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 1
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 2
Muon Campus overview After a few turns all π + convert to μ + Protons separate and are removed 3.1 GeV 8.89 GeV p secondaries ( π , beam impacts μ + are extracted μ , p) travel the target from the ring and along M2 & M3 μ + enter the g-2 transferred into the storage ring storage ring via M4, M5 3
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 4
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 5
Beam production target Target Li-lens Collimator Pulsed magnet Parameter Value Intensity per pulse 10 12 Proton energy 8.0 GeV Secondary energy 3.1 GeV π + Selected particle 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) 6
Secondary beam transport lines M2 T G4BL model M2 Switch M3 M3 DR • 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 7
Optics in M2 & M3 beamlines 120 0 90 0 72 0 18 0 Match to cells cells cells bend DR M2-M3 switch Dispersion, D (m) Beta, β (m) Johnstone, GM2-doc-700-v13 (2014) 8
Tracking in M2 & M3 beamlines 1.37x10 -4 POT 1.87x10 -5 POT 2.62x10 -6 POT Entrance to DR 9
Injection: Conceptual design & model • 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) 10
Performance
Performance along the DR • After 4 turns near 90% of muons are transmitted towards the extraction line 12
Delivery ring & M4/M5 lines G4BL model DR M4 M5 g-2 storage ring • Near magic momentum μ + are extracted into the M4 line and bent into M5 for transport to the g-2 storage ring 13
Optics of M4 & M5 beamlines 27.1 0 Final Ring extraction M5 FODO h bend focus M4-M5 switch Dispersion , D (m) Beta, β (m) Johnstone, GM2-doc-1568-v16 (2015) 14
Tracking in M4 & M5 beamlines Storage ring injection 15
Beam at the storage ring entrance 3 . 091 GeV/c p / 0 . 012 p p Particles Value 8.7x10 -7 POT Total number of muons ∆𝑞 𝑞 = ±1% Τ 4.4x10 -7 POT Muons in ∆𝑞 𝑞 = ±0.5% Τ Muons in 2.4x10 -7 POT 16
Benchmarking results • Our G4Beamline results were cross-checked against independent simulation codes Work done by: M. Korostelev (Cockcroft, Lancaster) & D. Stratakis (FNAL) 17
Spin Tracking Turn 3 DR entrance (CMAG) 𝑞𝑄 𝑦 = −0.01𝑄 𝑞𝑄 < 𝑦 = −0.56𝑄 𝑞𝑄 𝑨 = −0.96𝑄 𝑞𝑄 𝑨 = −0.78𝑄 𝒒𝑸 = 𝟏. 𝟘𝟕𝑄 𝒒𝑸 = 𝟏. 𝟘𝟕𝑄 Turn 4 Turn 2 𝑞𝑄 𝑦 = −0.38𝑄 𝑞𝑄 𝑦 = −0.71𝑄 𝑞𝑄 𝑨 = −0.88𝑄 𝑞𝑄 𝑨 = −0.65𝑄 𝒒𝑸 = 𝟏. 𝟘𝟕𝑄 𝒒𝑸 = 𝟏. 𝟘𝟕𝑄 18
New projects • Potential of using Muon Campus for neutrino research Short-Baseline Near Detector (SBND) will be one of It is a long the neutrino path of sector 10 three liquid argon neutrino detectors sitting in the of the Muon campus delivery ring Booster Neutrino Beam (BNB) at Fermilab as part of the Short-Baseline Neutrino Program. Collaboration with: J. Grange (ANL), J. Zennamo (UChicago) and Z. Pavlovic (FNAL) 19
Neutrino Detector • Three virtual detectors are placed at the end of straight sections 10, 30, and 50. Results for turn 1 only. 20
Straight 30 • At straight 30 the number of – ν 𝜈 is 6x10 -7 per POT ν 𝑓 is 10 -9 per POT – 21
Straight 10 • At end of straight 10 the number of: – ν 𝜈 is 1.3x10 -7 per POT ν 𝑓 is 10 -9 per POT – 22
Straight 50 • At end of straight 10 the number of: – ν 𝜈 is 5.8x10 -8 per POT ν 𝑓 is 10 -9 per POT – 23
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 24
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… 25
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