1 / 18

SPARC RF gun status

This report provides an update on the status of the SPARC RF gun, including the installation of the gun and solenoid, connection of vacuum pumps and temperature control system, and preparations for baking. The report also outlines the photoinjector specifications and goals to achieve ultra-high beam brightness for efficient SASE-FEL operation. Additionally, it discusses the gun characteristics, accessories, RF measurements, emittance compensation solenoid, and updates on the Octoyoke and magnetic lens center control. The report concludes with the near-future plans for the photoinjector, including vacuum testing, RF power conditioning, laser beam optimization, and outlooks on gun improvements based on experiences from the PAHBEB workshop and Erice October 05.

alanad
Download Presentation

SPARC RF gun status

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. SPARC RF gun status by P. Musumeci and F.Tazzioli Review committee 16/11/2005 Frascati

  2. status • Gun + solenoid +emittance-meter installed • Vacuum pumps connected. • Temperature control system connected • Baking in preparation • RF connection ready (see R. Boni’s report)

  3. Photoinjector specifications The goal is to achieve ultra-high beam brightness to drive efficiently the SASE-FEL • Ferrario working point • Laser pulse shaping • Beam emittance detailed study

  4. 1.6 cell RF Gun • S-band SLAC/UCLA/BNL design • Many of its kind in high brightness beam laboratories around the world • Baseline design for LCLS with relevant recent modifications

  5. SPARC gun design

  6. Gun and solenoid installed

  7. Gun and emittance meter installed

  8. Gun characteristics

  9. Gun Accessories • Gun chiller • Gun temperature independent from other accelerating cavities • Remotely controllable. • Measured water flow up to 5 l/min sufficient to guarantee stable operation at 10 Hz full power. • Support • Fully adjustable in 6 degrees of freedom: x,y,z pitch, yaw, and roll. • Solenoid independently adjustable • Ample longitudinal movement with slits for gun servicing / cathode replacement.

  10. p mode 0 mode LNF RF measurements

  11. LNF Measurements (cont) • Atmospheric pressure nitrogen n = 1.0003 • Df = + 850 KHz • Anticipated operating temperature 36 °C

  12. Emittance compensation solenoid • New design with four separately powered coils allows adjustment of lens center axial position. • New coil design - improved cooling. Maximum current now 300 A (previously 220 A) • Independently adjustable supports for gun and solenoid.

  13. Octoyoke (design)

  14. Work on Octoyoke at LNF • Fixing rods of Yoke plates strenghtened • Holes for alignment tool • Magnetic axis definition • Temperature and electrical characterization • 3 D magnetic field map done at LNF has evidenced quadrupolar components.

  15. (a) (b) (c) Magnetic lens center control To be optimized in SPARC initial phase emittance measurements

  16. UCLA measurements Good agreement with three dimensional simulations 4 coils excitation 2 coils excitation I = 150 Amp. Residual field on the cathode < 7 gauss

  17. Photoinjector near future • Vacuum test and baking • RF power conditioning ( two weeks) • Laser beam on cathode • Laser cleaning to optimize QE.

  18. Outlook on gun improvements News from Erice October 05 PAHBEB workshop, from SLAC-GTF and BNL experience. • Full cell tuning plungers favor RF arcing, therefore useless. New full cell tuning mechanism by deformation. • 3 MHz separation of 0 and π mode insufficient. Transient excitation of 0 -mode causes large anomalous correlated energy spread. Better 15 MHz separation. • Cleaning of Cu cathode with ion beamsor plasma is effective and less perturbing than laser cleaning. • Polished bulk Mg cathode proven with 10 MW RF power (100 MV/m). Research on Mg films at LNF. • New design of solenoid to minimize quadrupolar field component. Note: The gun for LCLS is being redesigned with double symmetrical RF power feeding ports, tuning of full cell by deformation and large mode separation.

More Related