There are 7 movable colliamtors against synchrotron radiation and off-momentum
a = von aussen = from outward
i = von innen = from inward
o = von oben = from top
u = von unten = from bottom
NL 52a against synrad from BH 64
NL 40i against off-momentum e+
NL 19i against synrad from BN 41
NL 15a against off-momentum e+
NL 6o, 6u against synrad in the vertical
Only needed for safety against mis-steering.
Closing to +-8 mm already causes increased background due to
outgassing and e+ beam-gas interactions.
Also edge-scattered synrad contributes to chamber currents.
NL 5a (Lohrmann's Kleiderbuegel) against horizontal outward synrad tail
For e+: positive current moves downward and inward.
A horizontal 3-coil bump around GJ is most effective: CH 44 11 02
Also CH 75 44 02 helps a bit.
Vertical bump CV 56 27 04 also helps
In addition there are the standard 4-coil lumi bumps CH 75 44 44 75
and CV 56 27 27 56. 'Symmetric' moves the beam position at the IP,
'asymmetric' changes the angle. These are used to steer the Bremsstrahlungs beam
into the lumi photon detector. The p beam is then moved to achive collisions.