Joint Workshop 4th Beam Physics Seminar & 9th ATF ...CLIC Forum, 14.05.2004 F. Zimmermann Joint...

CLIC Forum, 14.05.2004 F. Zimmermann

Joint Workshop 4th Beam Physics Seminar &

9th ATF International Collaboration Meeting

Kamogawa, Chiba ken, Sotobo “outside of Bozo Peninsula”, March 19-21, 2003


Joint Workshop • 55 participants: 31 Japan, 8 China, 3 SLAC, 3 Russia, 3 UK,

2 India, 2 Jordan, 1 UCLA, 1 Orsay,1 CERN

• sponsored by JSPS Core University Program – Beam Physics(‘Japanese Society for the Promotion of Science’)

• JSPS Subprogram: Linear Collider Accelerator R&D(responsible J. Urakawa)

• Beam Physics Seminar (1st at IHEP, 2nd at IHEP, 3rd at Nasu(Joint), 4th Kamogawa); China-Japan Collaboration

• ATF Int’l Collaboration Meeting (1st at KEK 1996, 2nd at SLAC, …, 7th at Nikkou (2001), 8th Nasu (2002), 9th Kamogawa 2004


Agenda of Joint Workshop:

• Review of ATF R&D• Hardware• Chief Director of JSPS Asian Program –

JSPS R&D• Extraction Line Diagnostics & Experiments• Instrumentation and Beam Physics• Future Plan


detailed schedule


I will present my impression from all talks & slides from:“Opening Remarks”

- Junji Urakawa“ATF Status”

- Hitoshi Hayano“Future Plans for ATF Instrumentation”

– Marc Ross“Laser Wire R&D and Plans in the Extraction Line”

– Grahame Blair“Welcome Talk JSPS”

– Tsyuyoshi Enomoto“Comments about ATF Instruments & Future Plan”

– Marc Ross“Plans for 2004-2005 ATF Run”

– Junji Urakawa “Developments at 2004 ATF Run”

- Hitoshi Hayano


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Å@ATFÅ@Damping Ring

Electoron Linac

BT( Beam Transport Line )

Extraction Line

SR Monitor

RF Cavity

Wiggler

Injection Kicker

Seputum Magnets

Extraction KickerWiggler

East Arc

North Straight

South Straight

West Arc

Wire scanner

E=1.28GeVNe=1x1010 e-/bunch

1 ~ 20 bunchesRep=1.5HzX emit=2.5E-6 µm ( at 0 intensity)

Y emit=2.5E-8 µm ( at 0 intensity)

Accelerator Test Facility

Damping ring

Linac

this and many following slides from H. Hayano!

ATF is the largest LC Test Facility


Low Emittance Tuning• Beam-based optics modeling

Q-magnet strength correction in model

• Beam based BPM offset measurementQ, SX trim excitation & bump orbit to orbit response

• COD correction• Dispersion correction• Coupling correction

horizontal kick to vertical response, then skew corrector

H. Hayano


1

10

100

108 109 1010 1011

Est

imat

ed R

esol

utio

n [µ

m]

Bunch Intensity [electrons/bunch]

Existing circuit(estimated by beam)

Improved circuit(estimated by calibration pulser)

BPM Resolution Improvement

Min. resolution ~ 2µm


Vertical dispersion Improvement

-15.0

-10.0

-5.0

0.0

5.0

10.0

15.0

0 20 40 60 80 100

Y dispersion before BPM improvement (26Nov2002)

Y d

ispe

rsio

n [m

m]

BPMnumber

-15.0

-10.0

-5.0

0.0

5.0

10.0

15.0

0 20 40 60 80 100

Y dispersion after BPM improvement (20May2003)

Y d

ispe

rsio

n [m

m]

BPMnumber


X to Y coupling Improvement

-200.0-150.0-100.0

-50.00.0

50.0100.0150.0200.0

0 20 40 60 80 100

dY by ZH2R 26Nov2002

dY[m

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n]

BPMnumber

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dY by ZH4R 26Nov2002

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Laser wire beam size monitor in DR

14.7µm laser wire for X scan5.7µm for Y scan(whole scan: 15 min for X,6 min for Y)

300mW 532nm Solid-state LaserFed into optical cavity


Beam profile by Laser wire

σe2 = σmeas

2 - σlw2

εβ = σe2 – [η(∆p/p)]2 β:measured by Q-trim excitation


Bunch Length by SR monitor streak camera

15

20

25

30

35

40

0 2 109 4 109 6 109 8 109 1 1010 1.2 1010

bunch length(runD') [psec]bunch length(runE') [psec]bunch length(runF') [psec]simulation (0.4% coupling)simulation (6% coupling)simulation (3% coupling)

Bun

ch L

engt

h (r

ms)

[pse

c]



Energy Spreadby beam size monitor at EXT dispersive point

4.5 10-4

5.0 10-4

5.5 10-4

6.0 10-4

6.5 10-4

7.0 10-4

7.5 10-4

8.0 10-4

8.5 10-4

0 2 109 4 109 6 109 8 109 1 1010 1.2 1010

Energy Spread (runD)Energy Spread (run E)simulation (0.4% coupling)simulation (6% coupling)

Ene

rgy

Spre

ad



Transverse Emittance by Laser wire

< 0.4% y/x emittance ratio

Y emittance =4pm at small intensity

0.8

1.0

1.2

1.4

1.6

1.8

2.0

0 2 109 4 109 6 109 8 109 1 1010

Horizontal Emittancex emittance (run B)x emittance (run D)simulation (0.4% coupling)

x e

mitt

ance

[10-9

]

bunch intensity [electrons/bunch]

2.0

3.0

4.0

5.0

6.0

7.0

8.0

0 2 109 4 109 6 109 8 109 1 1010

Vertical Emittancey emittance (run B)y emittance (run D)simulation (0.4% coupling)

y e

mitt

ance

[10-1

2 ]bunch intensity [electrons/bunch]


demonstrated single bunch emittanceγεx~3.5-4.3 µm

(1.4-1.7 nm)γεy~13-18 nm

(5-7 pm)

CLIC target valuesγεx~0.45 µm γεy~3 nm

?


(<5 ntorr)

(>7.6 ntorr)

ODR monitor?


“at large amplitudes tail from elastic gas scattering like ~1/y3”?

TorRauben-heimer,KEK-92-7,1992

observed pressure sensitivity in striking contrast to prediction

10 ntorr

0.1 ntorr

1000 ntorr


T. Naito et al.,“Observation of the Longitudinal Beam Oscillation at ATF-DR”KEK Preprint 2003-73October 2003A

the amplitude of thelongitudinal oscillationat each bunch (1σ)

for comparison

full bucket size: 1.4 nsrms bunch length:0.017 ns

6x1010

total intensity

measured by streak camerasimilar scatter seen in energy profilessensitive to rf temperature, suspect HOM


γθy γθy


BINP-SLAC-LLNL-KEK collaboration on nanometre BPM;thermal noise level 1 nm, measures position and angle


X-ray SR monitor real time measurement <20 msavoids diffraction limitFZP as lens on CCDMeasured 6.5-7 micronExpected 5 micronWhy? magnification (checked!), vibration, alignment

ODR monitorfirst observation of ODR from slit targetSR suppressed by mask20 micron sensitivity achievedmeasured beam size too large

both ODR & XSR give 20% larger σ than laser wire


• multibunch emittance increases about 2x faster with intensity than single bunch emittance

• gas pressure effect not consistent with Tor’s prediction(sensitivity to vacuum much higher than expected,

direct correlation)

• performance with wigglers (planned)

• e-cloud coating tests in the ATF (M. Ross’ proposal) what should be measured?

outstanding questions


ATF Plans for 200420 weeks operation JFY 2004 and 2005April-June: high current multibunchMB emittance study: vacuum scrubbing, high current,

x/y emittance by laser wire, longitudinal oscillationsnm resolution BPM test: new mover & new cavity electronics

compare with nm BPMs from KEK fast feedback test & demonstration: basic test BPM &

kicker first, test for 1-3 train extraction, FEATHER -> FONT instrumentation developments

ODR, laser wire, X-ray monitor, fast sweep laser (UK)October-December: performance of wiggler magnets

From 2005: “ATF R&D 2nd phase”unique studies as determined by GDO


(J. Urakawa)


Marc Ross


Laser Wire R&D +Laser Wire R&D +Plans in the ATF Extraction Plans in the ATF Extraction

LineLine

G. A. BlairG. A. BlairRoyal Holloway Univ. LondonRoyal Holloway Univ. London

Joint Workshop for Joint Workshop for 44thth Beam Physics Seminar andBeam Physics Seminar and

99thth ATF International Collaboration ATF International Collaboration MeetingMeeting

2020thth March 2004March 2004

Laser-wire at PETRA- Environment at PETRA- Installation of Hardware- First measurements

UK R&D PlansExtraction LineConclusions and Outlook


Setup at PETRASetup at PETRA

HALL EAST

Q-SWITCH

TUNNEL AREA

EMBL HUT

OUTIN

OUT IN

INOUT

LASER

PD TRIGGER BOX

SCOPE

PIT.Y

PIT.E

CAL

BPM

IP

PD@IP

PETRATIMING

e+

COMPTONPHOTONS

this and the following slides from G. Blair!


Results 04.12.03 DataResults 04.12.03 Data

Gaussian approximation of beam shapeGaussian approximation of beam shapeσσm m =(68 =(68 ± ± 3 3 ± ± 20) 20) µµm at low currentm at low current

σσm m =(80 =(80 ± ± 6 6 ± ± 20) 20) µµm at high currentm at high current


Next stepsNext steps

Laserwire at PETRA produced first compton photons and Laserwire at PETRA produced first compton photons and measure vertical beam size Next steps:measure vertical beam size Next steps:

•• Full characterisation of laser: beam size, divergence, and Full characterisation of laser: beam size, divergence, and power (stability) with slot scans and imaging techniquespower (stability) with slot scans and imaging techniques

•• Update all readout software, merge BPM and PMT softwareUpdate all readout software, merge BPM and PMT software•• Do more systematic scans with the fast scannerDo more systematic scans with the fast scanner•• Go to smaller spot sizes and reduce errorsGo to smaller spot sizes and reduce errors•• Build second dimension (x) scanner.Build second dimension (x) scanner.

•• Start designing a complete laserStart designing a complete laser--wire emittance wire emittance measurement system for the LC BDS. measurement system for the LC BDS.

•• Look to ATF for micronLook to ATF for micron--scale laserwire systemscale laserwire system


UK funding for accelerator science UK funding for accelerator science for particle physics 2004 for particle physics 2004 -- 20072007

UK funding agency, PPARC, secured from Govt. £11M for UK funding agency, PPARC, secured from Govt. £11M for ‘accelerator science’ for particle physics, spend period April 0‘accelerator science’ for particle physics, spend period April 04 4 –– March 07 March 07

Called for bids from universities and national labs; large consoCalled for bids from universities and national labs; large consortia rtia were explicitly encouragedwere explicitly encouraged

Bids peerBids peer--reviewed and preliminary new allocations made Oct 21 reviewed and preliminary new allocations made Oct 21 2003:2003:

Funding Funding ((http://http://www.pparc.ac.uk/Nw/accelerators.aspwww.pparc.ac.uk/Nw/accelerators.asp):):

LCLC--Beam Delivery £9.1MBeam Delivery £9.1MUKNF £1.9MUKNF £1.9M2 university2 university--based accelerator institutes: based accelerator institutes:

Oxford/RHULOxford/RHULCockroftCockroft: Liverpool, Manchester, Lancaster, NW dev. : Liverpool, Manchester, Lancaster, NW dev.

agency agency.


LCLC--ABD ABD CollaborationCollaboration

•• AbertayAbertay•• Bristol Bristol •• Birmingham Birmingham •• Cambridge Cambridge •• Durham Durham •• LancasterLancaster•• Liverpool Liverpool •• Manchester Manchester •• Oxford Oxford •• Queen Mary, Univ. LondonQueen Mary, Univ. London•• Royal Holloway, Univ. Of LondonRoyal Holloway, Univ. Of London•• University College, London University College, London •• DaresburyDaresbury and Rutherfordand Rutherford--Appleton Labs; Appleton Labs;

41 post41 post--doctoral physicists (faculty, staff, research associates)doctoral physicists (faculty, staff, research associates)+ technical staff + graduate students+ technical staff + graduate students


Lattice design + Simulation8%

Beam Transport + Backgrounds

9%

Laser-wire15%

Longitudinal Profile7%

Polarisation1%

LiCAS15%

FONT+ BPM Spectrometry17%

Polarised Positron Undulator

8%

Crab Cavity13%

Collimation5%

Training+ General2%

Overview of LC ProjectsOverview of LC Projects

Essentially independent of Linac-technology


International ATF LaserInternational ATF Laser--wire wire ProjectProject

Extraction line: Extraction line: sigma_ysigma_y ~ 5 ~ 5 µµm, intram, intra--train fast train fast scanningscanning

Clear additional technical challenges to PETRA experimentClear additional technical challenges to PETRA experimentUK funding introduces the possibility to collaborate on an UK funding introduces the possibility to collaborate on an

international ATF laserinternational ATF laser--wirewireSLAC expertise will bolster the projectSLAC expertise will bolster the project

Looking forward to making this happen.Thank you to our ATF hosts.

Very constructive discussions this weekWe will explore the technical details and start preliminary designsExciting opportunity to establish a nucleus within a future GDO.


by Marc Ross


other topics:• highlights from APAC’04• wiggler for CLIC DR• electron cloud in LCs

(ECLOUD’04 etc.)


APAC’04 Highlights:• many participants from Asia & Russia (unlike in US!)• push to build LC in Asia/Japan; endorsed by ACFA• T. Shintake: 6-GeV SASE FEL at SPring-8, novel gun

design achieves 1 micron emittance in both planes• BEPC & Shanghai Light Source approved• BEPC e-cloud study: octupoles, solenoids, BPM bias,

all reduce vertical blow up • CSR calculations by Yokoya and Angoh• Compact SASE FEL at PAL (3rd largest e- linac) by 2008• V. Parkhomchuk: beam-beam, e-cloud and heating,

longitudinal effect of e-cloud plasma waves?• KEKB will install 1st crab cavity in 2005, new target

luminosity is 3e34 in 2006• W. Chou: proton driver for superneutrino beam (high flux,

long baseline), FNAL-Beijing – 9400 km under study• K. Yokoya: ERL project at KEK


full gap [m]

λ = 10 cmpeak field [T]

s.c. (12 mm gap)

s.c. (8 mm gap)

hybrid with vanadium permendur

Sm2Co17

el.magnet

which wiggler for CLIC DR?P. Elleaume et al., NIM A 455, 503 (2000)


Observed Electron Cloud Threshold vs. Bunch Spacing Future & Proposed Machines

SPS, PS, Tevatron,APS thresholds areall similar

DAFNE and KEKB look better, RHIC worse

extrapolation to shorter spacings?


DR e-cloud simulations and estimates at ECLOUD04 http://icfa-ecloud04.web.cern.ch/icfa-ecloud04/agenda.html

• M. Pivi (SLAC) for NLC & TESLA>> disaster for TESLA, NLC 30% above threshold

• K. Ohmi (KEK) for JLC/GLC>> threshold ~1012 m-3 but scaling is broken

• A. Ghalam (USC) for TESLA>> disaster for TESLA

• R. Wanzenberg (DESY) & F. Zimmermann (CERN) for TESLA & CLIC>> pessimistic? BBR model suggests TESLA a factor 2 below threshold, CLIC near threshold

huge controversy


Scaling of νs and cloud density• In the theory of the strong head-tail instability, the

instability should be scaled by the ratio of the wake strength (cloud density) and the synchrotron tune.

0

1e-05

2e-05

3e-05

4e-05

5e-05

6e-05

0 1000 2000 3000 4000 5000

sigy

(m

)

turn*rho/1e11

rho/Qs=1e11/0.001

rho=10e11 rho=1,2,5e11

K. Ohmi


e- cloud effects in single-passsystem (LC beam delivery)

• e- can build up along bunch train and reach densities up to 1014 m-3

• blow up of IP spot size for densities abovethreshold of 1011 m-3

• two effects: breakdown of –I in CCS anddirect focusing effect at IP

γβρ

νCr ee≈∆ [ ]∫ −≈

∆ ∗∗

∗ C

yey

y dss0

2 )(sin4 φφβργπ

σσ

phase advance change direct focusing effect(D. Chen, et al., 2003)


IP beam size and central electrondensity 100 m upstream of IP,vs. position along the bunch

IP beam size vs electrondensity, revealing thresholdat 1011 m-3

(D. Chen, A. Chang, M. Pivi, T. Raubenheimer, 2003)

e- cloud effect in NLC beam delivery


recent e-cloud studies for CLIC damping ring (design by Maxim Korostelev)

collaboration with R. Wanzenberg and D. Schulte


no design of CLIC DR vacuum system yet;for the moment we assume vacuum chamberssimilar to those of the TESLA DR

arc chamberhx=22 mm, hy=18 mm(half axes)

wiggler chamberhx=16 mm, hy=9 mm (half axes) half height of a.c. slot 3 mm


without any antechamber with continuous antechamber

photon flux around the CLIC DR

5x1019 m-1 s-1 1x1019 m-1 s-1

1x1019 m-1 s-1

(simulated by PHOTON code)


without any antechamber with continuous antechamber

photons per meter per e+ around CLIC DR

10 m-1 10 m-1

1 m-1

(simulated by PHOTON code)

1 m-1

~6 /m/e+ in wiggler~2/m/e+ in arcs

~4 /m/e+ in wiggler~0 /m/e+ in arcs


dipole field in arcs field-free region in arcs

e- build up in CLIC DR arcs1x1010 m-1

1.6x1010 m-1

assuming 0.06 e- /m/e+ (which relates to Yeff=0.01% w/o antechamber)typical high density is reached, not very sensitive to δmax

(simulated by ECLOUD code)

λ=1010 m-1 ~ ρ=8x1012 m-3


e- build up in CLIC DR wiggler

(simulated by ECLOUD code)

2x1010 m-1

assuming 0.11 e- /m/e+ (which relates to Yeff=0.01% w/o antechamber)1-2x higher density than arc, more sensitive to δmax

λ=2x1010 m-1 ~ ρ=3.5x1013 m-3


e- pinch during bunch passage in CLIC wiggler450

density enhancement factoralong the bunch at the centreand at 1σ

s/σz

(simulatedby

PINCHcode)

cloud rms=30 σ


e- pinch during bunch passage in TESLA wiggler500

s/σz

(simulatedby

PINCHcode)

cloud rms=30 σ


e- driven TMCI instability in CLIC DR

(simulated by HEADTAIL code)

thresholde- volumedensity~1x1012 m-3

all around the ring

synchrotron motion smeared out around the ring


e- driven TMCI instability in TESLA DR

(simulated by

HEADTAILcode)

thresholde- volumedensity<2.5x1011 m-3

in the wiggler

no synchrotron motion inside the wigglers


thank you for attention!

Joint Workshop 4th Beam Physics Seminar & 9th ATF ...CLIC Forum, 14.05.2004 F. Zimmermann Joint...

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Transcript of Joint Workshop 4th Beam Physics Seminar & 9th ATF ...CLIC Forum, 14.05.2004 F. Zimmermann Joint...