ILC Accelerator Activities in North America (cooperation with France )

12013 IRFU Linear Collider Days

ILC Accelerator Activities in North America(cooperation with France)

Presentation at IRFU Linear Collider Days prepared by:

Marc Ross (SLAC)

November 29, 2013


TDP Goals:» R & D to enable Project Proposal and updated Value estimate –

with Cost Containment» SC RF Technology Transfer

• development of a strong industrial base Technical Design Report:

» Consists of two parts: 1) R & D Report and 2) Design Description Beam Test Facilities:

» SRF Linac: Fermilab NML, DESY E-XFEL and FLASH, KEK STF » Beam Dynamics: Cornell CesrTA (2008 – 2010)» Beam Tuning: KEK ATF2

Production / Industrialization:» CEBAF Upgrade and E-XFEL

Completing the ILC Technical Design Phase

January 2013


Completing the TDP: Outline TDP Goals:

» R & D to enable Project Proposal and updated Value estimate – with Cost Containment

» SC RF Technology Transfer • development of a strong industrial base

Technical Design Report:» Consists of two parts: 1) R & D Report and 2) Design Description

Beam Test Facilities:» SRF Linac: Fermilab NML, DESY E-XFEL and FLASH, KEK STF » Beam Dynamics: Cornell CesrTA (2008 – 2010)» Beam Tuning: KEK ATF2


Present


SC RF Technology Transfer » Development of a strong industrial base


Beam Test Facilities:» SRF Linac: Fermilab NML, DESY E-XFEL and FLASH, KEK STF » Beam Dynamics: Cornell CesrTA (2008 – 2010)» Beam Tuning: KEK ATF2

US contribution to ‘Linear Collider Collaboration’ (LCC) ‘P5’ prioritization activity

ILC Accelerator Activities: OutlineBy the end of the XFEL Production > 1000 cavities will have been fabricated by industry and processed using the basic TESLA – recipe.


Cavity production lines fully functioning: 8 cavities / week» Two companies

Cryomodule production:• Three pre-series CM (XM-3, XM-2, XM-1) in process; typical

time to construct 4 months; time to test unknown • Production series of 81 each started Sep. 02, 2013; • One CM / week nominal; one production line (CEA-Saclay)

24 cavities to be used for high – gradient development» (See E. Elsen)

EU - XFEL

6'BB Lunch', M. Ross (SLAC)

Jefferson Lab CEBAF 12 GeV Upgrade



Slide dated late 09.2013All C100 cryomodules are now installed (11.2013)



Following BESAC (Basic Energy Sciences Advisory) report in late July 2013:» Shakeup of US accelerator construction projects:» SLAC LCLS-II project redefined» ANL APS upgrade program redefined

SLAC Proposal:» 4 GeV CW SRF Linac-based FEL» Use ILC / XFEL 1.3 GHz technology» Installed in the upstream 1/3 of the SLAC linac housing» (50 year old S-band linac to be completely removed)» First light end of FY 2019

SLAC Proposal:

11

SLAC Director Chi-Chang Kao, 27 September 2013:

12

Chi-Chang Kao, 27 September 2013:

13

LCLS-II and ILC

Much LCLS-II construction will be done at Fermilab, using infrastructure intended for ILC

18 CM? (50%)Other CM to be made at JLab (and Cornell)

Saclay CM assembly industrial experience unique

US team have made ~ two ILC CM. LCLS-II effort will help understand US-domestic technical, cost, and industrialization

14

RF Parameters:


15

RF Parameters (2)


LCLS-II - Linac and Compressor Layout for 4 GeV

CM01 CM2,3 CM04 CM15 CM16 CM35BC1

270 MeVR56 = -65 mm

Ipk = 60 ALb = 0.40 mmsd = 1.4 %

BC21550 MeV

R56 = -65 mmIpk = 1000 A

Lb = 0.024 mmsd = 0.50 %

GUN0.75 MeV

LH98 MeV

R56 = -5 mmIpk = 12 A

Lb = 2.0 mmsd = 0.006 %

L0j 0

V0 97 MV

L1j =-26°

V0 =235 MV

HLj =-170°

V0 =40 MV

L2j = -28°

V0 = 1448 MV

L3j = 0

V0 = 2460 MV

LTU4.0 GeVR56 = 0

Ipk = 1000 ALb = 0.024 mmsd 0.02 %

100 pC; Machine layout 26SEP2013; Bunch length Lb is FWHM

3.9GHz

Linac V(MV)

j(deg)

Acc. Grad.

(MV/m)

No. Cryo Mod’s

No. Cav’s

Spare Cav’s

Cavities per

Amplifier

L0 97 * 14.6 1 8 1 1

L1 235 -26 15.1 2 16 1 ?

HL -40 -170 - 3 (3.9GHz) 12 0 12?

L2 1448 -28 15.5 12 96 6 32?

L3 2460 0 15.7 20 160 10 32?

* L0 phases: (-40, -52, 0, 0, 0, 13, 33), with cav-2 at 20% of other L0 cav’s.

Includes 2-km RW wake

2013 IRFU Linear Collider Days 16

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First 800 m of SLAC linac (1964):

350 m

Marc Ross, SLAC LCLS-IISeptember 6, 2013

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ILC R & D initiative: Power Coupler development

Mandated by PAC (12.2012) technical reviewCommon activity with Orsay /LAL

Issues:• Cost• Copper coating / flaking• Complex Assembly • Plug-compatibility

TTF3/XFEL coupler

STF-2 coupler

TDR coupler

(1) Deep Technical Review of Input Couplers

ILC specification• Power requirements

– We recommend to match the coupler to 30 MV/m for reduced filling time and smaller Qext range– Max coupler power at operation 450 kW (for 8.8 mA, 10Hz, Eacc=31.5 MV/m ±20%)– RF processing to at least four times max input power ~ 1.8 MW up to 500 us at test stand TW– Surface field not a problem for both designs, i.e. 40mm and 60mm are both ok– Should check flattop regulation at 25 MV/m and Qext ~ 1e7 (LFD)– TW testing on test stand up to 1.8MW has to be done for both: TTF3 and STF2

• Q-ext– Variable coupling is needed, remote operation– QL tuning range: 2-7x106 is needed, but we recommend 1-10 x 106

– 1-10 10∙ 6 is achieved with TTF3– STF2 has to be improved

• Antenna alignment:– Design should be +-2mm– For TTF3 coupler the most sensitive parameter is a horizontal antenna shift/tilt. 3mm shift change

QL by ~20%. Vertical tolerances are relaxed.– For STF-2 coupler this is not issue, mechanical design guarantee small shift.– TTF3 has to be improved

• Cryogenic loss:– Coupler contribution to cryogenic losses at 2K is ~5%. = not critical. – Major contribution from coupler is 70K

• Conditioning time– Both designs are ok– The nominal conditioning time of < 50h is achieved/demonstrated.

• Multipacting– DESY and SLAC simulations, tests and operation show no problem with TTF3– STF2 will be simulated, tests show no problem

• One vs. two windows– Many single window coupler are successful under operation– The single window would need to seal-off the cavity before the cavity-string installation into the

cryomodule. – Single window coupler for ILC would need complete new development and test program of

coupler (and module)– But it could be a significant cost saving

• Compatibility– Cavity and attached parts (power coupler, tuner, HOM coupler, feedthroughs, He vessel, thermal

connections, magnetic shield…) are tuned/balanced, it is not easy to exchange only parts of this composition

– STF2 coupler design does not fit in the compatibility requirements of the TDR (40mm cavity coupler flange)

• Cost– CPI: STF2 price is 1.9 higher– Toshiba: STF2 slightly lower price– RI: about same price– Industrial study of STF2 for design optimization and cost reduction is recommended– The TTF3 coupler mass fabrication has to be investigated

Recommendation:• STF2 coupler has to demonstrate stable long time (>6 month) beam operation in a

CM (TTF3 coupler has a long history in FLASH)• The ILC management recommend an adapted STF2 design with 40mm cavity flange.

In this case more development steps have to follow in order to realize the compatible design. The new design has to be proven with beam operation.

• The concept of plug compatibility has to be further developed in view of a spare part concept. We recommend spare modules, not individual parts.

• An industrial study of mass production for both designs is recommended• Industrial study of STF2 for design optimization and cost reduction is recommended.

ATF2 Program Status

Glen White, SLACJanuary 2013


　 Detector measures signal Modulation Depth “M” 　

N +

N -

[rad]

[rad]


　 measurable range determined by fringe pitch　

　 depend on crossing angle θ (and λ ) 　

N: no. of Compton photonsConvolution between e- beam profile and fringe intensity

)2/sin(2

ykd

--

-

-

Md

kNNNN

y

yy

)cos(ln2

2

)(2exp)cos( 2

s

s

M

Focused Beam ： large M

Dilluted Beam ： small M

Small σy

Large σy

13/05/29 24

Crossing angle 　 θ

174° 30° 8° 2°

Fringe pitch 266 nm 1.03 μm 3.81 μm 15.2 μm

Lower limit 20 nm 80 nm 350 nm 1.2 μm

Upper limit 110 nm 400 nm 1.4 μm 6 μm

)2/sin(2

ykd

Md

y

)cos(ln2

2

s

Measures σy* = 20 nm 〜 few μm with < 10% resolution

Expected Performance

select appropriate mode according to beam focusing


σy and M for each θ mode

13/05/29 25

174 deg. 30 deg.

2 - 8 deg

Crossing angle continuously adjustable by prism 13/05/29

2013 IRFU Linear Collider Days26

Vertical table 1.7 (H) x 1.6 (V) m

• Interferometer• Phase control (piezo stage)

path for each θ mode 　（ auto-stages + mirror

actuators ）

beam pipe

Laser transported to IP

optical delay

half mirror

transverse ： laser wire scan 　　　　　　　

precise position alignment by remote control


Role of IPBSM in Beam Tuning 　　

13/05/2927

beforehand …. Construct & confirm laser paths, timing alignment

Longitudinal ： z scan 　

After all preparations ……….

continuously measure σy using fringe scans Feed back to multi-knob tuning

laser spot size σt,laser = 15 – 20 μm

12/20 : 　1st success in M detection

at 174 deg mode

Beam time status in 2012 　

stable measurements of M 〜 0.55

Feb ； 30 deg mode commissioned ( 1st M detection on 2/17)


　　 M = 0.52 ± 0.02 (stat) σy = 166.2 ± 6.7 (stat) [nm]

• 2 - 8 ° mode: clear contrast （ Mmeas ～ 0.9)• Prepared 174 deg mode commissioning

Suppress systematic errors Higher laser path stability / reliability

High M measured at 　 30 ° mode 　 Contribute with stable operation to

ATF2 beam focusing / tuning study 　　

(10 x bx*, 3 x by* optics)

　 Spring run

Major optics reform of 2012 summer

　 Winter runLast 2 days in Dec runMeasured many times 　 M = 0.15 – 0.25 　　（ correspond to σy 〜 70 – 82 nm ）　　

　Large step towards achieving ATF2 ‘s goal !!　 error studies ongoing aimed at deriving “true beamsize”　

　 preliminary

　 preliminary

* IPBSM systematic errors uncorrected** under low e beam intensity ( 〜 1E9 e / bunch)

　 10 x βx* , 1 x βy*

By IPBSM group@KEK

13/05/29 28

measured M over continuous reiteration of linear /nonlinear@ tuning knobs @ 174 ° mode 　

Beam time status in 2013 Spring 　


dedicated data for error studies under analysis

ex ）　 consecutive 10 fringe scans

　 preliminary

Time passed

measure M vs time after all conditions optimized

preliminary

Stable IPBSM performance major role in beam tuning

10 x bx*, 1 x by*

13/05/29

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　　 174 ° mode ”consistency scan”

moving towards goal of σy = 37 nm :higher IPBSM precision and stability & looser current limits of normal / skew sextupoles current

　　 M 〜 0.306 ± 0.043 (RMS) correspond to σy 〜 65 nmBest record

from Okugi-san’s Fri operation meeting slides

The Reality… May 2 week Cont. Run

• Summary of all scans during 2 week ops period– Summary plot courtesy of Edu.


Documents

ILC Accelerator Activities in North America (cooperation with France )