FACET Update ARD Status Meeting
Christine ClarkeApril 14th 2011
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The FACET Project
Facilities for Accelerator science and Experimental Test beams.
FACET
ESA
ESB
Beam at FACET
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At IP
• FACET uses the first two-thirds of the linac• Energy = 23 GeV• 3.2 nC• Sigma x = 14 um• Sigma y = 6 um• Sigma z = 14 um minimum (20 um typical)• Bunch length can be increased up to a factor of 3• Electron beam (2011)
The Facility
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Stairway in Sector 19
User Trailer Experiments Dump
Towards end of linacBeam Direction
Plan – THz and IP Tables
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• Optical Tables for experimenters to mount hardware
• Optics set up for each experiment• Small beam spots in IP region
THz Table (Experimental Area 1)
IP Table (Experimental Area 2)
Beam Direction
THz and IP Optical Tables
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THz Table (looking east towards dump)
IP Table (looking east towards dump)
• Photos taken Feb 11 (Mark Hogan)
• Magnets installed since then.
March…• Some magnets installed in sector 20 – photo taken March 16th :
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THz Table (looking east towards dump)
IP Table
April…• All magnets in sector 20 – photo taken last Tuesday :
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THz Table (looking east towards dump)
IP Table
Close-up of THz• Beamline almost complete
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Initial THz diagnostics with OTR foils (1um titanium)
Cubes
Beam here large in x (>1mm)
Future location of Smith-Purcell experiment.
Close-up of IP Table• Could be complete end of next week
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IP experiments located here (second table to come).
For tuning, vacuum drifts, wire scanner and OTR screens.
SAREC Final Report• SLAC Accelerator Research Experimental program Committee• Convened in January to review 8 proposals• 6 proposals accepted as Experimental Programs• 1 proposal incorporated into FACET diagnostics (ODR)• 1 letter of intent – requested to present two proposals in the next
round.• 1 expression of interest – asked to make preliminary
measurements this summer (THz).
• Second call for proposals this fall for the spring 2012 and 2013 runs
• SAREC review in the early winter of 2012.
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Plasma Wakefield Acceleration
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• Continuation of very successful FFTB experiments
• Heat-pipe oven to be installed this July• Lithium metal vaporized at 800ºC• Length of plasma controllable by controlling
heaters and pressure of helium buffer gas• Phase One: Begin with single electron
bunch in field ionized lithium plasma.• Phase Two: Single bunch in field ionized
cesium plasma.• Phase Three: Use Notch Collimator.• Phase Four: Two electron bunches (drive
and witness) in field ionized cesium plasma.• After first year, pre-ionized plasma,
positrons, positrons and electrons.
Smith Purcell
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• Bunch Time Profile measurements with Coherent Smith-Purcell Radiation
• Moderate band-width terahertz
• Beam passes by grating which has a dispersive effect
• Continuation of experiment at ESA
• Not sensitive to beam spot size (will be situated upstream of IP).
• Non-destructive (parasitic running).
Wakefield Acceleration in Dielectric Structures
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• GV/m class DWA for use in linear colliders and future light sources.
• Previous work at FFTB/SLAC, UCLA, BNL.• High gradient regime at FACET.• FACET beam sent through prototype
dielectric wakefield acceleration structures.• Parametric breakdown studies and lifetime
effects.• Vary structures (dimensions, materials etc). • Use drive and witness bunches to observe
acceleration.• Use coherent Cerenkov radiation• Next year, use protons.
Ultrafast Magnetic Switching• Continuation of FFTB work.• Change in magnetization of a sample on ultrafast
timescales• Change pulse-lengths with constant Q - do longer
pulse-lengths have more energy deposition?• Expose sample to electron bunch• Then image with spin-sensitive scanning electron
microscope.• Different patterns on same film indicate different
physical processes.• Chaos cannot be explained• Need to rule out experimental artefacts.
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2.3ps
70fs
Additional Experiments• Metallic Periodic Structures (Accepted Proposal)
– Short-pulse, high fields to study breakdown physics.• High gradient dielectric wakefield measurements (Accepted Proposal)
– dielectric based collimating systems• CLIC Studies (letter of intent)
– Dispersion-free steering – Accelerating structure Wakefield Studies– Collimator Wakefield Studies
• THz extraction (expression of interest)– Extract radiation to an experimental area
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30cm High Power test structure (CLIC Studies)
Suggested extraction of THz
Short Metallic Accelerating Structure
Schedule 2011• Construction Phase 1 will be complete in May.• Beam Commissioning starts June 13th
• Experiments are installed July 5th- July 14th • Experimental program in August• Users meeting August 29th /30th • Next round of proposals coming up (fall)
• Construction Phase 2… positron arm of the bunch compressor in S10• Experimental PPS zone
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Schedule 2012 and Beyond• FACET will run for 4 months each year for the next five years.• In 2012 the 4 months are likely to be February - June.• Electron beams and positron beams will be available to the
experimenters.
• 2013? Phase Three: positron arm of the bunch compressor in S20 (aka the sailboat chicane) for simultaneous electron and positron beams
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Summary• FACET is currently near the end of its primary construction phase.• First Beam June 13th
• Approximately 3 weeks of beam commissioning, some User assistance.• User aided commissioning / experiment commissioning program,
August.• New round of proposals for 2012 due (provisionally) October.• 4 months of FACET running in 2012 and every year until 2017.
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