Neutron activation analysis thermal

Thermal neutron activation analysis has been used for archeological samples, such as amber, coins, ceramics, and glass biological samples and forensic samples (see Forensic chemistry) as weU as human tissues, including bile, blood, bone, teeth, and urine laboratory animals geological samples, such as meteorites and ores and a variety of industrial products (166). 

MetaUic impurities in beryUium metal were formerly determined by d-c arc emission spectrography, foUowing dissolution of the sample in sulfuric acid and calcination to the oxide (16) and this technique is stUl used to determine less common trace elements in nuclear-grade beryUium. However, the common metallic impurities are more conveniently and accurately determined by d-c plasma emission spectrometry, foUowing dissolution of the sample in a hydrochloric—nitric—hydrofluoric acid mixture. Thermal neutron activation analysis has been used to complement d-c plasma and d-c arc emission spectrometry in the analysis of nuclear-grade beryUium. 

Picatinny Arsenal Thermal Neutron Activation Analysis Facility. N... 

This can result in a radioactive product from the A(n, t)A reaction where A is the stable element, n is a thermal neutron, A is the radioactive product of one atomic mass unit greater than A, and y is the prompt gamma ray resulting from the reaction. A is usually a beta and/or gamma emitter of reasonably long half-life. Where access to a nuclear reactor has been convenient, thermal neutron activation analysis has proven to be an extremely valuable nondestructive analytical tool and in many cases, the only method for performing specific analyses at high sensitivities... 

Twitty BL, Boback MW. 1970. Rapid determination of thorium in urine by thermal neutron activation analysis. Anal Chim Acta 49 19-24. 

Thermal Neutron Activation Analysis Activation thermal neutrons 30 min in flux,... 

Thermal Neutron Activation Analysis (NAA). The amount of sample adhering to the quartz sampling plate is variable. It is normally considered to be of the order of 100-200 /xg. Because of the size of the metallurgical samples available for this study, the average mass sampled was estimated to be in the range 1-5 /xg. 

Thermal neutron activation analysis was done on small samples from Sasanian silver objects to determine the concentrations of three major elements, Ag, Cu, and An, and 16 trace elements, Na, K, Sc, Cr, Mn, Fe, Ni, Co, Zn, As, Br, Sn,... 

In this report we describe our quantitative analyses for three major components and for 16 trace elements present from parts per billion (ppb) to parts per million (ppm) in Sasanian silver by thermal neutron activation analysis. The analytical data are discussed element by element. Some of the conclusions which can be drawn from the objects are discussed. Since the amount of comparative data available is too small for generalizations, many of our conclusions and assumptions are subject to change when more data and information become available. 

In order not to disfigure valuable ancient silver objects, only minute specimens can be removed for analysis. Sample size is thus a major restriction on the analytical method chosen. Thermal neutron activation analysis provides excellent opportunities for quantitative multi-element analysis of these small samples. The question as to how accurately these samples represent the entire specimen is considered in detail later. 

It is obvious, therefore, that 14 MeV neutron activation analysis can not compete with thermal neutron activation analysis as a technique for trace element analysis. In simple matrices, however, the rapid and non-destructive nature of the technique recommends its use for routine analysis of large numbers of samples for elemental abundances at the one milligram level, or above. It is unfortunate that the element carbon can not be determined by this technique. The nuclear reaction 12C(n, 2n)1 C which would be of great analytical importance is endoergic to the extent of nearly 19 MeV. This reaction is obviously not energetically possible using the 14.7 MeV neutrons produced by the 2H(3H,w)4He reaction commonly employed in most neutron generators. 

Alian, A., Djingova, R Kroener, B, Sansoni, B 1984. The monostandard method in thermal neutron activation analysis of geological, biological and environmental materials. Fresenius Z. Anal. Chem. 319, 47-53. Alian, A., Djingova. R., Sansoni, B., 1985. Comparison of different neutron activation analysis methods for multielement analysis of geological materials. In Sansoni, B. (Ed.), Instrumentelle Multielementanalyse. VCH Publishers, Weinheim, pp. 123-132. 

Photon activation analysis can be regarded as a complementary technique to thermal neutron activation analysis, with some advantages and several drawbacks. Particularly advantageous features of photon activation analysis as compared to neutron activation include ... 

Thermal neutron activation analysis Sound Chemical analysis ... 

Trace gold determination by on-line preconcentration with flow injection atomic absorption spectrometry, by use of di(methylheptyl)methyl phosphonate (DMHMP) as the immobilized phase loaded onto a macroporous resin Radiochemical separation and determination of gold complex matrices employing substoichiometric thermal neutron activation analysis... 

Protein-Bound Iodine (PBI) In Human Plasma by Thermal Neutron Activation Analysis. J. Nucl. Med. 5., 828 (1964). 19 5784... 

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