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- Author or Editor: P. Stegnar x
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Abstract
The k0-standardization method of neutron activation analysis was applied for the multielement analysis of the NIST (National Institute of Standards and Technology) proposed Standard Reference Material (SRM) No. 1547 Peach Leaves. At the moment, 50 elements can be determined from a one day irradiation, using the TRIGA Mark II reactor of the 
Jo
ef Stefan
Institute, Ljubljana. Among them, 28 elements were determined quantitatively, and for the remaining 22 elements, less than values were obtained.
Abstract
A radiochemical procedure for simultaneous determination of the trace elements As, Mo, Sb and Se after thermal neutron irradiation, based on destruction of the sample with saturated Mg/NO3/2 or oxygen combustion, followed by solvent extraction of each element from a common aliquot in 6M hydrochloric acid is deterials was analyzed and good agreement with certified values was obtained.
Abstract
A suite of natural matrix reference materials (RMs) were used to assess the quality of analytical results obtained by k
0-instrumental neutron activation analysis (k
0-INAA) at the Jo
ef Stefan Institute (IJS). Five certified reference materials (CRMs) from the Institute for Reference Materials and Measurements (IRMM), two standard reference materials (SRMs) from the National Institute of Standards and Technology (NIST), three RMs from the International Atomic Energy Agency (IAEA) and one RM from IJS were analyzed. Altogether, results for twenty-four elements in inorganic matrices and twenty-nine elements in organic matrices, obtained by k
0-INAA, were compared to certified values. Results obtained show good agreement with certified or assigned values except for Fe, La, Nd, Sm and U in inorganic matrices, and Ag, Al and Cr in organic matrices.
Abstract
Neutron-flux behaviour during irradiation should be known when applying the ko-method of neutron activation analysis /NAA/. During two 100-hour operating periods of the TRIGA MARK II reactor, Ljubljana, the flux was measured by means of a197Au/n,
/198Au monitor /E
=411.8 keV/. Cadmium-covered irradiations were also performed to obtain the epithermal flux and thermal-to-epithermal flux ratio variations. Consistency was found between these results and the reactor operators' logbook record.
Abstract
In this work the use of the reagents 4-NDP and Na-DDTC in the radiochemical separation of Cd, Co, Cu, Se and Zn from a single aliquot of sample shortly after the end of irradiation in a flux of thermal neutrons is described. The performance of the proposed separation method was tested by means of analyses of these elements in a series of SRMs and good agreement with certified values was obtained.
Abstract
The nonideality of the epithermal neutron flux distribution at a reactor site can be described by a 1/E1+
spectrum representation, with parameter being a measure of the nonideality. -values were determined in 3 typical irradiation positions of the TRIGA MARK II reactor of the 
Jozef Stefan
Institute, Ljubljana, Yugoslavia, using the Cd-ratio for multi-monitor method. The simpler Cd-ratio for dual monitor method (monitors:197Au–94Zr) also yielded reliable results. This characterisation is of use in the k0-method of NAA, which is recently introduced at the Institute.
Abstract
On the basis of tracer experiments, a simple and rapid radiochemical separation method for simultaneous determination of I–, Br– and Cl– in one aliquot of a water sample (only 2–4 ml) has been developed. The method is based on short irradiation of the water sample and separation of the halogens using sequential ion exchange columns filled with Dowex 1×8, 100–200 mesh anionic resin prepared in I–/I2, Br–/Br2 and Cl– form. After washing the columns with an appropriate volume of 2% NaCl solution, the resins were transferred to vials and activities of the isolated radionuclides128I,82Br and38Cl measured together with standards in a 
well type
or on a coaxial Ge detector connected to a Canberra 90 multichannel analyzer. Besides high chemical yields, from the 
-spectra of the isolated radionuclides, it is evident that high decontamination fac-
Abstract
A number of investigations of trace elements in the waters, organisms and sediments of the Adriatic, using neutron activation analysis with radiochemical, separations are reported. These include studies of Hg in mussels from the Northern Adriatic, of Hg and Se in edible animals from the Rijeka region, and of seven elements (As, Cd, Cu, Hg, Mn, Se and Zn) in marine invertebrates from the Slovene coast. Additionally, plankton, sediment cores and water samples were taken from a grid of stations covering the whole Adriatic and analyzed for 6 to 11 of the trace elements As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Sb and Zn (Hg only in water). Generally, levels found were not indicative of pollution as compared with oceanic samples, but some evidence of locally increased levels was found, especially for Hg. The levels of eleven trace elements in three marine Intercomparison samples prepared by the IAEA Monaco Laboratory are also presented.
