us-larp progress on ir upgrades

US-LARP Progress US-LARP Progress on on

IR UpgradesIR Upgrades

Tanaji SenTanaji Sen

FNALFNAL

Tanaji SenTanaji Sen US-LARP: IR UpgradesUS-LARP: IR Upgrades 22

TopicsTopics

IR optics designsIR optics designs

Energy deposition calculationsEnergy deposition calculations

Magnet designsMagnet designs

Beam-beam experiment at RHICBeam-beam experiment at RHIC

Strong-strong beam-beam simulationsStrong-strong beam-beam simulations

Future plansFuture plans


US-LARP effort on IR designsUS-LARP effort on IR designs

Main motivation is to provide guidance for Main motivation is to provide guidance for magnet designersmagnet designersExample: aperture and gradient are no longer Example: aperture and gradient are no longer determined by beam optics alone. Energy determined by beam optics alone. Energy deposition in the IR magnets is a key component deposition in the IR magnets is a key component in determining these parametersin determining these parametersUse as an example for field quality requirementsUse as an example for field quality requirementsExamine alternative scenarios Examine alternative scenarios Not intended to propose optimized optics Not intended to propose optimized optics designsdesigns


IR designsIR designs

Quadrupoles first – extension of baselineQuadrupoles first – extension of baseline

Dipoles first – triplet focusingDipoles first – triplet focusing

Dipoles first – doublet focusingDipoles first – doublet focusing


Triplet first opticsTriplet first optics

J. Johnstone β* = 0.25Nominal β* = 0.5

Lattice Vers. 6.2


Gradients, beta max – quads first opticsGradients, beta max – quads first opticsQuadQuad B’[T/m]B’[T/m]

LeftLeft

B’[T/m]B’[T/m]

RightRight

ββmaxmax[m][m]

LeftLeft ββmaxmax[m][m]

RightRightQ1Q1

Q2Q2

Q3Q3

Q4Q4

Q5Q5

Q6Q6

Q7Q7

Q8Q8

Q9Q9

Q10Q10

QT11QT11

QT12QT12

QT13QT13

-200-200

200200

-200-200

8282

-67-67

5959

-199-199

150150

-164-164

184184

5757

-43-43

-40-40

-Q1.L-Q1.L

-Q2.L-Q2.L

-Q3.L-Q3.L

-Q4.L-Q4.L

-Q5.L-Q5.L

-58-58

199199

-155-155

166166

-193-193

-56-56

-55-55

-QT13.L-QT13.L

45374537

91899189

93339333

94409440

33223322

15591559

984984

285285

241241

291291

141141

170170

176176

45454545

92059205

93509350

94249424

33273327

15611561

986986

285285

261261

270270

154154

179179

174174


Dipole first optics Dipole first optics

Earlier layoutEarlier layout

(PAC 03)(PAC 03)

Present layoutPresent layout

D1 dipoleD1 dipole

TAN absorberTAN absorber

ββ* *

ββmaxmax

10m long10m long

After D1After D1

0.26 m0.26 m

23 km23 km

D1a 1.5m long, D1a 1.5m long, D1b 8.5m longD1b 8.5m long

TAS2, after D1aTAS2, after D1a

TAN after D1bTAN after D1b

0.25 m0.25 m

27 km27 km

Additional TAS absorber in the present layout – per N. Mokhov

IPD1a TAS2 D1b TAN


Dipoles First - MatchingDipoles First - MatchingBeams in separate focusing channels Beams in separate focusing channels Matching done from QT13(left) to QT13(right)Matching done from QT13(left) to QT13(right) Lattice Version 6.2Lattice Version 6.2Triplet quads Q1 – Q3 at fixed gradient = 200 Triplet quads Q1 – Q3 at fixed gradient = 200 T/m, exactly anti-symmetricT/m, exactly anti-symmetricPositions and lengths of magnets Q4-QT13 kept Positions and lengths of magnets Q4-QT13 kept the same the same Strengths of quads Q4 to Q9 < 200 T/mStrengths of quads Q4 to Q9 < 200 T/m

Q10 on the left has 230 T/m. Could be changedQ10 on the left has 230 T/m. Could be changed if positions and lengths of Q4-Q7 are changed.if positions and lengths of Q4-Q7 are changed.

Trim quad strengths QT11 to QT13 < 160T/mTrim quad strengths QT11 to QT13 < 160T/m


Dipole first – collision optics, tripletsDipole first – collision optics, triplets

TAS1 absorber (1.8m) before D1a Dipole D1a starts 23 m from IP TAS2 absorber (1.5m) after D1a 0.5m space between D1a-TAS2 and TAS2-D1b L(D1b) = 8.5m D1, D2 – each 10m long, ~14T 5m long space after D2 for a TAN absorber Q1 starts 55.5 m from the IP L(Q1) = L(Q3) = 4.99 m, L(Q2a) = L(Q2b) = 4.61m

Collision optics β*= 0.25m


Gradients, beta max – dipoles first, tripletsGradients, beta max – dipoles first, tripletsQuadQuad B’[T/m]B’[T/m]

LeftLeft

B’[T/m]B’[T/m]

RightRight

ββmaxmax[m][m]

LeftLeft

ββmaxmax[m][m]

RightRight

Coil apertureCoil aperture

2(1.1*9*2(1.1*9*σσ+8.6++8.6+4.5+3) mm4.5+3) mm

Q1Q1

Q2Q2

Q3Q3

Q4Q4

Q5Q5

Q6Q6

Q7Q7

Q8Q8

Q9Q9

Q10Q10

QT11QT11

QT12QT12

QT13QT13

-200-200

200200

-200-200

7878

-104-104

8080

-146-146

107107

-92-92

230230

170170

161161

-158-158

-Q1.L-Q1.L

-Q2.L-Q2.L

-Q3.L-Q3.L

-112-112

137137

-38-38

172172

-196-196

3131

-120-120

4141

-156-156

-160-160

1847818478

2693626936

2713527135

81838183

34413441

28582858

21852185

953953

14181418

210210

192192

185185

176176

1861918619

2714327143

2692626926

82538253

38453845

932932

30893089

460460

164164

206206

210210

167167

174174

9393

106106

106106

7373

6060

5656

5757

4646

4949


Dipoles first and doublet focusingDipoles first and doublet focusing

IP D1

D2

D2

Q1

Q2

Features

• Requires beams to be in separate focusing channels

• Fewer magnets

• Beams are not round at the IP

• Polarity of Q1 determined by crossing plane – larger beam size in the crossing plane to increase overlap

• Opposite polarity focusing at other IR to equalize beam-beam tune shifts

• Significant changes to outer triplet magnets in matching section.

Focusing symmetric about IP


Doublet Optics – Beta functionsDoublet Optics – Beta functions

J. Johnstone


Gradients, beta max – dipoles first, doubletsGradients, beta max – dipoles first, doubletsQuadQuad B’[T/m]B’[T/m]

LeftLeft

B’[T/m]B’[T/m]

RightRight

ββmaxmax[m][m]

LeftLeft

ββmaxmax[m][m]

RightRight

Coil apertureCoil aperture

2(1.1*9*2(1.1*9*σσ+8.6++8.6+4.5+3) mm4.5+3) mm

Q1Q1

Q2Q2

Q3Q3

Q4Q4

Q5Q5

Q6Q6

Q7Q7

Q8Q8

Q9Q9

Q10Q10

QT11QT11

QT12QT12

QT13QT13

-200-200

200200

4646

-50-50

00

-155-155

-31-31

147147

-204-204

186186

-98-98

-27-27

9292

Q1.LQ1.L

Q2.LQ2.L

Q3.LQ3.L

-Q4.L-Q4.L

-Q5.L-Q5.L

-Q6.L-Q6.L

-Q7.L-Q7.L

-147-147

205205

-198-198

7878

-44-44

-108-108

2444624446

2444624446

44624462

39083908

15491549

13541354

443443

388388

267267

199199

185185

168168

176176

2444624446

2444624446

44624462

39093909

15471547

13671367

512512

356356

257257

209209

190190

170170

173173

102102

102102

6262

6060

5050

4949

4242

4141


Features of this doublet opticsFeatures of this doublet opticsSymmetric about IP from Q1 to Q3, anti-symmetric from Symmetric about IP from Q1 to Q3, anti-symmetric from Q4 onwardsQ4 onwardsQ1, Q2 are identical quads, Q1T is a trim quad (125 Q1, Q2 are identical quads, Q1T is a trim quad (125 T/m). L(Q1) = L(Q2) = 6.6 mT/m). L(Q1) = L(Q2) = 6.6 m Q3 to Q6 are at positions different from baseline opticsQ3 to Q6 are at positions different from baseline opticsAll gradients under 205 T/mAll gradients under 205 T/mPhase advance preserved from injection to collisionPhase advance preserved from injection to collisionAt collision, At collision, ββ**xx= 0.462m, = 0.462m, ββ**yy = 0.135m, = 0.135m, ββ**effeff= 0.25m= 0.25mSame separation in units of beam size with a smaller Same separation in units of beam size with a smaller crossing angle crossing angle ΦΦEE = √( = √(ββ**RR/ / ββ**EE) ) ΦΦR R = 0.74 = 0.74 ΦΦR R

Luminosity gain compared to round beamLuminosity gain compared to round beam

Including the hourglass factor,


Chromaticity comparisonChromaticity comparison

ββ* = 0.25m* = 0.25m

CompleteComplete

Q’Q’xx

InsertionInsertion

Q’Q’yy

InnerInner

Q’Q’xx

MagnetsMagnets

Q’Q’yy

Quads firstQuads first

Dipoles first – Dipoles first – tripletstriplets

Dipoles firstDipoles first

- doublets- doublets

-48-48

-99-99

-105-105

-48-48

-96-96

-121-121

-44-44

-82-82

-103-103

-44-44

-82-82

-112-112

Including IR1 and IR5Chromaticity of dipoles first with triplets is 99 units larger per plane than quads firstChromaticity of dipoles first with doublets is 31 units larger per plane than dipoles first with triplets


Chromaticity contributionsChromaticity contributions

Inner triplet and inner doublet dominate the chromaticity Anti-symmetric optics: upstream and downstream quads have opposite chromaticities Symmetric optics: upstream and downstream quads have the same sign of chromaticities


Energy DepositionEnergy Deposition


Energy Deposition IssuesEnergy Deposition Issues

Quench stability: Peak power densityQuench stability: Peak power density

Dynamic heat loads: Power dissipation and Dynamic heat loads: Power dissipation and cryogenic implicationscryogenic implications

Residual dose rates: hands on maintenanceResidual dose rates: hands on maintenance

Components lifetime: peak radiation dose and Components lifetime: peak radiation dose and lifetime limits for various materialslifetime limits for various materials


Energy Deposition in Quads FirstEnergy Deposition in Quads FirstEnergy deposition and radiation are Energy deposition and radiation are majormajor issues for new IRs. issues for new IRs.

In quad-first IR, Edep increases with L and decreases with quad aperture.In quad-first IR, Edep increases with L and decreases with quad aperture.

– Emax > 4 mW/g, (P/L)max > 120 W/m, Ptriplet >1.6 kW Emax > 4 mW/g, (P/L)max > 120 W/m, Ptriplet >1.6 kW at L = 10at L = 103535 cm cm-2-2 s s-1-1..

– Radiation lifetime for G11CR < 6 months at hottest spots. More radiation hard material required.Radiation lifetime for G11CR < 6 months at hottest spots. More radiation hard material required.

A. Zlobin et al, EPAC 2002N, Mokhov


Energy deposition in dipolesEnergy deposition in dipolesProblem is even more severe for dipole-first IR.

Cosine theta dipoleOn-axis field sprays particleshorizontally power deposition is concentrated in the mid-plane

L = 1035 cm-2 s-1

Emax on mid-plane (Cu spacers) ~ 50 mW/g; Emax in coils ~ 13 mW/gQuench limit ~ 1.6 mW/gPower deposited ~3.5 kW

Power deposition at the non-IP end of D1N. Mokhov et al, PAC 2003


Open mid-plane dipoleOpen mid-plane dipole

Open mid-plane => showers originate outside the coils; peak power density in coils is reasonable.Tungsten rods at LN temperature absorb significant radiation.

Magnet design challenges addressed• Good field quality• Minimizing peak field in coils• Dealing with large Lorentz forces w/o a structure between coils• Minimizing heat deposition• Designing a support structure

R. Gupta et al, PAC 2005


Energy deposition in open mid-plane dipoleEnergy deposition in open mid-plane dipoleTAS TAS2 TAN

Optimized dipole with TAS2IP end of D1 is well protected by TAS.Non-IP end of D1 needs protection. Magnetized TAS is not useful. Estimated field 20 T-mInstead split D1 into D1A and D1B. Spray from D1A is absorbed by additional absorber TAS2Results (N. Mokhov) Peak power density in SC coils ~0.4mW/g, well below the quench limit Dynamic heat load to D1 is drastically reduced. Estimated lifetime based on displacements per atom is ~10 years


MagnetsMagnets

Tanaji Sen US-LARP: IR Upgrades 24

Gradient vs Bore size

Nb3Sn at 1.8K

Nb3Sn at 4.35K

NbTi at 1.8K

NbTi at 4.35K

CurrentLHC

mm


Magnet Program GoalsMagnet Program GoalsProvide options for future upgrades of the LHC Interaction RegionsProvide options for future upgrades of the LHC Interaction Regions

Demonstrate by 2009Demonstrate by 2009 that Nb3Sn magnets are a viable choice for an LHC that Nb3Sn magnets are a viable choice for an LHC IR upgrade (Developed in consultation with CERN and LAPAC)IR upgrade (Developed in consultation with CERN and LAPAC)

Focus on major issues: consistency, bore/gradient (field) and lengthFocus on major issues: consistency, bore/gradient (field) and length

1.

Supporting R&D o Sub-scale dipoles & quads with L=0.3 m, Bcoil = 11-12 T issues relevant to the whole program (end-preload, training, quench protection, alignment of support structures) o Long coil fabrication and tests with L=4 m, Bcoil = 11-12 To Radiation hard insulation

1. Capability to deliver predictable, reproducible performance: TQ (Technology Quads): D = 90 mm, L = 1 m, Gnom > 200 T/m2. Capability to scale-up the magnet length: LQ (Long Quads) : D = 90 mm, L = 4 m, Gnom > 200 T/m 3. Capability to reach high gradients in large apertures: HQ (High Gradient Quads): D = 90 mm, L = 1 m, Gnom > 250 T/m


Short Quad Models: FY08-FY09

Goal: increase Quad gradient using 3-layer and/or 4-layer coils

Engineering design starts in FY06 and fabrication in FY07

3-layer: G=260-290 T/m 4-layer: G=280-310 T/m


Magnet R&D challengesMagnet R&D challengesAll designs put a premium on achieving very high field:

Maximizes quadrupole aperture for a given gradient.Separates the beams quickly in the dipole first IR => bring quads as close as possible to the IP.Push Bop from 8 T -> 13~15 T in dipoles or at pole of quad => Nb3Sn.

All designs put a premium on large apertures:Decreasing * increases max => quad aperture up to 110 mm?Large beam offset at non-IP end of first dipole.=> Dipole horizontal aperture >130 mm.

Energy deposition: quench stability, cooling, radiation hard materials. Nb3Sn is favored for maximum field and temperature margin, but considerable R&D is required to master this technology.


Beam-beam phenomenaBeam-beam phenomena


RHIC Beam-beam experimentRHIC Beam-beam experiment

Beam Conditions 1 bunch of protons in each ring Injection Energy 24,3 GeV Bunch intensities ~ 2 x 1011

1 parasitic interaction per bunch Bunches separated by ~10σ at opposite parasitic

Question: Do parasitic interactions in RHIC have an impact on the beam ?

Experiment – April 2005 Change the vertical separation between the beams at 1 parasitic interaction Observe beam losses, lifetimes, tunes vs separation


RHIC beam-beam experimentRHIC beam-beam experiment

Observations !st set of studies: tunes of blue and yellow beam were asymmetric about diagonal Blue beam losses increased as separation decreased. No influence on yellow beam.

Next set of studies: tunes symmetric about diagonal Onset of significant losses in both beams for separations below 7σ

There is something to compensate Phenomena is tune dependent Remote participation at FNAL

W. Fischer et al (BNL)

Orbit data – time stamp corresponds to time of measurement, Not to time of orbitchangeShift orbit data to the right


RHIC – Wire compensatorRHIC – Wire compensator

Possible location of wire

Parasitic interaction

Phase advance from parasitic to wire = 6o

IP6

RHIC provides unique environmentto study experimentally long-range beam-beam effects akin to LHC

Proposal: Install wire compensatorIn summer of 2006, downstream of Q3 in IR6

Proposed TaskDesign and construct a wire compensatorInstall wire compensator on movable stand in a ringFirst study with 1 proton bunch in each ring with 1 parasitic at flat top. Compensate losses for each separation with wireTest robustness of compensation w.r.t current ripple, non-round beams, alignment errors, …

New LARP Task for FY06


Strong-strong beam-beam simulationsStrong-strong beam-beam simulations

Strong-strong simulations done with Strong-strong simulations done with PIC style code Beambeam3D (LBNL)PIC style code Beambeam3D (LBNL)Emphasis on emittance growth due to Emphasis on emittance growth due to head-on interactions under different head-on interactions under different situationssituationsBeam offset at IP Beam offset at IP Mismatched emittances and Mismatched emittances and intensitiesintensities

Numerical noise is an issue – growth Numerical noise is an issue – growth rate depends on number of macro-rate depends on number of macro-particles M. Continuing studies to particles M. Continuing studies to extract asymptotic (in M) growth extract asymptotic (in M) growth rates. rates. Continuing additions to code: Continuing additions to code: crossing angles, long-range crossing angles, long-range interactionsinteractions

Nominal case

Beams offset by 0.15 sigma

Emittance growth 50% larger

J. Qiang, LBL


IR and Beam-beam tasks – FY06-07IR and Beam-beam tasks – FY06-07

IR designIR design

Quad first – lowest feasible Quad first – lowest feasible * consistent with gradients and * consistent with gradients and apertures, field qualityapertures, field quality

Dipoles first – Triplet: Dipoles first – Triplet: *, apertures, gradients, field quality*, apertures, gradients, field quality

Dipoles first – Doublet: explore feasibilityDipoles first – Doublet: explore feasibility

Beam-beam compensationBeam-beam compensation

Phase 2: Build wire compensator, machine studies in RHIC Phase 2: Build wire compensator, machine studies in RHIC and weak-strong simulations with BBSIMand weak-strong simulations with BBSIM

Strong-strong beam-beam simulations: emittance growth with swept Strong-strong beam-beam simulations: emittance growth with swept beams (luminosity monitor), beams (luminosity monitor), wire compensationwire compensation, and halo , and halo formation (Beambeam3D)formation (Beambeam3D)

Energy DepositionEnergy Deposition

IR designs (quadrupole and dipole first), tertiary collimators, and IR designs (quadrupole and dipole first), tertiary collimators, and the forward detector regions (CMS, TOTEM, FP420 and ZDC). the forward detector regions (CMS, TOTEM, FP420 and ZDC).


IssuesIssuesIR design issuesIR design issues

- What are the space constraints from Q4 to Q7?- What are the space constraints from Q4 to Q7? - By how much can L* be reduced, if at all?- By how much can L* be reduced, if at all? - Solutions need to be updated for Lattice Version 6.5. MAD8 version - Solutions need to be updated for Lattice Version 6.5. MAD8 version

of the lattice would be helpful.of the lattice would be helpful.

Beam-beam experiment at RHICBeam-beam experiment at RHIC - How can the RHIC experiments be more useful to the LHC? Is a - How can the RHIC experiments be more useful to the LHC? Is a

pulsed wire necessary in the LHC?pulsed wire necessary in the LHC?

Crab cavitiesCrab cavities - How much space will be needed?- How much space will be needed? - Cornell has expertise and interest in designing these cavities- Cornell has expertise and interest in designing these cavities

Energy DepositionEnergy Deposition - Progress on quadrupole design which can absorb heat load at 10 - Progress on quadrupole design which can absorb heat load at 10

times higher luminositytimes higher luminosity


IR Workshop at FNALIR Workshop at FNAL

October 3-4. 2005 at FNALOctober 3-4. 2005 at FNAL

TopicsTopics

- IR designs for the upgrades- IR designs for the upgrades

- Energy deposition, quench levels, TAN/TAS - Energy deposition, quench levels, TAN/TAS integrationintegration

- Magnet designs for the IR magnets- Magnet designs for the IR magnets

- Beam-beam compensation: wires, e-lens- Beam-beam compensation: wires, e-lens

- Feasibility of large x-angles and crab cavities in - Feasibility of large x-angles and crab cavities in hadron collidershadron colliders


Backup Slides


Doublet optics - dispersionDoublet optics - dispersion


Design StudiesDesign Studies

A. ZlobinA. Zlobin– IR MagnetsIR Magnets

Magnetic design and analysisMagnetic design and analysis

Mechanical design and analysisMechanical design and analysis

Thermal analysisThermal analysis

Quench protection analysisQuench protection analysis

Test data analysisTest data analysis

Integrate with AP and LARP magnet tasksIntegrate with AP and LARP magnet tasks

– CryogenicsCryogenics

IR cryogenics and heat transfer studiesIR cryogenics and heat transfer studies

Radiation heat depositionRadiation heat deposition

Cryostat quench protectionCryostat quench protection


Model Magnet R&DModel Magnet R&D

G.L. SabbiG.L. Sabbi

Main program focus (Technology Quadrupoles)Main program focus (Technology Quadrupoles)– 2-Layer quads, 90 mm aperture, G > 200 T/m ASAP2-Layer quads, 90 mm aperture, G > 200 T/m ASAP

ConsiderationsConsiderations

– Design approach – end loading options, preloadDesign approach – end loading options, preload– Fabrication techniquesFabrication techniques– Structure options – TQS, TQCStructure options – TQS, TQC

Opportunity to arrive at best-of-the-best and increase confidence in modeling

Convergence through working groups and internal reviews


Technology Quads: Features and Goals

Objective: develop the technology base for LQ and HQ:

• evaluate conductor and cable performance: stability, stress limits• develop and select coil fabrication procedures • select the mechanical design concept and support structure• demonstrate predictable and reproducible performance

Implementation: two series, same coil design, different structures:

• TQS models: shell-based structure • TQC models: collar-based structure

Magnet parameters:

• 1 m length, 90 mm aperture, 11-13 T coil peak field• Nominal gradient 200 T/m; maximum gradient 215-265 T/m


FY08-09: Long Quads (LQ)

FY06: fundamental scale-up issues addressed by Supporting R&D:

• general infrastructure and tooling• long racetrack coil fabrication and test• scale-up and alignment issues for shell-based structure

R&D issues:

• long cable fabrication and insulation• stress control during coil reaction, cable treatment, pole design• coil impregnation procedure, handling of reacted coils• support structures, assembly issues• reliability of design and fabrication

Plan: scale-up the TQ design to 4 meter length (LQ)


Block-type IRQ coils and mechanical structure (FNAL)


Larger-aperture separation dipole (LBNL)

~200 mm horizontal aperturethick internal absorber

Bmax=15-16 T, good field quality1.5-2 m iron OD

Shell-type coil design Block-type coil design

Current Status: Several IR quad designs were generated and compared with 90 mm shell-type quads including magnetic and mechanical parameters.

us-larp progress on ir upgrades

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