Jan Kameník

Radiochemical separation of mostly short-lived neutron activation products

It is demonstrated that radiochemical separation in neutron activation analysis (RNAA) is usually the most effective means of optimization of the technique for many elements, if achieving the lowest detection limits and uncertainties are required. Examples are provided for low-level determination of vanadium, iodine, manganese, silicon, mercury, selenium in mostly biological materials. Further, it is also shown that RNAA is a superior tool for the low-level determination of natural radionuclides 232Th and 238U in shielding and construction materials for underground physics experiments on rare nuclear events, such as the search for neutrinoless double β-decay in SuperNEMO experiment.

Determination of vanadium in titanate-based ferroelectrics by INAA with discriminating gamma-ray spectrometry

Instrumental neutron activation analysis was used for determination of vanadium mass fraction in crystals of incipient ferroelectric strontium titanate and ferroelectric barium titanate. In order to improve vanadium limit of detection, discriminating gamma-ray spectrometry was used by inserting an absorption filter between the samples and an HPGe detector. The use of the absorption lead filter 6-mm thick yielded improvement of the vanadium limit of detection by a factor of two. The vanadium mass fraction determined in a quality control sample, which was NIST standard reference material SRM 1648 Urban Particulate Matter, was in close agreement with the certified value.

Determination of elemental impurities in phosphoric acid by INAA employing a novel method of phosphate precipitation

Banned irradiation of liquid acids in many nuclear reactors requires a transformation of these compounds into a solid substance to be able to perform the determination of impurities using instrumental neutron activation analysis. For this purpose, a novel, simple, and contamination-free procedure for the transformation of phosphoric acid into ammonium phosphate has been developed, which is based on isothermal distillation of ammonia vapours. Favourably low detection limits for more than 35 elements have been achieved and the accuracy of the results has been established by analysis of NIST SRM 1515 Apple Leaves.

INAA and ion-beam analysis of elemental admixtures in carbon-based nanomaterials for battery electrodes

Six carbon materials with potential application in research and development of battery electrodes were tested for mass fractions of more than 40 elements by instrumental neutron activation analysis and ion-beam methods. The results indicate potential of the methods for characterization of materials with very low content of impurities (carbon black) as well as those with relatively high content of certain transition metals (e.g., single walled carbon nanotubes, SWCNT). A batch-to-batch variability of elemental impurities was found for commercial SWCNT. Quality control was performed by analysis of CRM SWCNT-1, NIST SRM 1633b, NIST SRM 2711, and NIST SRM 1547.

Mercury species in formerly contaminated soils and released soil gases

Total mercury (T-Hg), elemental mercury (Hg0), methylmercury (MeHg+), phenylmercury (PhHg+), and gaseous elemental mercury (GEM) species were determined in soils formerly contaminated by different processes from two sites in the Czech Republic. Analytical methods involved atomic absorption spectrometry (AAS) using a single-purpose Advanced Mercury Analyser AMA-254 and radiochemical neutron activation analysis (RNAA) for T-Hg determination, a thermal desorption method was used for Hg0 determination, gas chromatography coupled with atomic fluorescence spectrometry (GC-AFS) was employed for assay of MeHg+ and PhHg+, while GEM measurement was carried out using a portable Zeeman-AAS device Lumex RA-915+. The first sampling site was in the surroundings of a former PhHgCl-based fungicide processing plant next to Příbram (central Bohemia). Although the use of Hg-based fungicides as seed mordant have been banned, and their production stopped at the end of 1980s, highly elevated Hg contents in soil are still observed in the vicinity of the former plant, reaching T-Hg values >13mgkg-1. The second sampling site was an abandoned mining area named Jedová hora Hill near Hořovice (central Bohemia), where cinnabar (HgS) was occasionally mined as by-product of Fe ores hematite and siderite. Mining activities have been stopped here in 1857. Very high contents of T-Hg are still found at this site, up to 144mgkg-1. In most cases we found a statistically significant correlation between T-Hg and Hg0 values regardless of the pollution source. On the contrary, insignificant correlation was observed neither between T-Hg and GEM values, nor between GEM and Hg0. Concentrations of the investigated organomercury species were above a limit of detection (LOD) only in the most contaminated samples, where their levels were about two to three orders of magnitude lower compared to those of T-Hg.

Instrumental neutron activation analysis of environmental samples from a region with prevalence of population disabilities in the North Gondar, Ethiopia

Abstract Instrumental neutron activation analysis (INAA) of soil, coal, water, and crops from the village of Awdarda in the North Gondar, Ethiopia, where the residents suffer from various disabilities, was performed in an attempt to elucidate the existing health problems. More than forty elements were determined in the samples analyzed. Comparison of our results with literature values indicates highly elevated contents of terrigenous elements in Awdarda cereals, possibly due to contamination by excavation and indoor combustion of local coal-bearing sediments. Impact is discussed of the elevated aluminium and the rare earth elements levels in crops on the health problems.

Determination of elemental content in the Rumanová, Uhrovec, Veľké Borové, Košice and Chelyabinsk chondrites by instrumental neutron activation analysis

Chondrites are the most frequently studied extraterrestrial material. We present new data on the concentrations of 43 major and trace elements found in the Uhrovec, Veľké Borové (Nagy-Borove), Rumanová, Košice and Chelyabinsk meteorites, which were analyzed using INAA. The results are in good agreement with the mean data for an average ordinary chondrite of the respective class; normalization of the values to CI chondrites also showed similar outcome. Additionally, for the Rumanová, Košice and Chelyabinsk meteorites, INAA results of the bulk chemical composition are reasonably consistent with the data obtained by the same and/or different methods published earlier.

Ion and Neutron Beams Discover New Facts from History

Nuclear physics applications in medicine and energy are well known and widely reported. For example, the recent report “Nuclear Physics for Medicine,” published by the European Science Foundation [1] or “Energy for the Future: The Nuclear Option,” written by scientists at the European Physical Society (EPS) [2] can be mentioned. Less well known are the many important nuclear and related techniques to study objects of cultural heritage. There has been enormous progress in this field in recent years and our current contribution provides some snippets of the comprehensive topical paper “Nuclear Physics for Cultural Heritage” published by the EPS recently [3], which aims for a popular and accessible account showing the broad nuclear physics applications in cultural heritage investigation and preservation. Nuclear Physics contributes to archaeometry mainly by non-invasive investigation of cultural heritage objects with ion and neutron beams.