Post date: Apr 4, 2014 6:36:25 AM
We have attempted to match the horizontal orbit with 700A corrector current. It was not as successful as we'd hoped!
First we verified that the matching with the lower corrector setting from yesterday was reproducible, which it was.
Then we took out the probe that is at the same azimuthal position as the foil, and slowly turned up the corrector setting adjusting the foil position slightly to maintain the number of turns.
This was OK but when we put the probe back in we didn't get many circulating turns.
A lot of effort later (!) after many attempts at changing the ST6 steerer to adjust angle at the foil, changing the foil position to adjust injection position and eventually changing the injection line bending magnets to change the position that the beam enters the main magnet, we were unable to find a good combination of settings to get a good number of circulating turns.
This is a bit strange. We already know from last year that it is possible to inject onto the un-distorted closed orbit without the cavity present, and we can inject OK onto the CO with 468A corrector settings. So why can't we inject at a position which should be somewhere between those two?
We would have liked to attempt the same thing for 550A setting to see if that works, but unfortunately time doesn't permit it today.