80 likes | 205 Views
Vertical Correction update. David Kelliher ASTEC/CCLRC/RAL 5 th June, 2007. BPMs and vertical kicker location. Neil Bliss 3/4/07. Find optimal vertical corrector strengths Least-Squares Minimisation method. Input Error (BPM data) Vertical magnet misalignments.
E N D
Vertical Correction update David Kelliher ASTEC/CCLRC/RAL 5th June, 2007
BPMs and vertical kicker location Neil Bliss 3/4/07
Find optimal vertical corrector strengthsLeast-Squares Minimisation method Input Error (BPM data) Vertical magnet misalignments Apply a set of vertical corrector strengths from within some range 2 > target value Calculate TWISS orbit at select energies Calculate penalty function 2 - Given by the sum of vertical orbit distortion squared over select energies. Output vertical orbit distortion at each energy 2 < target value Use vertical corrector strengths over entire energy range
MADX – MATCH moduleLeast-Squares Minimisation method MATCH,use_macro; //vary mrex for bpmf vary,name=vk1,step=1e-4,lower=-1e-2,upper=1e-2; vary,name=vk3,step=1e-4,lower=-1e-2,upper=1e-2; vary,name=vk5,step=1e-4,lower=-1e-2,upper=1e-2; … c2: macro={ ekmev=10.0; TWISS,DELTAP=dponp,table=twissmatch; ycormsnow1=table(summ,YCORMS); ekmev=10.09; TWISS,DELTAP=dponp,table=twissmatch; ycormsnow2=table(summ,YCORMS); … constraint,expr= ycormsnow1=0.0; constraint,expr= ycormsnow2=0.0; lmdif,calls=50,tolerance = 1E-8; (Fast Gradient Minimisation algorithm)
Correction over full rangeConstraints in troughs Mean distortion reduced by 12%
Correction over full rangeConstraints in troughs and near peaks
Conclusions • Difficult to reduce peaks in vertical orbit distortion around every integer tune • Need to run tracking code to more accurately calculate orbit distortion over energy range • Other sources of error (monitor offset etc) should be included in the analysis.