Closing Corrector Multiknob Bumps in PEP-II

11/14/00 B. Murphy

Initialize MICADO steering package in the ring in question.

Calibrate BPMs in the ring, ideally with a short train of bunches, ~1 mA/bucket for HER, ~2mA/bucket for LER.

Pick out BPMs that look unphysical or give erratic readings. Disable these BPMs in steering.

Disable all correctors in steering except those used in the bump knob to be closed.

Disable BPMs in steering for the area where the bump is supposed to affect the orbit.

Take an instant reference orbit. Plot BPM diff to reference orbit.

Turn off all orbit feedbacks in the ring in question.

Save a magnet config. This will be used to calculate the new coefficients.

Make a bump of at least 1mm if position, 2mm peak-to-peak if angle, compared to the reference orbit.

Hit scan/calc/trim. Write down the corrector MICADO thinks will best fix the orbit. Use that corrector by hand

to close the orbit as well as is possible.

Iterate the above step until the orbit is satisfactory outside the area where the bump is active.

The goal is to close the orbit using only correctors in the bump knob, if possible.

Save a magnet config. Calculate the delta for each corrector magnet. Make a list of deltas. This list represents the

vector coefficients of the new, closed multiknob. The new knob should be calibrated so that one knob unit equals

one millimeter, or micron, and so on.