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An experiment investigating the photoelectron instability has been performed in BEPC at IHEP, China. The betatron oscillation of each bunch was observed and recorded by a single pass beam position monitor system which has a capability to measure the transverse position of every bunch over 16000 turns. The effect of an octupole magnet on the instability was… (More)
This paper describes an experimental study of the enlargement of the vertical beam size observed in single beam operation at the KEKB LER.
For the stable high-luminosity operation and luminosity-increase, the electron and positron storage rings of the KEK B-Factory (KEKB) is equipped with various beam instrumentations, which have being working well since the start of the commissioning in December, 1998. Details and performance of the beam-position monitor system based on the spectrum analysis… (More)
In order to investigate the single-beam vertical beam-size blow-up observed in the KEKB 3.5 GeV positron ring (LER), we performed beam-size observations using a high-speed gated camera capable of recording the image of a single bunch in the ring. Using this technique, we measured the beam-size dependence on bunch position along a train, and studied the… (More)
Transverse bunch-by-bunch feedback systems for damping coupled-bunch instabilities in the KEKB rings have been working since the early stage of the commissioning of the rings. Stabilization of the beams with the system have been successful, permitting tests of higher beam currents and various filling patterns. The performance of these systems has been… (More)
Recent activities at optical laboratories 1 and 2 at the Photon Factory are presented. The activities are (i) construction of optical laboratory 1, (ii) reconstruction of optical laboratory 2, (iii) construction of a visible synchrotron radiation beam extraction mirror made of beryllium, (iv) small-beam-profile measurement by means of the image restoration… (More)
The Data Acquisition System of Beam Position Moni-tors(BPMs) in J-PARC Main Ring consists of 186 Linux-based Data Processing Circuits(BPMCs) and 12 EPICS IOCs. It is an important tool to see the COD and turn-by-turn (bunch-by-bunch) beam positions. This report describes the process of the data reconstruction which include how the various calibration… (More)
Crab cavities have been installed in the KEKB B– Factory rings to compensate the crossing angle at the collision point and thus increase luminosity. The beam operation with crab crossing has been done since February 2007. (IP). Although there are a lot of merits in the crossing angle scheme, the beam-beam performance may degrade. The design of KEKB… (More)
The effects of electron clouds on positively charged beams have been an active area of research in recent years at particle accelerators around the world. Transverse beam-size blowup due to electron clouds has been observed in some machines and is considered to be a major limiting factor in the development of higher-current, higher-luminosity… (More)
This paper will present an overview of beam instru-mentation with a view towards relevance for future accelerator projects on the basis of experience at KEKB. The KEKB B-Factory shares with other existing and planned electron and positron machines the requirement for precise measurements at high beam intensities .