A Reduced Emittance Lattice for the NLC Positron Predamping Ring

This is an updated version of [1]. In the design presented there the horizontal emittance of the extracted beam is too large by about 20%. In order to get the emittance down to the required value the quadrupole magnets in the dispersive regions in the ring are moved to provide J_x=1.1 which gives a small enough emittance. In addition a better model of the wiggler fields is used. The new design meets requirements. The lattice and dynamic aperture studies (assuming no machine errors) are presented. . CBP Tech-Note 280 LCC-0114 A Reduced Emittance Lattice for the NLC Positron Pre-Damping Ring Ina Reichel, Andrzej Wolski Lawrence Berkeley National Laboratory February 24, 2003 Abstract This is an updated version of [1]. In the design presented there the horizontal emittance of the extracted beam is too large by about 20 %. In order to get the emittance down to the required value the quadrupole magnets in the dispersive regions in the ring are moved to provide Jx = 1.1 which gives a small enough emittance. In addition a better model of the wiggler fields is used. The new design meets requirements. The lattice and dynamic aperture studies (assuming no machine errors) are presented.This is an updated version of [1]. In the design presented there the horizontal emittance of the extracted beam is too large by about 20 %. In order to get the emittance down to the required value the quadrupole magnets in the dispersive regions in the ring are moved to provide Jx = 1.1 which gives a small enough emittance. In addition a better model of the wiggler fields is used. The new design meets requirements. The lattice and dynamic aperture studies (assuming no machine errors) are presented.