Proton Driver Design
Keith GollwitzerFermilab
February 19, 2014
Keith Gollwitzer | DOE Review of MAP (FNAL, February 19-20, 2014) 2
Proton Driver Outline
• Overview– History
• Accomplishments– Current Concept
• Initial Baseline Selection Schedule• Personnel and Effort• Technology & Challenges
February 19, 2014
Keith Gollwitzer | DOE Review of MAP (FNAL, February 19-20, 2014) 3
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)
February 19, 2014
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
February 19, 2014
Keith Gollwitzer | DOE Review of MAP (FNAL, February 19-20, 2014) 5
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
Keith Gollwitzer | DOE Review of MAP (FNAL, February 19-20, 2014) 6
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
February 19, 2014
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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
February 19, 2014
Keith Gollwitzer | DOE Review of MAP (FNAL, February 19-20, 2014) 8
• Previous work had been for 8 GeV
Revisit of Rings’ Designs
February 19, 2014
Accumulator
Compressor
Keith Gollwitzer | DOE Review of MAP (FNAL, February 19-20, 2014) 9
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
Keith Gollwitzer | DOE Review of MAP (FNAL, February 19-20, 2014) 11
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
February 19, 2014
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Initial Baseline Selection Schedule
February 19, 2014
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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
February 19, 2014
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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
February 19, 2014
Keith Gollwitzer | DOE Review of MAP (FNAL, February 19-20, 2014) 16
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
February 19, 2014
Keith Gollwitzer | DOE Review of MAP (FNAL, February 19-20, 2014) 19February 19, 2014
Extras
Keith Gollwitzer | DOE Review of MAP (FNAL, February 19-20, 2014) 20
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
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