Accumulator Skew-Sextupole Specification

1
Accumulator Skew-Sextupole Specification

• Overview of the need for skew-sextupole
  correctors
• Determination of the magnet specification

2
Why does the Accumulator require skew-sextupole
correction?

• Observation of momentum dependent coupling during
  previous running.
• LQF quadrupoles installed for the Accumulator gt
  upgrade initially showed an anomalously high skew
  sextupole.
• This problem was ultimately corrected
• Large measured skew-sextupole content in two
  modified B1 dipoles that were repaired and
  installed late in 1998.

3
LQF Quadrupole Skew-Sextupole

• Technical Division invented an adjustable wedge
  that allows correction of the skew-sextupole at
  the 8 GeV operating current of the magnet.

4
Skew-Sextupole Magnet Specification

• Correct the momentum dependent coupling arising
  from all known sources of skew sextupole.
• Add a large safety margin due to uncertainties in
  the determination of the skew-sextupole content
  of the various magnets in the Accumulator.