NuFACT06 Muon Source at Fermilab David Neuffer Fermilab

2 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 p’s

3 Proton Linac (H - ) 8 GeV? NewRing (P) H-H- t 8 GeV f Proton sources

“Proton Driver” Linac (H - ) 4 Fermilab facilities

5 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 ParameterSymbol AccumulatorDebuncher Circumference C=2πR ave ~474m504m MomentumP 8.89 GeV/c Transition γ T γTγT betatron fns β x, β y, η max 47, 40, , 17, 2.2 Tunesν x, ν y 6.9, , 9.76 aperturea, b

6 Scenario overview  Protons from Booster injected into accumulator  Stack 1 to 4 booster turns, debunch (w/extraction gap)  ~4·10 12 n turns protons  Extract into Debuncher  Rebunch in Debuncher  to ~40ns rms single bunch  Slow extract to muon conversion experiment  over ~1.5s Booster Protons from Booster Slow extraction Transfer to Debuncher

7 Momentum stacking in Accumulator

COEXISTING WITH THE NEUTRINO PROGRAM Booster Batches Accumulator Recycler Debuncher 22 batches = s MI cycle 4.6  p/batch 4  4.6  p/1467ms = 12.5  p/sec 56  p/sec 0.1s1.367s NEUTRINO PROGRAMMUONS (NuMI +Muons) (NuMI) (Muons) (Alternative: 24 batches=1.6s MI cycle  11.5  p/s)

9 Longitudinal stacking in the Accumulator ΔE = 20 MeV

10 Bunch compression-Accumulator  Example: Compression within ~0.1s  A:Rf-60kV barrier bucket  Square wave rf  30kV also OK  B: h=4 rf 60 to 160 kV  Sinusoidal rf at~2.5 MHz  Start:±150°, σ E = 3.3MeV  ~4 batches  L = 6πσ t σ E = ~24 eV-s  Finish: σ < 40ns, σ E = 32MeV  Small dilution

11 Barrier bucket in Debuncher  γ T =7.6- more isochronous  Needs less rf but more time  Compression within ~0.2s  A:Rf-14kV barrier bucket  Square wave rf  B: h=4 rf 14 to 30 kV  Sinusoidal rf ~2.5 MHz  Start:±150°, σ E = 3.3MeV  ~4 batches  L = 6πσ t σ E = ~24 eV-s  Finish: σ < 30ns, σ E = 42MeV  Small dilution

12 multi-harmonic bunching  T = 7.5, C=504m  More isochronous, smoother harmonic buncher  Example: h=1, V rf = 6kV; h=2, Vrf = 70kV, h=4, V rf =200kV  0.073s for bunching

13 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  S. Geer organizer

14 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  R&D 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

15 4 MW Proton Driver Parameters (short list) 8 GeV Superconducting LINAC (1300 MHz rf) EnergyGeV8 Particle Type H- Ions, Protons, or Electrons Rep. RateHz2.5 to 10 to 20 Active Lengthm614 Beam CurrentmA25 Pulse Lengthmsec3 to 1 Beam IntensityP / pulse1.5E+14 (can also be H-, P, or e-) P/s1.5E+15 Linac Beam PowerMW avg.0.5 to 2 to 4 MW peak200

16 Proton Linac (H - ) 8 GeV? NewRing (P) H-H- t 8 GeV f Proton sources Transfer to debuncher

17 New 8 GeV Accumulator/buncher/stretcher  Type: FODO racetrack,  Superferric arcs  nonscaling  H - injection into NewRing (10Hz)  700 turns  Transverse emittance can be enlarged (ε N =120π mm-mrad or more 20mm-mrad rms )  Harmonic 4 buncher for ν- Factory, single bunch extraction (400ns spacing)  single bunch extraction mode  Also useful for PRISM/PRIME, muon collider, … CircumferenceC=2πR ave ~454m MomentumP8.89 GeV/c rf frequency, Voltage h=4 V MHz <1MV Slip factor η =1/ γ 2 - 1/ γ t Tunes ν x, ν y 6.9, 8.9 aperturea, b~8, 5 cm Linac injection

18 Space Charge Difficulty  Space Charge tune shift:  Parameters: N tot =1.5  10 14,ε N =120π mm-mrad  Emittance was increased to reduce δν  Booster-size Ring: 4 bunches, 4*10ns/1.5μs : B F = → δν = ~ : not too large  σ z = ~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

19 Bunching example (454m ring)  Bunch to short bunches with barrier-bucket rf within ~0.05s  V rf = 250kV, 5  pulse width  Compresses to ~5ns rms  Add h=36 rf to get <3ns  Compression not optimized  smaller ring better

20 270m Buncher  Bunch to short bunches with barrier-bucket rf within ~0.027s  OK  V rf = 250kV, 5  pulse width  h=2 bunches  Compresses to ~6ns rms  Add h=18 rf (2MV) to get <4ns  2ns bunches with h=4  Compression not optimized

21 Plans