OVERVIE WO FBEA MINSTRUMENTATIO NFO RHIGH-INTENSITY STORAG ERINGS

This paper will present an overview of beam instru- mentation with a view towards relevance for future ac- celerator projects on the basis of experience at KEKB. The KEKB B-Factory shares with other existing and planned electron and positron machines the require- ment for precise measurements at high beam intensi- ties. New accelerators and upgrade plans always seek higher beam currents (bunch currents, number of bunches). Beam instrumentation needs to handle the associated heating and dynamic range issues, and provide diagnosis of the increased instabilities that arise. In striving to reach its design goals, KEKB has also encountered many of these issues. This paper will present an overview of beam instrumentation at KEKB, and of our experience of such issues. KEKB is an electron-positron collider with two rings: the 8 GeV High Energy Ring (HER) for elec- trons, and the 3.5 GeV Low Energy Ring (LER) for positrons. The rings have circumference of approxi- mately 3 km, and intersect with a crossing angle of 22 mrad at the interaction point. The total number of rf buckets in each ring is 5120, with about 1150 be- ing used at present for physics running. The maximum stored currents have been gradually raised to 1100 mA for the LER, and 873 mA for the HER.