e-81cf-4b2b851b581d,
  abstract     = {{<p>A field survey was conducted in Sweden with the purpose to revisit the ground deposition of Chornobyl <sup>137</sup>Cs and the associated ambient dose equivalent rate, H<sup>∗</sup> (10), at various measuring locations in the Gävle and Älvkarleby municipalities. The specific purpose was to compare the <sup>137</sup>Cs deposition values as measured in situ using a field portable gamma spectrometer [3″(Ø) × 3″ NaI(Tl)-crystal] with the ex situ estimates obtained from gamma spectrometry of soil cores taken at the measuring locations. An additional purpose was to re-assess the effective ecological half-times of the Cs-contribution to the H<sup>∗</sup> (10) and compare with a previous assessment done for data until 2013. The results show that ex-situ soil sample data exceed the <sup>137</sup>Cs deposition values from the field portable NaI(Tl) gamma spectrometer by, on average, 50%. The discrepancy could mainly attributed to the difference between the actual field-of-view seen by the portable device at 1 m above ground compared with the calibration geometry of an infinite planar surface with a Cs ground penetration at 3 g cm<sup>-2</sup>. The H<sup>∗</sup> (10) measurements collected in 2022 could indicate that the effective ecological half-time of <sup>137</sup>Cs attributed ambient dose equivalent rate in the area ranges between 10 and 20 y instead of the 6.8 y obtained from the previous assessment of data between 1987 and 2013. The findings demonstrate, however, the usability of the portable field gamma spectrometer when used to characterize the long-term time dynamics of external doses from <sup>137</sup>Cs in cases where the <sup>137</sup>Cs dose contribution is well below normal background levels.</p>}},
  author       = {{Rääf, Christopher and Jönsson, Mattias and Bernhardsson, Christian}},
  issn         = {{0144-8420}},
  language     = {{eng}},
  number       = {{13-14}},
  pages        = {{941--947}},
  publisher    = {{Oxford University Press}},
  series       = {{Radiation Protection Dosimetry}},
  title        = {{Revisiting external dose rate and ground deposition of Chornobyl fallout in the Gävle region in Sweden : Comparison between estimates from soil sampling vs in situ measurements using a field portable NaI(Tl) gamma spectrometer}},
  url          = {{http://dx.doi.org/10.1093/rpd/ncaf040}},
  doi          = {{10.1093/rpd/ncaf040}},
  volume       = {{201}},
  year         = {{2025}},
}