THE NEW NUCLEAR MICROPROBE AT LIVERMORE

Lawrence Livermore National Laboratory (LLNL) and Sandia National Labo ratories/California have jointly constructed a new nuclear microprobe beamline. This beamline is located on the LLNL 10 MV tandem accelerato r and can be used for multidisciplinary research using PIXE, PIGE, ene rgy loss tomography, or IBS techniques. Distinctive features of the be amline include incorporation of magnet power supplies into the acceler ator control system, computer-controlled object and image slits, autom ated target positioning to sub-micron resolution, and video optics for beam positioning and observation. Mitigation of vibrations was accomp lished with vibration isolators and a rigid beamline design while inte gral beamline shielding was used to shield from stray magnetic fields. Available detectors include a wavelength dispersive X-ray spectromete r, a High-Purity Germanium detector (HPGe), a Lithium-Drifted Silicon X-Ray detector (SiLi), and solid state surface barrier detectors. Alon g with beamline performance, results from recent measurements on deter mination of trace impurities in an International Thermonuclear Experim ental Reactor (ITER) super conducting wire strand, determination of Ca /Sr ratios in seashells, and determination of minor and trace element concentrations in sperm cells are presented.