Speaker
Description
The Mainz Energy-Recovering Superconducting Accelerator (MESA), an
energy-recovering (ER) LINAC, is currently under construction at the Institute
for Nuclear physics at the Johannes Gutenberg-Universit ̈at Mainz, Germany. In
the ER mode continues wave (CW) beam is accelerated from 5 MeV up to 105
MeV. The energy gain of the beam is provided through 2 ELBE-type cryomod-
ules containing two 1.3 GHz 9-cell TESLA cavities each. By pushing the limits
of the beam current up to 10 mA, a quench can occur at the HOM Antennas.
This is caused by an extensive power deposition within the antenna. Calcula-
tions have shown, that a power transfer of 1 W has to be assumed. However
tests of the 1.5 GHz version of the TESLA HOM coupler has shown a quench
limit of 43 mW in CW. To prevent a quench of the HOM antennas by high
beam currents without mayor modification of the design of the HOM antenna
and F-part it is necessary to find suitable materials. Nb3Sn and NbTiN can be
applied as a coating to the HOM antennas and have higher critical parameters
than Nb which will lead to a higher power limit. The limit of the coated anten-
nas will be tested with the cavities of a cryomodule from the decommissioned
ALICE accelerator from STFC Daresbury.
