•In order to Reduce radiation, a “notch” is made in the beam
early in the booster
cycle.
•Currently, the
extraction time is based on the counted number of revolutions (RF
buckets) of the Booster. This ensures that the notch is in the
right place.
•The actual time can vary by > 5 usec!
•This is not a problem if booster sets the timing, but
it’s incompatible with
multi-batch running (e.g. Slipstacking or NuMI)
•We must be able to fix this total time so
we can synchronize to the M.I. orbit.
•This is called “beam cogging”.