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- Y.-C. Chao, H. Areti, F.J. Benesch, B. Bevins, S.A. Bogacz, S. Chattopadhyay, J.M. Grames, J. Hansknecht, A. Hutton, R. Kazimi, L. Merminga, M. Poelker, Y. Roblin, M. Tiefenback
Jefferson Lab, Newport News, Virginia
- D. Armstrong
The College of William and Mary, Williamsburg
- D. Beck, K. Nakahara
University of Illinois, Urbana
- K. Paschke
University of Massachusetts, Amherst
- M. Pitt
Virginia Polytechnic Institute and State University, Blacksburg
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Measurement of asymmetry between alternating opposite electron polarization in electron-nucleon scattering experiments can answer important questions about nucleon structures. Such experiments impose stringent condition on the electron beam quality, and thus the accelerator used for beam creation and delivery. Of particular concern to such ?parity? experiments is the level of correlation between beam characteristics (orbit, intensity) and electron polarization that can obscure the real asymmetry. This can be introduced at the beam forming stage, created due to scraping, or not damped to desired level due to defective transport. Suppression of such correlation thus demands tight control of the beam line from cathode to target, and requires multi-disciplined approach with collaboration among nuclear physicists and accelerator physicists/engineers. The approach adopted at Jefferson Lab includes reduction of correlation source, improving low energy beam handling, and monitoring and correcting global transport. This paper will discuss methods adopted to meet the performance criteria imposed by parity experiments, and ongoing research aimed at going beyond current performance.
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