||The main project on superconducting
RF at CERN in the period from 2001 to 2003 has been the 400MHz SC
system for the LHC. Five modules, each containing four single cell
niobium sputtered cavities, have been assembled and low power tested at
room temperature and at 4.5K. Production of the first four series power
couplers has been delayed but high power tests should start on the
first module this fall. A small program of RD is maintained on the SPL.
Both the beta=0.7 and beta=0.8 cavities have been high power tested up
to nominal field without particular problems. A detailed
characterization of the cavity mechanical resonances is ongoing and
some preliminary results are presented. A computer code has been
written to predict the effects of Lorentz detuning and microphonics on
the stability of the RF feedback loops in SC linacs where several
cavities are driven by a single high power source. Fast ferrite
phase shifters are being developed to allow the decoupling of the
feedback loops of individual cavities attached to the same klystron.
Several collaborations e.g. SOLEIL, PACO and S3HC, have successfully
achieved their objectives. The collaboration established with Cornell
to develop a 200 MHz SC cavity has not yet led to the desired level of
performance. The RD program on 1.5 GHz is continuing. Based on an
optimised electropolishing process for surface preparation, the study
is at present focused on the effect of hydrogen in the Nb films.