Beam DeliveryBeam Delivery

Toward the ILC:A Fermilab Community School on R&D

Challenges and OpportunitiesJuly 25-27, 2007, Fermilab, Batavia, IL

Toward the ILC:A Fermilab Community School on R&D

Challenges and OpportunitiesJuly 25-27, 2007, Fermilab, Batavia, IL

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BDS layout

• Single IR push-pull BDS, upgradeable to 1TeV CM in the same layout, with additional bends

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BDS beamline

14mr IR

FF

E-collimator

-collimator

Diagnostics

Tune-up dump

BSY

Sacrificial collimators

Extractiongrid: 100m*1m Main dump

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polarimeterskew correction /emittance diagnostic

MPScoll

betatroncollimation

fastsweepers

tuneupdump

septa

fastkickers

energycollimation

betamatch

energyspectrometer

finaltransformer

finaldoublet

IP

energyspectrometer

polarimeter

fastsweepers

primarydump

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BDS optics for incoming beam

FF

E-c

ollim

ator

-collim.Diagnostics

BSY

Pol

arim

eter

E-s

pect

rom

eter

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QFSM1moves~0.5 m

polarimeterchicane

septafastkickers

“Type B” (×4)

500GeV => 1TeV CM upgrade example for BSY

M. Woodley et al

Magnets and kickers are added in energy upgrade

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• Collimators: spoiler-absorber pairs

• In Final Doublet & IP phase• Spoilers can survive direct

hit of two bunches • Can collimate 0.1% of the

beam• Muons are produced

during collimation• Muon walls reduce muon

background in the detectors

Magnetized muon wall

2.25m

collimator

Collimators & muon walls

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Minimize wakefields: tapered Be ( with thin ~um Cu coating) and Copper in the middle.

Recently also considered Beryllium-free design:

To avoid damage by 1-2 bunches, beam size need to be large enough at spoilers.

Beam tests to study the threshold of damage

Field emission in e+ collimators – recent question

Collimators: wakefields & survivability

0.6 Xo of Ti alloy leading taper (gold), graphite (blue), 1 mm thick layer of Ti alloy

Beam damage experiment at FFTB, 30GeV, 3-20x109 e-, 1mm length, s~45-200um2. Test sample is Cu, 1.4mm thick. Damage observed for densities > 7x1014e-/cm2. Picture is for 6x1015e-/cm2

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FF with local chromatic correction

• Chromaticity is cancelled locally by two sextupoles interleaved with FD, a bend upstream generates dispersion across FD

• Geometric aberrations of the FD sextupoles are cancelled by two more sextupoles placed in phase with them and upstream of the bend

• If this scheme would be implemented as shown, there will be large second order dispersion left uncorrected. To cancel that:

• The -matching section produces as much X chromaticity as the FD, so the X sextupoles run twice stronger and cancel the second order dispersion and chromaticity simultaneously

• FF with local chromatic correction can be, for the same energy reach and L*, several times shorter than the traditionally designed FF

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IR coupling compensation

When detector solenoid overlaps QD0, coupling between y & x’ and y & E causes large (30 – 190 times) increase of IP size (green=detector solenoid OFF, red=ON)

Even though traditional use of skew quads could reduce the effect, the local compensation of the fringe field (with a little skew tuning) is the most efficient way to ensure correction over wide range of beam energies

without compensation y/ y(0)=32

with compensation by antisolenoid

y/ y(0)<1.01

QD0

antisolenoid

SD0

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Detector Integrated Dipole

• When beams cross solenoid field, vertical orbit arise• For e+e- the orbit is anti-symmetrical and beams still collide

head-on• If the vertical angle is undesirable (to preserve spin

orientation or the e-e- luminosity), it can be compensated locally with DID

• Alternatively, negative polarity of DID may be useful to reduce angular spread of beam-beam pairs (anti-DID)

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Use of DID or

anti-DID

Orbit in 5T SiD

SiD IP angle zeroed w.DID

DID field shape and scheme DID case

anti-DID case

The present assumption is to use anti-DID polarity in ILC

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Optics for outgoing beam

Extraction optics can handle the beam with ~60% energy spread, and provides energy and polarization diagnostics

100GeV

250GeV

“low P”

“nominal”

Beam spectra

Pol

arim

eter

E-s

pect

rom

eter

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Beam dump

• 17MW power (for 1TeV CM) • Rastering of the beam on 30cm double

window• 6.5m water vessel; ~1m/s flow• 10atm pressure to prevent boiling • Three loop water system

• Catalytic H2-O2 recombiner

• Filters for 7Be• Shielding 0.5m Fe & 1.5m concrete

Window prototypeDamage studyRemote replacement

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Shock wave generation in 18 MW water dumps

• Pressure wave in water vessel 22 µs after a 20°C rise in temperature over 10µs beam pulse• Similar to ILC beam dump parameters at shower maximum with rastered beam • Maximum pressure = 120 bar

Chris Densham, et al

The beam is deliberately off-center in the vessel; waves are generated primarily in radial direction; 1/r reduction; the ILC dump is by a factor of four more difficult that SLC dump in terms of Joules/g – all these factors are helping to make the issue of shock waves not a problem. However detailed studies are needed.

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old / newHOM coupler

Crab cavity design

FNAL 3.9GHz 9-cell cavity in Opega3p. K.Ko, et al

• Based on FNAL design of 3.9GHz CKM deflecting cavity• Initial design been optimized now to match ILC requirements on damping of parasitic modes, and to improve manufacturability• Design & prototypes been done by UK-FNAL-SLAC collaboration

3.9GHz cavity achieved 7.5 MV/m (FNAL)

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• LLRF phase and synchronization stability

• Required: ~67fsec or 0.094o for <2% luminosity loss (7 cell 1.5GHz cavity at JLab achieved 37fsec)

• Design features: digital phase detector, RF interferometer

• Simulations predict that specs can be met

Crab cavity LLRF

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detectorB

may be accessible during run

accessible during run Platform for electronic

and services. Shielded. Moves with detector. Isolate vibrations.

Concept of single IR with two detectors

The concept is evolving and details being worked out

detectorA

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Concept of detector systems connections

fixed connections

long flexible connections

detectordetector service platform or mounted on detector

high V AC

high P room T Hesupply & return

chilled water for electronics

low V DC forelectronics

4K LHe for solenoids

2K LHe for FD

high I DC forsolenoids

high I DC for FD

gas for TPCfiber data I/O

electronics I/O

low V PShigh I PSelectronic racks4K cryo-system2K cryo-systemgas system

sub-detectorssolenoidantisolenoidFD

move together

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IR integration

(old location)

Final doublet magnets are grouped into two cryostats, with warm space in between, to provide break point for push-pull

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• Interaction region uses compact self-shielding SC magnets• Independent adjustment of in- & out-going beamlines• Force-neutral anti-solenoid for local coupling correction

Shield ONShield ON Shield OFFShield OFFIntensity of color represents value of magnetic field.

to be prototypedduring EDR

new force neutral antisolenoid

Actively shielded QD0

BNL

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cancellation of the external field with a shield coil has been successfully demonstrated at BNL

BNL prototype of self shielded quad

prototype of sextupole-octupole magnet

Coil integrated quench heater

IR magnets prototypes

at BNL

winding process

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• Detailed engineering design of IR magnets and their integration has started

Service cryostat & cryo connections

BNL

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IRENG07 Workshop

http://www-conf.slac.stanford.edu/ireng07/

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Present concept of cryo connection

• B.Parker, et al• Result of deliberations of IRENG07 preparatory meetings of WGs

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photos courtesy CERN colleagues

Detector assembly

• CMS detector assembled on surface in parallel with underground work, lowered down with rented crane

• Adopted this method for ILC, to save 2-2.5 years that allows to fit into 7 years of construction

28250mSv/h

Shielding the IR hall

Self-shielding of GLD Shielding the “4th“ with walls

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Pacman design

John Amann

Pac Man Open

Pac Man Closed

Beam Line Support Here

CMS shield opened

Considered tentative versions

SLD pacman open

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Moving the detector

Air-pads at CMS – move 2000k pieces

5000 ton Hilman roller module

Is detector (compatible with on-surface assembly) rigid enough itself to avoid distortions during move?

Concept of the platform to move ILC detector, A.Herve, H.Gerwig, at al

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IR alternatives, 0mrad

• FD: NbTi @ 500GeV CM (250T/m, 7T/bore); Nb3Sn @ 1TeV CM (~370T/m, 10.5T/bore)

• Separator: =12mm at 55m from IP (to control parasitic crossing beam-beam instability) => 2.6MV/m (±130kV over 100mm gap) & *2 at 1TeV CM), split gap, overlapped with dipole field; low spark rate is essential

• Challenges: intermediate ~1MW dump, possible back shine to detector; design of downstream diagnostics

Overlapping bends

separator

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IR alternatives, 2mrad

• Focus of latest optics work: trying to design minimal system, shortest, most economical, without downstream diagnostics (added later if new ideas found)

• FD reoptimized with new ILC parameters: SC QD0/SD0 &warm QF1/SF1• FD is NbTi at 500GeV CM (225T/m, 6.3T/bore) and Nb3Sn at 1 TeV CM

(350T/m, 8.8T/bore)• Beamline downstream of FD to be designed & studied. Study feasibility

of downstream diagnostics, study beam & SR losses and evaluate backscattered background

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ATF2

Test facilities: ESA & ATF2

ESA: machine-detector tests; energy spectrometer; collimator wake-fields, etc.ATF2: prototype FF, develop tuning, diagnostics, etc.

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BDS beam tests at ESA

Runs: three 2-weeks runs in 2006 & 07;request two runs in 2008

Latest run: March 7-26, 2007~ 40 participants

BPM energy spectrometer (T-474/491)Synch Stripe energy spectrometer (T-475)Collimator design, wakefields (T-480)IP BPMs/kickers—background studies (T-488)EMI (electro-magnetic interference)Bunch length diagnostics (T-487)

more in talk of E.Torrence

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Collimator Wakefield study at ESA

• Spoilers of different shape investigated at ESA (N.Watson et al)

• Theory, 3d modeling and measurements are so far within a factor of ~2 agreement

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ATF and ATF2

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Final Focus Test Beam

Achieved ~70nm vertical beam size

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ATF2 goals(A) Small beam size

Obtain y ~ 35nmMaintain for long time

(B) Stabilization of beam center Down to < 2nm by nano-BPM Bunch-to-bunch feedback of ILC-like

train

ATF2 – model of ILC BDS

Scaled down model of ILC final focus (local chromatic correction)

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ATF collaboration & ATF2 facility• ATF2 will prototype FF,• help development tuning

methods, instrumentation (laser wires, fast feedback, submicron resolution BPMs),

• help to learn achieving small size & stability reliably,

• potentially able to test stability of FD magnetic center.

• ATF2 is one of central elements of BDS EDR work, as it will address a large fraction of BDS technical cost risk.

• Constructed as ILC model, with in-kind contribution from partners and host country providing civil construction

• ATF2 commissioning will start in Autumn of 2008

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ATF2 schedule

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Advanced beam instrumentation at ATF2

• BSM to confirm 35nm beam size• nano-BPM at IP to see the nm stability• Laser-wire to tune the beam• Cavity BPMs to measure the orbit• Movers, active stabilization, alignment system• Intratrain feedback, Kickers to produce ILC-like

train

IP Beam-size monitor (BSM)(Tokyo U./KEK, SLAC, UK)

Laser-wire beam-size Monitor (UK group)

Cavity BPMs, for use with Q magnets with 100nm resolution (PAL, SLAC, KEK)

Cavity BPMs with 2nm resolution, for use at the IP (KEK)

Laser wire at ATF

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BPM at ATF & ATF2

Sean Walston (LLNL), et al

Nano-BPM work: use cavity BPMs of BINP and KEK design, put them in triplet in metrology frame, and find resolution. So far achieved ~15nm resolution

ATF2 will use primarily the cavity BPMs (> 30).

ATF2 will be (one of the) first large accelerator system that rely entirely on cavity BPMs.

Issues of reliable signal processing, first pulse calibration, are crucial Y.Honda (KEK), et al

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J.Nelson (at SLAC) and T.Smith (at KEK) during recent "remote participation" shift. Top monitors show ATF control system data. The shift focused on BBA, performed with new BPM electronics installed at ATF by Fermilab colleagues.

ATF & ATF2

T.Smith is commissioning the cavity BPM electronics and the magnet mover system at ATF beamlineImprovement of soft & hardware for remote

participation

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High Availability PS for ATF2

KEK colleagues at SLAC for PS review

Stimulated failure and recovery in the redundant module configuration

ILC-like High Availability (HA) power supplies developed for ATF2. HA is provided by redundancy (“four out of five” configuration).

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FD magnets & IR integration

• The FD stability requirements are in the 100-200nm range– luminosity reduction is 1-2%, 5%, 15-20% for rms FD vibration of

100nm, 200nm and 500nm, correspondingly (with fast IP feedback)

• Very rough estimation, comparing with existing cryo magnets of completely different design which show 0.3-1micron level vibration, tell that the needed improvement is about a factor of three to five

BNL developing optical methods to measure vibration of cold mass. Recently started to develop methods to measure nm level motion of magnetic center of quads with use of stabilized long coils.

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Final doublet for ATF2 (SC at 2nd stage?)

• The final doublet for the ATF is built with conventional quadrupoles and sextupoles, placed on movers. The FD is placed on a table with specially developed support.

• Stability of the FD built with ILC-like technology could be tested at ATF2 at the second stage, once the primary goals are reached

Mover

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FD designed with the same approach as for ILC: QD0 and QF1 with skew and dipole correctors and combined sextupole-octupole packages with skew sextupoles. The coils would be wound on a single tube with 30mm radius of the aperture, and placed in a common cryostat. For ATF2, either the super-fluid He or normal He can be used. To match the design to low energy of ATF2, the coils would be wound with single wire (not with 7 strand cable), which would also decrease the needed current, make current leads easier, and would also allow to have six layers and allow to measure and correct the field harmonics during manufacturing.

SC FD for

ATF2, tentative

Brett Parker, BNL

Nov.2005 version

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BDS Movers

• Need 5dof, 50nm step movers. • FFTB movers achieved ~300nm step• Being developed by D.Warner, Colorado State University

• Also need mover for FD (move QD0 cryostat as a whole) – that should be compact (fit in small space between FD and detector), radiation resistant, with small sub um step, and should not amplify vibration

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HTS quads for extraction line

• Ramesh Gupta (BNL) made a fist look on the use of HTS quads for ILC extraction system

• Based on HTS R&D quad built for RIA• HTS quads allow large loss on the coils and may in

a long run prove economical

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Stability

PMD/eentecliquid sensor

2hrs puzzle disappeared

Effect of water well pump on ground motion at MI8 (BINP-FNAL study)

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Instrumentation and other needs

• Alignment system• Deflecting y-t cavity• OTR monitors• PMT & ion chamber loss monitors• Polarimeters *• X synch light profile monitor • BDS BPMs * • BPM based energy spectrometer * • Feedbacks *• SR based energy spectrometer *• Interferometer to measure FD position *• * means that some groups are working on that

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…Instrumentation and other needs

• Crystal collimation* and halo monitor• MPS system including checking status of fields before next

train• Seismic sensor that works near-FD (magnetic field, radiation,

tight space), such as PMD liquid sensor• Stable supports with movers• Active vibration decoupling of vibration coming via cryo lines

or water cooling pipes, reduction of turbulence produced vibration

• Beam size monitor ideas (such as Y.Honda’s nano-pattern BSM)

• Near IR vacuum system including reliable valves with RF shield

• Real time monitoring of doses (e.g. of beam dump window)• …

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Thanks to

J.Amann, R.Arnold, F.Asiri, K.Bane, P.Bellomo, E.Doyle, A.Fasso, K.Jonghoon, L.Keller,K.Ko, Z.Li, T.Markiewicz, T.Maruyama, K.Moffeit, S.Molloy, Y.Nosochkov, N.Phinney,

T.Raubenheimer, S.Seletskiy, S.Smith, C.Spencer, P.Tenenbaum, D.Walz, G.White, M.Woodley,M.Woods, L.Xiao (SLAC),M.Anerella, A.Jain, A.Marone, B.Parker (BNL),O.Delferriere, O.Napoly,

J.Payet, D.Uriot (CEA), N.Watson (Birmingham Univ.), I.Agapov, J-L.Baldy, D.Schulte (CERN),G.Burt, A.Dexter (Lancaster Univ.), K.Buesser, W.Lohmann (DESY), L.Bellantoni, A.Drozhdin,V.Kashikhin, V.Kuchler, T.Lackowski, N.Mokhov, N.Nakao, T.Peterson, M.Ross, S.Striganov,

J.Tompkins, M.Wendt, X.Yang (FNAL), A.Enomoto, S.Kuroda, T.Okugi, T.Sanami, Y.Suetsugu,T.Tauchi (KEK), M.del Carmen Alabau, P.Bambade, J.Brossard, O.Dadoun (LAL), P.Burrows,G.Christian, C.Clarke, B.Constance, H.Dabiri Khah, A.Hartin, C.Perry, C.Swinson (Oxford),A.Ferrari (Uppsala Univ.), G.Blair, S.Boogert, J.Carter (RHUL), D. Angal-Kalinin, C.Beard,

C.Densham, L.Fernandez-Hernando, J.Greenhalgh, P.Goudket, F.Jackson, J.Jones, A.Kalinin, L. Ma,P. McIntosh (STFC), H.Yamamoto (Tohoku Univ.), T.Mattison (UBC, Vancouver), J.Carwardine,

C.Saunders (ANL), R.Appleby (Manchester Univ.), E.Torrence (Univ. Oregon), J.Gronberg (LLNL),T.Sanuki (Univ. Tokyo), Y.Iwashita (Kyoto Univ.), V.Telnov (BINP), D.Warner (Univ. Colorado)

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END