A novel method is presented for the calculation of uncertainties of neutron flux parameters and element mass fractions and
their uncertainties in k0-neutron activation analysis (k0-NAA) using the Kragten universally applicable spreadsheet technique. The results obtained are compared with other approaches
for evaluation of uncertainties of the neutron flux parameters and element mass fractions, namely with the Kayzero for Windows,
k0-IAEA and ERON programs. The differences observed are discussed in terms of how the above programs take into account various
uncertainty sources and their correlations.
A boron nitride irradiation vessel designed for use with a pneumatic tube transfer system has been used to analyze short-lived radionuclides by NAA. Bare and Cd-shielded irradiations on Co, Zr and Au were made to characterize the neutron fluxes in the irradiation position. Bare and BN-shielded irradiations were performed to determine epithermal advantage factors for 16 short-lived reactions and interference factors for a total of 11 (n, p) and (n, ) reactions induced by reactor fast neutrons. To illustrate application of these data, several biological and geological reference materials were analyzed.
The program ROMOS and the assisting program RECAL are presented. These programs were designed to facilitate nuclide identification and concentration calculation in NAA using the k0-concept. For nuclide identification classical tests (energy match, decay factor) are complemented with a test of the saturation factor including the sensitivity of neutron acctivation analysis for the candidate nuclide. For nuclides emitting more than one gamma-energy the intensity of the observed peaks in the spectrum are compared. Thereby full account is taken of relative detection efficiency and true coincidence effects. Practical experience in using the interactive code shows that it is a convenient and time-saving working aid for an experienced experimenter.
Elemental analysis of some herbal plants used in the ayurveda for curing of cardiovascular diseases has been performed using the techniques of neutron activation analysis and atomic absorption spectroscopy. The concentration of elements Mn, Na, K and Cl has been estimated by NAA using a252Cf neutron source and a high purity gemanium detector coupled to a multichannel analyzer, while the elements Ca, Cr, Co, Cu, Fe, Pb, Zn, Ni, Cd and Hg were analysed by AAS using a Perkin Elmer 3100 instrument.
in NAA is investigated. Attention is paid to fundamental considerations such as definitions and approximations, error propagation functions, uncertainty statements, reliability of nuclear data and formal dimensioning problems. As to the latter, it is concluded that the applicability of the
in NAA is demonstrated by new experimental evidence obtained from and Q0 determinations in three different reactors: the WWR-M reactor (Budapest, Hungary), the THETIS reactor (Gent, Belgium) and the DR-3 reactor (Risø, Denmark).
Authors:A. Figueiredo, J. Enzweiler, J. Sarkis, A. Jorge, and E. Shibuya
NAA and UV laser ablation ICP-MS were used to determine platinum group elements (PGEs) and gold in the geological reference materials UMT-1, WPR-1, WMG-1, GPT-4 and GPt-6, after NiS fire assay. Both methods presented results were good agreement with the recommended values. NAA gave more accurate values for Ir (relative errors between 0 to 9%) and UV-LA-ICP-MS presented better results for Pt (relative errors less than 12%, except for WPR-1). UV-LA-ICP-MS showed better sensitivity than NAA for Pd and Os. On the other hand, NAA showed lower detection limits for Ir and Au. Advantages and disadvantages of each method are discussed.
Authors:H. Dung, M. Freitas, S. Sarmento, M. Blaauw, and D. Beasley
A new Compton suppression system (CSS) for the gamma-ray spectrometer portion of the neutron activation analysis (NAA) was
set up at the RPI/ITN. The pneumatic transfer system, SIPRA, for short-lived nuclides and cyclic irradiations was improved.
A full calibration procedure of the CSS and SIPRA systems was performed. Two certified reference materials, NIST-SRM-1572
(Citrus Leaves) and NIST-SRM-1633a (Coal Fly Ash) were analyzed using the calibration factors. The CSS was instrumental in
lowering the detection limits of Cr, Fe, Hg, Rb, Sr, Th and Zn by reducing background and/or spectral interference considerably.
The analytical results were evaluated by comparison to the NIST certified values with deviations ranging from 2% to 8% for
the above mentioned elements, except Zn ranging from 10% to 15% for biological and environmental samples, respectively.
Authors:R. Dutta, R. Acharya, V. Chakravortty, A. Nair, A. Reddy, S. Chintalapudi, and S. Manohar
Three ferromanganese crusts from different locations of the Indian Ocean were analysed by neutron activation analysis using
thek0 method (k0 NAA method) for studying the distribution of some trace elements along with Fe and Mn. Another crust from the Lau basin of
the Pacific Ocean was investigated for comparison of the influence of different oceanic conditions on the trace element distributions
in ferromanganese crusts. Variation in Co concentration along with the Mn/Fe ratio were discussed in terms of the hydrogenous/hydrothermal
nature of the crusts. The normalised REE content was used to identify possible anomalies. The observed Ce anomaly is discussed
in the light of the depositional environment. The precision and accuracy of the method were confirmed by measuring the elemental
concentrations in a USGS nodule standard NOD A-1.
Authors:M. Eguskiza, P. Robouch, U. Wätjen, and F. De Corte
Three new synthetic multi-element standards (SMELS) were developed for testing the performance of the k0-standardization neutron activation analysis (k0-NAA) method when implemented in a laboratory. SMELS consist of a phenol-formaldehyde polymer matrix spiked with different groups of elements according to the half-lives of the formed radionuclides. They are classified as Type I for short-, Type II for medium- and Type III for long-lived radionuclides. This article presents the preparation of SMELS including different aspects such as choice of the matrix and spiking elements, chemical compounds, target concentrations, purity of the matrix and spiking procedure and the homogeneity study for all the spiked elements in order to demonstrate the quality of the produced materials.
Authors:Lin Xilei, F. De Corte, L. Moens, A. Simonits, and J. Hoste
USGS BCR-1 and G-2, NBS 1633a Coal Fly-Ash and a 7-element synthetic standard for biological material have been analysed in this work by reactor NAA, using the k0-standardization method. The analyses were performed independently in the analytical laboratories of the Institute for Nuclear Sciences (INW), Gent, and the Central Research Institute for Physics (KFKI), Budapest. This procedure allowed not only a comparison with the specified data or with other published values, but enabled a check of the consistency of our own results obtained in largely different experimental circumstances. As concluded the k0-standardization method combines general versatility (with respect to irradiation and counting conditions) with good accuracy, while keeping the experimental work as simple as possible. Since the k0 method is a computer-oriented technique, a FORTRAN IV program was designed and applied on a VAX 11/780 machine.