Cl. Foerster et al., PHOTON-STIMULATED DESORPTION MEASUREMENT OF AN EXTRUDED ALUMINUM BEAMCHAMBER FOR THE ADVANCED PHOTON SOURCE, Journal of vacuum science & technology. A. Vacuum, surfaces, and films, 14(3), 1996, pp. 1273-1276
Citations number
10
Categorie Soggetti
Physics, Applied","Materials Science, Coatings & Films
The Advanced Photon Source (APS), presently being commissioned, will p
roduce x rays of unprecedented brightness. The high energy ring of the
APS is a 7 GeV positron storage ring, 1104 m in circumference designe
d to operate at less than 10(-9) Torr with 300 mA of beam and a greate
r than 10 h lifetime. The storage ring vacuum chamber is constructed f
rom an extruded 6063 aluminum alloy. During the construction phase, a
2.34-m-long section of the APS extruded aluminum chamber was set up on
National Synchrotron Light Source (NSLS) X-ray Beamline X28A and phot
on stimulated desorption (PSD) was measured. Cleaning and preparation
of the chamber was identical to that of the APS construction. In addit
ion to the chamber, small samples of Al, Be, and Cu were also exposed
to white light having a critical energy of 5 keV. In addition to PSD,
measurements were made of the specular and diffuse scattering of photo
ns. The chamber and samples were each exposed to a dose greater than 1
0(23) photons per m. Desorption yields for H-2, CO, CO2, CH4, and H2O
are reported as a function of accumulated flux, critical energy, incid
ence angle, and preparation. These results are compared with previous
results for aluminum on NSLS Beamline U10B and PSD results of other la
boratories published for aluminum. (C) 1996 American Vacuum Society.