MATERIAL ANALYSIS & CHARACTERIZATION
Ion Beam Reactions and Materials Characterization
The Materials Analysis/Characterization and Ion Beam Reaction group has completed the installation, testing, and calibration of a 1.7 million-volt PelletronTM accelerator from the Los Alamos National Laboratory. This tandem machine delivers precisely controlled proton beams of energies up to 3.4 MeV at currents ranging to 200 nanoamperes. Ion source modifications permit acceleration of carbon, oxygen and other semi-heavy beams into 10-15 MeV energy ranges. Energetic ion beams are excellent analytical probes for condensed matter investigation as well as for initiating nuclear and atomic reactions for further study. Four beam lines support a variety of experiments.
Recent investigations have employed the laboratory's PIXE [Particle-Induced X-ray Emission] analysis capability, wherein traces of materials as small as a few parts per million are identified. Interdisciplinary collaborations with other scientists include forensic identification of substances from crime scenes, a search for elemental anomalies in tissues of diseased alligators from Florida lakes, an investigation of heavy metal uptake in melanistic cowrie shells, and identification of contamination/pollutants in air samples. Ion-channeling studies complemented by scanning surface and epitaxial layer growth. Other laboratory capabilities include gamma-ray spectroscopy and Rutherford backscattering [RBS] analysis of energy loss parameters, film thickness and elemental distributions in materials. MeV-range semi-heavy ions are also employed in simulating cosmic rays in the development of an improved detector that simultaneously measures mass, kinetic energy and charge state of energetic particles.