IBIC2013 - List of Authors (Wesch, S.)

Paper	Title	Page
MOPC37	Longitudinal Bunch Profile Reconstruction Using Broadband Coherent Radiation at FLASH	154
	E. Hass Uni HH, Hamburg, Germany C. Behrens, C. Gerth, B. Schmidt, M. Yan DESY, Hamburg, Germany S. Wesch HZB, Berlin, Germany
	The required high peak current in free-electron lasers is realized by longitudinal compression of the electron bunches to sub-picosecond length. Measurement of the absolute spectral intensity of coherent radiation emitted by an electron bunch allows monitoring and reconstruction of the longitudinal bunch profile. To measure coherent radiation in the teraherz and infrared range a in-vacuum coherent radiation intensity spectrometer was developed for the free-electron laser in Hamburg(FLASH). The spectrometer is equipped with five consecutive dispersion gratings and 120 parallel readout channels: it can be operated either in short (5-44 um) or in long wavelength mode (45-430 um). Fast parallel readout permits the monitoring of coherent radiation from single electron bunches. Large wavelength coverage and superb absolute calibration of the device allows reconstruction of the longitudinal bunch profile using Kramers-Kronig based phase retrieval technique. The device is used as a bunch length monitor and tuning tool during routine operation at FLASH. Comparative measurements with radio-frequency transverse deflecting structure show excellent agreement of both methods.

Paper

Title

Page

Longitudinal Bunch Profile Reconstruction Using Broadband Coherent Radiation at FLASH

154

E. Hass
Uni HH, Hamburg, Germany
C. Behrens, C. Gerth, B. Schmidt, M. Yan
DESY, Hamburg, Germany
S. Wesch
HZB, Berlin, Germany

The required high peak current in free-electron lasers is realized by longitudinal compression of the electron bunches to sub-picosecond length. Measurement of the absolute spectral intensity of coherent radiation emitted by an electron bunch allows monitoring and reconstruction of the longitudinal bunch profile. To measure coherent radiation in the teraherz and infrared range a in-vacuum coherent radiation intensity spectrometer was developed for the free-electron laser in Hamburg(FLASH). The spectrometer is equipped with five consecutive dispersion gratings and 120 parallel readout channels: it can be operated either in short (5-44 um) or in long wavelength mode (45-430 um). Fast parallel readout permits the monitoring of coherent radiation from single electron bunches. Large wavelength coverage and superb absolute calibration of the device allows reconstruction of the longitudinal bunch profile using Kramers-Kronig based phase retrieval technique. The device is used as a bunch length monitor and tuning tool during routine operation at FLASH. Comparative measurements with radio-frequency transverse deflecting structure show excellent agreement of both methods.