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Step IV Studies

Step IV Studies. Timothy Carlisle Oxford. Intro. . CM28 – Step III vs Step IV Cooling formula & G4MICE disagree on Also observed in ICOOL (note #199 – Marco/John Cobb). Step IV, 63mm LiH + AFC inc. windows. [from CM28]. PDG:. From Moliere.

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Step IV Studies

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  1. Step IV Studies Timothy Carlisle Oxford

  2. Intro. • CM28 – Step III vs Step IV • Cooling formula & G4MICE disagree on • Also observed in ICOOL (note #199 – Marco/John Cobb) Step IV, 63mm LiH + AFC inc. windows [from CM28]

  3. PDG: From Moliere • Cooling formula assumes Gaussian approximation: G4MICEGEANT4: uses Lewis Theory, “develops a theory valid for any angle by using Legendre polynomials and then goes over into the small Angle” ...simple then!

  4. Compare PDG with scattering in G4MICE. G4MICE: Nm=10,000 pencil beam on axis no fields Px 58cm LH2 Pz

  5. Absorbers in Step IV scaled so DE = const. • Instead fix the scattering angle  •  scaled to 63mm LiH = const.

  6. Scattering Angle Al Cu Carbon LiH Li LH2 Atomic Number Z

  7. Energy Loss MeV LH2 LiH Al Carbon Cu Atomic Number Z

  8. Scattering isn’t so simple to predict it seems. • Energy Loss seems fine however. • MICE acceptance limited to • i.e. measure up to Carbon (maybe Aluminium) • Find in G4MICE in different materials, for: pz= 207 MeV/c Nm= 10,000 sPz= 1MeV/c bT= 41cm

  9. Absorber study De C LH2

  10. Equilibrium Emittance C Be Li LiH LH2 PolyE Atomic Number Z

  11. MuScat Experiment • Measured muon scattering. • Compared with • GEANT 4.7.0 (10yrs old now) • ELMS 15.9cm LH2 Target

  12. Summary • Cooling formula/Moliere disagree with G4MICE • 1.5-2x less than predicted • Particularly bad with LH2 • MuScat • Moliere & GEANT 4.7.0 overestimate scattering at low Z • ELMS code much better • G4MICE uses GEANT 4.9.2 however... • Is this closer to MuScat? • ELMS in MAUS?

  13. Scattering Angle (Li fraction) LH2 Li LiH Li mass fraction (mLi/mLi+mLH2)

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