• C. Yao, N.P. Di Monte, V. Sajaev
  ANL, Argonne

A bunch-by-bunch feed­back sys­tem was in­stalled at the APS in 2008. Close-loop tests were con­duct­ed and im­prove­ments have been made to the sys­tem that in­clude two 500-watt am­pli­fiers, a new lo­ca­tion for the hor­i­zon­tal drive stripline, a two-blade new hor­i­zon­tal stripline, and up­grade of front-end elec­tron­ics. With these im­prove­ments we are able to sta­bi­lize beam with a re­duced chro­matic­i­ty of 0.45 in the hor­i­zon­tal plane and 2.5 in the ver­ti­cal plane for the 24-sin­glet bunch pat­tern. Beam life­time has in­creased from 8.5 hours to 15 hours. We did not ob­serve any ob­vi­ous in­crease in the ef­fec­tive beam emit­tance and rms beam mo­tion. More stud­ies will be per­formed to ex­plore the po­ten­tial of im­prov­ing beam per­for­mance of the hy­brids fill pat­tern, which has a 16-mA lead­ing bunch. We re­port the sys­tem im­prove­ments and the re­sults of our test re­sults.

cyao@aps.anl.gov