Low Proton Energy Running

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Low Proton Energy Running
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Adiabatic damping and aperture limitations
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Proton beam-beam Tuneshift
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Electron Beam Size Matching
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Electron Beam-Beam Tune shift
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Lumi-scaling with Energy
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First simple Version

• Protons of 460GeV with Positrons of 27.5GeV
• Concept
• Do not touch the positron magnets in the IR
• Thus the e IR trajectory as in standard running
• Increase Beta functions and emittances by a
  factor of two
• Minimize distance between p beam envelope and GM
  Mirror plate
• Move all proton magnets GM-QR10

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Beam Optics
bxp4.9m bxe 1.20m byp0.36m bye
0.52m eNp16 mm exe
40nm eye 6 nm
e-Quadrupoles within 40m of IP not
changed Proton Optics
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Beam-Beam Tuneshift
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Proton Trajectories for 920GeV and for 460 GeV
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Magnet Positions for 920GeV and 460GeV Proton
Trajectories
460GeV Magnet Axis Positions
920GeV Magnet Axis Positions
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Top View 460GeV/27.5GeV proton /positron
trajectories
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2nd Iteration

• ? Reduce GM magnets in strength and
• ? leave all p-magnets in the nominal proton-
  
• positron/electron positions
• ? Positron Lattice unchanged,
• positron IR quads unchanged
• ? Positron optics in the arc assume 60 degree
• ?positron/proton IP (-7.5mm radially)
• ? Optical Parameters
• bxp4.9m bxe 1.20m
• byp0.36m bye 0.52m
• eNp16 mm exe 40nm
• eye 6 nm

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IR Top View
P-Magnets Nominal positron/electron
positions E-Magnets Nominal positron positions
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IR Top View Close-up
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All p-magnets are now at nominal positions
GM GM GN GN GN GA GB GB GB9 QR QR QR QR
4mm
P-magnets axis
IP
P-Trajectory
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P-Optics
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Effort to readjust magnets

• Discussion with surveillers
• für die vorgeschlagene "Lösung 2" mit einer
  Justage von 3-4 Magneten habe ich die folgenden
  Zeiten kalkuliert Aufmaß
• 3-4 Standpunkte pro Seite (NR,NL,SR,SL)  x 
  4 12-16 Std. Justierung von 3
  Magneten                          x  4 12 Std.
  Kontrollaufmaß                                   
                   12 Std.
• Gesamt                                       
                           36 - 40 Std. bei
  Einsatz von zwei Trupps ergibt sich ein Aufwand
  von 18-20 Stunden.
• Spaeter geht es wahrscheinlich etwas fixer,
  so daß es in knapp zwei Tagen geschafft würde.

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To Do List until PRC in May

• Match p Optics for left hand side IR
  (Bernhard/Alexander)
• Design trajectories for right hand side IR
  (Joachim) ok
• Positron Optics with 40nm (Mathias)
• Explore alternative p-Optics with larger Lumi
• GM weaker, GN-1 GN-2 stronger (factor 2),
  GA stronger, 2nd GN8 off, need GN9, QR10,QR14?
  (Ferdinand) done
• Exact Calculation of e and p trajectories with
  Mike Seidels program (refine Magnet positions if
  needed) and generate magnet position lists, BPM
  offsets etc(Joachim) ok
• Recalculate SR deposition (Boris) for the case
  the GMs are moved
• Check to which extend magnets can be moved (April
  5) (Michael/Peter) this Friday
• Discuss with surveillers, make schedule
  (Michael/Ferdinand) in progress
• Lumimonitor Acceptance (Uwe/Guenther) no problem
  for 2nd version without moving GM