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The Center for Bright Beams, A National Science Foundation Science and Technology Center

Optical Stochastic Cooling with an Arc-Bypass in CESR

A jumble of blue, black, and red lines with many peaks and valleys.

M. B. Andorf, W. F. Bergan, I. V. Bazarov, J. M. Maxson, V. Khachatryan, D. L. Rubin, and S. T. Wang

Advanced beam cooling techniques are being developed to address the challenge of luminosity degradation that occurs during a beam store in high brightness hadron and heavy-ion colliders. One such technique is Optical Stochastic Cooling (OSC) which aims to leverage the large bandwidth that optical amplifiers can support in order to make extraordinarily precise corrections to the particle beam distribution. A major challenge that needs to be addressed before OSC can be used in a collider is a bypass design that is compatible with the necessary optical delay needed for a high-gain amplifier. This paper explores a proposed test of such a bypass in the Cornell Electron Storage Ring (CESR). In it we report our bypass design, analyze the required stability of such a bypass and propose a feedback mechanism to relax the found stability requirements. The results are applied to the CESR experiment but are general to any OSC setup.

Figure: Schematic of the arc-bypass in CESR. Light is ex-tracted from the vacuum chamber in the immediate down-stream dipole (blue) of the PU (green) and reenters in theimmediate upstream dipole of the KU. Dimensions are in m.

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