Geant4 Simulations of the MICE Beamline

1. Geant4 Simulations of the MICE Beamline Tom Roberts Illinois Institute of Technology 7/30/03

2. MICE Beam Layout and Tune • Layout from “LAYOUT-MICE 14May03” • Bend 1 is 60°, Bend 2 is 32° • Target to Diffuser1 is 18.8 m • Quad (Type IV) and Bending Magnet (Type I) parameters are from RAL drawings and tables. • Fringe fields for Bending Magnets were computed via Laplace’s equation; quads are ideal (no fringe fields). • Bend 1 is tuned for 300 MeV/c pions • Bend 2 is tuned for 200 MeV/c muons • Quads are tuned for maximum mu/pi ratio at Diffuser1 (using minuit) – the triplet is configured DFD (~20% better than FDF) • Quad tuning gives ~60 times better mu/pi than reported in New York

3. Input Beam • Pi+ beam • 200 MeV/c < P < 400 MeV/c (uniform) • dxdz and dydz generated to cover Q1 aperture (uniform) • Target is 10 mm high, 10*cos(25°) mm wide (uniform) • All materials kill tracks instantly, without secondaries Absolute normalization to the proton beam is needed, as is the proton background, and the other backgrounds.

4. Momentum at Diffuser1

5. P at Q1 for mu+ at Diffuser1

6. Mu+ Correlation Matrix (normalized) P < 250 MeV/c

7. Summary • The major correlations in the beam should be removable by the diffusers • More tunes should be explored (e.g. Bend1 tuned to 350 MeV/c and 400 MeV/c) • We need absolute normalization to the proton beam • We need to understand the beam backgrounds

8. Additional Slides The following plots are all at Diffuser1.

9. Mu+ X vs Y

10. Pi+ X vs Y

11. Mu+ X vs P

12. Pi+ X vs P

13. Mu+ X’ vs P Note where X’=0 is.

14. Pi+ X’ vs P Note where X’=0 is.

15. Mu+ X vs X’ Note where X’=0 is.

16. Pi+ X vs X’ Note where X’=0 is.