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T: Fachverband Teilchenphysik
T 83: Beschleunigerphysik 5
T 83.2: Vortrag
Mittwoch, 29. Februar 2012, 17:00–17:15, VG 1.103
On the online monitor for longitudinal beam profile measurements at FLASH — •Andy Langner1,2, Christopher Behrens2, Christopher Gerth2, Bernhard Schmidt2, Stephan Wesch2, and Minjie Yan1,2 — 1Universität Hamburg, Institut für Experimentalphysik, Luruper Chaussee 149, 22761 Hamburg, Germany — 2Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
The Free-Electron Laser in Hamburg (FLASH) is equipped with a tranverse deflecting structure (TDS) for longitudinal beam profile measurements. As FLASH is a multi-bunch machine, an online monitor for these measurements would facilitate the analysis of single bunches within the bunch train. The setup of the TDS as an online monitor requires to apply a special accelerator optics inside its section. Phase advances and beta-functions need to be set in order to allow an effective kicking of a single bunch to the diagnosis screen, as well as to allow an adequate time resolution for the beam profile measurements. Furthermore a matching into the adjacent undulator section is crucial. Simulations have been performed using MAD to optimise the optics for this application. A bunch which is kicked for the measurement, will hit a copper absorber and cause electromagnetic cascade showers. These showers have been observed to be a threat to the machine protection system, as they cause alarms at beam loss monitors, which are distributed along the undulators. Simulations have been performed in order to study the benefit of additional shielding.