München 2009 – scientific programme

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T: Fachverband Teilchenphysik

T 80: Beschleunigerphysik 3

T 80.8: Talk

Wednesday, March 11, 2009, 18:30–18:45, A213

Beam based alignment simulations and measurements at the S-DALINAC* — •Florian Hug, Ralf Eichhorn, and Achim Richter — Institut für Kernphysik, Technische Universität Darmstadt, Schloßgartenstraße 9, 64289 Darmstadt

Operational Experience at the Darmstadt superconducting electron linac (S-DALINAC) showed unexpected effects on beam dynamics and beam quality. So operators could observe transverse beam deflections by changing phases of the SRF-Cavities. Furthermore there has been occurred a growth of normalized tranverse emittance by a factor of 2. The beam current at the S-DALINAC does not exceed 60 µA so space-charge effects could be eliminated to be the reason for the observations. In this work the effect of misalignment of the SRF-Cavities in the linac has been examined using beam-dynamic simulations with the tracking code GPT and measurements on the electron beam of the S-DALINAC. By measuring the transverse deflection of the beam by changes of the phases of the SRF-Cavities and comparing results with GPT-simulations a misalignment of the 5-cell capture cavity and first 20-cell cavity of several mm in both transverse directions could be found. This misalignment can explain transverse deflections as well as emittance growth. A correction of misalignment has been carried out using the described results. First measurements showed no more emittance growth and less beam-deflections by SRF-Cavities.

* Supported by DFG through SFB 634