post-merge guggenheim stage 12 r.c. fernow bnl aag thursday meeting 27 december 2012
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Post-merge Guggenheim stage 12 R.C. Fernow BNL AAG Thursday Meeting 27 December 2012. Introduction. we have been working on post-merge Guggenheim channel ring simulations curved lattice cells dipole fields from tipping the solenoids - PowerPoint PPT PresentationTRANSCRIPT
Post-merge Guggenheim stage 12
R.C. FernowBNL
AAG Thursday Meeting
27 December 2012
2
Introduction
• we have been working on post-merge Guggenheim channel ring simulationscurved lattice cellsdipole fields from tipping the solenoidsgenerate Icool field maps in cylindrical coordinatesemittance exchange by tracking thru wedgesuses RF Be windows scaled from Study 2
• we have working files for all the (11) flip stages• now looking at first non-flip stage
3
Small ring
• first tried small ring (ρ = 1.53 m), similar to last flip lattice• could not find a reasonable closed orbit• tried varying starting parameters for orbit finder by hand• computed 2D beta functions were not reasonable• transmission thru cooling cell was very small
4
Larger ring
• looked at larger ring with ρ = 5.47 m•found a good closed orbit solution•2D beta functions still bad ( β ~ 2 mm, should be ~5.9 cm)•dispersion was small D = 3.3 cm•for 120o wedge
met reference emittance goals for this stageεTN = 0.432 mm, εLN = 2.37 mm after 12 cells
•but transmission was very poor ~0.476
5
Still larger ring
• looked at even larger ring with ρ = 10.95 m•found a good closed orbit•beta functions were still bad ( β ~ 2 mm)•dispersion was very small D = 1.7 cm•for 120o wedge
not able to meet both reference emittance goals for this stageεTN = 0.452 mm, εLN = 2.68 mm after 39 cellstransmission increased, but was still poor ~0.707
•tried wedge angles up to 140o
but was unable to reach the longitudinal emittance goal
6
Eigenvalue analysis
ρ [m] mag phase mag phase
5.47 1.000000 ±170.93 0.999999 ±5.83
10.95 1.000000 ±170.93 0.999999 ±5.83
∞ 1.000011 ±169.45 0.999989 ±6.08
• for ∞ case, both eigenvalues must be the same• possible trouble with
intrinsic design of the lattice ?errors or bad approximations in the simulation ?methods used in the analysis program ?
• currently looking with Scott at eigenvalues of the one-cell transport matrix• trying to find evidence for the source of poor performance