TGRS Measurements of the Positron Annihilation Spectrum from the
M. J. Harris
B. J. Teegarden, T. L. Cline, N. Gehrels
D. M. Palmer
The TGRS experiment on board the Wind spacecraft includes a Ge
detector with very high resolution (3-4 keV FWHM) at energies around
511 keV. To take advantage of WIND 's fixed pointing at the
south ecliptic pole, and its 3 s rotational stabilization period, TGRS
also includes a Pb occulter fixed on the spacecraft body, subtending an
arc of 90 deg along the ecliptic plane. Spectra of the Galactic
center region, identified by this occultation method, have been
accumulated since 1994 November. In this paper we present updated
results for the Galactic center positron annihilation line and
continuum from analysis of these occulted spectra. The quantities that
can be extracted from the data include the intensity, width, energy and
variability of the line, the positronium fraction, and limited
information about the spatial distribution of the line.
File translated from TEX by TTH, version 2.32.
On 16 Jul 1999, 09:18.