S F 0 05 15 . Emittance Dilution by Ions in the SLC Arcs ∗
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چکیده
Since the start of flat-beam operation in 1993 typical vertical IP spot sizes in the SLC are well below 1 micron, and the luminosity is highly sensitive to dilutions of the vertical emittance. In the arcs, the ionization of the residual gas by the bunch head gives rise to an ion cloud, whose electric field deflects the tail of the bunch and may cause an unre-coverable filamentation in phase space. The effect of the ions is particularly important in regions with large dispersion , due to the strong correlation of energy and longitudinal position within a bunch. Computer simulations of a bunch passage in the presence of ions have been performed to estimate the magnitude of the emittance dilution.
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تاریخ انتشار 1994