• J. Fang, P. Lu, Q. Luo, B. Sun, X.H. Wang
  USTC/NSRL, Hefei, Anhui

The en­er­gy spread mea­sure­ment by use the en­er­gy spec­trum anal­y­sis sys­tem at HLS LINAC now is an in­ter­cept­ing mea­sure­ment which can't mea­sure the real in­jec­tion beam. To achieve the non-in­ter­cept­ing mea­sure­ment, a new Beam po­si­tion mon­i­tor (BPM) with eight stripline elec­trodes in four-ax­is sym­me­try is de­signed, which can mea­sure the en­er­gy spread at HLS LINAC in real time. This paper has in­tro­duced the phys­i­cal struc­ture of this new BPM which in­clude eight 20 de­gree open­ing angle, 1/4 wave­length (26.2mm) length Stripline elec­trodes in de­tail, an­a­lyzed and cal­cu­lat­ed the elec­trode re­sponse and pick­ing up the quadrupole com­po­nent, and got the the­o­ret­i­cal sen­si­tiv­i­ties of dif­fer­ent meth­ods. The BPM is sim­u­lat­ed and cal­cu­lat­ed by CST Mi­crowave Stu­dio Pro­gram. The re­sults shows the pa­ram­e­ters such as char­ac­ter­is­tic impedance, elec­trode cou­pling de­gree, time-do­main re­sponse and fre­quen­cy-do­main re­sponse etc are all meet the re­quire­ment of HLS LINAC and trans­fer line.

• Q. Luo, J. Fang, D.H. He, B. Sun
  USTC/NSRL, Hefei, Anhui

An s-band re-en­trant cav­i­ty BPM sys­tem is de­signed for new high bright­ness in­jec­tor at HLS. A pro­to­type cav­i­ty BPM sys­tem was man­u­fac­tured for off-line test, which is also called cold test. Ac­cord­ing to the re­sults of com­put­er sim­u­la­tion, wire scan­ning off-line test method can be used to cal­i­brate the BPM and es­ti­mate the per­for­mance of the on-line BPM sys­tem. Cross-talk prob­lem was de­tect­ed dur­ing the cold test. Ig­nor­ing non­lin­ear ef­fect, trans­for­ma­tion ma­trix is a way to cor­rect cross-talk. Anal­y­sis of cold test re­sults showed that po­si­tion res­o­lu­tion of pro­to­type BPM is bet­ter than 3 μm.