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Abstract  

In April 2007 the new nuclear research reactor, OPAL, was opened at Lucas Heights in Sydney. OPAL is a 20 MW open pool light water reactor with a heavy water reflector vessel and contains a cold neutron source. It is a multi-purpose facility for radioisotope production, irradiation services and neutron beam research. The OPAL design includes purpose-built facilities for instrumental neutron activation analysis (INAA) and delayed neutron activation analysis (DNAA). For INAA there is a short residence time facility in a neutron flux of around 2·1013 cm−2·s−1 and a number of long residence time facilities providing fluxes from 3·1012 to 1·1014 cm−2·s–1. The flux at the short residence time DNAA facility is around 6·1012 cm−2·s−1. The main focus for INAA at OPAL is the research community, meeting the needs of a wide range of disciplines, including mineral processing, geology, the environment, health and archaeology. Both the relative (comparator) method and the k 0-method of standardization for INAA are being established in OPAL. A description of progress, plans and capabilities are presented.

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Abstract  

It has been demonstrated that the Shape Independent Model for k0 based INAA can be applied in the Slowpoke-2 beryllium moderated reactor. The elemental concentration determined using this methodology agreed well with both certified values and those determined by the more conventional 'B'-value method. However, the facility characterising parameter B(x,46Sc,124Sb) differed significantly from that determined in other reactor types.

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Abstract  

Aircraft engines and transmissions are regularly monitored by several integrated techniques such as periodic analysis of the metallic wear debris deposited in the lubricating oil, termed Aircraft Oil Analysis (AOA). Trending of these results indicate to the fleet manager the operational health of each aircraft. Instrumental neutron activation analysis (INAA) provides similar results and for a greater range of metals than the analytical techniques used in the field laboratories. However, for new oil-lubricated systems with fine filtration, the wear debris collects on the oil filter and little debris remains in the oil for analysis. The wear debris must be removed from the filter and ends up as a solid sample. Ultrasonic cleaning is used and the wear debris may be inspected qualitatively to determine the wear mechanism, termed Filter Debris Analysis (FDA). Quantitative analysis follows, termed Quantitative Filter Debris Analysis (QFDA) and, for techniques other than INAA, the sample must be dissolved. A combination of three acids and microwave digestion are then used. Then, to use the present field technique, this aqueous sample is then converted to an appropriate organic matrix before analysis. Again, INAA has been used to develop and monitor this QFDA technique for field application.

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Abstract  

The purpose of this study was to demonstrate the versatility of combining the use of high resolution, Ge(Li) γ-detectors with the techniques of fast neutron activation analysis. A compilation of γ-ray spectra are presented for irradiation of 30 elements with 14.8 MeV neutrons under standard conditions and the origin of all major photopeaks is determined.

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Abstract  

The increasing trend towards the use of fine oil filtration in modern jet engines suggests that the Spectrometric Oil Analysis Program (SOAP), which routinely monitors the health of aeroengines, may no longer be effective in detecting abnormal wear trends. Since the oil filter contains a wealth of information on wear in a system, it may be necessary to perform engine health monitoring through Filter Debris Analysis (FDA). In the present study, a method was developed for the determination of 19 wear elements (Ag, Al, Au, Cd, Co, Cr, Cu, In, Fe, Mg, Mn, Mo, Ni, Sb, Sn, Ti, V, W and Zn) in aircraft engine oil filter debris samples using the analytical technique of Neutron Activation Analysis (NAA). Results obtained by NAA for the analysis of two types of filter debris samples compared well with results obtained previously for similar samples and it appears that FDA should be very useful for following wear trends.

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Abstract  

Used lubricating oil analysis programs are currently employed by both the military and industry in an attempt to minimize some of the costs associated with equipment failure. The periodic determination of water elements in the lubricant of an oil-wetted system can provide very useful information on the condition or health of the system and an early indication of impending failure. In the present study, the application of Neutron Activation Analysis (NAA) to used oil analysis was investigated. The method developed allowed for the determination of fifteen elements (Ag, Al, Cl, Cr, Cu, Fe, In, Mg, Mn, Mo, Na, Ni, Sn, Ti and Zn) associated with engine wear or deterioration. Results obtained for the analysis of used naval diesel oils exhibited good agreement with results obtained by Atomic Absorption Spectrophotometry (AAS) methods. A drawback of the NAA procedure is that the determination of Fe, a major wear element in most systems, involves an analysis time of approximately one week.

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Abstract  

A new utility program for processing data in neutron activation analysis (NAA) has been developed for use on MS-DOS microcomputers. Peak areas are read from ASCII data files of gamma-ray spectra which have been processed by a Gaussian peak fitting program, GAMANAL-PC. Elemental concentrations are then calculated by this new program, QUACANAL, via a semi-absolute algorithm that uses pre-determined activation constants. User-defined ASCII library files are employed to specify the elements of interest required for analysis, and (n, p) and (n, ) interferences are taken into account. The program has been written in turbo PASCAL, is menu driven and contains options for processing data from cyclic NAA. An interactive philosophy has been used in designing the program.

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Abstract  

The use of depleted uranium in military ordinance has led to an increasing need to determine isotope-specific uranium concentrations in environmental matrices. To this end, gamma-ray spectrometry, ICP-MS and INAA methods have been validated, in accordance with the ISO 17025 standard. Reporting limits of 0.21 (U-235) and 0.91 (U-238) ng/L were obtained by ICP-MS analysis of water. Higher reporting limits were obtained for INAA (U-238 only) validations of water and gamma-ray spectrometric validations of soil and water. Accredited methods have been used to determine uranium concentration and isotope ratio of samples obtained from the Defence Research and Development Canada Valcartier, Quebec.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
A. Hoover
,
M. Bacrania
,
N. Hoteling
,
P. Karpius
,
M. Rabin
,
C. Rudy
,
D. Vo
,
J. Beall
,
D. Bennett
,
W. Doriese
,
G. Hilton
,
R. Horansky
,
K. Irwin
,
J. Ullom
, and
L. Vale

Abstract  

Microcalorimeter detectors provide superior energy resolution for the detection of X-rays and gamma-rays. The technology utilizes a cryogenic transition-edge sensor (TES) coupled to a tin bulk absorber. We are working on fabrication methods for the production of arrays with many sensors. In this paper, we present data collected with an array of microcalorimeters using as many as 26 sensor elements simultaneously. Advances in sensor design have extended the useful dynamic range to photon energies up to ∼200 keV, while providing resolution performance in the 80–90 eV FWHM range, significantly better than planar high-purity germanium. These sensor arrays have applications in the measurement of nuclear materials. We present data collected from 153Gd, a highly-enriched uranium sample, and a plutonium isotopic standard source. We also demonstrate clean separation of the 235U 185.715 keV peak from the ubiquitous 226Ra 186.211 keV background peak interference.

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