Author: Roussel, E.
Paper Title Page
TUPP15
 DEOS: A New Scheme for Recording Electron Bunch Shapes With High Resolution and Record Recording Length - Principle and Tests at EuXFEL  
 
  • S. Bielawski
    PhLAM/CERCLA, Villeneuve d’Ascq Cedex, France
  • C. Evain, E. Roussel, C. Szwaj
    PhLAM/CERLA, Villeneuve d’Ascq, France
  • C. Gerth, B. Steffen
    DESY, Hamburg, Germany
  • B. Jalali
    UCLA, Los Angeles, California, USA
  
  Funding: CEMPI LABEX, CPER Photonics for society, ULTRASYNC ANR, METEOR CNRS MOMENTUM grant
Recording electron bunch longitudinal profiles in single-shot, and non-destructively is largely needed in accelerator operation. A common strategy consists in probing the near-field of the bunch using femtosecond laser pulses. These two last decades, such electro-optic detection schemes have evolved to compact and reliable techniques. However, serious limitations have been limiting the time-resolution, when long recording lengths are needed. This has been recognized as a fundamental bottleneck and even coined the term "Fourier limit". We present here a novel electro-optic sampling strategy that is theoretically capable to overcome this limit and achieve femtosecond resolution for any recording length. This new approach is based on the mathematical concept of information diversity. We present first results of DEOS (Diversity Electro-Optic Sampling) obtained both in table-top experiments, as well as at the European XFEL. This technique opens the way to electric field shape characterization with femtosecond resolution in new situations, including longitudinal bunch profile monitoring, studies of microbunching instabilities, and THz pulses generated at free-electron lasers.
https://arxiv.org/abs/2002.03782 		 
poster icon Poster TUPP15 [1.683 MB]  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPP31
 Micro-Bunching Measurements at FERMI  
 
  • M. Veronese, E. Allaria, S. Di Mitri, M. Ferianis, L. Giannessi, G. Penco, P. Rebernik Ribič, S. Spampinati, C. Spezzani, M. Trovò
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • E. Ferrari
    PSI, Villigen PSI, Switzerland
  • G. Perosa
    Università degli Studi di Trieste, Trieste, Italy
  • P. Rebernik Ribič
    University of Nova Gorica, Nova Gorica, Slovenia
  • E. Roussel
    PhLAM/CERLA, Villeneuve d’Ascq, France
  
  The origin and evolution of micro-bunching (u-B) in a LINAC is very important for Free Electron laser (FEL), a key knowledge to full control and highest quality of the FEL radiation. The experimental u-B characterization is not simple, due to the measurement complexity, considering the u-B extended spectral range and its interplay with other machine effects. At FERMI, we have measured u-B signatures using different techniques, including intensity characterization of Coherent OTR(visible range) and the FFT based modulation analysis performed on the spectrometer images. The latter available both at the first bunch compressor and at the diagnostics beam dump. The beating of two laser pulses at laser heater has been used to induce narrow-band micro-bunching modulations, used as a known probe, to study the FEL / u-B instability spectra. As spectral measurement technique, the distribution of Coherent-TR in the IR region, using BP filters and PbSe detectors, has been implemented. More recently, a new IR spectrometer based on a CaF2 prism and a scanning technique has been developed and installed. Here we present techniques and the experimental results obtained and future perspectives.  
poster icon Poster TUPP31 [2.732 MB]  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)