Paper |
Title |
Page |
TUPC042 |
Limitations of Electro-optic Longitudinal Electron Bunch Length Measurements
|
1149 |
|
- S. P. Jamison
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
- G. Berden
FOM Rijnhuizen, Nieuwegein
- W. A. Gillespie, P. J. Phillips
University of Dundee, Nethergate, Dundee, Scotland
- A. MacLeod
UAD, Dundee
|
|
|
Electro-optic (EO) techniques are becoming increasingly important in ultrafast electron bunch longitudinal diagnostics and have been implemented at various accelerator labs. A crucial aspect of any implementation is a robust assessment of its resolution capabilities. However the assessments of the temporal limitations often differ between groups and the assumptions employed in deriving these limitations are frequently not addressed. With EO measurements of intense CTR pulses and ultrafast Coulomb fields, it may also be necessary to reconsider the validity of the usual interpretation of the EO effect as a phase retardation proportional to the Coulomb field. From a generic analysis of various sources of the temporal limitations we present a summary of the capability of various EO techniques which can be applied to specific implementations with differing laser and bunch parameters. As well as specifying the quantitative limitations and their scaling with experimental parameters, the qualitative effects of distortion in the measured profile are also summarised. Additional limitations, which arise from a breakdown of the phase-retardation interpretation of the EO effect, are discussed.
|
|
TUPC081 |
Single-shot Longitudinal Bunch Profile Measurements at FLASH Using Electro-optic Detection Techniques
|
1242 |
|
- P. J. Phillips, W. A. Gillespie
University of Dundee, Nethergate, Dundee, Scotland
- V. R. Arsov, H. Schlarb, B. Schmidt, P. Schmüser
DESY, Hamburg
- G. Berden, A. F.G. van der Meer
FOM Rijnhuizen, Nieuwegein
- S. P. Jamison
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
- A. MacLeod
UAD, Dundee
- B. Steffen
PSI, Villigen
|
|
|
At the superconducting linac of FLASH at DESY, we have installed an electro-optic experiment for single-shot, non destructive measurements of the longitudinal electric charge distribution of individual electron bunches. The profile of the electron bunch field is electro-optically encoded onto a streched Ti:Sa laser pulse. In the decoding step, the profile is retrieved from a spectral measurement of the encoded pulse or from a cross-correlation of the encoded pulse with a 35 fs laser pulse , obtained from the same laser. At FLASH, sub-100 fs electron bunches have been measured during FEL operation with a resolution of better than 50 fs. The electro-optic measurements have been validated with a tranverse deflecting cavity measurements.
|
|