| Paper | Title | Page |
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| TUPPH045 | Tolerance Studies for APPLE Undulators in FEL Facilities | 348 |
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| Errors in the undulator fields are a potential source of performance degradation especially in FELs where the undulator sections reach lengths of up to 100m. The strong transverse field variations of APPLE undulators tighten the tolerances even further. Beyond sorting methods of the magnetic blocks, the shimming of undulators is a widely accepted tool to improve the field quality of undulators and wigglers. In order to calculate realistic tolerance margins for undulator errors it is essential to take the effect of the shimming into account when the FEL performance is simulated. This paper presents GENESIS calculations for STARS, the planned BESSY FEL test facility, and for the 4GeV lattice of the LCLS. | ||
| TUPPH058 | Developments in Cascaded HGHG-FELs | 378 |
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Seeding in combination with frequency up conversion is widely recognized as a method to provide FEL radiation with properties superior to the SASE output. In addition to High Gain Harmonic Generation (HGHG) scheme, successfully demonstrated in Brookhaven* and proposed for the BESSY soft X-ray FEL, several alternative schemes have been proposed during the last years. This paper discusses and compares these proposals to the original cascading of HGHG-stages which includes the fresh bunch technique.
* L. H. Yu, Phys. Rev. Letters, 91, 074801, 2003 |