Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

CLASSECLASSECLASSECLASSECLASSECLASSECLASSECLASSE

1

1 4

3

2

5

7

8

6

XXXX----ray applications and accelerator ray applications and accelerator ray applications and accelerator ray applications and accelerator physics for the Cornell ERLphysics for the Cornell ERLphysics for the Cornell ERLphysics for the Cornell ERL

Georg H. HoffstaetterCornell Physics Dep. / CLASSE

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

CLASSECLASSECLASSECLASSECLASSECLASSECLASSECLASSE

2OverviewOverviewOverviewOverview

• Principle and history of ERLs

• How good of an X-ray source could an ERL be?

• What could it do?

• What remains challenging and what challengesare being addressed?

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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3Principle of an XPrinciple of an XPrinciple of an XPrinciple of an X----ray ERLray ERLray ERLray ERL

approx. 500mapprox. 500mapprox. 500mapprox. 500m

Challenges:• Low emittance, high current creation• Emittance preservation• Beam stability at insertion devices• Accelerator design• Component properties, e.g. SRF

X-ray analysis with highestresolution in space and time:

5GV*100mA = 0.5GW(good size power plant)

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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4

approx. 500mapprox. 500mapprox. 500mapprox. 500m

Principle of an XPrinciple of an XPrinciple of an XPrinciple of an X----ray ERLray ERLray ERLray ERL

Challenges:• Low emittance, high current creation• Emittance preservation• Beam stability at insertion devices• Accelerator design• Component properties, e.g. SRF

X-ray analysis with highestresolution in space and time:

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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5

5GeV ERL Upgrade for CESR5GeV ERL Upgrade for CESR5GeV ERL Upgrade for CESR5GeV ERL Upgrade for CESRCornell ERLCornell ERLCornell ERLCornell ERL

Cornell 5GeV ERL

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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6

650m240m

JAEA Naka (East)

JAEA Naka (West)6GeV-ERL

5GeV-ERL

KEK

5GeV ERL Upgrade for CESR5GeV ERL Upgrade for CESR5GeV ERL Upgrade for CESR5GeV ERL Upgrade for CESRCornell / KEK / JAEA Cornell / KEK / JAEA Cornell / KEK / JAEA Cornell / KEK / JAEA ERLsERLsERLsERLs

Cornell 5GeV ERL

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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7

650m240m

JAEA Naka (East)

JAEA Naka (West)6GeV-ERL

5GeV-ERL

KEK

5GeV ERL Upgrade for CESR5GeV ERL Upgrade for CESR5GeV ERL Upgrade for CESR5GeV ERL Upgrade for CESRCornell / KEK / JAEA / APS Cornell / KEK / JAEA / APS Cornell / KEK / JAEA / APS Cornell / KEK / JAEA / APS ERLsERLsERLsERLs

Cornell 5GeV ERL

APS 7GeV ERL

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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8The injector: goals for the ERLThe injector: goals for the ERLThe injector: goals for the ERLThe injector: goals for the ERL

<1<1<1<10.250.250.250.25

3333

50505050

1022102210221022

5.05.05.05.0

0.10.10.10.1

10001000100010000.10.10.10.12.52.52.52.5

(D)(D)(D)(D)High chargeHigh chargeHigh chargeHigh charge

One passOne passOne passOne pass

micro Amicro Amicro Amicro A< 1< 1< 1< 1< 1< 1< 1< 1< 1< 1< 1< 1Beam loss Beam loss Beam loss Beam loss MWMWMWMW500500500500125125125125500500500500Beam power Beam power Beam power Beam power

10101010----333311110.20.20.20.20.20.20.20.2Relative energy spreadRelative energy spreadRelative energy spreadRelative energy spread

fsfsfsfs10010010010020002000200020002000200020002000Rms bunch lengthRms bunch lengthRms bunch lengthRms bunch length

pmpmpmpm1031031031038.28.28.28.231313131Geom. emittance Geom. emittance Geom. emittance Geom. emittance

mm mm mm mm mradmradmradmrad

11110.080.080.080.080.30.30.30.3Norm. emittanceNorm. emittanceNorm. emittanceNorm. emittance

MHzMHzMHzMHz130013001300130013001300130013001300130013001300Repetition rate Repetition rate Repetition rate Repetition rate

pCpCpCpC777777771919191977777777Bunch charge Bunch charge Bunch charge Bunch charge mAmAmAmA10010010010025252525100100100100Current Current Current Current GeVGeVGeVGeV555555555555Energy Energy Energy Energy

Units Units Units Units (C)(C)(C)(C)ShortShortShortShort----Pulse Pulse Pulse Pulse

(B)(B)(B)(B)Coherence Coherence Coherence Coherence

(A)(A)(A)(A)Flux Flux Flux Flux

Modes: Modes: Modes: Modes:

Energy recovered modes Energy recovered modes Energy recovered modes Energy recovered modes

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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Transverse emittance reduction:

Advantages of ERL beamsAdvantages of ERL beamsAdvantages of ERL beamsAdvantages of ERL beams

ESRF 6GeV@200mA ERL 5GeV@100mA

ERLERLERLERL

100fs 2ps16ps

Bunch-length reduction:

ESRF 6GeV@200mA ERL 5GeV@100mA

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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• Coherent x-ray diffraction imaging

• It would, in principle, allow atomic resolutionimaging on non-crystalline materials.

• This type of experiments is completely limitedby coherent flux.

coherentcoherent

3rd SR

ERL

Factor 100 more coherent flux for ERLfor same x-rays, or provide coherence for

harder x-rays

Smaller Beams and more CoherenceSmaller Beams and more CoherenceSmaller Beams and more CoherenceSmaller Beams and more Coherence

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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11How large is the advantage of How large is the advantage of How large is the advantage of How large is the advantage of ERLsERLsERLsERLs ????

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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12ERL workshops on areas of opportunityERL workshops on areas of opportunityERL workshops on areas of opportunityERL workshops on areas of opportunity

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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13 Microprobe: higher resolutionMicroprobe: higher resolutionMicroprobe: higher resolutionMicroprobe: higher resolutionfrom narrower xfrom narrower xfrom narrower xfrom narrower x----ray beamsray beamsray beamsray beams

Ben Larson (2000), ERL science

workshop, Cornelll

3-D Studies of StructureOrientation of crystals and

Stress and strain in crystals

� Smaller beams lead to betterSmaller beams lead to betterSmaller beams lead to betterSmaller beams lead to betterspatial resolution (currently sub spatial resolution (currently sub spatial resolution (currently sub spatial resolution (currently sub µµµµm)m)m)m)

DifferentialDifferentialDifferentialDifferential----Aperture Aperture Aperture Aperture XXXX----ray Microscopy (DAXM)ray Microscopy (DAXM)ray Microscopy (DAXM)ray Microscopy (DAXM)

ERL: smaller area

Cargill (intro to Larson), Nature 2002

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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• HP experiments for HP experiments for HP experiments for HP experiments for µµµµm samplesm samplesm samplesm samplesare brightnessare brightnessare brightnessare brightness----limited. Timelimited. Timelimited. Timelimited. Timeresolved experiments forresolved experiments forresolved experiments forresolved experiments forplasticity, plasticity, plasticity, plasticity, rheologyrheologyrheologyrheologymeasurements,measurements,measurements,measurements,phase transitions, etc. arephase transitions, etc. arephase transitions, etc. arephase transitions, etc. areespecially photon starved.especially photon starved.especially photon starved.especially photon starved.

• Higher P Higher P Higher P Higher P ⇒⇒⇒⇒ smaller samples.smaller samples.smaller samples.smaller samples.• No ideal pressurization mediumNo ideal pressurization mediumNo ideal pressurization mediumNo ideal pressurization medium

⇒⇒⇒⇒ need to scan sample.need to scan sample.need to scan sample.need to scan sample.• PeakPeakPeakPeak----totototo----background critical.background critical.background critical.background critical.• ERL will greatly extend pressures andERL will greatly extend pressures andERL will greatly extend pressures andERL will greatly extend pressures and

samples that can be studied.samples that can be studied.samples that can be studied.samples that can be studied.Parise, Hemley & Mao

High pressure: more flux through a small probeHigh pressure: more flux through a small probeHigh pressure: more flux through a small probeHigh pressure: more flux through a small probe

High Pressure: Materials, Engineering, Geological a nd Space Sciences.

J. B. Parise, H.- K. Mao, and R. Hemleyat ERL Workshop (2000)

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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Wang &Zhao, Science, 312 (2006) 1149; Sun et al., Science, 312 (2006) 1199.

High pressure in carbon High pressure in carbon High pressure in carbon High pressure in carbon nanotubesnanotubesnanotubesnanotubes

Up to 1600GPawith multi-wallnanotubes.

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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• Examples: folding/unfolding of proteins & RNA; ass embly of fibers; polymer collapse upon solvent changes; conformation al changes upon ligand binding; monomer/multimer association.

• Microfabricated laminar flow cells access microseco nd equilibration mixing times.

• Data acquisition entirely limited by source brillia nce. The ERL will

extend time scales from present milliseconds to mic roseconds.

Thanks to Lois Pollack

Cornell Univ.

Bio and polymer science:Bio and polymer science:Bio and polymer science:Bio and polymer science:more flux through thin sheet probesmore flux through thin sheet probesmore flux through thin sheet probesmore flux through thin sheet probes

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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1. Obtaining good crystals is rate limiting. Easier to obtain microcrystals. Radiation limits crystals to >~(20µm )3.

2. Single image sufficient to determine orientation matrix.

3. Plate microcrystals in random orientations onto ultrathin film support.

4. Scan film w/microbeam, recording diffraction imag es.

5. ERL microbeam intensity and low divergence allows this to be done with micron-sized crystals.

ERL enables new crystallographic method

?

Coherent beams from ERLs

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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18Coherent beams from ERLs

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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19RealRealRealReal----time insect breathingtime insect breathingtime insect breathingtime insect breathing

Science (2003) 299, 598-599.

Field museum of Chicago & APS, Argonne National Lab .

wood beetle

• Animal functions• Biomechanics• Internal movements• New findings

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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20RealRealRealReal----time insect breathingtime insect breathingtime insect breathingtime insect breathing

Science (2003) 299, 598-599.

Field museum of Chicago & APS, Argonne National Lab .

wood beetle

• ERL would extend these studies to much higher lateral resolution (sub µµµµm) and faster time scales

• Animal functions• Biomechanics• Internal movements• New findings

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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21Coherent imaging

Diffraction image to ~30nm resolution

Total dose to specimen ~ 8x106 Gray

E. Coli bacteria ~ 0.5 µm by 2 µm

SPring-8, λ = 2 Å, pinhole 20 µm

Miao et al., Proc. Nat. Acad. Sci. (2003)

Labeled with maganese oxide

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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22ERL workshops on areas of opportunityERL workshops on areas of opportunityERL workshops on areas of opportunityERL workshops on areas of opportunity

• Do we understand the makeup of the Earth and planets?

• How does life behave at the bottom of the ocean?

• Can we meet the challenges of the energy crisis?

• Can we improve polycrystalline materials?

• How do macromolecules (proteins) behave in solution?

• Can we find he structure of life?

• Do we understand the glass transition?

•Can we see structural changes on the ps timescale?

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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23

DC Photo Cathode

DC source for high current & low emittancesDC source for high current & low emittancesDC source for high current & low emittancesDC source for high current & low emittances• Simulations show 10 times smaller emittances than

previously thought possible, and 50 times smaller than standard.

• Gun development, coating for low field emission• Photocathode development, neg. el. affinity GaAs,

cooled• Laser beam shaping

The injector: round beam optimizationThe injector: round beam optimizationThe injector: round beam optimizationThe injector: round beam optimization

px

pz

x

z

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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24The injector optimizationThe injector optimizationThe injector optimizationThe injector optimization

CSR emittancegrowth

Space chargeemittance

growth

µm1.0=∆ε

µm1.0=∆ε

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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25(1) Challenges for x-ray ERLs

• Production of low emittances + limiting emittance g rowth

– Optics in the linac for very different energies (0. 01 - 5GeV)– Limit coupler kicks / cavity misalignments– Limit optics errors and adjust fields to radiated e nergy– Low emittance growth optics similar to light source s

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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26 Cornell Injector prototype:Cornell Injector prototype:Cornell Injector prototype:Cornell Injector prototype:Verification of beam productionVerification of beam productionVerification of beam productionVerification of beam production

Photo emitterPhoto emitterPhoto emitterPhoto emitterPower sup.Power sup.Power sup.Power sup. CathodeCathodeCathodeCathode gungungungun

SC injectorSC injectorSC injectorSC injectordumpdumpdumpdump diagnosticsdiagnosticsdiagnosticsdiagnostics gungungungun

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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27Gun prototype: well advancedGun prototype: well advancedGun prototype: well advancedGun prototype: well advanced

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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28ERL accelerator R&D and constructionERL accelerator R&D and constructionERL accelerator R&D and constructionERL accelerator R&D and construction

Superconducting Cavities, high Superconducting Cavities, high Superconducting Cavities, high Superconducting Cavities, high power input coupler, and high power input coupler, and high power input coupler, and high power input coupler, and high precision frequency tuners are all precision frequency tuners are all precision frequency tuners are all precision frequency tuners are all developed and build at Cornell developed and build at Cornell developed and build at Cornell developed and build at Cornell (with outside collaborators)(with outside collaborators)(with outside collaborators)(with outside collaborators)

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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29First vertical testFirst vertical testFirst vertical testFirst vertical test

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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30Assembly of the injector acceleratorAssembly of the injector acceleratorAssembly of the injector acceleratorAssembly of the injector accelerator

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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31Assembly of the injector acceleratorAssembly of the injector acceleratorAssembly of the injector acceleratorAssembly of the injector accelerator

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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32List of desired xList of desired xList of desired xList of desired x----ray beamlinesray beamlinesray beamlinesray beamlines

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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33

1 4

3

2

5

7

8

6

5GeV ERL extension to CESR5GeV ERL extension to CESR5GeV ERL extension to CESR5GeV ERL extension to CESR

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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34One pass, high charge mode (D)One pass, high charge mode (D)One pass, high charge mode (D)One pass, high charge mode (D)

A separate injector linac injects into the second 2.5GeV linac at 100kHz with up to 1nC per bunch.

Two-stage bunch compression with 3rd-harmonic linearizercavity at low energy produces bunches as short as 50fs.

The 125kW beam is not energy recovered, but dumped.

A optics, beam dynamics, and implications of simultaneous operation with other running modes (A, B, C) needs more analysis.

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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35Incoherent Synchrotron Radiation (ISR)Incoherent Synchrotron Radiation (ISR)Incoherent Synchrotron Radiation (ISR)Incoherent Synchrotron Radiation (ISR)

LATA

LB SA

CE

NA

LATA

LB

CE

NALA

LB

TA

SA

TS.SE.SSNAM#S.DDD#DC”

MA.SA.CELLB05.Qua03a

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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36(2) Challenges for x-ray ERLs

• Limit energy spread after deceleration by a factor of 500

– Accurate time of flight correction, including sextu poles– Limit energy spread from wake fields– Limit energy spread from intra beam scattering (IBS ) and

rest gas scattering– Limit energy spread from incoherent / coherent sync hrotron

radiation (ISR / CSR)

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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37

-3 -2 -1 0 1 2 3t HpsL

-10

-5

0

5

10

p HmcL Phase spacewithHblueL, without HredL CSR

CSR in ERL bendsCSR in ERL bendsCSR in ERL bendsCSR in ERL bends

ELEGANT used here

Denser region radiates moreRadiation from tailaccelerates head

For shorter bunchesor for not optimizedoptics the energy spreadbecomes too large.

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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38(3) Challenges for x-ray ERLs

• Beam loss concerns

– Beam loss from IBS / Tourschek– Rest gas scattering– Disturbance from ions / ion removal– Halo development

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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0 1000 2000 3000 40000

5.µ10-8

1.µ10-7

1.5µ10-7

2.µ10-7

Scattering and background: IBSScattering and background: IBSScattering and background: IBSScattering and background: IBS

0 1000 2000 3000 40000

1.µ10-8

2.µ10-8

3.µ10-8

4.µ10-8

element number element number

nA

50

100

150

200nA

10

20

30

40

0 0

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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40Shielding and xShielding and xShielding and xShielding and x----ray opticsray opticsray opticsray optics

1st optics at 35m after center of undulator, outside shielding wall.80m long x-ray beamlines.

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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41Ion focusingIon focusingIon focusingIon focusing

• Ion are quickly produced due to high beam density

• Ion accumulate in the beam potential. Since the beam is very narrow,

ions produce an extremely steep potential – they have to be eliminated.

• Conventional ion clearing techniques:

1) Long clearing gaps have transient RF effects in the ERL [2ms every 7ms2ms every 7ms2ms every 7ms2ms every 7ms].

2) Short gaps have transient effects in injector and gun and produce more

beam harmonics that excite HOMs [0.4 ms every 7ms0.4 ms every 7ms0.4 ms every 7ms0.4 ms every 7ms].

3) DC fields of about 150kV/m have to be applied to appropriate places of

the along the accelerator, without disturbing the electron beam.

But remnant ion density before clearing can still cause emittance growth.

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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42

-4 -3 -2 -1 0 1 2 3 x (ssss)

Ions in an ERL beamIons in an ERL beamIons in an ERL beamIons in an ERL beam

-5 -4 -3 -2 -1 0 1 2 3 4 x (ssss)rr rr

(a.u

.)

100m between clearing fields

X’( mm mm

rad)

-20/6

0

10/6

-10/6

-30/6

-0.4 -0.3 -0.2 -0.1 0 0.1 0.2 x (mm)

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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-4 -3 -2 -1 0 1 2 3 x (ssss)

Ions in an ERL beamIons in an ERL beamIons in an ERL beamIons in an ERL beam

-5 -4 -3 -2 -1 0 1 2 3 4 x (ssss)rr rr

(a.u

.)

100m between clearing fields

X’( mm mm

rad)

-20/6

0

10/6

-10/6

-30/6

-0.4 -0.3 -0.2 -0.1 0 0.1 0.2 x (mm)

20m between clearing fields

X’( mm mm

rad)

-80/6

0

40/6

-40/6

-0.4 -0.3 -0.2 -0.1 0 0.1 0.2 x (mm)

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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44

-4 -3 -2 -1 0 1 2 3 x (ssss)

Ions in an ERL beamIons in an ERL beamIons in an ERL beamIons in an ERL beam

-5 -4 -3 -2 -1 0 1 2 3 4 x (ssss)rr rr

(a.u

.)

100m between clearing fields

X’( mm mm

rad)

-20/6

0

10/6

-10/6

-30/6

-0.4 -0.3 -0.2 -0.1 0 0.1 0.2 x (mm)

20m between clearing fields

X’( mm mm

rad)

-80/6

0

40/6

-40/6

-0.4 -0.3 -0.2 -0.1 0 0.1 0.2 x (mm) -0.1 -0.05 0 0.05 0.1 x(mm)

X’( mm mm

rad)

-4

0

2

-2

realistically placed ion clearing

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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45(4) Challenges for x-ray ERLs

• Superconducting RF challenges

– Phase and amplitude control for very narrow frequen cy window (10 -8)

– Avoid heating / Higher order mode absorption– Limit cooling power

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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46

0 1

-100

0

100

phas

e [d

eg]

time [sec]

0 10

5

10ac

cele

ratin

g fie

ld [M

V/m

]

time [sec]

Without feedback:

-1000 -500 0 500 10000

1

cavi

ty fi

eld

[arb

. uni

ts]

Frequency – 1.3 GHz [Hz]

13 Hz bandwidth

Cavity control for SC linacs (ERL & ILC)Cavity control for SC linacs (ERL & ILC)Cavity control for SC linacs (ERL & ILC)Cavity control for SC linacs (ERL & ILC)

• Run cavity with lowest possible bandwidth for ERL.

• But frequency stabilization becomes very critical.

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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47

0 1

-100

0

100

phas

e [d

eg]

time [sec]

0 10

5

10ac

cele

ratin

g fie

ld [M

V/m

]

time [sec]

Without feedback:

0

1

-1000 -500 0 500 1000cavi

ty fi

eld

[arb

. uni

ts]

frequency – 1.3 GHz [Hz]

For strong fields

Cavity control for SC linacs (ERL & ILC)Cavity control for SC linacs (ERL & ILC)Cavity control for SC linacs (ERL & ILC)Cavity control for SC linacs (ERL & ILC)

• Run cavity with lowest possible bandwidth for ERL.

• But frequency stabilization becomes very critical.

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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48

0 1

-100

0

100

phas

e [d

eg]

time [sec]

0 10

5

10ac

cele

ratin

g fie

ld [M

V/m

]

time [sec]

Without feedback:

0

1

-1000 -500 0 500 1000 (Hz)

cavi

ty fi

eld

[arb

. uni

ts]

frequency – 1.3 GHz

Add Microphonics !

Cavity control for SC linacs (ERL & ILC)Cavity control for SC linacs (ERL & ILC)Cavity control for SC linacs (ERL & ILC)Cavity control for SC linacs (ERL & ILC)

• Run cavity with lowest possible bandwidth for ERL.

• But frequency stabilization becomes very critical.

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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49

0

1

-1000 -500 0 500 1000 (Hz)

cavi

ty fi

eld

[arb

. uni

ts]

frequency – 1.3 GHz

Vibration Mode

Add Microphonics !

Cavity control for SC linacs (ERL & ILC)Cavity control for SC linacs (ERL & ILC)Cavity control for SC linacs (ERL & ILC)Cavity control for SC linacs (ERL & ILC)

0 112.1

12.212.3

12.4

time [sec]acce

lera

ting

field

[MV

/m]

0 199.510

10.511

phas

e [d

eg]

time [sec]

σσσσA/A ≈≈≈≈ 1·10 - 4

σσσσϕϕϕϕ ≈≈≈≈ 0.02 deg

• Run cavity with lowest possible bandwidth for ERL.

• But frequency stabilization becomes very critical.

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50

Bilderback

Hartill

Vibration measurementsVibration measurementsVibration measurementsVibration measurements

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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51BBU: Collective InstabilitiesBBU: Collective InstabilitiesBBU: Collective InstabilitiesBBU: Collective Instabilities

∫∞−

−−=t

rxxce

x dttIttVttWTtV ')'()'()'()( 12

Higher Order Modes

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

CLASSECLASSECLASSECLASSECLASSECLASSECLASSECLASSE

52BBU: Collective InstabilitiesBBU: Collective InstabilitiesBBU: Collective InstabilitiesBBU: Collective Instabilities

∫∞−

−−=t

rxxce

x dttIttVttWTtV ')'()'()'()( 12

Higher Order Modes

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

CLASSECLASSECLASSECLASSECLASSECLASSECLASSECLASSE

53BBU: Collective InstabilitiesBBU: Collective InstabilitiesBBU: Collective InstabilitiesBBU: Collective Instabilities

∫∞−

−−=t

rxxce

x dttIttVttWTtV ')'()'()'()( 12

Higher Order Modes

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

CLASSECLASSECLASSECLASSECLASSECLASSECLASSECLASSE

54HOM with BBU: Starting from NoiseHOM with BBU: Starting from NoiseHOM with BBU: Starting from NoiseHOM with BBU: Starting from Noise

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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55HOM absorbers a la CornellHOM absorbers a la CornellHOM absorbers a la CornellHOM absorbers a la Cornell

The CornellThe CornellThe CornellThe Cornell----type HOM absorbers:type HOM absorbers:type HOM absorbers:type HOM absorbers:�first developed for CESRfirst developed for CESRfirst developed for CESRfirst developed for CESR�adopted internationallyadopted internationallyadopted internationallyadopted internationally�Refined for the ERLRefined for the ERLRefined for the ERLRefined for the ERL

From designFrom designFrom designFrom design

to production and to production and to production and to production and

Installation, made in Cornell Installation, made in Cornell Installation, made in Cornell Installation, made in Cornell

HOM absorbers quickly reduce HOM absorbers quickly reduce HOM absorbers quickly reduce HOM absorbers quickly reduce unwanted field components.unwanted field components.unwanted field components.unwanted field components.

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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56

Two designs: 25 X 55 X 7m and 35 X 65 X 12m

Cryogenic buildingCryogenic buildingCryogenic buildingCryogenic building

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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57Cryogenic buildingCryogenic buildingCryogenic buildingCryogenic building

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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58

New floor space:likely as large as existing Wilson lab.

Beamline location:out of the hillside next to existing Wilson lab

Conceptual building designConceptual building designConceptual building designConceptual building design

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

CLASSECLASSECLASSECLASSECLASSECLASSECLASSECLASSE

59Future accelerator developmentsFuture accelerator developmentsFuture accelerator developmentsFuture accelerator developments

3) Development of higher current operation

1) SASE FEL development in parallel with ERL operation(1nC, 50fs can support SASE amplification)

2) HGHG development in parallel with ERL operation(1nC, 1ps can support radiator/modulator HGHG)(1nC, 50fs can support modulator free HGHG)

Georg H. Hoffstaetter Elbe Workshop 10 / 04 / 2007

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60Amplifier FEL operationAmplifier FEL operationAmplifier FEL operationAmplifier FEL operation

From ERL07 Workshop

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61Conclusions and Contributors*Conclusions and Contributors*Conclusions and Contributors*Conclusions and Contributors*

Cornell has an experienced team of accelerator experts who have laid out an ERL for the Cornell campus that extends the CESR ring, and have defined working modes that accommodate all considered accelerator physics issues.

Injector parametersUser requirements for layout and beam parametersLayout, optics considerations, ISR, CSRCoupler kicksIon effects with clearing electrodesIon gap optionsCavity alignments, orbit correction techniques, BBUBPM solutions for 2 beams, ERL impedancesTransverse orbit feedback considerationsx-ray loadsGas and pressure profileGas and Touschek scattering, beam halo, collimationRadiation shieldingCode developments

* Several people contributed to more than one subject.* Several people contributed to more than one subject.* Several people contributed to more than one subject.* Several people contributed to more than one subject.

Ivan Ivan Ivan Ivan BazarovBazarovBazarovBazarov, Charlie Sinclair, Charlie Sinclair, Charlie Sinclair, Charlie Sinclair

Don Don Don Don BilderbackBilderbackBilderbackBilderback, Dana Richter, Dana Richter, Dana Richter, Dana Richter

Chris MayesChris MayesChris MayesChris Mayes

Brandon BuckleyBrandon BuckleyBrandon BuckleyBrandon Buckley

Christian Christian Christian Christian SpethmannSpethmannSpethmannSpethmann, Yi , Yi , Yi , Yi XieXieXieXie

Bob Bob Bob Bob MellerMellerMellerMeller

ChangshengChangshengChangshengChangsheng SongSongSongSong

Mike Billing, Mark PalmerMike Billing, Mark PalmerMike Billing, Mark PalmerMike Billing, Mark Palmer

Jerry Jerry Jerry Jerry CodnerCodnerCodnerCodner, Don , Don , Don , Don HartillHartillHartillHartill , John , John , John , John SikoraSikoraSikoraSikora

Mike ForsterMike ForsterMike ForsterMike Forster

YulinYulinYulinYulin LiLiLiLi

Sasha Sasha Sasha Sasha TemnykhTemnykhTemnykhTemnykh, Mike , Mike , Mike , Mike EhrlichmannEhrlichmannEhrlichmannEhrlichmann

Ken Finkelstein, , Steve Gray, Val Ken Finkelstein, , Steve Gray, Val Ken Finkelstein, , Steve Gray, Val Ken Finkelstein, , Steve Gray, Val KostrounKostrounKostrounKostroun

Dave SaganDave SaganDave SaganDave Sagan