Recent work on 750 - x 750 GeV Recent work on 750 - x 750 GeV ColliderCollider

C. Johnstone and P. SnopokC. Johnstone and P. SnopokFermilab and UC RiversideFermilab and UC Riverside

M. BerzM. BerzMSUMSU

MCD WorkshopMCD WorkshopBNLBNL

Dec 3-7, 2007Dec 3-7, 2007

Current Design OverviewCurrent Design Overview

750 GeV750 GeV Arc: FMC module ~5.3T dipole fields: Arc: FMC module ~5.3T dipole fields:

Fits ~circumference, surrounds present Tevatron tunnelFits ~circumference, surrounds present Tevatron tunnel Direct piping of existing electrical, water, cryo servicesDirect piping of existing electrical, water, cryo services

Negative momentum compactionNegative momentum compaction Can be isochronous up to 3Can be isochronous up to 3rdrd order in order in

Peak beta functions are half of equivalent FODO cell Peak beta functions are half of equivalent FODO cell 40% smaller beam size in arcs40% smaller beam size in arcs

Lower fields allow potential for increased collider energyLower fields allow potential for increased collider energy Potentially up to 1 x 1 TeVPotentially up to 1 x 1 TeV

IR straight design: currently IR straight design: currently *=1cm*=1cm IR quads ~10TIR quads ~10T 6m IP to first quad spacing for detector6m IP to first quad spacing for detector Non-zero dispersion derivative at IP (D=0 @IP)Non-zero dispersion derivative at IP (D=0 @IP)

Allows immediate linear chromatic correctionAllows immediate linear chromatic correction

Magnetic components:Magnetic components: Magnets, in particular SC arc magnets, will resemble design Magnets, in particular SC arc magnets, will resemble design

in feasibility I study – see figures belowin feasibility I study – see figures below

Dipole (left) and cryostat design (right) for arcs of SR racetrack: Feasibility I Study

Site ConsiderationsSite Considerations

DepthDepth Water tablesWater tables Geological constraints for tunnel constructionGeological constraints for tunnel construction Civil engineering for tunnels “hundreds of meters” deepCivil engineering for tunnels “hundreds of meters” deep

Example: Fermilab Site-specific Example: Fermilab Site-specific

constraints: constraints: from Feas. I Study for a U.S. Neutrino Factoryfrom Feas. I Study for a U.S. Neutrino Factory

50 GeV Fermilab Storage 50 GeV Fermilab Storage Ring: racetrackRing: racetrack 1313 declination angle declination angle circumference, C = 1753 mcircumference, C = 1753 m 39% ratio (1 prod str./C)39% ratio (1 prod str./C)

Design predicated on ~6T SC Design predicated on ~6T SC

arc dipolesarc dipoles

600 Feet Ring Vertical Drop

10 Feet Tunnel ceiling to floor

10 Feet Shielding above ring

50 Feet Undisturbed bottom layer of Galena Platteville

10 Feet For uncertainties in the above three numbers

680 Feet Total from Surface to Bottom of Galena Platteville

Example: BNL site specific constraints:Example: BNL site specific constraints:from from Feas. II study for a U.S. Neutrino FactoryFeas. II study for a U.S. Neutrino Factory

20 GeV BNL Storage Ring: 20 GeV BNL Storage Ring: racetrackracetrack 1010 declination angle declination angle C = 358 mC = 358 m 35% ratio35% ratio

Design predicated on ~7T SC Design predicated on ~7T SC arc dipoles- (hence the short arc dipoles- (hence the short circumference achieved at 20 circumference achieved at 20 GeV)GeV)

General limitationsGeneral limitations

Site depth and civil engineering:Site depth and civil engineering:

Fermilab and BNL have depth constraints, for example; the Fermilab and BNL have depth constraints, for example; the larger of the two, restricted to <200m down.larger of the two, restricted to <200m down. Municipal water supply + substrate will not support tunnel.Municipal water supply + substrate will not support tunnel.

The NUMI project at Fermilab entailed considerable civil The NUMI project at Fermilab entailed considerable civil engineering for an ~1 km long tunnel only 100 m deep – (won engineering for an ~1 km long tunnel only 100 m deep – (won the 2005 civil engineering award)the 2005 civil engineering award)

Maintenance, water leaks are a problem even with the NUMI Maintenance, water leaks are a problem even with the NUMI depth (muons are much nicer, however, from an activation depth (muons are much nicer, however, from an activation standpoint)standpoint)

Ring Structures: IR + High – order correction Ring Structures: IR + High – order correction insertioninsertion

Ring Structures: FMC Arc moduleRing Structures: FMC Arc module

Ring Structures: General InformationRing Structures: General Information

IR: final focus + aberration correction section:IR: final focus + aberration correction section: Relatively compact: ~425 mRelatively compact: ~425 m Peak Beta function ~43 kmPeak Beta function ~43 km Linear chromaticity ~-500 to -700Linear chromaticity ~-500 to -700

ArcsArcs Flexible Momentum compaction, ~70 m longFlexible Momentum compaction, ~70 m long Momentum compaction corrected up to 3Momentum compaction corrected up to 3rdrd order order Peak beta function, ~110 mPeak beta function, ~110 m

Scraping and utility sectionScraping and utility section Presently a simple representative R matrixPresently a simple representative R matrix

RingRing ~ 1 km radius for 750 x 750 GeV~ 1 km radius for 750 x 750 GeV 2-fold symmetric2-fold symmetric 64 arc modules64 arc modules

Preliminary results with present lattice:Preliminary results with present lattice:

DA – rough MAD optimization: sextupoles onlyDA – rough MAD optimization: sextupoles only Chromatic and tune-shift sextupole familiesno Chromatic and tune-shift sextupole familiesno Envelope ~50Envelope ~50 Resonance correctionResonance correction very crude tune optimizationvery crude tune optimization

Momentum acceptance:Momentum acceptance: Linear chromaticity correction onlyLinear chromaticity correction only +/- 0.05% dp/p+/- 0.05% dp/p Oide-like lattice (beta functions are huge ~10Oide-like lattice (beta functions are huge ~1066 m m

and chromaticity is all in one plane) have much and chromaticity is all in one plane) have much larger momentum acceptanceslarger momentum acceptances

Present and Future WorkPresent and Future Work Implementation in COSY for high-order studies and correctionImplementation in COSY for high-order studies and correction

Kinematical corrections are important!Kinematical corrections are important! Cannot be done in MADCannot be done in MAD Field-map codes such as ZGOUBI have limited optimization toolsField-map codes such as ZGOUBI have limited optimization tools

Tune optimiztionTune optimiztion Tune sweep is automatically performed in COSY using a simple R Tune sweep is automatically performed in COSY using a simple R

matrix to jump fractional tune (preserves match to all optical functions)matrix to jump fractional tune (preserves match to all optical functions) High-order correctionHigh-order correction

Ocutpole families: DA was doubled using COSY to fit DA in 50 x 50 GeV Ocutpole families: DA was doubled using COSY to fit DA in 50 x 50 GeV collidercollider

Decapole – duo-decapoleDecapole – duo-decapole High-order chromatic correctionHigh-order chromatic correction

22ndnd order chromatic correction appears essential order chromatic correction appears essential

Final momentum compaction adjustmentFinal momentum compaction adjustment This is easy in FMC module – beta functions essentially do not This is easy in FMC module – beta functions essentially do not

change, dispersion change is small so re-matching is not a problem.change, dispersion change is small so re-matching is not a problem.

Tracking with fringe fields – will be bad newsTracking with fringe fields – will be bad news

Example: DA optimization in COSY Example: DA optimization in COSY using octupole families for 50 x 50 using octupole families for 50 x 50 GeV colliderGeV collider

Before:

After:

(x-x’): (y-y’):