Fermilab, Proton Driver, Muon Beams, Recycler David Neuffer Fermilab NufACT05
Jan 02, 2016
Fermilab, Proton Driver, Muon Beams, Recycler
David Neuffer
Fermilab
NufACT05
2
Proton Driver and Muon beams
8GeV Linac can produce streams of 1.5×1014 8GeV protons at 10Hz > 1022 protons/year
Only 1/15 of these needed for Main Injector
Are there muon beam experiments that could use this intensity ??
Tertiary muon beams: P + X → π π → μ + ν
10-2 μ/p → 1020 μ/year or more
~ 700m Active Length
8 GeV Linac
X-RAY FEL LAB
Slow-Pulse Spallation Source& Neutrino Target
Neutrino“Super-
Beams”
MainInjector@2 MW
8 GeVBooNe
NUMI
Anti-Proton
SY-120Fixed-Target
Off-Axis
Neutrinos to Homestake…
~ 700m Active Length
8 GeV Linac
X-RAY FEL LAB
Slow-Pulse Spallation Source& Neutrino Target
Neutrino“Super-
Beams”
MainInjector@2 MW
8 GeVBooNe
NUMI
Anti-Proton
SY-120Fixed-Target
Off-Axis
Neutrinos to Homestake…
Main Injector: 120 GeV, 0.67 Hz Cycle, 2.0 MW Beam PowerLinac Protons: 8 GeV, 4.67 Hz Cycle, 0.93 MW Beam Power Linac Electrons: 8 GeV, 4.67 Hz Cycle, 0.93 MW Beam Power
8 GeV Linac Cycles 1.5E14 per Pulse at 10Hz
Main Injector Energy
H-Injection
8 GeVProtons
8 GeVElectrons
0
20
40
60
80
100
120
140
0 0.5 1 1.5 2 2.5 3
Time (sec)
MI Energy
H- Injection
8 GeV Protons
Electrons
3
Proton Linac (H-)
4
LFV: A eA can use high intensity
Experiment I0/Im T
[ns]
T
[s]
p
[MeV]
p/p
A eA
e eee
e e
1021
1017
1017
1016
< 10-10
n/a
n/a
< 10-4
< 100
n/a
n/a
< 1000
> 1
n/a
n/a
> 20
< 80
< 30
< 30
< 30
< 5
< 10
< 10
1…2
1014 < 10-4 100 > 20 30 < 10
g-2
EDM
1015
1016
< 10-7
< 10-6
< 50
< 50
> 103
> 103
3100
<1000
< 2
< 2
dtI
Desirable Beam Characteristics
But bunched beam is needed
5
A eA experiments
Next generation of A eA experiments has been proposed MECO – based at BNL PRISM-PRIME – based at KEK/JHF
Neither experiment is fully funded
Could either (or both) be hosted at FNAL proton driver ?
A eA produces monoenergetic e- (~105MeV)
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100 300 100 300 GeV
Past and future LFV limits
SUSY SUSY predictions predictions ofof AA e e--A A
0 0
MECO single event MECO single event sensitivitysensitivity
10 -11
10 -13
10 -15
10 -19
10 -17
10 -21
PRIME single event sensitivityPRIME single event sensitivity
Rem (GeV)
10 -11
10 -13
10 –5
From Barbieri,Hall, Hisano …
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MECO layout
Superconducting Production Solenoid
(5.0 T – 2.5 T)
Muon Stopping Target
Muon Beam Stop
Crystal Calorimeter
Superconducting Transport Solenoid
(2.5 T – 2.1 T)
Superconducting Detector Solenoid
(2.0 T – 1.0 T)
Collimators
Tracker
Time structure
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PRISM-PRIME (Y. Kuno et al.)•High intensity pulsed proton beam (bunch length <10ns)
•100-1000Hz bunches•Pion capture solenoid & decay
•Phase rotation with rf field
Δp/p : ±30% 3%
•Similar to the front end of the neutrino factory
9
Proton Beam requirements MECO experiment
Requires pulses of ~8 GeV protons (<30ns long) every ~1μs (1.4μs) – Obtained by slow extraction of short bunches (in AGS)
Design requires 41013 p/s, 1.5 10-3 captured μ’s/proton ~61017 μ/year from ~4 1020 p/year
PRISM-PRIME experiment Requires proton pulses (<10ns long) at 103/s (~1ms)
– 4 1014 p/s (50GeV) 10-2 to 10-3 μ’s/proton– Up to 1022 p/year, > 1019 μ/year
Single-turn extraction of short bunches (<10ns)
Both require pulsed beams, proton linac beam must be repackaged in an accumulator ring
10
Recycler as accumulator ring ? 8GeV Linac produces
1ms pulses at 10 Hz
H- injection into Recycler 1ms fills circumference
– (100 turns) Bunch beam into pattern
required for expt.
Harmonic 10 buncher for MECO, slow extraction
Harmonic 100 buncher for PRIME, single bunch extraction
Circumference C=2πRave 3320m
Momentum P 8.89 GeV/c
Rev. frequency,
Period
f0
T0
89.8 kHz
11 μs
Slip factor η=1/γ2- 1/γt2 0.0085
Tunes νx, νy 25.4,24.4
But:
Recycler circumference is large
100ms may be too short a time for bunching
11
Space Charge Difficulty Space Charge tune shift:
Parameters: Ntot=1.51014,εN =20π mm-mrad
MECO: 30ns/1μs : BF= 0.03 →δν = 4 : too large
Reduce N to 1.51013 →δν = 0.4 Reduce N to 0.41013 →δν = 0.1
PRISM/PRIME 10ns bunches, 100/ring BF= 0.1 →δν =1.2: too large (but closer)
Larger εN, smaller Ntot,
Smaller circumference ring would be better
p tot
2F N
3r N
B
F
0.12
B
12
Recycler – Bunching (~for PRISM) Harmonic 100 buncher (9MHz)
Bunch for 0.1s (Vrf ramps to 140kV)
Bunch lengths reduced to
~5ns rms(Prism wants < 10ns full width.)
Could then extract bunches one at a time over ~0.1s
Uses 1/2 the possible linac pulses (500 bunches/s for PRISM) (100 at 5Hz)
13
Recycler – Bunching for ~MECO Harmonic 10 buncher
(0.9MHz) Barrierbucket rf
Bunch for ~1s (Vrf ramps to ~30kV)
Bunch lengths reduced to
~50ns rms(MECO wants ~30ns full width.)
Could then extract bunches in slow extraction over ~1s
14
Other potential proton storage schemes Accumulator or Debuncher (C= ~454m) after
2010… Large aperture machines
Difficult to inject H- (must bend beam from Linac) (B < 0.05T, ρ > ~600m)
Could take debunched protons from Recycler or Main Injector(in ~450m chunks) Or Old linac + Booster
Bunch into pattern needed for experiments Bunching easier than Recycler Better match for MECO
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• Detailed source design does not exist Straw man design worked out for the front end of a factory supported by MARS simulations (Ray et al.)
•Target + capture solenoid + drift (forward capture)
• 1.4 x 1022 protons/year at 8 GeV yields ~3 x 1021 muons/year.
Charged particlespectra at end ofdecay channel
Generic High intensity muon beam
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References W. Foster et al., Proton Driver http://tdserver1.fnal.gov/project/8GeVLinac/DesignStudy/
W. Molson, “The MECO Experiment to Search for -Ne-N with 10-17 Sensitivity”, U. Va. Seminar, June 2004
MECO ‘RSVP’ Rare Symmetry Violating Processes (MECO-
KOPIO) NSF proposal, October 1999. PRISM Working group “An Experimental Search for the μ−−e− Conversion
Process at an Ultimate Sensitivity of the Order of 10−18 with PRISM”, The Prime Working Group, Jan. 1, 2003.
R. Ray & D. Roberts, Proton Driver physics study
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Summary Muon Beams from the Proton Driver could be
very useful Potential muon beam facilities could be
developed:
MECO, PRISM … could be hosted More Detailed design needed
Proton Collection– Recycler, Accumulator, Debuncher, …– New Stretcher/Buncher ring ??
Beam line(s) Experimental area(s)
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Proton Driver Parameters8 GeV LINACEnergy GeV 8Particle Type H- Ions, Protons, or ElectronsRep. Rate Hz 10Active Length m 671Beam Current mA 25Pulse Length msec 1Beam Intensity P / pulse 1.5E+14 (can also be H-, P, or e-)
P/s 1.5E+15Linac Beam Power MW avg. 2
MW peak 200
MAIN INJECTOR WITH 8 GeV LINACMI Beam Energy GeV 120MI Beam Power MW 2.0MI Cycle Time sec 1.5 filling time = 1msecMI Protons/cycle 1.5E+14 5x designMI Protons/hr P / hr 3.6E+17H-minus Injection turns 90 MI Beam Current mA 2250