W. E. Gabella
FEL Center, Vanderbilt University
The operation of the Vanderbilt FEL has benefited greatly from the
recent upgrade of the cooling system for the linac, and from the installation
of a carrousel that holds all four laser cavity output mirrors needed
to cover the wavelength range of the laser. The cooling system, built
and designed by Innoventor Engineering Inc., has demonstrated linac
temperature stability of +/- 0.05 degrees F with a 35 kilowatt load
(the klystron and RF power). The resulting electron energy stability
gives improved wavelength stability even during the hottest months.
The laser cavity uses four broadband, dielectric coated output mirrors
with 15 per cent transmission through the entire wavelength range,
2 to 9.4 microns. The four mirror carrousel allows scanning through
the entire wavelength range with minimal time to remotely change and
align mirrors. These and other improvements allowed 2540 hours to
be delivered to infrared experiments and another 500 hours for operational
use in 1999.
