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Hall C SHMS Fringe Field AnalysisMichael Moore
Hall C Winter Meeting 2-22-2014
Outline
• The Fringe Field Problem• TOSCA model• Results of simulations• Conclusions• Work that still needs to be done
SHMS Elements
Q3 Q2 Q1 HBTarget
Dipole
How Close is too Close?
HB Yoke
Cryostat(coils inside)
Beamline
HMS Q1
The Model
MSU’s 1006 Fe 1006 Fe 1010
HB Q1
Q2Q3
Displacements
Beam Dump Window4” diameter
x
𝑥=(𝑟 −𝐷𝑥)cos (𝛼)cos (𝛾−𝛼)
3𝑜
𝜃
𝛼
𝛾
z
x 𝐷𝑥𝑟
𝐷
Target (9.21,-175.76)
49 m, target to dump distance
*Not drawn to scale
∎3𝑜 𝑖𝑠𝐻𝐵𝑏𝑒𝑛𝑑𝑖𝑛𝑔𝑎𝑛𝑔𝑙𝑒
Beamline axis
Displacement from center of beamdump window
∎𝜃 𝑖𝑠𝑆𝐻𝑀𝑆𝑠𝑐𝑎𝑡𝑡𝑒𝑟𝑖𝑛𝑔𝑎𝑛𝑔𝑙𝑒∎𝛾=𝜃+3
Beam Trajectory
“As Built” Fringe Fields
HB Q1 Q2 Q3
Integral: -126664Maximum: 1825.34Minimum: -2796.38
By Along Beampipe “As Built”, 11 GeV
By (G
)
Z (cm)
Wedges Fringe Fields
By (G
)
Z (cm)
By Along Beampipe “Extra Fe”, 11 GeV
HB Q1 Q2 Q3
Integral: -72477.1Maximum: 1427.82Minimum: -1814.02
“As Built” and Wedges Displacements
60 cm Pipe
HB
Pipe
Two meter Pipe
HB
Pipe
Two meter Pipe with Q2 Collar
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
Fitting the Beam in the Beamdump Window