Speaker
Mr
Wojciech Cichalewski
(Technical University of Lodz)
Description
As every high power amplifier also the pulse microwave 10 MW klystrons (in the VUV-
FEL accelerator) have nonlinear output power vs. input power characteristic near to
the device saturation point. This undesirable behavior of the tube amplifier may
cause lower efficiency of the close loop RF field regulation in LLRF control
system.
In order to provide a solution for existing distortion compensation it is necessary
to examine each of the RF-power station. The main goal is then designing and
establishing an on-line measurement system and appropriate procedures that would
give comprehensive knowledge about distortions introduced by the klystron and power
preamplifiers and will be transparent for regular accelerator operation.
In this paper the problems concerning appropriate amplifiers characterization as
well as propositions for on-line nonlinearities monitoring will be discussed. Also
the currently used solutions for the high power amplifiers linearisation will be
presented and a proposition for VUV-FEL RF-station high power chains distortion
compensation will be described.
Primary author
Mr
Wojciech Cichalewski
(Technical University of Lodz)
Co-authors
Mr
Boguslaw Koseda
(Technical University of Lodz)
Dr
Stefan Simrock
(DESY)
