Beam dynamics study for the Muon Campus at Fermilab Diktys - - PowerPoint PPT Presentation

Beam dynamics study for the Muon Campus at Fermilab

Diktys Stratakis

Fermi National Accelerator Laboratory

Physics with muons beyond g-2 and Mu2e, Fermilab, Batavia, IL May 03, 2016

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Outline

• Overview of the Fermilab Muon Campus
• Simulation model & results

– Target and M2-M3 beamlines – Delivery ring – M4-M5 beamlines

• Delivery ring for neutrino research
• Conclusion & Future work

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Muon Campus overview

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8.89 GeV p beam impacts the target

3.1 GeV secondaries (π, μ, p) travel along M2 & M3 μ+ are extracted from the ring and transferred into the storage ring via M4, M5 After a few turns all π+ convert to μ+

μ+ enter the g-2 storage ring

Protons separate and are removed

Challenges

• Beam requirements at the g-2 ring entrance:

– At least 7x10-7 muons per POT within ±2% ∆𝑞/𝑞 – Maintain an average polarization 90% or better

• At the same time, the beamlines have bends, elevation

changes, complex injection and extraction schemes:

– Can cause severe particle loss – Trigger spin correlations that could increase systematic error

• At the same time most beamlines need to be compatible

with the Mu2e experiment

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Approach

• The aim of this work is to deliver an end-to-end simulation

for g-2 so that the above issues can be addressed

• To achieve this we have developed simulation models for

different parts of the lines

– Targetry: MARS & GEANT4 – Beamline optics: MADX – Beam and spin tracking: BMAD, GEANT4, G4Beamline

• Validated our results against:

– Theoretical models – Independent simulation codes

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Beam production target

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Pulsed magnet Collimator Target Li-lens

Parameter Value Intensity per pulse 1012 Proton energy 8.0 GeV Secondary energy 3.1 GeV Selected particle π+ Beam size at target 0.15 mm Distance between Li-lens and target 31.0 cm Focusing field gradient of Li-lens 232 T/m Grange et al., Muon Technical Design Report (2015)

Secondary beam transport lines

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• M2 & M3 lines will carry the secondary beam from the

target (T) to the delivery ring (DR)

• Loop four times until μ+ yield peaks and all p are removed

M2 M3

DR

T

G4BL model

Switch

M2 M3

Optics in M2 & M3 beamlines

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Match to DR 720 cells 900 cells 1200 cells

Beta, β (m) Dispersion, D (m)

Johnstone, GM2-doc-700-v13 (2014)

M2-M3 switch 180 bend

Tracking in M2 & M3 beamlines

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Entrance to DR

1.37x10-4 POT 1.87x10-5 POT 2.62x10-6 POT

Injection: Conceptual design & model

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• Conceptual design
• Simulation model
• Vertical injection with a combination of a C-magnet, 303

quadrupole, magnetic septum and kicker magnets

Morgan, GM2-doc-3312 (2015) & Morgan, GM2-doc-2244 (2014)

Performance

Performance along the DR

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• After 4 turns near 90% of muons are transmitted towards

the extraction line

Delivery ring & M4/M5 lines

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• Near magic momentum μ+ are extracted

into the M4 line and bent into M5 for transport to the g-2 storage ring

M4 M5 DR g-2 storage ring

G4BL model

Optics of M4 & M5 beamlines

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Final focus

Johnstone, GM2-doc-1568-v16 (2015)

27.10 h bend M5 FODO Ring extraction M4-M5 switch

Dispersion, D (m)

Beta, β (m)

Tracking in M4 & M5 beamlines

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Storage ring injection

Beam at the storage ring entrance

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012 . / GeV/c 091 . 3     p p p

Particles Value Total number of muons 8.7x10-7 POT Muons in Τ ∆𝑞 𝑞 = ±1% 4.4x10-7 POT Muons in Τ ∆𝑞 𝑞 = ±0.5% 2.4x10-7 POT

Benchmarking results

• Our G4Beamline results were cross-checked against

independent simulation codes

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Work done by: M. Korostelev (Cockcroft, Lancaster) & D. Stratakis (FNAL)

Spin Tracking

<

𝑞𝑄

𝑦 = −0.71𝑄

𝑞𝑄

𝑨 = −0.65𝑄

𝒒𝑸 = 𝟏. 𝟘𝟕𝑄 𝑞𝑄

𝑦 = −0.56𝑄

𝑞𝑄

𝑨 = −0.78𝑄

𝒒𝑸 = 𝟏. 𝟘𝟕𝑄 𝑞𝑄

𝑦 = −0.38𝑄

𝑞𝑄

𝑨 = −0.88𝑄

𝒒𝑸 = 𝟏. 𝟘𝟕𝑄 𝑞𝑄

𝑦 = −0.01𝑄

𝑞𝑄

𝑨 = −0.96𝑄

𝒒𝑸 = 𝟏. 𝟘𝟕𝑄 DR entrance (CMAG) Turn 2 Turn 3 Turn 4

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New projects

• Potential of using Muon Campus for neutrino research

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Short-Baseline Near Detector (SBND) will be one of three liquid argon neutrino detectors sitting in the Booster Neutrino Beam (BNB) at Fermilab as part

• f the Short-Baseline Neutrino Program.

It is a long the neutrino path of sector 10

• f the Muon campus delivery ring

Collaboration with: J. Grange (ANL), J. Zennamo (UChicago) and Z. Pavlovic (FNAL)

Neutrino Detector

• Three virtual detectors are placed at the end of straight

sections 10, 30, and 50. Results for turn 1 only.

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Straight 30

• At straight 30 the number of

– ν𝜈 is 6x10-7 per POT – ν𝑓 is 10-9 per POT

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Straight 10

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• At end of straight 10 the number of:

– ν𝜈 is 1.3x10-7 per POT – ν𝑓 is 10-9 per POT

Straight 50

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• At end of straight 10 the number of:

– ν𝜈 is 5.8x10-8 per POT – ν𝑓 is 10-9 per POT

Conclusion

• Developed a simulation model for the g-2 beam lines
• At the SR entrance parameters match the desired criteria:

– The beam is >95% polarized – Τ ∆𝑞 𝑞 = ±1.2% and centered near magic momentum – 8.4X10-7 muons per POT

• Our results agree well with independent simulation codes
• The number of neutrinos in the DR is estimated
• As a next step

– Estimate the number of neutrinos in the SBND detector – Produce DR beam fluxes for a range of proton energies

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Acknowledgment

• Thanks to Ao Liu (Fermilab) for allowing me to use his

plotting program

• Thanks to Tom Roberts for helping me with G4Beamline
• Special thanks to: Bill Morse, Jason Crmkovic, Jean-

Francois Ostiguy, Jim Morgan, Mary Convery, Maxim Korostelev, Mike Syphers, Nathan Froemming, Volodya Tishchenko for many discussions…

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