Values of 2200 m.s-1 cross sections, together with the associated nuclear data, are tabulated for 128 (n,g) reactions of interest in NAA. The values are derived from the Y2K database of experimentally measured k0-factors.
This work shortly describes the main steps involved in the design and development of the software package Quantu, created to conduct k0-standardized NAA. The package comprises a database as well as two individual programs. Quantu-MCA is dedicated to (g-ray spectrum analysis and Quantu-INAA is the interface for the database administration, also dealing with k0-method calculations.
Authors:R. Zeisler, R. Demiralp, and M. Makarewicz
A source of error in the gamma-spectrometric registration of the analytical signal in neutron activation analysis is its dependency on the overall count rate. Losses in the accuracy of quantitation occur due to hardware and software. This paper presents examples for solutions to these problems and demonstrates that accurate NAA can be accomplished under high-rate counting conditions with commercially available technology.
Authors:Danas Ridikas, Pablo Adelfang, Kevin Alldred, and Marta Ferrari
Although the number of research reactors (RRs) is steadily decreasing, more than half of the operational RRs are still heavily
underutilized, and in most cases, underfunded. The decreasing and rather old fleet of RRs needs to ensure the provision of
useful services to the community, in some cases with adequate revenue generation for reliable, safe and secure facility management
and operations. Enhancement of low and medium power research reactor (RR) utilization is often pursued by increasing the neutron
activation analysis (NAA) activities. In this paper we will present the strategy and concrete actions how NAA as one of the
most popular RR applications can contribute to the above goals in particular through (a) RR coalitions and networks, (b) implementation
of automation in different stages of NAA, (c) QA/QC, including skills improvement of involved personnel, (d) dedicated proficiency
tests performed by a number of targeted analytical laboratories. We also show that despite the IAEA’s efforts, some of the
NAA laboratories still perform badly in proficiency tests, do not have formal QA/QC procedures implemented, have not implemented
automation to process large number of samples or lack of clear marketing strategies. Some concrete actions are proposed and
outlined to address these issues in the near future.
Authors:Rachel Popelka-Filcoff, Claire Lenehan, Michael Glascock, John Bennett, Attila Stopic, Jamie Quinton, Allan Pring, and Keryn Walshe
Ochre is a significant material in Aboriginal Australian cultural expression from ceremonial uses to its application on many
types of artifacts. However, ochre is a complex material, with associated surrounding minerals potentially challenging the
overall analysis. In recent literature several studies have attempted to characterize ochre by a variety of techniques to
understand procurement and trade. However, ochre is difficult to differentiate on major elemental or mineralogical composition
and requires a detailed analysis of its geochemical “fingerprint”. Neutron activation analysis (NAA) provides the high sensitivity
(sub-ppm), precision and accuracy in multi-elemental analysis required for ochre. The elements of interest for ochre generally
include rare earth elements (REEs) and certain transition metal elements as well as arsenic and antimony. Data from relative
comparator NAA (MURR, University of Missouri, USA) is compared with data from k0-NAA OPAL (ANSTO, Lucas Heights, Australia). A discussion of the two methods will be examined for their utility in “fingerprinting”
the provenance of ochre. The continuing importance of NAA to archaeometry will also be discussed.
The fundamental parameters method (FPM) for X-ray fluorescence (XRF) has been applied to determine the MN, Cr and Sr components of aluminium wires and sheets. The results are compared with neutron activation analysis (NAA) and atomic absorption spectrometry (AAS). The FPM does not require standards, however, it requires the spectra of the pure element for the concentration determination.
Authors:P. Albert, J. Bajard, R. Delmas, and M. Fedoroff
The determination of Ir and Pt in rhodium neutron monitors was investigated via192Ir and199Au after neutron activation, via191Pt and194Au–196Au after proton activation. Ir was determined by instrumental NAA. A chemical separation of gold, with a yield measurement method by a radioactive tracer, was developed for platinum determination after neutron or proton irradiation.
Information properties of analytical results together with other important parameters especially economic ones can be used for the optimization of analytical procedures. Therefore, we have proposed a computational technique for the optimization of multielement neutron activation analysis (NAA) based on the information content and profitability. The optimization starts with the prediction of the -ray spectra to be expected during analysis under given experimental conditions (sample size, irradiation, decay and counting times etc.) and with the calculation of detection and determination limits. In the next step, the information contents for the determination of particular elements and for the simultaneous determination of element groups are computed. The information content depends or is closely connected with such properties of the method as selectivity, sensitivity, precision, accuracy and, as in the other cases of trace analysis, also with the detection limit. Then, the information profitability (IP) taking into account the information content and relevance (appreciation of specific information according to its contribution to the solution of a given problem) together with economic aspects can be calculated. This function can be used for the optimization of a particular NAA procedure, for the mutual comparison of different variants of NAA and also for the comparison with other analytical methods. The use of information profitability for the optimization of NAA is shown on a practical example of the INAA analysis of urban particulate matter SRM 1648 produced by NBS (USA).
With SLOWPOKE and MNS reactors which have reproducible neutron fluxes, the standardization of multielement NAA can be reduced to measuring activation constants once for all elements and then determining relative detection efficiencies for new detectors and counting geometries. In this work, a method has been developed for the parameterization of the efficiency of gemanium detectors. The gamma-ray detection efficiency was measured as a function of energy and distance for three detectors. The variation with distance was found to follow a modified EID law, within 1%, for point sources 1 mm to 250 mm from the detector. A model, including coincidence summing corrections, was developed to calculate efficiency for NAA samples; it requires 16 measured parameters. Tests showed that the calculated relative detection efficiencies are accurate to better than 3% for close counting geometries and sample volumes up to a few millilitres. Areas of possible improvement to the accurarcy of the method are suggested.
An extensive database of analytical results from a recent biological matrix Reference Material Characterization Campaign permitted an intercomparison of the performances of various methods among each other and with "true" best estimate concentration values established for these materials. Six different variants of neutron activation analysis (NAA) methods were employed including: instrumental neutron activation analysis, instrumental neutron activation analysis with acid digestion, neutron activation analysis with radiochemical separation, neutron capture prompt gamma activation analysis, epithermal instrumental neutron activation analysis, and neutron activation analysis with preconcentration. The precision and accuracy performance of NAA-based analytical methods are compared with three other major techniques, atomic absorption spectrometry (AAS), atomic emission spectrometry (AES) and mass spectrometry (MS) for 28 elements in 10 natural matrix materials.