1. Hall C SHMS Fringe Field Analysis Michael Moore Hall C Winter Meeting 2-22-2014

2. Outline The Fringe Field Problem TOSCA model Results of simulations Conclusions Work that still needs to be done

3. SHMS Elements Q3 Q2 Q1 HB Target Dipole

4. How Close is too Close? HB Yoke Cryostat (coils inside) Beamline HMS Q1

5. The Model MSU’s 1006 Fe 1006 Fe 1010 HBQ1 Q2 Q3

6. Displacements Beam Dump Window 4” diameter x z x Target (9.21,-175.76) *Not drawn to scale Beamline axis Displacement from center of beamdump window Beam Trajectory

7. “As Built” Fringe Fields HB Q1Q2 Q3 Integral: -126664 Maximum: 1825.34 Minimum: -2796.38 By Along Beampipe “As Built”, 11 GeV By (G) Z (cm)

8. Wedges Fringe Fields By (G) Z (cm) By Along Beampipe “Extra Fe”, 11 GeV HB Q1 Q2 Q3 Integral: -72477.1 Maximum: 1427.82 Minimum: -1814.02

9. “As Built” and Wedges Displacements

10. 60 cm Pipe HB Pipe

11. Two meter Pipe HB Pipe

12. Two meter Pipe with Q2 Collar

13. Conclusions Run pipe and Q2 collar at more angles and energies Optimize for smallest pipe length Add HMS (at least Q1) to the model Still to do As built, the SHMS is a >10 degree spectrometer With extra Iron on the yoke it is a > 9 degree spectrometer Iron pipe with wedges shows promise as a solution

14. Fitting the Beam in the Beamdump Window