Proton Driver Design

Keith GollwitzerFermilab

February 19, 2014

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Proton Driver Outline

• Overview– History

• Accomplishments– Current Concept

• Initial Baseline Selection Schedule• Personnel and Effort• Technology & Challenges

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Proton Driver at August 2012 MAP Review

• Overview– Assumed Project X existed– Outlined how to increase Project X

beam to 4 MW of 8 GeV H- ions– Accumulation Ring converts ions to

protons as well as formats beam into a few intense bunches

– Compressor Ring bunch rotates beam to the desired short bunch(s)

– Delivery beam line(s)

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Keith Gollwitzer | DOE Review of MAP (FNAL, February 19-20, 2014) 4

Since Last August 2012 MAP Review

• Project X was split into stages• MASS looked at facilities starting with stage 2

of Project X– Proton Driver at 3 GeV

• Proton Improvement Plan (PIP) II has become the start of a new facility for the Proton Driver

• MASS assumes that there is a follow-on to PIP II resulting in the equivalent of stage 2

• MASS proposes Dual Use Linac– Proton Driver delivers 6.75 GeV proton beam

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Dual Use Linac

• MAP linac for muon acceleration can be used for H- acceleration– muon beam 1.25 - 5 GeV– H- beam 3 - 6.75 GeV

– FNAL SRF expertise is 325 MHz, 650 MHz and 1300MHz

• MAP has moved to adopt these frequenciesFebruary 19, 2014

1-3GeV

3-6.75GeV

1.25-5GeV

0.2-1.25GeV

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Key Proton Driver Accomplishments Since the August 2012 MAP Review

Date Description

FY13 Q2 Provided appendix to Project X design report ("Project X Accelerator Reference Design, Physics Opportunities, Broader Impacts") describing upgrade path to MAP Proton Driver

FY13 Q3 Completed contribution to Proton Driver section and FNAL Project X appendix to IDS-NF RDR

FY13 Q4 Provided feedback to MASS on 3 GeV Proton Driver option

FY14 Q1 Interfaced with MASS on 6.75 Proton Driver option based on Dual Use Linac

FY14 Q1 Accepted initial concept specification described in IPAC12 paper “Design of Accumulator and Compressor Rings for the Project X Based Proton Driver.” (Design concept will be adjusted for operation at 6.75 GeV as well as 8 GeV)

FY14 Q2 Developed a work plan for executing the IBS process

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Present Day Assumptions• PIP II: Ion source (5mA) & RFQ (162.5 MHz)

provides 1.92 x 108 particles per linac bunch.

• Follow on to PIP II: an additional non-MAP linac supporting high power beam to 3 GeV. – Similar to Stage 2 of Project X

• 1 MW scenario: Dual Use Linac accelerating ions at 15 Hz to 6.75 GeV– 4 ms pulses where 50% beam is chopped in front end so

that linac bunches are synched with Accumulator Ring RF

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• Previous work had been for 8 GeV

Revisit of Rings’ Designs

February 19, 2014

Accumulator

Compressor

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Revisit of Rings’ Designs• Previous work has been for 4 MW at 8 GeV

• Start by revisiting rings for 1 MW at 6.75 GeV– Follow with larger beam power studies

February 19, 2014

Parameters Accumulator Compressor

Circumference (m) 308.23 308.23

Momentum Compaction -0.052 0.001

Slippage Factor -0.063 -0.01

RF Frequency (MHz) 3.87 3.87

RF Voltage (kV) 10 240

Synchrotron Tune 2.1 x 10-4 4.2 x 10-4

Peak Current (A) 100 1040

Final rms Bunch Length (ns) 29.2 3.2

Final rms Energy Spread 5.2 x 10-4 6.9 x 10-3

Threshold Impedance (Ohm) 20 3 53

Emittance rms (μm) 5 5

Space Charge Tuneshift h/v 0.02/0.02 0.14/0.16

Betatron Tunes h/v 7.94/6.91 6.76/8.44

Keith Gollwitzer | DOE Review of MAP (FNAL, February 19-20, 2014) 10

Stripping System

• Conversion of MW (or more) ion beam to protons for accumulation will be studied.– Stripping at 6.75 (or 8) GeV– Leveraging

• SNS experience: 1 MW at 1 GeV• Continue Project X work: 300kW at 8 GeV

– Same FNAL personnel involved

• Ideas– Foil (stationary, multiple, rotating)– Laser stripping

February 19, 2014

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Delivery Beam Line(s) & Focusing System

• Based upon IDS-NF design.• Focusing system will be interfaced with Target

system. • Bunch instabilities may require extraction of

several bunches from the Compressor Ring to be sent through different beam lines to arrive simultaneously at the target.– Focusing system could require a non-standard

magnetic element(s) that focuses multiple beams that have little separation

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Initial Baseline Selection Schedule

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Personnel & Effort Required

• A magnet expert is available for consulting• Effort to reach IBS will be 1 FTE x 20 months

February 19, 2014

Personnel Institution TaskAlexahin, Yuri Fermilab Rings, Focus System, InstabilitiesAnkenbrandt, Charles Muons Inc Rings, Focus System, Instabilities, StrippingGollwitzer, Keith Fermilab Rings, Focus System, Instabilities, StrippingJohnson, David Fermilab Rings, Focus System, StrippingKapin, Valery Fermilab Rings, Focus System, InstabilitiesLebedev, Valeri Fermilab Rings, Focus System, Instabilities, StrippingNeuffer, David Fermilab Rings, Focus System, InstabilitiesPopovic, Milorad Fermilab Rings, Focus System, Instabilities, Stripping

Keith Gollwitzer | DOE Review of MAP (FNAL, February 19-20, 2014) 14

Conventional Technology

• Ring and beam line magnets– Dipoles– Quads– Sextupoles– Kickers

• RF Systems• Collimators

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Novel Technologies

• Stripping System– Greater than 1 GeV ion beam energy– Greater than 1 MW beam power

• Target Focus System– Focus element(s) within greater than 1 T solenoid

magnetic field– Multiple beams with small separation being

focused

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Stripping System Challenges

• Static Foil or Rotating Foil– What beam power can be endured?– Multiple beam passes. Scattering.

• Laser– Viability for MW beam

• Unconverted Beam– Capture of non-protons (dump)– Limit activation of tunnel and components

February 19, 2014

Will extend on-going work for linac beam

conversion to protons and injection into the

Main Injector

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Focus System Challenges

• Target Solenoid Field– A “fringe” field > 1 T exists 5 m upstream of target

• Magnetic shielding or canceling magnetic field– Off-axis proton beam path is helical

• Multiple beams with small crossing angles at target– Previous work showed that the separation of 4

beams 5 m upstream of target to be ~15 cm.

February 19, 2014

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Proton Driver Conclusion

• Design work– Revisit of rings designs almost complete– Delivery beam line to be based upon IDS-NF

• Technology– Most components are conventional– Stripping system will be leveraged from SNS

experience and work done for linac beam injection into the Main Injector

– Final Focusing element(s) may require design of a non-conventional magnet

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Extras

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Possible Layout

February 19, 2014

NuMAX:ns to SURF

300m Higgs FactoryMuon Collider

1 GeV Muon Linac (325MHz)

To SURF

1 GeV Proton Linac

3-6.75 GeV Proton &1.25-5 GeV MuonDual Use Linac

1-3 GeV Proton Linac

FrontEnd

Accumulator&CompressorRingsInitialCool 6DCool

FinalCool

RLA to 63 GeV

Target