Thorium, uranium and potassium levels in Brazilian geological sediment as determined by gamma-ray spectroscopy and instrumental neutron activation analysis

Brazilian coastal terraces contain abundant evidence that can be used to explain how the coastal plain evolved during the last 120k years. These studies include geochronology of marine sediments based on physical methods of dating by dosimetry, especially thermoluminescence. To determine terrace ag...

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Main Author: Rogerio Baria
Format: Article
Language:English
Published: Brazilian Radiation Protection Society (Sociedade Brasileira de Proteção Radiológica, SBPR) 2022-12-01
Series:Brazilian Journal of Radiation Sciences
Subjects:
Online Access:https://bjrs.org.br/revista/index.php/REVISTA/article/view/1984
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author Rogerio Baria
author_facet Rogerio Baria
author_sort Rogerio Baria
collection DOAJ
description Brazilian coastal terraces contain abundant evidence that can be used to explain how the coastal plain evolved during the last 120k years. These studies include geochronology of marine sediments based on physical methods of dating by dosimetry, especially thermoluminescence. To determine terrace age by luminescence dosimetry methods is necessary to determine the exact mass fractions of 238U, 232Th and 40K. The values for these mass fractions are used to calculate the annual dose rate of ionizing radiation. In this context, in the present work, we studied eight marine sediment samples collected in the city of São Vicente on the coast of São Paulo state, Brazil, and determined the mass fractions of elements 238U, 232Th and 40K through instrumental neutron activation analysis (INAA) and γ-ray spectroscopy. The mathematical method of linear regression was used to evaluate the precision of the analytical methods. The results indicate excellent correlations with R2 values above 0.71. The resulting mass fractions can calculate dose rates in these sediments, thus contributing to their dating.
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spelling doaj.art-5d821f106084470ba01e383ccd77ec8d2022-12-22T02:51:07ZengBrazilian Radiation Protection Society (Sociedade Brasileira de Proteção Radiológica, SBPR)Brazilian Journal of Radiation Sciences2319-06122022-12-01103B10.15392/2319-0612.2022.1984Thorium, uranium and potassium levels in Brazilian geological sediment as determined by gamma-ray spectroscopy and instrumental neutron activation analysisRogerio Baria0Universidade de São Paulo Brazilian coastal terraces contain abundant evidence that can be used to explain how the coastal plain evolved during the last 120k years. These studies include geochronology of marine sediments based on physical methods of dating by dosimetry, especially thermoluminescence. To determine terrace age by luminescence dosimetry methods is necessary to determine the exact mass fractions of 238U, 232Th and 40K. The values for these mass fractions are used to calculate the annual dose rate of ionizing radiation. In this context, in the present work, we studied eight marine sediment samples collected in the city of São Vicente on the coast of São Paulo state, Brazil, and determined the mass fractions of elements 238U, 232Th and 40K through instrumental neutron activation analysis (INAA) and γ-ray spectroscopy. The mathematical method of linear regression was used to evaluate the precision of the analytical methods. The results indicate excellent correlations with R2 values above 0.71. The resulting mass fractions can calculate dose rates in these sediments, thus contributing to their dating. https://bjrs.org.br/revista/index.php/REVISTA/article/view/1984Marine terrace, dose rate, INAA, γ-ray spectroscopy, 238U, 232Th, 40K.
spellingShingle Rogerio Baria
Thorium, uranium and potassium levels in Brazilian geological sediment as determined by gamma-ray spectroscopy and instrumental neutron activation analysis
Brazilian Journal of Radiation Sciences
Marine terrace, dose rate, INAA, γ-ray spectroscopy, 238U, 232Th, 40K.
title Thorium, uranium and potassium levels in Brazilian geological sediment as determined by gamma-ray spectroscopy and instrumental neutron activation analysis
title_full Thorium, uranium and potassium levels in Brazilian geological sediment as determined by gamma-ray spectroscopy and instrumental neutron activation analysis
title_fullStr Thorium, uranium and potassium levels in Brazilian geological sediment as determined by gamma-ray spectroscopy and instrumental neutron activation analysis
title_full_unstemmed Thorium, uranium and potassium levels in Brazilian geological sediment as determined by gamma-ray spectroscopy and instrumental neutron activation analysis
title_short Thorium, uranium and potassium levels in Brazilian geological sediment as determined by gamma-ray spectroscopy and instrumental neutron activation analysis
title_sort thorium uranium and potassium levels in brazilian geological sediment as determined by gamma ray spectroscopy and instrumental neutron activation analysis
topic Marine terrace, dose rate, INAA, γ-ray spectroscopy, 238U, 232Th, 40K.
url https://bjrs.org.br/revista/index.php/REVISTA/article/view/1984
work_keys_str_mv AT rogeriobaria thoriumuraniumandpotassiumlevelsinbraziliangeologicalsedimentasdeterminedbygammarayspectroscopyandinstrumentalneutronactivationanalysis