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Topic: Neutron activation analysis

	Neutron activation analysis - Wikipedia, the free encyclopedia
		In chemistry, neutron activation analysis is a technique used to very accurately determine the concentrations of elements in a sample.
		The particular advantage of this technique is that it does not destroy the sample, and thus has been used for analysis of works of art and historical artifacts.
		The sample is thus bombarded with neutrons, causing the elements to form radioactive isotopes.
	en.wikipedia.org /wiki/Neutron_activation_analysis (192 words)

	Neutron Activation Analysis
		Neutron Activation Analysis is an analytical technique based on the measurement of characteristic gamma rays emitted by isotopes of the sample that are produced by irradiation with thermal neutrons.
		Neutron Activation Analysis is a comparative technique; standards are prepared from certified solutions of known concentration of the elements of interest.
		The sensitivity obtained by activation analysis is a function of the neutron cross section of the element in question, available neutron flux, length of irradiation, resolution of the detector, matrix composition, and the "total" sample size.
	www.ne.ncsu.edu /NRP/naa.html (677 words)

	NEUTRON ACTIVATION ANALYSIS (Site not responding. Last check: 2007-11-03)
		Neutron activation analysis (NAA) is a sensitive analytical technique useful for performing both qualitative and quantitative multi-element analysis of major, minor, and trace elements in samples from almost every conceivable field of scientific or technical interest.
		The use of neutron activation analysis to characterize archaeological specimens (e.g., pottery, obsidian, chert, and limestone) and to relate the artifacts to source materials through their chemical signatures is a well-established application.
		Analysis of rock specimens by neutron activation analysis assists geochemists in research on the processes involved in the formation of different rocks through the analysis of the rare earth elements (REEs) and other trace elements.
	www.me.wpi.edu /Nuclear/Reactor/Labs/R-naa.html (1366 words)

	neutron activation analysis - Hutchinson encyclopedia article about neutron activation analysis
		Chemical analysis used to determine the composition of a wide range of materials found in archaeological contexts.
		A specimen is bombarded with neutrons, which interact with nuclei in the sample to form radioactive isotopes that emit gamma rays as they decay.
		The energy spectrum of the emitted rays is detected with a counter and constituent elements and concentrations are identified by the characteristic energy spectrum of emitted rays and its intensity.
	encyclopedia.farlex.com /Neutron+activation+analysis (134 words)

	Elemental Analysis Incorporated - Neutron Activation Analysis (Site not responding. Last check: 2007-11-03)
		In this respect, NAA is capable of providing a comprehensive determination of the samples total elemental content regardless of oxidation state, chemical form, or physical state of the desired element(s).
		Neutron activation is a physical technique that is based on nuclear reactions whereby the elemental content is determined by irradiating the subject sample with neutrons, creating radioactive forms of the target element in the sample.
		When neutrons activate the nucleus of the atom, it allows the total elemental content to be observed regardless of the oxidation state, physical location, or chemical form of the desired element.
	www.elementalanalysis.com /naa (1550 words)

	NEUTRON ACTIVATION ANALYSIS (Site not responding. Last check: 2007-11-03)
		Neutron Activation Analysis (NAA) is a quantitative and qualitative method of high efficiency for the precise determination of a number of main-components and trace elements in different types of samples.
		NAA, based on the nuclear reaction between neutrons and target nuclei, is a useful method for the simultaneous determination of about 25-30 major, minor and trace elements of geological, environmental, biological samples in ppb-ppm range without or with chemical separation.
		But, as the neutron flux is rather low in comparison to a nuclear reactor their use in NAA is limited to the determination of elements of high activation cross section which are present in major concentrations.
	www.reak.bme.hu /nti/Education/Wigner_Course/WignerManuals/Budapest/NEUTRON_ACTIVATION_ANALYSIS.htm (2941 words)

	Becquerel Laboratories \| Neutron Activation Analysis
		NAA is a physical technique that is based on nuclear reactions.
		NAA is especially attractive for matrices that are not suited for other analytical methods.
		NAA is an alternative procedure that expands and verifies results obtained by other analytical techniques.
	www.becquerellabs.com /naa.html (254 words)

	[No title]
		Neutron activation analysis is a sensitive multielement analytical method for the accurate and precise determination of elemental concentrations in unknown materials.
		It is generally referred to as INAA (instrumental neutron activation analysis) for the purely instrumental version of the technique.
		FNAA (fast neutron activation analysis) is the form of the technique if higher energy neutrons, usually from an accelerator based neutron generator, are used.
	www.chem.tamu.edu /services/naa/naa.htm (658 words)

	Nuclear Engineering Teaching Laboratory - Neutron Activation Analysis
		Neutron Activation Analysis (NAA) is one of the most sensitive methods used to measure the concentration of trace amounts of many elements.
		NAA has been in routine use to measure trace element concentrations in complex matrices such as human and animal tissue, coal, coal fly ash, petroleum, river sediments, waste water, geological deposits, paper, air particulates, high purity metals, blood, urine, feces, sweat, tobacco, rocks, paint chips, animal feed, detergents and cereals.
		The cost of analysis by NAA depends on the number of samples to be analyzed and the number of elements to be measured in a sample.
	www.me.utexas.edu /~netl/NeutronActivationAnalysis.htm (517 words)

	Neutron activation analysis installation - Patent 4302285
		A neutron activation analysis installation comprises a neutron generator whose target chamber communicates through a transport means with a test sample receiving and loading assembly which, in its turn, communicates with a test sample impurity concentration measuring unit.
		The known neutron activation analysis installations may not be used with pure and highly pure materials having an oxigen content of 1.multidot.10.sup.-3 % by weight, maximum, a disadvantage associated with the fact that the surface of test samples is contaminated before or during the analysis.
		The neutron activation analysis installation forming the subject of the present invention permits high-accuracy quantitative determination of an impurity and macrocomponent content in various materials, an advantage associated with the fact that the effect of surface contamination on analysis results is excluded.
	www.freepatentsonline.com /4302285.html (3311 words)

	Neutron Activation Analysis (Site not responding. Last check: 2007-11-03)
		Neutron Activation Analysis (NAA) is a highly sensitive method for the accurate determination of elemental concentrations in material.
		The NAA method is based on the detection and measurement of characteristic gamma rays emitted from radioactive isotopes produced in the sample upon irradiation with neutrons.
		Neutrons are absorbed in the nuclei of constituent atoms, and later these nuclei emit radiation with energy and quantity characteristic of the particular element.
	reactor.engr.wisc.edu /UWNRNAA.htm (280 words)

	CHP - Neutron Activation Analysis (Site not responding. Last check: 2007-11-03)
		Neutron Activation Analysis (NAA or INAA for Instrumental Neutron Activation Analysis) is a radiochemical method of analyis that uses neutron irradiation of a sample to convert analyte elements to radioactive isotopes.
		The usual procedure to perform NAA is to irradiate samples and standards in a reactor chamber for a period of time of minutes to hours, remove and allow to "cool" for a period of time, and then count.
		NAA is also possible using a discrete neutron source or an accelerator.
	www.chem.vt.edu /chem-ed/spec/uv-vis/spec/material/naa.html (203 words)

	Neutron activation analysis (Site not responding. Last check: 2007-11-03)
		This is a popular trace element analysis technique used in archaeology to indicate where things were made (provenance studies) for ceramics, and rocks such as obsidian and marble.
		When some of this sample is placed in a stream of neutrons, such as in a nuclear reactor, the atoms of the chemical elements of the material capture some of the passing neutrons and are transformed into radioactive versions (isotopes) of the same element, which emit radiation.
		After the sample has been removed from the reactor it continues to emit radiation as the radioactive isotopes decay, and if placed in front of suitable radiation detectors, the radioactivity of each element can be isolated and is a direct measure of the amount of that element in the material.
	www.thebritishmuseum.ac.uk /science/text/techniques/sr-tech-naa-t.html (196 words)

	Neutron activation analysis method
		Neutron activation analysis was discovered in 1936 by Hevesy and Levi.
		Neutron activation analysis was soon established as a method of qualitative and quantitative element analysis.
		The sample material is irradiated with neutrons in a neutron source.
	lch.web.psi.ch /naa/naa_method.html?forprint (122 words)

	Neutron-activation offers better prospects
		Neutron activation is a method of determining the elemental composition of a sample.
		Neutron activation is free from effects of sample size that plague other nuclear techniques; because the entering neutrons are uncharged (they pass right through the sample) and the exiting gamma rays are energetic enough not to be attenuated by large samples.
		Neutron activation analysis can determine to the millionth of a part the composition of a metal fragment and establish whether or not it is identical with another sample.
	karws.gso.uri.edu /JFK/Scientific_topics/NAA/NAA_and_assassination_II/NAA_and_better_prospects.html (2020 words)

	McClellan Nuclear Radiation Center
		Neutron activation analysis, discovered in 1936, stands at the forefront of techniques for the quantitative multi-element analysis of major, minor, trace and rare elements.
		Today, instrumental neutron activation analysis is used for diverse applications in studies requiring nondestructive analysis of samples and/or low levels of sensitivity for the elements of interest.
		MNRC's neutron activation analysis laboratory was designed to analyze for the major, minor, and trace element content of samples covering a wide spectrum of material types and involving many scientific and technical fields.
	mnrc.ucdavis.edu /irradiation_apps.html (459 words)

	Solids Solutions Netherlands Delft: Laboratory for particle characterization, pore size distribution,porosity ... (Site not responding. Last check: 2007-11-03)
		The analysis of porosity by the adsorption isotherm and desorption isotherm of nitrogen, adsorption isotherm of argon or adsorption isotherm of krypton is performed at different low pressures and low temperature, often the boiling point of liquid argon or nitrogen.
		Prior to the analysis of the adsorption isotherm the sample is pretreated or degassed (outgassed) in vacuum at elevated temperatures.
		Analysis of CO2 adsorption is performed at 273 K on microporous carbons or activated carbons or charcoals for determination of the micropore size and micropore surface area and microporosity.
	www.roswebdesign.nl /solids-solutions/links.html (12537 words)

	Neutron activation analysis - Patent 4361534
		Neutron activation is used to analyse the silicon and aluminium content of samples of material, such as bauxite ore and coal.
		Neutron activation analysis, which is the basis of the present invention, does not have the problems associated with wet chemical assaying or the X-ray fluorescence technique, noted above, when applied to the analysis of large bulk samples.
		The thermal neutron flux generated within the sample 13 was monitored by thermal neutron detector 11, which was a high efficiency neutron detector (filled to a pressure of 4 atmospheres with a mixture of.sup.3 He and Kr) which was also located beneath the sample container and adjacent to the neutron source.
	www.freepatentsonline.com /4361534.html (4763 words)

	Delft Solids Solutions - (INAA) Instrumental Neutron Activation Analysis
		Neutron activation analysis (NAA) is a sensitive analytical technique for performing qualitative and quantitative multi-element analysis of major, minor, and trace elements in samples of approximately 60 elements (30-40 elements simultaneously).
		The reason for the high sensitivity of NAA is that most sample matrices appear to be transparent; H, C, O, N, P, and Si hardly form any radioactive isotopes.
		The method is based on the conversion of stable nuclides into radioactive nuclides (radionuclides) by irradiation with thermal neutrons (neutrons of low energy).
	www.solids-solutions.com /txt-instrumental.html (218 words)

	Delft Solids Solutions is a testing laboratory for analysis of porous and nonporous solids, powders and gases. ...
		Gravitational sedimentation In gravitational sedimentation (originally the pipette method) the settling rate of particles in liquid is measured and related to the mass by use of the Stokes law.
		Delft Solids Solutions is located in Delft and is a testing laboratory for measurement and analysis and characterization of porosity, pore size, pore size distribution, specific surface area, pore volume, particle size, particle size distribution, sprays, and chemical composition and chemical analysis of solid materials (solids), liquids and gases.
		The analysis of the texture of solid materials and porosity of solid samples is determined by different surface science techniques and surface characterization techniques, as physical gas adsorption, chemical gas adsorption, mercury intrusion porosimetry and helium pycnometry.
	www.solids-solutions.com (1550 words)

	United States Geological Survey TRIGA Reactor Services
		Neutron activation analysis (NAA) is an analytical technique that relies on the measurement of gamma-rays emitted from a sample that was irradiated by neutrons.
		The principal error in the analysis of materials by NAA is the counting statistic error, which is based on the signal to background ratio at the gamma-ray energy region of interest.
		Neutron activation analysis remains at the forefront of techniques for the quantitative multi-element analyses of major, minor and trace elements in hundreds of different types of materials.
	geology.cr.usgs.gov /facilities/gstr (1594 words)

	McMaster Nuclear Reactor - Centre for Neutron Activation Analysis
		ctivation analysis is a method for determining the elemental content of samples by irradiating the sample with neutrons, which creates radioactive forms of the elements in the sample.
		NAA is an established analytical technique for determining trace elements in a wide variety of materials, including rocks and other geological samples, as well as ceramics, oils, plastics, metals, water, biological and botanical materials.
		A significant advantage of NAA over the techniques is the simplicity of sample treatment before analysis: in most cases, the only requirement is that the sample be reduced to a size suitable for encapsulation.
	www.science.mcmaster.ca /mnr/NAA-Page/naa.htm (334 words)

	[No title] (Site not responding. Last check: 2007-11-03)
		Neutron activation analysis (NAA) with (mostly thermal) neutrons is a useful method for the simultaneous determination of about 25-40 major, minor, and trace elements in small geological samples.
		NAA was first proposed by von Hevesy and Levi in 1936, but had to await the development of suitable electronic equipment before being useful as an analytical technique.
		Irradiation with epithermal neutrons is advantageous in cases where a nuclide has a high I/s ratio (I= resonance activation integral), which means that these isotopes have much higher cross-sections by resonance capture of epithermal neutrons, while the interfering elements have not.
	www.univie.ac.at /geochemistry/neut.html (3037 words)

	Large sample Prompt-Gamma Neutron Activation Analysis (Site not responding. Last check: 2007-11-03)
		Neutron activation analysis can now be applied to samples of kilogram scale without a priori knowledge of the sample’s composition.
		Their quantitative analysis has been based on comparison of the object studied with samples of known, and similar matrix composition in order to avoid the corrections for neutron and gamma-ray self-attenuation.
		One of these neutron beams will be available for prompt gamma NAA which will have an end-point location at 25-30 m distance from the reactorcore.
	www.iri.tudelft.nl /~rc/fmr/pgnaa_abs.html (459 words)

	Neutron Activation Analysis
		A simple example of neutron activation analysis involves the measurement of iridium in soils.
		This is the measurement that led to the theory that the extinction of the dinosaurs, 65 million years ago, was caused by the impact of an asteroid or comet somewhere on Earth.
		In 1979, a group of scientists reported that neutron activation analysis had shown unusual amounts of the element iridium in Italian Cretaceous-Tertiary boundary sediments.
	www.lbl.gov /abc/wallchart/chapters/13/5.html (298 words)

	Archaeometry, Neutron Activation Analysis, Jan Gunneweg: The importance and procedure of a nuclear method applied to ...
		Neutron Activation Analysis borrows its name from the BIG BANG during which event a mammoth flux of neutrons was created.
		Neutron Activation Analysis is a collective name for a scientific method to obtain quantification of the chemical elements in the domain of six important fields in Archaeology:
		In 1967, a nuclear technique, Instrumental Neutron Activation Analysis was developed to establish a quantitative chemical "fingerprint" of ceramic and volcanic obsidian, basalt and pumice.
	micro5.mscc.huji.ac.il /~msjan/neutron.html (786 words)

	Blakey's Linchpin Pt 2
		The theory behind neutron activation analysis is that irradiation and decay produce qualitative and quantitative data on all elements present in a given specimen.
		Thus, the first of two overriding hypotheses on which the principle of neutron activation analysis of bullet lead depends is that it possible to accurately measure the amounts of antimony, silver, and copper in a given sample of bullet material.
		NAA tests for composition of antimony, silver, and copper were then run on the bullet fragments.
	www.geocities.com /whiskey99a/milam2.html (6083 words)

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