Fermilab and MuonsBooster, Proton Driver

(MECO, PRISM/PRIME, …)

David Neuffer

Fermilab

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Outline Fermilab: Protons and Muons

Present Proton source: Booster

Future Source : Proton Driver

Possible configurations, intensities

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Present Proton Source: 8 GeV Booster

NOW: 400 MeV Linac8 GeV Booster (C=454m)

produces 80 bunches (53 MHz) Currently Limited by losses in Booster

5Hz, ~ 3 1012/ pulse: ~1.5×1020 p/year (0.02MW)

15Hz, 5 1012/pulse possible (0.1MW) (61013 protons/s)

NUMI, MiniBOONE, Tevatron p-source Tevatron, MiniBOONE will be completed…

Capacity for other experiments … But 15Hz cycle limits applications

Linac – 400MeV

Booster – 8 GeV

Main Injector,MiniBOONE

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Proton Driver and Muon beams

8GeV Linac can produce streams of 1.5×1014 8GeV protons at up to 10Hz > 1022 protons/year

Neutrino Physics: main goal But: Only 1/15 of these needed for

Main Injector/NUMI

Are there muon beam experiments that could use this intensity ??

Tertiary muon beams: P + X → π π → μ + ν

10-1 μ/p → 1021 μ/year or more

(other experiments will also be possible)

~ 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

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Primary Parameter List (Foster, March 2005 reference)

PRIMARY PARAMETERS 8 GeV Initial 0.5 MW {Ultimate 2MW in Brackets}Linac beam kinetic energy 8 GeVLinac Particle Types Baseline Mission

via foil stripping in transfer linePossible w/upgrade of Phase Shifters & Injector

Linac Stand-Alone Beam power 0.5 {2.0} MW 8 GeV beam power available directly from linacLinac Pulse repetition rate 2.5 {10} HzLinac macropulse width 3.0 {1.0} msLinac current (avg. in macropulse) 8.7 {26} mALinac current (peak in macropulse) 9.3 {28} mALinac Beam Chopping factor in macropulse 94 % For adiabatic capture with 700ns abort gap.Linac Particles per macropulse 1.56E+14Linac Charge per macropulse 26 uCLinac Energy per macropulse 208 kJLinac average beam current 0.07 {0.26} mALinac beam macropulse duty factor 0.75 {1.0} %Linac RF duty factor 1.00 {1.3} %Linac Active Length including Front End 614 m Excludes possible expansion lengthLinac Beam-floor distance 0.69 m =27 in. same as Fermilab Main InjectorLinac Depth Below Grade 9 m same as Fermilab Main InjectorTransfer Line Length to Ring 972 m for MI-10 Injection pointTransfer Line Total Bend 40 deg two 20-degree collimation arcsRing circumference 3319.4 m Fermilab Main InjectorRing Beam Energy 8-120 GeV MI cycle time varies with energyRing Beam Power on Target 2 MW ~ independent of MI Beam EnergyRing Circulating Current 2.3 ARing cycle time 0.2-1.5 sec depends on MI beam energy & flat-topRing Protons per Pulse on Target 1.50E+14 protonsRing Charge per pulse on target 25 uCRing Energy per pulse on target 200-3000 kJ at 8-120 GeVRing Proton pulse length on target 10 us 1 turn, or longer with resonant extractionLinac Wall Power 5.5 {12.5} MW approx 3 MW Standby + 1MW / Hz

ProtonsH - ions

Electrons

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Proton Driver Parameters8 GeV Superconducting LINACEnergy GeV 8Particle Type H- Ions, Protons, or ElectronsRep. Rate Hz 2.5 to 10Active Length m 671Beam Current mA 25Pulse Length msec 3 to 1Beam Intensity P / pulse 1.5E+14 (can also be H-, P, or e-)

P/s 1.5E+15Linac Beam Power MW avg. 0.5 to 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

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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

(Brice, Geer, Paul, Taylor, Fermilab-Conf-04-196-E)

•Target + capture solenoid + drift (forward capture)

• 1.5 x 1022 protons/year at 8 GeV yields ~3 x 1021 muons/year.

Charged particlespectra at end ofdecay channel

Generic High intensity muon beam

~0.2 µ/p

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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

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MECO expt. (BNL-based proposal)

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 producing π —> μ bunches

•Phase rotation with rf field: Δp/p : ±20% ± 2%

P = 68 MeV/c ±20%

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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, 2 10-3 captured μ’s/proton 105 μ/pulse (~5 107 p/pulse) ~81017 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) Up to 4109 μ/pulse (~ 1012 p/pulse)

Both require pulsed beams, proton linac beam must be repackaged in an accumulator ring

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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

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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

PRISM/PRIME 10ns bunches, 100/ring BF= 0.1 →δν =1.2: too large (but closer)

Use larger εN, smaller Ntot, Ntot 1 1014 OK

Smaller circumference proton ring could be better

p tot

2F N

3r N

B

F

0.12

B

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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

OK for 1013 protons/s

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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)

~5 1014 p/s possible

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Other potential proton storage schemes Accumulator or Debuncher (C= ~454m) after

2010… Large aperture machines t 5

Difficult to inject H- (must bend beam from Linac) (B < 0.05T at 8 GeV, ρ > ~600m)

Could take debunched protons from Recycler or Main Injector(in ~450m chunks) Bunch into pattern needed for experiments Bunching easier than Recycler

New 8 GeV Storage Ring ??

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New 8 GeV Accumulator/buncher/stretcher

FFAG Type: FODO racetrack,

Superferric arcs nonscaling

H- injection into NewRing (10Hz) 700 turns

δν = 0.4 at BF=0.15 (σ=1.5ns)

Harmonic 42 buncher for PRISM, single bunch extraction (40ns spacing)

Slow extraction, single bunch extraction modes

Circumference C=2πRave ~454m

Momentum P 8.89 GeV/c

rf frequency,

Voltage

h=42

V0

26 MHz

1MV

Slip factor η=1/γ2- 1/γt2 -0.02

Tunes νx, νy 6, 8

aperture a, b ~3,2cm

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Proton Linac (H-)

NewRing (P)

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Fermilab – w/o SRF linac proton driver

Upgrade: Linac8 GeV Booster From 5Hz ~ 3 1012/ pulse

15Hz, 5 1012/pulse possible (0.1MW) (61013 protons/s)

Single turn extraction is 1.5s onto production target (~ MiniBOONE), then e target

Adapt to e conversion experiment Not very well suited to ~1s µ-decay Most ’s decay before end of injection pulse ~1/3 of full pulse probably useful

Circumference C=2πRave ~454m

Momentum P 8.89 GeV/c

rf frequency h=84 53 MHz

Slip factor η=1/γ2- 1/γt

2

-0.022

Tunes νx, νy 6.6, 6.8

aperture a, b ~3,2cm

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Fermilab - Beam from Booster For pulsed experiments, need a storage ring Could use Accumulator, Debuncher (450m circ.)? Scenario:

Transfer into ring, bunch, extract short bunches onto targets ~80bunches, 15 Hz = 1200Hz (~PRISM) (6×1010 p/bunch) For ~MECO, bunch into single bunch? (<100ns out of 1.5µs)

– Slow extraction

Possible Long-term Future: New 8 GeV Booster With 1 GeV linac ?? larger apertures, larger injection energies, deeper tunnel (51013/ pulse ??) (1MW ??) With new storage ring

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Summary Muon Beams at Fermilab could be developed Potential muon beam facilities could be

constructed ~MECO or PRISM, etc. … could be hosted More Detailed design needed

Proton Collection– Recycler ….– New Stretcher/Buncher ring ??

Beam line(s) Experimental area(s)

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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

‘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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PRISM rf-rotation

P = 68 MeV/c ±20%t = ±12ns (5ns rms)

Pµ

p=±1.9%p=±3.4%

5-turns, 38% beam decay 6-turns, 44% decay