Electron beam dynamics Christelle Bruni LAL
Activities Linear accelerator Rings Effect of the CSR and the laser shape on the compression (CSRtrack, Astra) Beam Break Up estimation for ERL(BI) Photoinjector caracterisation on PHIL (experiment, ASTRA) Alternative ERL design for THOMX (Astra, beta) Rings Longitudinal dynamics (2D tracking home code) Super-ACO (includinf FEL effect), ATF, ThomX (including CBS recoil effect) FELs (models, feedback, non linear dynamics) 50 MeV ring optics design on ThomX (beta code) Vaccum effects : multiple scattering, ion instabilities Intrabeam scattering (Mtingwa model) X-ray brilliance and flux evaluation (CAIN)
ARC-EN-CIEL accelerator design
Emittance degradation in the chicane
Longitudinal phase space degradation Space charge force non linearities Non uniformity induced by the CSR
Ellipsoid shape of the laser can
Improvement of the longitudinal phase space Compression To improve the longitudinal phase space Harmonic cavity Lenghen the laser as possible To improve emittance Laser pulse shape Optical function
PHIL : photoinjector beam test line
PHIL with AlphaX gun
Laser on the virtual cathode Charge measurement Laser on the virtual cathode
Charge simulation Including Aperture of the beam line Schottcky effect
Transverse size characterization Experiment for different gradient Simulations including the non linearity of the solenoid field
Project on short bunches fs laser Ultimate electron beam performances 100 pC, 150 fs THz modulation To obtain fs bunch train ps modulated laser based on a Michelson interferometer as in the experiment on the Japanese synchrotron UVSOR (S. Bielawski and C. Szwaj from Lille) : “chirped pulse beating” Funding request to the ANR french agency
Difficulties due to short bunches Preserve duration during transport Avoid bunch lengthening due to different path length during focusing Take care of the transverse pointing stability for capillary injection (tolerance less than 10 µm) Evaluation of the emittance degradation due to multiple scattering in gas before the capillary ? If shortest bunches needed, is the magnetic chicane envisaged to be added at highest energy ? Laser fs at the photocathode ? Laser shaping existing ? If not required ?