Dortmund 2006 – scientific programme
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T: Teilchenphysik
T 310: Beschleuniger II
T 310.4: Talk
Tuesday, March 28, 2006, 17:30–17:45, HG2-HS4
Electron bunch length diagnostics using broadband single shot spectrometer — •Hossein Delsim-Hashemi1, Oliver Grimm2, Bernhard Schmidt2, Joerg Rossbach1, Peter Schmueser1, and A.F.G. van der Meer3 — 1University of Hamburg, Germany — 2DESY, Hamburg, Germany — 3FOM, Nieuwegein, The Netherlands
The electron beam peak current is one of the most important parameters for driving a free-electron laser (FEL). Typically, bunch compressors are used in a linear accelerator to reshape and compress the longitudinal profile of the electron bunch. For the VUV-FEL, structures in the order of ten micrometers play a crucial role in Self-Amplified Spontaneous Emission (SASE) production. Practically, single shot monitoring of the longitudinal profile of the electron bunch versus machine parameters is highly desirable. This is beyond the capability of existing spectroscopic diagnostic tools. This paper introduces a new diagnostics tool based on using THz radiation spectroscopy. The main parts of this device are: reflectance blazed gratings as the dispersive elements, focusing mirror designed for this application as the collecting optics and several series of pyroelectric detectors. Several experiments and tests at FELIX, Nieuwegein and DESY, Hamburg proved the feasibility of the concept and helped to improve the spectrometer design. This spectrometer will be able to fulfil both shot-to-shot broad-band spectral range coverage and the required resolution.