Title :
Lattice design for the High Energy Ring of the SLAC B-Factory (PEP-II)
Author :
Donald, M H R ; Cai, Y. ; Irwin, J. ; Nosochkov, Y. ; Ritson, D.M. ; Seeman, J. ; Wienands, H.-U. ; Yan, Y.T.
Author_Institution :
Stanford Linear Accel. Center, Stanford Univ., CA, USA
Abstract :
The design of the lattice for the High Energy Ring (HER) of the SLAC B-Factory has several special features, notably provision for octupole compensation of amplitude dependent tune shift effects and a beta-beat scheme for semi-local chromaticity correction. In the arcs adjacent to the interaction point (IP) the beta functions are enhanced to allow the use of non-interlaced sextupoles to compensate the chromaticity of the interaction region. A closed bump of beta “mismatch” is generated by two vertically focusing quadrupoles spaced 2 betatron wavelengths apart. The beta-beat has two advantages: it enhances the ratio between the horizontal and vertical beta functions at the sextupoles and, because of the locally higher beta function, allows weaker sextupoles to be used. The standard design uses a 60 degree/cell lattice but a 90 degree/cell lattice may also be used if lower emittances and momentum compaction factor are desired
Keywords :
electron accelerators; electron beam focusing; storage rings; High Energy Ring; PEP-II; SLAC B-Factory; amplitude dependent tune shift effects; beta functions; beta-beat scheme; chromaticity correction; emittances; lattice; momentum compaction factor; octupole; vertically focusing quadrupoles; Clocks; Compaction; Contracts; Electrons; Lattices; Linear accelerators; Magnetic fields; Positrons; Radio frequency; Storage rings;
Conference_Titel :
Particle Accelerator Conference, 1995., Proceedings of the 1995
Conference_Location :
Dallas, TX
Print_ISBN :
0-7803-2934-1
DOI :
10.1109/PAC.1995.504729
