Study the influences of the radionuclide depth distributions on the FEPE for the measurements of the soil activity using in situ HPGe gamma spectrometry

In this work, the influences of the soil densities and the radionuclide depth distributions(RDD) on the Full Energy Peak Efficiency (FEPE) calculation of the in-situ gamma rayspectrometer using the In Situ Object Counting Systems (ISOCS) software were studied. The data of the RDDs at the sites were investigated by using laboratory HPGe gamma spectrometer. Six different RDDs of 40K, 226Ra and 232Th were found at four studied sites with radionuclide deposition moving from surface to deeper positions. The results show that FEPE values vary strongly for the different RDDs, especially for the low gamma ray energies. Use of the uniform model for calculating FEPEs can result in noticeable errors from 29% to 101% for the realistic RDD of the exponential form (surfaceradionuclide deposition), negative variations from 14% to 30% for the realistic RDD of having a radionuclide deposition at the 30 cm depth, and negligible variations of less than 5 % for the realistic RDD of quasi uniform form in the range of gamma ray energies of interest.

Radiological impact assessment of different building material additives

In this study, samples of building material additives were analyzed for naturally occurring radioisotope activity such as uranium, radium, and radon. The radon exhalation and the annual effective doses, were also calculated. The activities of the samples, were determined using HPGe gamma spectrometry and ionization detector. The results were used to calculate dose values by using RESRAD BUILD code. The activity concentration of the samples ranges between 9–494 Bq/kg Ra-226, 1–119 Bq/kg Th-232 and 24–730 Bq/kg K-40. In conclusion the investigated samples can be used safely as building material additives as they do not pose a major risk to humans.

Determination of anthropogenic contamination by 137Cs, 240Pu/239Pu and 235U/238U in lichens and mosses from Russian Arctic areas

<p>Lichen and moss samples were collected from Russian Arctic areas (Kola Peninsula, Franz Josef Land and few other locations) in the 1990s. In 2020, <sup>137</sup>Cs was determined by HPGe gamma spectrometry from these samples after which isotopes of Pu and U were radiochemically separated from the samples. Mass ratios <sup>240</sup>Pu/<sup>239</sup>Pu and <sup>235</sup>U/<sup>238</sup>U were determined by ICP-MS for utilizing the characteristic isotopic fingerprints of different nuclear events. The aim of the work was to survey radioactive contamination sources in terrestrial environment in Russian Arctic regions, which have not yet been completely explored in respect to anthropogenic isotopes and their origin in the environment.</p>

Food Salt Characterization in Terms of Radioactivity and Metals Contamination

The analysis of food salt is very important because of its high consumption by the population, for both medicinal and nutritional use. In this study, nine different samples of food salt (Cyprus black, Himalayan pink, Hawaii red, iodized, hyposodic iodized, Maldon smoked sea, common sea, Breton sea and Persia blue), coming from large Italian retailers and employed by people for different cooking food purposes, were investigated through High Purity Germanium (HPGe) Gamma Spectrometry in order to evaluate the anthropogenic (137Cs) and natural (40K) radioisotopes activity concentration, and used Inductively Coupled Plasma Mass Spectrometry (ICP-MS) in order to assess any possible metals contamination by a comparison between Cu, As, Cd, Hg and Pb concentrations and the limits set by the Italian Legislation. The evaluation of dose levels due to the salt ingestion for the age category higher than 17 years was performed taking into account the human body daily need of about 10 g of salt, and in the precautionary hypothesis, this need was satisfied from a single type of salt. All obtained results are under allowable levels (1 mSv/year), thus excluding the risk of ionizing radiation effects on humans. Regarding to the metals concentration, experimental results show that it is lower than the contamination threshold values, thus excluding their presence as pollutants.

Thoron emanation and exhalation of Slovenian soils determined by a PIC detector-equipped radon monitor

The health risk from thoron (Rn-220) is usually ignored owing to its short half-life (55.6 s), but the generated thoron decay products can cause a significant dose contribution. In this study, altogether 51 Slovenian soil samples were investigated using an accumulation chamber technique to obtain information about thoron exhalation features. The obtained (massic) thoron exhalation results varied between 6.9 and 149 mBq·kg−1·s−1 (average: 55.2 mBq·kg−1·s−1). The Th-232 content was determined using HPGe gamma spectrometry. The Th-232 activity concentration ranged between 9.3 and 161.7 Bq·kg−1 (average: 64.6 Bq·kg−1). The thoron emanation features were also calculated from the obtained results (2.9 to 21.2% with an average of 8.6%). The thoron exhalation and emanation properties were compared with the radon exhalation and emanation features determined in a previous study. It was found that there was no correlation between the radon and thoron emanation features, according to the obtained data. This can be explained by the different Ra-224 and Ra-226 distributions in the soil grains. As a result, the thoron emanation factor cannot be predicted from radon emanation and vice versa.

The radioactivity of bricks produced in Serbia

Natural radioactivity of the brick, one of the most used building materials was investigated. The content of natural radionuclides in the samples was measured by HPGe gamma-spectrometry. The average values of specific activities of 226Ra, 232Th and 40K in the samples are: 31 ? 9, 40 ? 11 and 460 ? 118 in Bq kg-1, respectively. The absorbed dose in the air was computed by the method of buildup factors for the standard model of the room. The obtained values for the absorbed dose are in the range of 9 - 47 (nGy h-1), with the average of 36 ? 9 nGy h-1. The radiation hazard was estimated calculating the corresponding gamma index and the effective dose. The gamma index belongs to the range of 0.11 to 0.56, and the effective dose is in the range of 0.044 - 0.23 (mSv), far below the reference limit of 1 mSv.