Vacuum status at KEKBJunji Haba

KEKB Vacuum system

Vacuum monitoring

HER vacuum characteristicsDependence on HER current is clear. ~ 0.3 (0A) 1.2 (1.3A) x10-7Pa 1nTorr (PEPII) =1.3 x 10-7 Pa (KEKB)Far from base pressure dominanceNot always simple linear relationSome show a clear thermal behaviorBeam life time is a function not only of pressure but also luminosity or beam-beam effect.

2004 June 14-20

Discharge startsaround 0.9A at septum?Heat up at the feed back kicker structure

Life time is predetermined by luminosity

Beam-beam also affects the lifetimeLER currentHER beam size vs LER currentHER life and beam size

LER vacuum characteristicsCurrent dependence is clear~ 0.2 (0A) 0.8 (1.6A) x10-7PaThermal behavior everywhere we have the parts with a special internal shape like GV, crotches, injection chamber etc.