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

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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

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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, 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

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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 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