Determination of primordial radionuclides activity in a sample of volcanic tuff

M.B. Masaev, A.M. Gangapshev, D.A. Tekueva, A.M. Masaev

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Abstract: Given the widespread use of volcanic tuff in construction in the Kabardino-Balkarian Republic and the potential negative impact of radiation on health, it is becoming increasingly important to determine the presence of natural radiation in these materials. This is necessary to ensure background radiation control and minimize unavoidable radiation exposure during the operation of buildings constructed using volcanic tuff.
Aim. The study is to determine the presence of natural radiation activity in a sample of volcanic tuff under low-background conditions, which can form the basis for developing a method for sorting tuff minerals according to the degree of contamination with primordial radionuclides.
Materials and methods. A sample of pink tuff volcanic breccia was collected on the bank of the Baksan River near the village of Elbrus in the Kabardino-Balkarian Republic. The specific activities of the sample were measured, and the composition of the primordial radionuclides 40K and the daughter products of 238U and 232Th was determined using a high-resolution MKGB-01 “RADEK” scintillation γ-ray spectrometer under reduced cosmogenic background conditions. The scintillation spectrometer uses a 150×150 mm NaI (Tl) crystal. The energy range of the detected gamma radiation is from 40 to 10,000 keV.
The detector crystal has a well, allowing for highly efficient measurements in a 4π geometry.
Results. A study of the γ-activity of natural radionuclides in a sample of tuff breccia with complex mineral composition collected in the Elbrus volcanic recreation zone was conducted. Activity measurements were carried out using the peaks of total absorption of γ-lines of 212Pb (232Th), 214Bi (226Ra), and 40K. Based on the research, a method for determining the content of primordial radionuclides in tuff minerals is proposed to minimize unavoidable dose loads during their use in the construction of social facilities. The essence of the method consists of measuring the specific activity of 40K radionuclides, daughter products of 238U and 232Th decay, using a high-resolution scintillation γ-spectrometer under low-background conditions.
Conclusions. A gamma-spectrum analysis of a tuff breccia sample with a complex mineral composition collected in the Elbrus volcanic recreation zone revealed that the mineral raw materials used in onstruction contain naturally occurring radioactive substances. These are primarily 40K and daughter products of 238U and 232Th. The total activity of natural radionuclides in the pink volcanic tuff sample was 829 Bq/kg.

Keywords: primordial radionuclides, specific activity, scintillation spectrometry, pyroclastic rocks, tuff

For citation. Masaev M.B., Gangapshev A.M., Tekueva D.A., Masaev A.M. Determination of primordial radionuclides activity in a sample of volcanic tuff. News of the Kabardino-Balkarian Scientific Center of RAS. 2026. Vol. 28. No. 1. Pp. 135–146. DOI: 10.35330/1991-6639-2026-28-1-135-146

©   Masaev M.B., Gangapshev A.M., Tekueva D.A., Masaev A.M., 2026

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Information about the authors

Martin B. Masaev, Candidate of Physics and Mathematics, Associate Professor, Department of Telecommunications and Electronics, Institute of Mathematics and Natural Sciences, Kabardino-Balkarian State University named after Kh.M. Berbekov;
173, Chernyshevsky street, Nalchik, 360004, Russia;
masmartin@mail.ru, ORCID: https://orcid.org/0009-0007-6459-0221, SPIN-code: 6700-6542
Albert M. Gangapshev, Candidat of Physics and Mathematics, Deputy Head of Research, Department of Scientific Work, Institute for Nuclear Research of the Russian Academy of Sciences;
7a, 60th Anniversary of October prospekt, V-312, Moscow, 117312, Russia;
gangapsh@list.ru, ORCID: https://orcid.org/0000-0002-6086-0569, SPIN-code: 9323-4493
Dzhamilya A. Tekueva, Candidat of Physics and Mathematics, Researcher, INR RAS, Institute for Nuclear Research of the Russian Academy of Sciences;
7a, 60th Anniversary of October prospekt, V-312, Moscow, 117312, Russia;
ORCID: https://orcid.org/0009-0001-5676-1605, SPIN-code: 3777-7427
Aslan-Girey M. Masaev, Research Engineer, Kabardino-Balkarian State University named after Kh.M. Berbekov;
173, Chernyshevsky street, Nalchik, 360004, Russia;
masmartin@mail.ru

Funding

The study was performed without external funding.