| Paper | Title | Page |
|---|
| WEP21 | Electrical axes of TESLA cavities | 493 |
| | | |
| | Precise alignment of cavities to the beam is one of
strong requirements in order to obtain high quality beam.
A missalignment could cause unwanted interaction
between the beam and electromagnetic fields in the
cavity, both accelerating field and wakefields. Up to now
the eccentricity of cells is measured mechanically on the
outer side of cell equators. In this way measured
eccentricity could be not precise in case of not uniform
cavity wall thickness or in case of cavity wall deformation
on other place than measured equator. Therefore an
alternative method based on small perturbation field
mapping was developed and applied on some cavities. | |
| WEP22 | Electron activity interlock for XFEL input couplers | 498 |
| | | |
| | One of dangers for TESLA-based linacs is uncontrolled
discharge in vacuum parts of the input power couplers -
discharge in residual gasses, field emission and
multipacting. These may be destructive if the RF power is
not reduced or switched off at the right time. The recent
TTF3 input couplers have three electron pickups to detect
the electron activity. But these vacuum feed-throughs and
the electronic front-end are complicated and expensive.
The goal of this work is to replace them by simpler and
cheaper solution - by use of the inner conductor of the
coupler as electron pickup. | |