Pavel Povinec

Comenius University in Bratislava, Faculty of Mathematics, Physics and Informatics, Faculty Member

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Characterisation of low background CaWO$_4$ crystals for CRESST-III

SciPost Physics Proceedings

The CRESST-III experiment aims at the direct detection of dark matter particles via their elastic... more The CRESST-III experiment aims at the direct detection of dark matter particles via their elastic scattering off nuclei in a scintillating CaWO_44 target crystal. For many years CaWO_44 crystals have successfully been produced in-house at Technische Universität München with a focus on high radiopurity. To further improve the CaWO_44 crystals, an extensive chemical purification of the raw materials has been performed and the crystal TUM93 was produced from this powder. We present results from an \alphaα-decay rate analysis performed on 344 days of data collected in the ongoing CRESST-III data-taking campaign. The \alphaα-decay rate could significantly be reduced.

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Tree Rings as Archives of Atmospheric Pollution by Fossil Carbon Dioxide in Bratislava

Radiocarbon, Dec 1, 2022

Elemental composition of organic and non-organic foods determined by PIXE

Journal of Radioanalytical and Nuclear Chemistry, 2022

Nutrition and safety of foods is one of the more discussed topics in the modern society. We proce... more Nutrition and safety of foods is one of the more discussed topics in the modern society. We processed twenty food samples of the organic and non-organic origin in order to determine their elemental composition by the particle induced X-ray emission method. Except of some species (e.g., carrots), significant differences between the organic and non-organic types were not observed. Interestingly, the bananas’ pulps showed higher content of several elements (K, Ca, Sr) than their peels. Heavy metals (metalloids) were found to be below their limits of detection in the studied food samples.

Temporal changes in tritium and radiocarbon concentrations in the western North Pacific Ocean (1993–2012)

Journal of Environmental Radioactivity, 2020

The western North Pacific is one of the most studied oceanic basins due to its diverse structure ... more The western North Pacific is one of the most studied oceanic basins due to its diverse structure and important role in connection with the adjacent reservoirs. Tritium (3H) and radiocarbon (14C) have been frequently exploited as oceanographic tracers due to their suitable properties; several extensive observation projects, such as GEOSECS, WOCE and WOMARS, used these two radionuclides to investigate different oceanographic processes, pathways, ocean currents and time scales of deep and bottom water formation. Here we evaluate temporal changes in 3H and 14C levels in seawater of the western North Pacific Ocean from 1993 to 2012. When compared to the background levels from 1993, the data from 2012 suggests significant impact of the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident on surface and vertical 3H seawater profiles, increasing its water column inventories in the southern part of the 149°E meridian by a factor of 2-7. On the other hand, 14C content in surface seawater has been steadily decreasing from 1993, with the accelerated rate from 2005, probably due to downwelling of bomb-produced radiocarbon and its transport along isopycnal layers. The influence of the Oyashio current on 14C levels in the northern part of the investigated transect and formation of its intrusion was also clearly visible in the collected datasets. Regarding bomb-produced radiocarbon, its water column inventories decreased or remained same from 2005 to 2012 at all stations, except the ones located in the coastal areas of the New Guinea island (3.5°S).

Natural radionuclides as background sources in the Modane underground laboratory

Journal of Environmental Radioactivity, 2020

The Modane underground laboratory (LSM) is the deepest operating underground laboratory in Europe... more The Modane underground laboratory (LSM) is the deepest operating underground laboratory in Europe. It is located under the Fréjus peak in Savoie Alps in France, with average overburden of 4800 m w. e. (water equivalent), providing low-background environment for experiments in nuclear and particle physics, astrophysics and environmental physics. It is crucial to understand individual sources of background such as residual cosmic-ray flux of high-energy muons, muon-induced neutrons and contributions from radionuclides present in the environment. The identified dominant sources of background are radioactive contamination of construction materials of detectors and laboratory walls, radon contamination of the laboratory air, and neutrons produced in the laboratory. The largest neutron contribution has been identified from (α, n) reactions in low Z materials (10-7-10-4 n s-1 Bq-1) and from spontaneous fission of 238U (1.1× 10-6 n s-1 Bq-1).

Analysis of meteorite samples using PIXE technique

Journal of Radioanalytical and Nuclear Chemistry, 2019

A non-destructive approach to the sample treatment during the analytical process is one of the cr... more A non-destructive approach to the sample treatment during the analytical process is one of the crucial advantages of the particle induced X-ray emission technique. Rare and precious environmental and space samples can be analyzed in order to evaluate concentrations of individual elements presented in specimens. A non-destructive analysis of two meteorite samples was carried out using 3 MeV protons incident in a narrow ion beam (1.5 mm diam.). GUPIXWIN software package was used for spectra evaluation. Concentrations of several elements (Fe, Ni, Cu and Zn) were determined and quantitative surface elemental distribution maps were constructed.

Environmental radionuclides as contaminants of HPGe gamma-ray spectrometers: Monte Carlo simulations for Modane underground laboratory

Journal of Environmental Radioactivity, 2018

The main limitation in the high-sensitive HPGe gamma-ray spectrometry has been the detector backg... more The main limitation in the high-sensitive HPGe gamma-ray spectrometry has been the detector background, even for detectors placed deep underground. Environmental radionuclides such as 40K and decay products in the 238U and 232Th chains have been identified as the most important radioactive contaminants of construction parts of HPGe gamma-ray spectrometers. Monte Carlo simulations have shown that the massive inner and outer lead shields have been the main contributors to the HPGe-detector background, followed by aluminum cryostat, copper cold finger, detector holder and the lead ring with FET. The Monte Carlo simulated cosmic-ray background gamma-ray spectrum has been by about three orders of magnitude lower than the experimental spectrum measured in the Modane underground laboratory (4800 m w.e.), underlying the importance of using radiopure materials for the construction of ultra-low-level HPGe gamma-ray spectrometers.

Radiocarbon in the atmosphere around the Bohunice nuclear power plant in Slovakia

Journal of Radioanalytical and Nuclear Chemistry, 2018

Radiocarbon variations associated with releases from Bohunice nuclear power plant have been obser... more Radiocarbon variations associated with releases from Bohunice nuclear power plant have been observed in monthly atmospheric 14CO2 samples during the last 30 years with peak radiocarbon activity enrichment levels as high as 350‰. Simultaneously, relative depletion in radiocarbon levels as low as −10‰ has been observed due to radiocarbon-free fossil fuel emissions in the region (Suess effect).

Results on sub-GeV dark matter from a 10 eV threshold CRESST-III silicon detector

Physical Review D

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Development and applications of accelerator mass spectrometry methods for measurement of 14C, 10Be and 26Al in the CENTA laboratory

Journal of Radioanalytical and Nuclear Chemistry, Jan 8, 2024

Terrestrial and extraterrestrial radioisotope research has been strongly dependent on the develop... more Terrestrial and extraterrestrial radioisotope research has been strongly dependent on the development of analytical methods which would enable to trace radioisotopes at low concentrations in subgram samples (e.g., in tree rings, ice cores, meteorites, etc.). Accelerator mass spectrometry (AMS) has become the most sensitive technique for ultralow-level analysis of long-lived radioisotopes, such as 14 C, 10 Be and 26 Al. We review developments and applications carried out in the CENTA laboratory, and describe a recently installed fully equipped AMS line, designed for analysis of long-lived radioisotopes from tritium to curium.

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Corrigendum to “Charcoals as indicators of historical mortar age of medieval Czech castle Pyšolec” [Nucl. Instrum. Methods Phys. Res., Sect. B: Beam Interact. Mater. Atoms 528 (2022), 8–14]

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms

Tritium and radiocarbon in the water column of the Red Sea

Journal of Environmental Radioactivity

Charcoals as indicators of historical mortar age of medieval Czech castle Pyšolec

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms

Radiocarbon dating of charcoals and small pieces of wood collected from mortar in the torso of be... more Radiocarbon dating of charcoals and small pieces of wood collected from mortar in the torso of bergfried and buttress of the medieval Pyšolec castle was performed using accelerator mass spectrometers. Altogether, 37 samples were collected, of which 33 samples passed pre-processing criteria and chemical treatment and were dated. Two of them were Palaeolithic charcoals of likely sedimentary origin, one wood sample corresponded to a younger intrusion, six represented ‘old wood’ likely aged about 200 years when built in, and 24 originated from ‘young wood’ presumably not older than 50 years at the time of building. This highlights the need to collect large enough sample set when dating architectural remains using charcoals or wood splinters. As a rule of thumb, collecting at least 10 samples is recommended; otherwise, the dating might not be feasible at all or may yield unrealistically old estimates, by as much as 200 years for medieval castles.

Cosmogenic nuclides as an indirect method for cosmic ray investigation

IzSSR, Jul 1, 1981

Environmental Protection: The Oceans—Formation and Global Climate Change

Encyclopedia of Nuclear Energy, 2021

Nuclear reactions in extraterrestrial objects as a tool for studying the variations of cosmic radiation

Temporal evolution of 236U, 237Np and Pu isotopes in the Northwest Mediterranean Sea (2001-2013)

Trabajo presentado en la 14th International conference on Accelerator Mass Spectrometry, celebrad... more

Environmental Protection: The Oceans—Implications of Manmade Radiation

234Th vertical profiles at the são paulo bight as a prospective tracer to estimate export fluxes and particle dynamics

The neutron component of background of an HPGe detector operating in a surface laboratory

Applied Radiation and Isotopes, 2020

Investigation of neutron-induced background was carried out by studying interactions of cosmic-ra... more Investigation of neutron-induced background was carried out by studying interactions of cosmic-ray neutrons with an HPGe detector inside its shield placed on a ground floor of a 3-storey building. The study was conducted experimentally and by Monte Carlo simulations using GEANT4 simulation tool. Detailed analysis of measured background γ-ray spectra showed that many γ-lines visible in the spectra were induced by neutrons. The majority of detected γ-rays originated in germanium, copper, lead and tin. Iron and aluminium components were less important background sources. Inelastic scattering and neutron capture were the most often occurring processes of neutron interactions with the detector and its shielding. The contamination by natural radionuclides, specifically of 40 K, 214 Pb, 214 Bi and 208 Tl, was also present in the background spectra. Nevertheless, approximately 35% of 208 Tl peak at the energy of 2614.51 keV was produced by inelastic scattering of neutrons on 208 Pb nuclei. The experimental background was compared with GEANT4 simulations, which were carried out without and with the shielding layer of the building. The final integral counting rates for measured spectrum in the energy range from 50 keV to 2875 keV was 1.26 ± 0.07 s − 1 and for simulated one 1.25 ± 0.13 s − 1 , indicating very good agreement with the experiment.

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