První test nového neutronového generátoru na VŠB-TU Ostrava

The compact neutron generator MP320 (Thermo Scientific Inc.) operating on the principle of a deuterium-tritium reaction was tested before its planned application as the neutron source for the purpose of Fast Neutron Activation Analysis applications. Plates made from Al, Fe, Sn and Si were irradiated by a 14 MeV neutron beam and typical neutron induced reactions were identified.Kompaktní neutronový generátor MP320 (Thermo Scientific Inc.) pracující na principu deuterium-tritiové reakce byl testován před plánovaným využitím jako zdroj neutronů pro neutronovou aktivační analýzu pomocí rychlých neutronů. Destičky vyrobené z Al, Fe, Sn a Si byly ozářeny svazkem neutronů s energií 14 MeV a byly identifikovány reakce indukované neutrony typické pro uvedené prvky

High specific activity of radium isotopes in baryte from the Czech part of the Upper Silesian Basin- An example of spontaneous mine water treatment

Radium-bearing barytes (radiobarytes) have been known since the beginning of the 20th century. They are mainly found as precipitates of low-temperature hydrothermal solutions. In anthropogenic environments, they frequently occur as crusts on oil industry equipment used for borehole extraction, in leachates from uranium mill tailings, and as a by-product of phosphoric acid manufacturing. Recently, we recognized Ra-rich baryte as a precipitate in the water drainage system of a bituminous coal mine in the Czech part of the Upper Silesian Basin. The precipitate is a relatively pure baryte, with the empirical formula (Ba0.934Sr0.058Ca0.051Mg0.003)(Sigma 1.046)S0.985O4.000. The mean specific activity of Ra-226 was investigated by the two-sample method and it equals 39.62(22) Bq/g, a level that exceeds known natural occurrences. The values for Ra-228 and Ra-224 are 23.39(26) Bq/g and 11.03(25) Bq/g. The radium content in the baryte is 1.071 ng/g. It is clear that the Ra-rich baryte results from the mixing of two different mine waters-brines rich in Ba, Sr, and isotopes Ra-226 and Ra-228 and waters that are affected by sulfide weathering in mine works. When this mixing occurs in surface watercourses, it could present a serious problem due to the half-life of Ra-226, which is 1600 years. If such mixing spontaneously happens in a mine, then the environmental risks will be much lower and will be, to a great, extent eliminated after the closure of the mine.Web of Science102art. no. 10

Gama radioaktivita deště v lednu 2013 v Ostravě

Gamma radioactivity of an 8 mm thick ice layer formed after a modest rain on 21 January 2013 in the VŠB-Technical University of Ostrava campus was analyzed and gamma-ray emissions from primordial 40K have been found. Cosmogenic 7Be produced mainly in galactic cosmic-ray spallation processes on atmospheric nitrogen and oxygen and 226Ra, 235U and 137Cs have been also observed.Při analýze gama radioaktivity 8 mm silné vrstvy ledu, která se vytvořila při dešťových srážkách v areálu VŠB-Technické univerzity Ostrava 21.1.2013, bylo detekováno gama záření z izotopu 40K. Rovněž bylo pozorováno kosmogenní 7Be vznikající především v tříštivých reakcích galaktického kosmického záření s atmosférickým dusíkem a kyslíkem a také 226Ra, 235U and 137Cs

Evolution of nuclear shapes and structure in tellurium, xenon, barium and cerium isotopes

Different Skyrme functional parametrizations were tested for Te, Xe, Ba and Ce isotopes for N > 82. For the SVsym34 parametrization, which best fits the experimental binding energy, potential energy curves obtained from constrained beta(2), beta(3) and beta(4) Hartree-Fock+BCS calculations were investigated. Positions of the lowest quadrupole and octupole vibrational states and the lowest 2(+) rotational states in deformed nuclei were obtained within the Skyrme QRPA and compared to existing experimental data.Web of Science50356055

ANALYSIS OF THE INFLUENCE OF TRANSDUCER FREQUENCY ON THE ULTRASONIC MEASUREMENT OF CONCRETE HOMOGENEITY

The paper analyses the influence of transducer frequency on the determination of concrete homogeneity using the ultrasonic pulse velocity test. Transit time measurements were made on a 590×590mm concrete slab, with 110mm in thickness, in a raster of 5×5 points, which means the slab was tested in 25 places. The tests were made using a Pundit PL-200 ultrasonic tester using transducers set at 54, 82, and 150 kHz. Two types of measurements were performed – spot measurements of the ultrasonic pulse transit time at each point and full area scanning. The paper is concluded by an evaluation of the concrete slab’s homogeneity measured by different transducers and techniques in addition to a statistical analysis of how the results are affected by the transducer frequency

Radiocaesium contamination of mushrooms at high- and low-level Chernobyl exposure sites and its consequences for public health

We compare the specific activities of Cs-137 and K-40 in stipes and caps of three different common mushroom species (Xerocomus badius, Russula ochroleuca and Armillariella mellea) measured at the Czech Chernobyl hot spot in the Opava area (Silesia) and at a low-exposed site at the Beskydy mountains in 2011. The highest values of Cs-137 were found in caps of Xerocomus badius and Russula ochroleuca in the Opava area (11.8 and 8.77 kBq/kg, respectively). The source of Cs-137 was verified by the measurement of the Cs-134/Cs-137 ratio. Based on our results, we estimate an effective dose per year due to radiocaesium intake in the two investigated areas for Xerocomus badius, one of the most popular edible mushrooms in the Czech Republic. In 2011, the effective dose reached the maximum value of 0.102 mSv in the Opava area and 0.004 mSv at the low-exposed site at the Beskydy mountains. Therefore, it does not represent a significant risk for public health.Web of Science1112art. no. 137

The first experimental evidence for the (M1+E2) mixed character of the 9.2 keV transition in Th-227

The 9.2 keV nuclear transition in Th-227 was studied in the beta(-)-decay of Ac-227 by means of the internal conversion electron spectroscopy to clarify the spin-parity assignment of the ground state and the two lowest excited states of Th-227. The transition multipolarity was proved to be of mixed character M1+ E2 and the spectroscopic admixture parameter delta(2)(E2/M1) = 0.695 +/- 0.248(vertical bar delta(E2/M1)vertical bar = 0.834 +/- 0.149) was determined. Nonzero value of delta(E2/M1) questioned the present theoretical interpretation of low-lying levels of Th-227. Calculations performed prefer the 1/2(+), 3/2(+), and 3/2(+) sequence instead of the adopted 1/2(+), 5/2(+) and 3/2(+) one for the 0.0, 9.2, and 24.3keV levels, respectively.Web of Science820art. no. 13659

Study of Intermediate-spin States of Y-98

The nuclear structure of the odd–odd nucleus 98Y has been re-investigated by observing prompt γ rays emitted following the proton-induced fission of a 238U target, using the JUROGAM-II multidetector array. New highspin decays have been observed and placed in the level schemes using triple coincidences. The experimental level energies and γ-decay patterns are compared to GICM and QPRM calculations, assuming that this neutronrich N = 59 isotone is spherical at low energies and prolate deformed at intermediate spins.Web of Science47391691

Study of ordered hadron chains with the ATLAS detector

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