Update on FACET at SLAC

1. Update on FACET at SLAC • ESTB Users Meeting Christine Clarke 23rdAugust 2012

2. Introduction to FACET http://facet.slac.stanford.edu • FACET uses 2/3 SLAC linac to deliver electrons to the experimental area in Sector 20 • The FACET dump separates FACET from LCLS • Our first User Run was April-July 2012 Facility for Advanced Accelerator Experimental Tests

3. Beam Parameters Positrons will be commissioned in 2013 for delivery to experiments in sector 20 in 2014.

4. Proposal Process • In 2011 and 2012, we received 15proposals • The charge of the SAREC committee is to: • evaluate the scientific merit • evaluate the feasibility • review the progress of existing R&D • 7 proposals have led to beam-time as of now: • 6 further experiments have been approved and are waiting for beam-time in 2013 Receive Proposals Peer review (SAREC) SAREC ranks proposals Highest ranked proposals get beamtime

5. Time Allocation for 2012 • FACET’s first User Run was 12 weeks long (13th April – 5th July 2012) • Most of the time was allocated to experiments (65%) • Some time was set aside for machine development (20%) • One day a week is a scheduled access day for experimental installations and hardware maintenance (15%)

6. FACET Beamline Linac: Sector 10 Sector 20 Sector 0 FACET (Sector 20): Notch Collimator xTCAV Experimental Area (next slide)

7. FACET’s Experimental Area Sample chamber Plasma Experiment Profile measurement experiment Sample chamber Diagnostics

8. Notch Collimator and TCAV • Started commissioning transverse defecting cavity for bunch length measurements • Started commissioning Notch Collimator for creating two bunches

9. E-200 Multi-GeV Plasma Wakefield Acceleration • SLAC, UCLA, MPI • FACET’s high power electron beam ionises alkali gas and interacts with the plasma, wakefields accelerating part of the bunch • Lithium – small interaction, occasionally significant acceleration observed • Rubidium - consistently lots of interaction and good acceleration Beam bypassing plasma Beam going through plasma Significant interaction (energy loss) Energy gain by ~8% of beam

10. E-201 Wakefield Acceleration in Dielectric Structures • UCLA, Euclid Techlabs, Tech-X, Radiabeam Technologies, NRL, SLAC, MPI, Argonne • FACET provides unique high-field regime to test limits of dielectric wakefield structures • >1GV/m acceleration anticipated • Coherent Cherenkov Radiation (CCR) spectrum gives information about the excited modes • ~THz frequency light source Slab-symmetric Structures e- • The FACET beam is sent through prototype structures of varying dimensions and materials Axi-symmetric Tubes Sample holder on stages for alignment

11. E-202 Study of Ultrafast Processes in Magnetic Solids following Excitations with Electron Beams • SLAC, IBM, Univ. Regensburg, Bogolyubov Institute • A novel switching process - electrical field induced magnetic anisotropy • Fastest and most efficient method of switching • What is the microscopic origin for observed phenomena? • Exposed magnetic samples to the electron beam • Began study of ferroelectric films and resistive memories • Exposed materials used in spintronics applications Samples Spin-sensitive electron microscope images Thanks I. Tudosa CoFe Fe

12. E-203 Determination of the time profile by means of coherent Smith-Purcell radiation • Univ. Oxford, LAL Orsay, Univ. Valencia, ENS Lyon, Los Alamos, SLAC • Comparatively cheap, compact, non-destructive bunch length diagnostic • FACET provides ultra-short bunch length regime • Data from August commissioning and April this year • Main uncertainties from the inaccurate knowledge of the beam-grating distance • Not yet one-shot, data were averaged over time and beam conditions may have changed FWHM 310 fs = 93 µm Reconstructed bunch profiles from August 2011 Thanks G. Doucas Can directly compare measurements to transverse deflecting cavity and E-206 FWHM 600 fs = 180 µm FWHM 420 fs = 126 µm April 2012 12

13. E-206/T-500 THz Studies of FACET Source • THz frequency electromagnetic radiation is produced at 1μm titanium foil inserted into beamline upstream of IP Area • Goal: characterize THz pulses, determine peak fields • Measure temporal profile and spectrum – affected by source size • Determine peak electric and magnetic fields. • There is interest from SLAC’s PULSE and SIMES to use extracted THz for materials studies Thanks A. Fisher and Z. Wu

14. T-501 Linear Collider Final Focus and Alignment Algorithms • CERN, Univ. Oslo, PSI, EPFL, TU Graz, SLAC • Experimental verification of CLIC and ILC main linac corrections • linac system identification • global orbit correction • global dispersion correction • Measured machine responses and performed correction 24hr later • Good orbit correction over a test section of 500m of the linac Thanks E. Adli and A. Latina

15. Looking Ahead… • FACET’s second User run is in winter/spring 2013 • Proposals for 2013 and 2014 currently welcome! https://slacportal.slac.stanford.edu/sites/ard_public/facet/user/Pages/ProposalOverview.aspx • The proposal deadline is 1st September • FACET User Meeting 9th/10th October http://www-conf.slac.stanford.edu/facetusers/2012/ • Next SAREC review 11th/12th October • New features to the facility are coming: • E-200 is installing a 10TW Laser to pre-ionise plasma • Positrons will be commissioned in 2013 for delivery to experiments in 2014 • Designs for a THz transport line are in place to take THz up to the laser room • FACET continues to run ~4 months/year until 2016