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	atom - HighBeam Encyclopedia (Site not responding. Last check: 2007-11-04)
		The atom consists of a central, positively charged core, the nucleus, and negatively charged particles called electrons that are found in orbits around the nucleus.
		The nucleus of an atom consists of neutrons and protons, the neutron being an uncharged particle and the proton a positively charged one.
		Atom probe analysis: the atom probe microscope provides three-dimensional compositional and structural analysis at the atomic- and near-atomic scales.
	www.encyclopedia.com /doc/1E1-atom.html (1557 words)

	Seeing and Catching Atoms: ORNL's Atom Probe Field Ion Microscope
		Analysis of the atoms forming these dots in the mass spectrometer section of the atom probe revealed that they were individual boron atoms that had segregated to the grain boundary.
		Atom probe analysis also revealed that boron was present at all the other disturbances in the crystal structure, including dislocations, low-angle boundaries, stacking faults, and antiphase boundaries.
		Atom probe analysis has also revealed that the phosphorus had segregated to the grain boundaries but that its deleterious influence there was minimized because the grain boundaries were also coated with a thin film of molybdenum carbide and nitride precipitates, which prevents failure from occurring prematurely at these locations.
	www.ornl.gov /info/ornlreview/rev28-4/text/atoms.htm (3358 words)

	Atomic species identification in Scanning Tunneling Microscopy by Time-of-Flight spectroscopy
		Atoms are transferred from regions of interest identified in STM images to the tip, from which they are ejected into a time-of-flight spectrometer.
		The atom probe provides the ultimate in single-atom microanalysis, however the range of materials is limited, and crystal growth on extended flat surfaces cannot be studied.
		Following standard practice with atom probes, it may be possible to determine the number of atoms transferred to the tip from the height of the peaks in the spectrum if detection inefficiencies are allowed for.
	www.public.asu.edu /~weier/sap/sap.j.vac.sci.html (2133 words)

	Assembler Construction by Proximal Probe
		What remains to be specified in a mechanosynthesis approach is the process by which individual atoms are to be recognized and transferred, the number of transfer steps necessary per atom, and any materials on which the atoms are to be adsorbed intermediate to their initial state and final site in a crystal lattice.
		The imprecision of single atom placement experiments to-date can be explained in part by uncertainties related to atom migration and tip structure, but also by noting that field evaporation in picking adatoms from the Si(111)-7x7 surface breaks three silicon-silicon bonds (~169.5 kcal/mol) and releases further vibrational energy upon the formation of tungsten-silicon bonds.
		The carbon atom to be deposited also projects at a sixty degree angle to the substrate, so that it can act as the tunneling atom both in conventional STM imaging and as a side-wall imager while minimizing tip/sample convolution effects.
	www.zyvex.com /Research_Old/Publications/papers/Foresight97.html (3678 words)

	What is Atom Probe? (Site not responding. Last check: 2007-11-04)
		An atom probe field ion microscope (APFIM) is a combination of a field ion microscope (FIM) and a time-of-flight mass spectrometer of a single ion sensitivity.
		Atoms always evaporate from the surface, so the spacial resolution in the depth direction is a mono-atomic layer.
		A unique feature of the atom probe compared with the other analytical instrument is its extremely high spatical resolution and the equal detection efficiency for light elements.
	inaba.nims.go.jp /ifes/apfim.html (248 words)

	Highbeam Encyclopedia - Search Results for atom (Site not responding. Last check: 2007-11-04)
		Structure of the Atom The atom consists of a central, positively charged core, the nucleus, and negatively charged particles called electrons that are...
		Atoms are called monovalent, divalent, trivalent, or tetravalent, according to whether they form one, two, three, or...
		A single atom is usually not referred to as a molecule, and ionic compounds such as common salt are not made up of molecules.
	www.encyclopedia.com /SearchResults.aspx?Q=atom (721 words)

	Solid State Technology - Using an atom probe microscope to characterize read heads
		To analyze a sample for use with the atom probe, a specimen is prepared from the sample (e.g., the wafer) that has to be analyzed.
		Data sets generated by the local electrode version of the atom probe are typically a cube of 50 to 100nm.
		The atom probe microscope uses the principles of both time-of-flight mass spectroscopy and point-projection microscopy to identify individual elements and to locate them within the bulk of a material.
	sst.pennnet.com /Articles/Article_Display.cfm?Section=ARTCL&ARTICLE_ID=211233&VERSION_NUM=1&p=5 (2291 words)

	What is a Three Dimensional Atom Probe (Site not responding. Last check: 2007-11-04)
		The atom probe is a point projection microscope capable of resolving the chemical identity and position of individual atoms in 3D with atomic resolution in the z direction and subnanometer lateral resolution.
		The atom probe is capable of both analyzing a sample with sensitivities that no other system can match and providing a positional accuracy of individual atoms that is unmatched.
		What the atom probe uniquely does is to evaporate the atoms themselves from their positions in the lattice and then chemically identify and spatially locate them within the sample.
	www.polaron.com /ons/what-is.shtml (318 words)

	Atom Probes and 3D Atom Probes - How They Work and What They Are Used For
		An atom probe is a point projection microscope that uses field-ion-microscopy (FIM) and time-of-flight mass spectrometry to resolve the chemical identity and position of individual atoms.
		The numbers of atoms of various elements hitting the detector are recorded and a mass spectrum is extrapolated from that data.
		The atom probe can be used to exactly determine the location and distribution of all elements within the alloy microstructure.
	www.azonano.com /details.asp?ArticleID=1696 (548 words)

	LEAP
		A measure advantage of this atom probe is the data acquisition without a high voltage nanosecond pulser due to Magnetic sector lens, and further it shows a high mass resolution.
		Although, the imaging atom probe was a powerful tool to obtain a spatial distribution of an ion, unfortunately, the mass resolution was worse due to its short fright pass of traveling ions.
		The atom probe was used for the study of biological molecules.
	www.geocities.jp /u_saitani/leap.html (3166 words)

	fenetre principale
		Some of these atoms are ionised and repelled from the specimen towards a phosphor screen, on which they produce spots of light, and hence a field ion image.
		Precipitates of atoms of a different type or second phases usually exhibit a different image contrast from the matrix due to their slightly different evaporation fields.
		With the introduction of atom probe techniques by Müller in 1968, it was possible to identify the chemical nature of the individual atoms.
	www.univ-rouen.fr /gpm/caracterisation/sonde/sonde_gb.htm (731 words)

	What is Three Dimensional Atom Probe? (Site not responding. Last check: 2007-11-04)
		In 1988, by applying a position sensitive detector to a time-of-flight atom probe, Cerezo, Godfrey and Smith at the University of Oxford succeeded in determining both the mass to charge ratio (m/n) and the position of ions at the same time.
		Later, a group of University of Rouen developed a similar atom probe using a multiple-anode detector, which is capable of detecting multi-event of iron arrival at the detector.
		In essence, both of these atom probes use a position sensitive detector and can determine the mass and the positions of atoms in conductive materials, which enables us to observe atom distributions in metallic materials in a real space of a few tens nanometer dimensions.
	www.nims.go.jp /apfim/3DAP.html (326 words)

	Chemical & Engineering News: Cover Story - Atomic Imaging turns 50
		Müller died in 1977, and in 1986 the Nobel Prize in Physics was awarded to Binnig and Rohrer for their STM work and to Ernst Ruska of the Fritz Haber Institute in Berlin for designing the first electron microscope.
		In the years following the introduction of the first atom probe, later-generation instruments were built and shown to be unique in their ability to uncover atomic-scale details such as lattice defects, grain boundaries, chemical impurities, and other critical phenomena in metallurgy, materials science, and surface science.
		But according to Panitz, the outlook for atom probes may be changing: Researchers who study layered structures and other complex materials are discovering that the newest instruments can indeed record vast amounts of data quickly and provide detailed structure images that can be manipulated in three dimensions.
	pubs.acs.org /cen/coverstory/83/8348atoms.html (2338 words)

	The College of Engineering @ Iowa State University
		Atom probe microscopy is the direct descendant of the field ion microscope introduced in the 1930s, the first microscope to provide direct atomic level images.
		But while the earlier instrument was limited to defining the position of atoms in space on a single axis, an APM is capable not only of rendering the atomic structure of samples in three dimensions, but also of fully characterizing all of the elements comprising the sample—atom by atom.
		According to Hillier, the atom probe microscope applies a large electric field to a material sample that has been whittled down into a sharp tip and inserted into a cryogenically cooled analysis chamber to freeze out atomic motion.
	www.eng.iastate.edu /coe/feature/091306keck.asp (882 words)

	Three-Dimensional Nanoscale Composition Mapping of Semiconductor Nanowires
		A new class of atom probe, the local electrode atom probe (LEAP) microscope, was used to map the position of single Au atoms in an InAs nanowire and to image the interface between a Au catalyst and InAs in three dimensions with 0.3-nm resolution.
		The initial position of an atom on the nanowire tip is determined by reconstructing the flight path between the detector and the tip.
		Single atoms are represented by dots, and the dot color indicates its chemical identity as determined by the time-of-flight measurement.
	pubs.acs.org /cgi-bin/sample.cgi/nalefd/2006/6/i02/html/nl051602p.html (2589 words)

	Department of Physics - Opportunities
		Both the impurity atom and the probe atom are found at one of the lattice points.
		If the probe atom attempts to jump to a lattice point already occupied by a host atom, the probe atom cannot move and stays at its current position.
		The probe atom is considered to have captured the impurity atom when it comes right next to the impurity atom.
	www.phy.ilstu.edu /opportunities/skadron/SkadronPrize2003.html (1088 words)

	APFIM preprint and reprint
		;Atom probe studies on the early stages of precipitation in Al-Mg-Si alloys\, Mater.
		"Atom probe studies of nanocrystallization of amorphous alloys", Proc.
		Atom Probe and Phase Transformation - an invited article prepared for the Newsletter of Grant in Aid of Ministry of Education, Priority Area "Phase Transformations", 1998.
	inaba.nims.go.jp /apfim/preprint.html (687 words)

	History of Atom Probe (Site not responding. Last check: 2007-11-04)
		The Atom Probe was invented by Professor Erwin Wilhelm Müller who was a professor at Pennsylvania State University in the United states.
		The first publication associated with the Atom Prove was in 1967; besides he improved it as the Atom Prove Field Ion Microscope so that FIM has a capability to give an atomic map of the specimen surface.
		Nevertheless he was first person to identify individual atoms using FIM, unfortunately he passed away from cancer on May, 1977, at the age of 65.
	www.geocities.jp /u_saitani/aphistory.html (332 words)

	News: 3-D atom probe wins award for innovative measurement
		A combination of a field ion microscope, a single-atom sensitivity time-of-flight mass spectrometer, and a position-sensitive detection system; the device enables the visualisation and chemical identification of individual atoms on the surface of a solid specimen, and allows the location of the analysed atoms to be determined with sub-nanometre precision.
		By removing successive layers of atoms from the surfaces of specimens, using a series of high voltage pulses, fully three-dimensional, atomic-scale reconstructions of the structure and chemical composition of the samples are obtainable.
		The judges said information produced by the atom probe would grow in importance and underpin future developments in nanotechnology.
	www.admin.ox.ac.uk /po/news/2004-05/nov/25.shtml (303 words)

	New Version Of Software For 3DAP Atom Probe Accelerates Materials from Oxford Nanoscience (Site not responding. Last check: 2007-11-04)
		New display options allow matrix atoms to be removed from the display, enabling single clusters or all clusters to be seen more clearly.
		By using this parameter, atoms that are closer than the selected distance to other atoms in the matrix material can be eliminated from the periphery of detected particles or clusters.
		PoSAP software is used extensively on 3D atom probes throughout the world as well as to process results from Monte Carlo simulations of material structures.
	www.azom.com /details.asp?newsID=1730 (405 words)

	An Introduction to FIM and APFIM - (Atom Probe) Field Ion Microscopy
		The net effect of many gas atoms is to create a pattern on the flourescent screen showing spots of light which correspond to individual atoms on the tip surface.
		The atom probe is a related technique whereby a sudden voltage pulse is applied to the tip.
		The time taken for the atom to arrive at the detector is a measure of the mass of that atom.
	www.uksaf.org /tech/fim.html (286 words)

	apfim (Site not responding. Last check: 2007-11-04)
		In the field-ion image of a metal surface, individually imaged atoms appear within such a wide range of brightness and size that discrimination between chemically different atom species is usually impossible.
		With the introduction of atom probe, field-ion microscopy (FIM) assumes a new dimension by providing the mass-spectrometric identification of a single atom or of the constituents of a small surface area that can be selected from the ion image by thje observer.
		The atom probe is a microanalytical tool of ultimate sensitivity, requiring only one atom for analysis.
	physics.unipune.ernet.in /~fem/apfim.htm (263 words)

	Imago Scientific Instruments - Imago Corporation's Technology, in-house capabilities (Site not responding. Last check: 2007-11-04)
		After leaving the specimen, the atom is pulled (again, by the electric field) toward a detector that records the location and time of impact of the atom.
		As the analysis progresses, the entire surface layer of atoms on the specimen is removed, exposing the underlying layer.
		The position of the atom relative to other specimen atoms in the x,y plane can be computed from the position at which the atom collides with the detector.
	www.imago.com /imago/html/technology/tech_fundamentals.jsp (269 words)

	Methyl group tunnelling - a quantitative probe of atom-atom interactions
		Aswell as being a tool for investigating quantum tunnelling effects, the methyl group is also a sensitive probe of atom-atom interactions since the tunnel frequency depends exponentially on the height of the rotational barrier.
		Alternatively, deviations in the correlation can also indicate shortcomings in the modelling of an der Waals interactions (for example imposing isotropic interactions for atoms like oxygen and nitrogen which have lone pairs of electrons) or in the determination of atomic charges (for example when intermolecular hydrogen bonds are neglected).
		That the correlation is valid in many cases enables the methyl group to be used as a probe of its molecular environment and the numerical methods to be applied to less well characterised systems such as methyl group dynamics in amorphous polymers.
	www.ill.fr /mod/mark_web.htm (694 words)

	OxfordMaterials \| FIM \| Overview
		Atom probe microanalysis is able to provide unique information on the atomic-scale chemistry within the bulk of a conducting material.
		Over its 30 year history, the Oxford Atom Probe Group has been one of the world leaders in the development of the atom probe technique and its application to Materials Science problems, specially in the area of physical metallurgy.
		In 1988, we developed the first 3-dimensional atom probe (3DAP), and soon afterward developed the first energy compensated 3DAP.
	www.materials.ox.ac.uk /fim (257 words)

	OxfordMaterials \| FIM \| What is 3D Atom Probe ?
		As in the atom probe, single atoms on the surface of a sharply-pointed needle are ionised by field evaporation.
		Time-of-flight mass spectrometry is used to identify the atom, and the position of impact gives the original position on the specimen surface.
		As more atoms are removed, a 3-dimensional picture of the atom distribution is built up.
	www.materials.ox.ac.uk /fim/whatis3dap.html (160 words)

	Three-Dimensional Atom Mapping for Nanotechnology Applications with Atom Probe Tomography
		Atom probe tomography is the highest spatial resolution analytical technique.
		With recent developments in LEAP® technology by Imago Scientific Instruments, the atom probe’s compositional imaging capabilities are now accessible to non-experts for analysis of a wide variety of materials including metals, magnetic media, semiconductors, ceramics, geological materials, synthetic organics and polymers, and biological materials.
		The LEAP 3000X accomplishes these objectives while incorporating the ability to field evaporate the specimen atom by atom with either a laser pulse or a voltage pulse.
	www.nsti.org /Nanotech2006/showabstract.html?absno=1769 (223 words)

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