Sodium self-diffusion coefficient in sodium silicate glass by quasielastic neutron scattering

Using pulsed neutrons of 19.8 Å wavelength a quasielastic line broadening as low as 0.03 eV (FWHM) has been observed due to Na⁺ diffusion in the glass Na₂O·2SiO₂. From the linewidths a Na⁺ self-diffusion coefficient of 3.1·10^–8 cm²/s at 420°C was obtained in excellent agreement with the diffusion coefficient determined for the same sample batch using²²Na radioactive tracers. The experimental Q dependence of the quasielasic linewidths gives a hint for deviations from a purely random walk in an ionic glass.     

Separation and implantation of relativistic86Kr-fragments at the FrS; half-life measurement by ion-β time-correlations

Neutron-rich Co and Fe isotopes produced by⁸⁶Kr projectile fragmentation at 500 MeV/u were separated and identified using the fragment separator (FrS) in a bunched energy mode.⁶⁶Co and⁶⁵Fe ions were selectively implanted in a double PIN-diode array where the-decay signals were measured. The half-lives were deduced from time correlations between implantation and-decay signals. The remeasurement of the⁶⁶Co half-life confirms the isotope identification. The value of the⁶⁵Fe half-life was found to be 0.45±0.15 s.     

Radiotracer measurement of the volatilization of organic trace constituents from water

Abstract The mass-transfer coefficient for the volatilization of organic microconstituents from water can be determined by laboratory radiotracer experiments. Formulation and practical aspects are considered and illustrated by the example of a 5.10(-7) M solution of monochlorobenzene.     

Development of a beam of very slow polarized muons

During the last few decades, a variety of methods has been developed which makes use of polarized positive muons as a microscopic probe of the magnetic properties of condensed matter (muon spin rotation, relaxation, resonance,SR). Until now, available beams for SR studies have delivered 100% polarized muons with energies in the MeV range, resulting in a deep penetration of the muons into the sample material under investigation. This presently limits the applications of theSR technique to the study of the bulk characteristics of matter. To be able to control the implantation depth, a very low energy beam of polarized muons is being developed at the Paul Scherrer Institute. Very slow polarized muons (kinetic energy 10 eV, polarization 90%) are obtained from the moderation of a high energy muon beam in a thin film of an appropriate condensed gas. These muons can be used as a source for a beam of tunable energy between a few tens of eV and some tens of keV. Implantation depths in the range of few to a few hundreds of nanometers can thus be achieved by varying the energy.     

Determination of manganese in environmental samples (e.g. coal fly ash) by electrothermal AAS after its separation with a liquid chelating ion exchanger

An electrothermal atomic absorption spectrometric method is described for the determination of manganese in various coal fly ash samples after its separation with dissolved monothioxo--diketone as chelating ion exchanger. The detection limit is 1 ngml^-1. To study the accuracy of the method, a reference material of similar composition was analysed and recovery of spiked manganese was performed.     

Crystal and molecular structure of a new biguanide metal complex, [Cu(AMNH)2]Cl2

The crystal structure of C₆H₁₆N₈O₂·CuCl₂, a biguanide metal complex, has been determined by X-ray diffraction data using MoK radiation. The compound crystallizes in the monoclinic space groupP2₁/a, witha=11.074(4),b=12.061(4),c=5.312(3)Å and=102.8(1)°.The structure was solved by direct methods and refined by full-matrix least-squares to a finalR value 0.037 with 1245 unique reflections. The complex molecule is centrosymmetric, with the Cu atom (0.5,0.5,0.5) on a crystallographic center of symmetry. The complex molecule is rhombic planar with a trans configuration.