Accession Number : ADA299350

Title :   Development and Application of a Scanning Ion Microprobe.

Descriptive Note : Trident scholar project rept.,

Corporate Author : NAVAL ACADEMY ANNAPOLIS MD

Personal Author(s) : Meehan, Bernard T.

PDF Url : ADA299350

Report Date : 09 MAY 1995

Pagination or Media Count : 84

Abstract : A complete scanning ion microprobe system was developed for use in the Naval Academy Tandem Accelerator Laboratory. The microprobe employs a computer-controlled positioner to scan a sample while it is bombarded with a finely focused particle beam. The beam excites characteristic X rays from the sample atoms. The X-ray yields are converted to elemental concentrations. The concentration and position data are then used to create two dimensional surface concentration maps, which are analogous to microscope views of the sample. The microprobe was tested using a 200-mesh transmission electron microscope grid. The diameter of the beam spot on the sample surface was found to be approximately 30 micrometers. The capabilities of the microprobe were demonstrated by measuring the positional variation of elemental concentrations in several inclusions of the Allende meteorite. These inclusions are thought to predate the formation of the solar system. Extensive position dependent concentration data may eventually provide information on the formation mechanisms and temperature and radiation history of meteorites. jg p.5

Descriptors :   *SCANNING, *IONS, *MICROPROBES, *METEORITES, EMISSION, POSITION(LOCATION), RADIATION, EXCITATION, ION BEAMS, ATOMS, CARBON, X RAYS, PROTONS, VARIATIONS, ELECTRON MICROSCOPY, INCLUSIONS, SURFACES, HISTORY, YIELD, MAPS, CHEMICAL ELEMENTS, PARTICLE BEAMS, ION ACCELERATORS, SOLAR SYSTEM, ION BOMBARDMENT, SCANNERS.

Subject Categories : Physical Chemistry
      Atomic and Molecular Physics and Spectroscopy
      Optics
      Particle Accelerators

Distribution Statement : APPROVED FOR PUBLIC RELEASE