7 research outputs found
Calibration of the TWIST high-precision drift chambers
A method for the precise measurement of drift times for the high-precision
drift chambers used in the TWIST detector is described. It is based on the
iterative correction of the space-time relationships by the time residuals of
the track fit, resulting in a measurement of the effective drift times. The
corrected drift time maps are parametrised individually for each chamber using
spline functions. Biases introduced by the reconstruction itself are taken into
account as well, making it necessary to apply the procedure to both data and
simulation. The described calibration is shown to improve the reconstruction
performance and to extend significantly the physics reach of the experiment.Comment: 8 pages, 5 figure
Depth-controlled beta-NMR of 8Li in a thin silver film.
Depth-controlled beta-NMR can be used to probe the magnetic properties of thin films and interfaces on a nanometer length scale. A 30 keV beam of highly spin-polarized 8Li+ ions was slowed down and implanted into a 50 nm film of Ag deposited on a SrTiO3 substrate. A novel high field beta-NMR spectrometer was used to observe two well resolved resonances which are attributed to Li occupying substitutional and octahedral interstitial sites in the Ag lattice. The temperature dependence of the Knight shifts and spin relaxation rates are consistent with the Korringa law for a simple metal, implying that the NMR of implanted 8Li reflects the spin suspectibility of bulk metallic silver
The new beta-NMR facility at TRIUMF and applications in semiconductors
A new facililty for conducting beta-detected nuclear magnetic resonance (beta-NMR) investigations of condensed matter systems has recently been constucted at TriUniversity Meson Facility in Vancouver, Canada. The unique features of this new facility are described, and some preliminary results on Li-8(+) in GaAs are presented. (C) 2003 Elsevier B.V. All rights reserved