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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