Modified Bridgman anvils for high pressure synthesis and neutron scattering

ABSTRACT

A simple modified Bridgman design for large volume pressure anvils usable in the Paris-Edinburgh (PE) press has been demonstrated at Oak Ridge National Laboratory Spallation Neutron Source. The design shows advantages over the toroidal anvils typically used in the PE press, mainly rapid compression/decompression rates, complete absence of blow-outs upon drastic phase transitions, simplified cooling, high reliability, and relative low loads (～40 tons) corresponding to relatively high pressures (～20?GPa). It also shows advantages over existing large-volume diamond cells as sample volumes of ～2–3?mm³ can be easily and rapidly synthesized. The anvils thus allow sample sizes sufficient for in situ neutron diffraction as well as rapid synthesis of adequate amounts of new materials for ex situ analysis via total neutron scattering and neutron spectroscopy.     

Possibility of plasma density diagnostics using Langmuir-wave-caused dips observed in dense laser plasmas

A systematic study of the Langmuir-wave-caused dips (L dips) observed in profiles of the Al Ly γ line emitted from laser irradiated sandwich targets indicates that these fine spectral features can be used as a tool for density diagnostics in intermediately coupled plasmas. The spectroscopic data required for a reliable identification of L dips were collected by a vertical-geometry Johann spectrometer providing high spectral and spatial resolution. The electron densities deduced from the evolution of the L dips along the laser target axis compare well with those derived from hydrosimulations and from measurements of the line widths and shifts.     

Density measurements of thin germanium films by total reflection of X-rays

A double-crystal monochromator with the reflecting sample situated between both crystals was used to the determination of sample parameters by means of X-ray total reflection method. Theoretical discussion of the experimental arrangement was carried out and measurement performed on germanium single crystal proved the precision of the method. The densities of a-Ge films, prepared by standardly used technology of cathode sputtering, were on the average by 3.5% lower than the bulk density of germanium (5.35 g/cm³). The relative mean error of the density determination is less than 0.3%.Cukrovarnická 10, Praha 6, Czechoslovakia.In conclusion, I should like to thank prof. J. Bakovský and dr. J. Hrdý for a number of valuable discussions on this work. I am also indebted to Mr. J. Zemek and Mrs. M. lová from our institute for supplying me with the samples used in these measurements and to Mrs. R. Nováková for the careful elaboration of the programs for the Zuse 22R and Tesla 200 computers.     

Eine optische Methode zur Bestimmung von Perchlorat

Ohne Zusammenfassung