[en] The Moessbauer line broadening measured by R. LINDSEY in α-iron stabilized with vanadium is evaluated by an exponential fit described in the APPENDIX of this paper. By this procedure the low temperature Moessbauer line width GAMMAsub(m)⁰ the diffusion frequency factor D₀ and the activation enthalpy ΔH are computed. KNAUER'S and SOERENSEN-TRUMPY'S definitions of the time correlation factor fsub(t), necessary for the D₀ calculation from Moessbauer line broadening, are applied to the Fe-V diluted BCC solid solutions. (author)

[en] Favorable features of neutron activation analysis (NAA) are highlighted and the most important modes of the technique are mentioned. Examples are given of the advantageous use of NAA for elemental characterization of ambient air and combustion aerosols, studying transfer of pollutants to agricultural plants, and the technique's applications in occupational health and nutritional studies

[en] Neutron activation analysis has been continuously pursued in the former Czechoslovakia and in the Czech Republic since 1962, after an experimental nuclear reactor VVR-S became available. Activities in photon activation analysis started after the installation of a microtron, a source of high energy photons, in 1980. Methodological developments of both methods are described, as well as their applications in various fields of science and technology, namely in environmental research and occupational health studies, cosmo- and geochemical research, biomedical studies, agricultural, nutritional, material research, archaeological and cultural heritage studies, and in quality control and preparation of reference materials. (author)

[en] Owing to a number of assets, which are outlined, neutron activation analysis (NAA) finds application in chemical metrology, specifically in the preparation of reference materials (RMs) of chemical composition and in analytical quality control. The self-verification principle is a special feature of NAA serving to verify analytical data produced by this technique. The strategies of the self-verification principle are explained and examples of its utilization are presented. Recently, NAA has been recognized as a primary method of measurement

[en] We present a new activation method based on the ¹⁹F(n,2n)¹⁸F reaction using fast neutrons produced by a p(19 MeV) + Be accelerator-driven fast neutron source providing continuous neutron spectrum up to 17 MeV with a neutron fluence rate of approximately 9 × 10¹⁰ cm^-2 s^-1 at a 12-µA proton beam current. We describe elimination of interferences in measurement of ¹⁸F, a pure positron emitter with T_1/2 = 1.83 h. We present results of fluorine determination for several biological and environmental reference materials with the new procedure and compare them with those achieved by other methods in terms of limits of detection, accuracy and precision, where available. (author)

[en] Determination of sodium content in NIST standard reference materials (SRM) SRM 1547 and SRM 1515 in recent years yielded values higher than NIST certified values. Similarly, increased values were published for SRM 1547 by several laboratories, however, published sodium values SRM 1515 are in general in agreement with the certified value. Additional analysis of SRM 1547 and SRM 1515 using NIST SRM 3152a Sodium Standard Solution as a calibrator confirmed increased Na values. Inhomogeneity indicating external contamination of the stock material was not found. Moreover, increased Na value was also determined for freshly opened bottle of SRM 1547 material. Analysis of the historical material A-2 from our archive, which is identical with SRM 1515 and was distributed by NIST prior to the SRM 1515 certification and stored in a polyethylene vial, yielded a value in agreement with the certified value. A hypothesis was formulated that sodium in SRM 1547 and SRM 1515 materials could have been increasing after certification, perhaps due to the release of sodium from the glass bottle. (author)

[en] We show that use of the radionuclide ⁵⁶Co for calibration of the full energy peak efficiency, ε, of a coaxial HPGe detector, in addition to the commonly employed set of activity standards (¹³³Ba, ²⁴¹Am, ¹⁵²Eu, ⁵⁷Co, ¹³⁷Cs, ⁸⁸Y, ⁶⁵Zn), affects significantly the ε values in the high energy region. This change resulted in substantial improvement of the accuracy of Ca determination by k₀-INAA via the ⁴⁹Ca radionuclide, which emits predominantly the 3084 keV photons, as demonstrated by Ca results in NIST SRMs 1547 Peach Leaves, 1633b constituent elements in coal fly ash, and 2711 Montana II Soil. (author)

[en] Theories exist saying that the world-renowned Renaissance astronomer Tycho Brahe died of mercury intoxication. Brahe's grave was reopened in 2010 and new samples of his hair, beard-hair, and bones were taken and analysed. Evidence obtained by us suggests that Brahe was not administered lethal doses of mercury and that neither acute nor chronic mercury poisoning was the cause of his death. The INAA results of A piriformis suggest that his nasal prosthesis was most likely made of brass

[en] Long-time experience in neutron flux monitoring on irradiation in the LVR-15 research reactor in Rez gave evidence that the Au+Mn+Rb and Au+Mo+Rb(+Zn) monitor sets for short and long irradiation, respectively, are more suitable in our conditions than the most frequently used Au+Zr set. The advantages of the former monitor set have been described previously, in the present work we discuss the advantages of the latter monitor set for long irradiations in various active core configurations of the LVR-15 reactor. The successful application of the Au+Mo+Rb(+Zn) monitor set has been verified by comparative determination of the neutron flux parameters α, f, and fusing this and the Au+Zr monitor set, and by analyses of the NIS standard reference materials 1547 Apple leaves, 2711 Montana Soil, and 1633b Trace Elements in Coal Fly Ash. (author)

[en] An obsolete control unit of a fast transport (rabbit) system for short-time neutron activation analysis at the LVR-15 experimental reactor at Rez has been replaced. In the new system a PC is used to fully control the rabbit system and the subsequent gamma-ray spectrometry measurement. The modernization resulted in significant simplification of the operator work and improved documentation of the irradiation and spectra acquisition procedures. New nuclear safety features of the rabbit system are also described. (author)