| Paper |
Title |
Page |
| TUPCH057 |
A Diagnostic System for Beam Abort at KEKB
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1139 |
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- H. Ikeda, K. Akai, J.W. Flanagan, T. Furuya, S. Hiramatsu, M. Suetake, Y. Suetsugu, M. Tobiyama, T. Tsuboyama
KEK, Ibaraki
- S. Stanic
Tsukuba University, Ibaraki
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A controlled beam abort system has been installed at KEKB for the protection of the hardware components of the accelerator and detector from damage by ampere-class beam currents. In order to identify the reason for each abort and optimize the abort system to handle each type of problem as well as improve machine operation, a diagnostic system has been developed. Fast signals, such as beam currents, accelerating voltages of the RF cavities and beam loss monitor signals from PIN photo-diodes are recorded and analyzed by a data logger system with a high sampling rate at the moment of each abort. Beam oscillations, radiation dose at the detector and vacuum pressure are also examined to classify the reasons for beam loss and aborts. Statistics and typical examples of these aborts will be discussed.
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| TUPCH179 |
R&D on Copper Beam Ducts with Antechambers and Related Vacuum Components
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1438 |
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- Y. Suetsugu, H. Hisamatsu, K.-I. Kanazawa, K. Shibata, M. Shimamoto, M. Shirai
KEK, Ibaraki
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A beam duct with antechambers is able to reduce the effect of photoelectrons and, as a result, to suppress the electron cloud effect of positron or proton beam. It will be adopted for a future high current positron/proton rings and also a damping ring of a linear collider. Copper beam ducts with one or two antechambers were manufactured for test and the feasibility was studied. The test chambers were then installed into the KEK B-factory positron ring and the performance was investigated with a beam current up to 2000 mA. The temperature, the pressure and the electron density in the beam channel were measured during the beam operation. The photoelectron, for example, was found to be well suppressed as expected compared to that of a simple circular beam duct. The related vacuum components, such as a connection flange, a bellows chamber and a gate valve with the same cross section to the beam duct, were also developed and tested together with the beam duct.
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