Speaker
Mr
Micha Dehler
Description
To compensate nonlinearities in the longitudinal phase space at the injector prototype of the PSI-XFEL, PSI requires a high frequency RF structure in X band. At the same time CLIC is pursuing a program for producing and testing high gradient RF structures in the X band, exploring the effect of different geometries and materials on break down limits and rates.
Given that the PSI-XFEL has somewhat lower requirements in terms of gradient (40 MV/m) and efficiency, it may be interesting to share work and expense in designing and producing a common CLIC/PSI-XFEL structure. It would provide new data for the CLIC structure tests and be simultaneously a safe and low risk solution for the more relaxed operating gradient used at the PSI-XFEL. At the same time the prolonged operation of such a structure in the PSI FEL injector, albeit not at CLIC parameters, would constitute a good quality test for the procedure employed.
As a generic type, we foresee to use a structure with a 5 pi/6 phase advance and an active length of 750 mm similar to NLC type H75. Since the structure should not be used to test higher order mode damping, it will not have any HOM dampers. On the other hand, two wake field monitors near the beginning and the end of the structure are foreseen to allow an optimum alignment to the beam. Wakefield monitors are also planned for CLIC structures and their implementation in the PSI-FEL structures will represent an important performance test. In addition, the structure will feature race track type input and output couplers minimizing quadrupolar kicks in the accelerating field.
Author
Mr
Micha Dehler