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Abstract  

Steel plates about 80 years old from abolished rolling workshops of the POLDI factory at Kladno, Czechoslovakia, can be utilized for the construction of shielding in low activity measurement devices.

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Abstract  

Some species of higher fungi growing at localities with increased contamnation by fission products from radioactive fallout /about 10–20 kBq137Cs m–2 and more/ contain up to 200 kBq of radiocesium-137Cs and134Cs, per kilogram d. m. Simple isolation of the rationcesium preparation of fruittbodies of suchn mushroom accumlators of radiocesium is described.

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Abstract  

Ten selected rock reference materials (USGS diabase W-1, basalt BCR-1, andesite AGV-1, granite G-2, granodiorite GSP-1, and CRPG basalt BE-N, granite GS-N, trachyte ISH-G, serpentine UB-N, glass standard VS-N) were analyzed by instrumental neutron and photon activation analyses. The results have been evaluated on average for the entire set of samples to detect possible systematic deviations of the determined values from the reference values. Out of 47 elements determined, 43 elements have been determined with reasonable agreement (deviation < 10% on average) with the reference values. Au could not be determined because of a high blank from packaging polyethylene foil. Systematically higher Dy and lower Ho and Tm (by about 20% on average) in the present results require further investigation. In several cases, reasons for greater differences between the determined and recommended values could not be traced in the procedures used within the study. The most suspect is the recommended value for W in the CRPG BE-N basalt, which is twenty-five times higher than the present value, probably due to inconsistent contamination from a W carbide mill used in production of this reference material.

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Abstract  

As a part of a project aimed at precise correlation of the Jurassic–Cretaceous (J/K) boundary interval in the Tethyan and Boreal realms, neutron and photon activation analyses were employed in geochemical characterization of limestone samples from the Brodno section, Slovakia, which offers a record of hemipelagic marine sediments around the J/K boundary in the Tethyan realm. Nickel and antimony anomalies exceeding almost twenty times the levels in neighboring beds were found near the beds assigned recently to the J/K boundary. Elucidation of their origin (volcanism, isochronous meteoritic impact, concentrating in, e.g., sulfides) requires further investigation.

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Abstract  

Tables of nuclear data were compiled for the purpose of routine gamma (photon) activation analysis. The tables are arranged in two parts. The first one lists the readionuclides in order of their atomic number. In the second one, the emitted gamma-ray photons are tabulated in order of increasing energy. Tables contain the gamma emitters produced by the following photonuclear reactions: (γ, γ), (γ, n), (γ, p), (γ, p+n), (γ, 2n), (γ, 3n), (γ, 4n), (γ, 2p), (γ, α), (γ, α+n), (γ, α+p). This set corresponds to the maximum energy of the bremsstrahlung of roughly 45 MeV. The program for output of the tabulated data is made such that it is possible to reduce the data as required for specific irradiation and measuring conditions (reaction thresholds, energy and intensity of gamma-rays, half-lives and target elements).

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Abstract  

The fruit bodies of wild-growing higher fungi (macromycetes), commonly called mushrooms, of various genera and species collected in localities with different geochemical features and man-made burden in the Czech Republic were analyzed by different modes of activation analysis. The elements Na, Mg, Al, S, Cl, K, Ti, V, Mn, Cu, Br, Ba and Dy were determined by short-term instrumental neutron activation analysis (INAA). Short-term epithermal INAA (ENAA) was used for determination of I and other elements, such as Rb, Ag, and U. The elements Na, K, Sc, Cr, Fe, Co, Cu, Zn, As, Se, Br, Rb, Ag, Cd, Sb, Cs, Ba, La, Ce, Sm, Eu, Hf, Au, Hg and Th were determined by long-term INAA, whereas long-term ENAA enabled determination of several other elements, such as Ni, Ta, W and U. The analytical possibilities of instrumental photon activation analysis (IPAA) using a microtron were also explored and found useful for determination of several additional elements, namely Sr, Y, Zr, Nb, and Pb. High concentrations of several essential and toxic trace elements found (up to hundreds of mg.g-1, dry mass) should be of concern in nutritional studies, because mushrooms form non-negligible part of diet in many countries, especially in Middle and East Europe.

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Abstract  

A large set of impact glasses from the Zhamanshin crater in Kazakhstan was analyzed by various modes of instrumental neutron activation analysis, supplemented by instrumental photon activation analysis and prompt gamma-ray activation analysis. Results of the determination of more than forty major and trace elements have shown that the analyzed set of homogeneous, tektite-like impact glasses with size of several centimeters and of various forms could be divided into two geochemically different groups. The lustrous, silica rich (acidic) glasses with high Ni content have been classified conventionally as irghizites. The dull, silica poor (basic) glasses with very low Ni content should not be confused with the large, heterogeneous impactite forms—zhamanshinites, but considered as a separate type of impact glass. Within both primary groups, further division has been suggested based on lower contents of Ni in an irghizite subgroup, and evidence of mixing of source materials for both primary groups in a part of the basic glasses. Based on the contents of Ni, Cr, Mn, Fe and Co, an ordinary chondrite impactor has been suggested with its contribution to the irghizite matter ranging between 4 and 21%. Possible source materials and impact processes leading to irghizite formation have been outlined.

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Abstract  

Silver in selected, predominantly biological, reference materials (NIST SRM 1515, 1547, 1549, 1566a, 1571, 1577b, 2704, CTA-OTL-1, and Bowen’s Kale) was determined using neutron activation analysis (NAA) in two different analytical modes: instrumental NAA with epithermal neutrons (ENAA), and NAA with radiochemical separation (RNAA). The ENAA mode was based on long-time 5-hour irradiation of samples in a special Cd lined box with counting after 8-month decay. The RNAA procedure consisted in 20-hour irradiation of samples, their decomposition/dissolution by alkaline-oxidative fusion, and precipitation of AgCl including several purification steps. Both methods provided Ag contents in the analyzed reference materials consistent with certified and/or literature values down to the ng·g−1 level.

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Abstract  

As a part of geophysical, stratigraphical and paleontological study aimed at precise correlation of the Jurassic–Cretaceous (J/K) boundary interval in the Tethyan and Boreal Realms, detailed magnetostratigraphic and biostratigraphic profiles with well-calibrated J/K boundary have been selected from several localities for geochemical characterization. Instrumental and radiochemical neutron activation analyses (INAA and RNAA, respectively) were employed in the characterization of a vertical profile around the supposed J/K boundary in the Boreal Realm situated on the Nordvik Peninsula, Northern coast of Middle Siberia (Laptev Sea), Russia, for which an iridium anomaly has been reported in literature. INAA enabled determination of about forty major and trace elements. An RNAA procedure for assaying platinum group elements (PGE) has been tested consisting in sample decomposition by alkaline–oxidative fusion, reduction of PGE, and precipitation of their sulphides. Despite several difficulties, the procedure enabled to found Pt and Ir at ppb and sub-ppb levels, respectively, in several samples, namely in pyrite aggregates originated probably in diagenetic reductive processes following decomposition of burried organic matter. However, the existence of a pronounced PGE spike reported previously for the J/K boundary on the Nordvik Peninsula has not been confirmed.

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Summary  

Fruitbodies of wild-growing macromycetes (mushrooms) of various genera and species collected in localities with different geochemical features and man-made burden in the Czech Republic were analyzed using the short-term instrumental neutron activation, with both thermal and epithermal neutrons. Analytical possibilities of these methods were compared. Na, Mg, Al, Cl, K, Ca, V, Mn, Cu, and Br were determined regularly, whereas S, Ti, Rb, Cs, Ba, and Dy were determined occasionally with thermal neutron activation at irradiation-decay-counting times mode of 1-10-10 minutes. Because of high concentration of K and P in the macromycete dry matter (2-7% and 0.5-1%, respectively) and also high Cl concentration in some genera (up to 2.5%), all “1/v” absorbers, epithermal neutron activation in Cd box (1 mm thick wall) substantially suppresses their macroactivities and enhances sensitivity in the determination of elements with significant resonance integrals. Cu, Se, Rb, Ag, Hf, and sometimes Ba are determinable in the mode of 60-30-60 seconds, while K, Cu, As, Br, Rb, In, I, U (in some species also Co, Zn, Cs, Ba, and Hg) in the mode of 1-13-13 minutes. However, Na, Mg, Al, Cl, and Mn determination is not possible this way, as the (n,p) and (n,α) interfering reactions with fast neutrons and high K, P, and other interfering elements content make great interference contributions. Information about content of the essential and toxic elements in mushrooms is important in nutritional studies, because mushrooms form a non-negligible part of diet in many countries.

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