Paper 
Title 
Other Keywords 
Page 
TUPLB09 
Design and Beam Test of Sixelectrode BPMs for Secondorder Moment Measurement 
factory, electron, multipole, linac 
464 

 K. Yanagida, H. Hanaki, S. Suzuki
JASRI/SPring8, Hyogoken, Japan



In the SPring8 linac, fourelectrode beam position monitors (BPMs) have been utilized for the measurement of the transverse firstorder moments, which correspond to the centroids of beam charge distributions. We have planed to measure the transverse secondorder moments of beams to obtain information of beam optics and its energy deviations during the topup beam injection without destruction of beams. Therefore, sixelectrode BPMs with circular and quasiellipse crosssections have been developed on the basis of a newly introduced theory. A lownoise signal processor for the sixelectrode BPM has also been developed to perform fine measurement. We expected the following resolutions determined by the S/N ratio of the circuit; the first order moments (beam positions) > 1 μm, and the second order moments with a size > 110 μm. The first beam test was carried out using the sixelectrode BPM with circular crosssection and the old signal processor. The measured sensitivities and resolutions of the secondorder moments showed good agreement with the theory.



Slides TUPLB09 [8.248 MB]



TUPB079 
Design and Beam Test of SixElectrode BPMs for SecondOrder Moment Measurement 
factory, electron, multipole, linac 
654 

 K. Yanagida, H. Hanaki, S. Suzuki
JASRI/SPring8, Hyogoken, Japan



In the SPring8 linac, fourelectrode beam position monitors (BPMs) have been utilized for the measurement of the transverse firstorder moments, which correspond to the centroids of beam charge distributions. We have planed to measure the transverse secondorder moments of beams to obtain information of beam optics and its energy deviations during the topup beam injection without destruction of beams. Therefore, sixelectrode BPMs with circular and quasiellipse crosssections have been developed on the basis of a newly introduced theory. A lownoise signal processor for the sixelectrode BPM has also been developed to perform fine measurement. We expected the following resolutions determined by the S/N ratio of the circuit; the first order moments (beam positions) >1 μm, and the second order moments with a size >110 μm. The first beam test was carried out using the sixelectrode BPM with circular crosssection and the old signal processor. The measured sensitivities and resolutions of the secondorder moments showed good agreement with the theory.


