Earth Sciences Division (ESD) Department of Energy (DOE) Lawrence Berkeley National Laboratory (LBNL)

Glenn Waychunas's Technical Expertise

Equipment

Computer interfacing of multiaxis x-ray diffractometers to minicomputer systems; Reconfiguration of 2 axis diffractometer into 4 axis geometry for single crystal and texture measurements; Design and development of a new special focusing diffractometer (GFD) for textured thin films on substrates; Addition of position sensitive linear detector system for use with GFD; Development of unique focusing optics for GFD; Design and development of energy-dispersive, theta-theta high temperature diffractometer system for the study of molten materials and phase transitions; Development of laboratory Mössbauer spectrometer system with laser interoferometric calibration for mineral and silicate glass 57Fe site partitioning studies; Design and development of a high X-ray flux laboratory scattering facility (rotating anode);Design and construction of a ultra-high vacuum (UHV) system for single crystal characterization and surface preparation including LEED, quadrupole mass spect. analysis, TDS analysis, Plasma ablation sources with subsidiary chamber for X-ray diffraction and spectroscopy; Design and construction of instrumentation for grazing-incidence small angle scattering (GISAXS) at synchrotron sources including He beam paths

Software

(written in Fortran, basic, C, assembly code):

Complete computer analysis package for Mössbauer spectroscopy including non-linear full-matrix least squares spectrum fitting progam; Spectral subtraction and rescaling programs; Fourier deconvolution programs for source lineshape extraction;

Program package for pole figure texture analysis  including contoured maps of stereo-projection of pole density; orientation distribution function (ODF) program;

Program package for quantitative analysis of X-ray powder diffraction patterns including data plotting programs, peak deconvolution codes, powder structure refinement program with texture analysis; various powder data manipulation programs

EXAFS program package including: background fitting program (non-linear full matrix least squares with multi-region n-order spline functions and interactive graphics); Fourier transform programs (both forward and  backward with windowing and interactive graphics); CHIFIT6 program for modeling of EXAFS functions with up to 8 shells of atoms and fitting of Fourier filtered EXAFS  data sets; Programs for manipulation of near-edge spectral data (XANES); generation of pair distribution functions for materials of known structure using atomic, EXAFS

or X-ray scattering amplitudes;

Program to calculate effects of polarization of incident X-ray synchrotron beam on RDF obtained from single crystal EXAFS experiment; Fourier deconvolution program for noise filtering, Program package for analysis of diffuse x-ray scattering from melts, amorphous solids with generation of radial distribution functions (RDFs) including: Calibration, Data scaling, Fourier transformation, Scattering factor generation, Compton approximation, Multiple scattering corrections;

Adaptation of DBWiles Rietveld analysis program to to include interactive graphics; Implementation of SPEC package for 4-circle diffractometer control with custom in-house system.

Software packages or programs used (high familiarity):

CERIUS2 (Biosym/MSI Corporation): Crystal builder, Amorphous builder, Surface builder, Interface builder, Molecular builder, Electron and x-ray diffraction, Non-crystalline x-ray diffraction, LEED/RHEED, Energy minimization, Molecular Dynamics, Rietveld;

DLS76 (Baerlocher); SHADOW; Feff 6.0/7.0/8.0 (Rehr); DBWS; SPEC; SUPER; Philips APD software; MRD software, Reciprocal lattice simulation software; GSAS; popLA (texture analysis software); EXAFSPAK (George and Pickering/ SSRL); JCPDS/IDD analysis package; TTMultiplets (DeGroot); Feff3- Feff8 (J.J. Rehr and associates); SIXPACK (Sam Webb, SSRL).

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