•Number of pbars!!!
–NOT (primarily) due to protons on target or pbar production
rate.
–Typically only around 50% of pbars from
the accumulator make it to collisions.
–Some of this is due to large emittances out of the accumulator.
This gets worse with larger
stacks.
–Some is due to aperture and matching problems throughout the
system.
•Long range beam interactions in the Tevatron:
–Limit total number of protons.
–Due to aperture and helix problems.
•General reliability problems:
–It’s a very complicated system
–If we lose the antiprotons, it takes at least 12 hours to recover.