FACET Status
ESTB 2011 Workshop
Christine Clarke
March 17th 2011
The FACET Project
Facilities for Accelerator science and Experimental Test beams.
FACET
ESB
ESA
FACET Status
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Beam at FACET
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FACET uses the first two-thirds of the linac
Energy = 23 GeV
3.2 nC
Sigma x = 14 um
At IP
Sigma y = 6 um
Sigma z = 14 um minimum (20 um typical)
Bunch length can be increased up to a factor of 3
Electrons and positrons
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The Facility
Stairway in Sector 19
User Trailer
Experiments
Dump
Towards end of linac
Beam Direction
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Plan – THz and IP Tables
THz Table
(Experimental Area 1)
IP Table
(Experimental Area 2)
• Optical Tables for experimenters to mount
hardware
• Optics set up for each experiment
• Small beam spots in IP region
Beam Direction
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THz and IP Optical Tables
IP Table (looking east
towards dump)
THz Table (looking east
towards dump)
• Photos taken Feb 11 (Mark Hogan)
• Magnets installed since then.
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Current Status
• Magnets installed in sector 20 – photo taken yesterday:
THz Table (looking east
towards dump)
IP Table
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Plan – Dump Table
Dump Table
(Experiment Area 3)
• Beam size: 55um x 25um
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Plasma Wakefield Acceleration
• Continuation of very successful FFTB
experiments
• Heat-pipe oven to be installed this
summer
• Lithium metal vaporized at 800ºC
• Length of plasma controllable by
controlling heaters and pressure of
helium buffer gas
• Isolated by Be windows
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Plasma Wakefield Acceleration cont.
• What is maximum energy gain
available?
• Instabilities?
• Self-injected particles?
• 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.
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Smith Purcell
• 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).
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Wakefield Acceleration in Dielectric Structures
• 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.
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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
2.3ps
• Need to rule out experimental artefacts.
70fs
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Other Experiments
• Metallic Periodic Structures
– Short-pulse, high fields to study breakdown physics.
• CLIC Studies (letter of intent)
– Dispersion-free steering
– Accelerating structure Wakefield Studies
– Collimator Wakefield Studies
• THz extraction (expression of interest)
– Power meter and thermal camera to measure the THz
from the existing FACET bunch length monitor foil.
– Extract radiation to an experimental area
Suggested
extraction
of THz
Short Metallic Accelerating Structure
30cm High Power test structure (CLIC Studies)
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Schedule 2011
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Construction Phase 1 will be complete in May.
Beam Commissioning starts June 13th
Transitioning to…
User-aided commissioning/Experimental program in July and
August
Users meeting in August
Next round of proposals coming up
Second SAREC review likely October
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.
• Sector 20 has areas in which experiments can be installed with good
support.
• Very flexible facility
• 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 a test facility for Plasma Wakefield experiment with flexibility
to serve many other experiments.
• Unique high power beams
• Installation on track
• First Beam June 13th
• Approximately 2 weeks of beam commissioning
• User aided commissioning / first science, July and August.
• New round of proposals for 2012 due (provisionally) October.
• 4 months of FACET running in 2012 and every year until 2017.
• See you at the FACET satellite Meeting at PAC? Marriott Marquis
Tuesday March 29, 2011 from 6:00pm-8:00pm in the Brecht Room on
the 4th Floor.
FACET Status
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