NuFACT06 Muon Source at Fermilab

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NuFACT06 Muon Source at Fermilab

• David Neuffer
• Fermilab

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Fermilab proton sources

• Existing facility
• Current intensity
• Future upgrades- configurations
• Protons for muon source A-D configuration
• Proton Driver 8 GeV future source
• 1 to 4 MW 8 GeV SRF Linac
• Need buncher ring to accumulate ps

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8 GeV f Proton sources
NewRing (P)
Proton Linac (H-) 8 GeV?
H-
t
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Fermilab facilities
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8 GeV Accumulator/Debuncher Parameters

• After 2009, accumulator and Debuncher are not
  needed for Fermilab Collider
• Can be used for other programs
• Accumulator is being considered for momentum
  stacking from booster for NUMI
• Stacked beam could also be used

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Scenario overview

• Protons from Booster injected into accumulator
• Stack 1 to 4 booster turns, debunch (w/extraction
  gap)
• 41012 nturns protons
• Extract into Debuncher
• Rebunch in Debuncher
• to 50ns rms single bunch
• Slow extract to muon conversion experiment
• over 1.5s

Protons from Booster
Transfer to Debuncher
Booster
Slow extraction
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Momentum stacking in Accumulator
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COEXISTING WITH THE NEUTRINO PROGRAM
22 batches 1. 467s MI cycle
Booster Batches
4.6?1012 p/batch
NEUTRINO PROGRAM
MUONS
Accumulator
(NuMI Muons)
Recycler
56 ?1012 p/sec
(NuMI)
(Muons)
Debuncher
4?4.6?1012 p/1467ms 12.5 ?1012 p/sec
(Alternative 24 batches1.6s MI cycle? 11.5
?1012 p/s)
0.1s
1.367s
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Longitudinal stacking in the Accumulator
?E 20 MeV
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Bunch compression-Accumulator

• Example
• Compression within 0.1s
• ARf-60kV barrier bucket
• Square wave rf
• 30kV also OK
• B h4 rf 60 to 160 kV
• Sinusoidal rf at2.5 MHz
• Start150, sE 3.3MeV
• 4 batches
• ?L 6pstsE 24 eV-s
• Finish s lt 40ns, sE 32MeV
• Small dilution

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Barrier bucket in Debuncher

• ?T7.6- more isochronous
• Needs less rf but more time
• Compression within 0.2s
• ARf-14kV barrier bucket
• Square wave rf
• B h4 rf 14 to 30 kV
• Sinusoidal rf
• 2.5 MHz
• Start150, sE 3.3MeV
• 4 batches
• ?L 6pstsE 24 eV-s
• Finish s lt 30ns, sE 42MeV
• Small dilution

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multi-harmonic bunching

• ?T 7.5, C504m
• More isochronous, smoother harmonic buncher
• Example h1, Vrf 6kV h2, Vrf 70kV, h4,
  Vrf 200kV
• 0.073s for bunching

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Needed to develop concept

• Longitudinal buncher scenario
• Injection/Extraction lines
• Slow extraction line
• Location of mu-e detector
• Extinction calculations/methods improvements
• Fermilab Workshop September 15-16
• S. Geer organizer

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Future Option f Proton Driver

• Fermilab may develop new proton source to replace
  8-GeV Booster at a multi-MW level
• Studied at Fermilab but deferred to focus on ILC
• RD continues on technology
• deferral will be reevaluated as ILC develops
• Upgrade options
• 8-GeV SRF proton linac
• Booster-like rapid-cycling synchrotron but higher
  intensity
• Larger apertures, injection linac upgrade, deeper
  tunnel

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4 MW Proton Driver Parameters (short list)
8 GeV Superconducting LINAC (1300 MHz rf)
Energy
GeV
8
Particle Type
H- Ions, Protons, or Electrons
Rep. Rate
Hz
2.5 to 10 to 20
Active Length
m
614
Beam Current
mA
25
Pulse Length
msec
3 to 1
Beam Intensity
P / pulse
1.5E14
(can also be H-, P, or e-)
P/s
1.5E15
Linac Beam Power
MW avg.
0.5 to 2 to 4
MW peak
200

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8 GeV f Proton sources
Transfer to debuncher
NewRing (P)
Proton Linac (H-) 8 GeV?
H-
t
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New 8 GeV Accumulator/buncher/stretcher

• Type FODO racetrack,
• Superferric arcs
• nonscaling
• H- injection into NewRing (10Hz)
• 700 turns
• Transverse emittance can be enlarged (eN 120p
  mm-mrad or more 20mm-mrad rms)
• Harmonic 4 buncher for ?-Factory, single bunch
  extraction (400ns spacing)
• single bunch extraction mode
• Also useful for PRISM/PRIME, muon collider,

Linac injection
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Space Charge Difficulty

• Space Charge tune shift
• Parameters Ntot1.5?1014,eN 120p mm-mrad
• Emittance was increased to reduce d?
• Booster-size Ring 4 bunches, 410ns/1.5µs BF
  0.027 ?d? 0.375 not too large
• sz 4ns, up to 40 Hz bunches on target
• Shorter bunch possible
• Smaller circumference proton ring could be better
• C 227m, 2 bunches would obtain 20Hz on target

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Bunching example (454m ring)

• Bunch to short bunches with barrier-bucket rf
  within 0.05s
• Vrf 250kV, 5? pulse width
• Compresses to 5ns rms
• Add h36 rf to get lt3ns
• Compression not optimized
• smaller ring better