TY - JOUR
T1 - Design of a two-cell rf-deflector cavity for ultra-short electron bunch measurement
AU - Nishimura, Y.
AU - Sakaue, K.
AU - Nishiyama, M.
AU - Takahashi, T.
AU - Washio, M.
AU - Takatomi, T.
AU - Urakawa, J.
N1 - Funding Information:
Authors are grateful to Mr. Kudo of KEK Mechanical Engineering Center for his support on manufacturing the rf-deflector cavity and Dr. K. Watanabe of KEK Accelerator Laboratory for his support on HFSS simulation. This work was supported by a JSPS Grant-in-Aid for Scientific Research (A) 10001690 and the Quantum Beam Technology Program of MEXT .
PY - 2014/11/11
Y1 - 2014/11/11
N2 - For a longitudinal characterization of an ultra-short electron bunch, an rf-deflector cavity is the best resolution technique that can directly convert longitudinal distribution to transverse. This paper describes the principle of longitudinal diagnostics using an rf-deflector cavity, the design details of an rf-deflector cavity and the results of rf-characteristics for a manufactured cavity. The cavity is based on a rectangular two-cell structure operating on standing wave π-mode, dipole (TM120) mode at 2856 MHz. We have confirmed using HFSS simulation that this cavity can produce a deflecting voltage of 1.63 MV with an input rf-power of 750 kW. The results of low power rf-measurement of the manufactured cavity show an effective deflecting voltage of 1.00 MV which corresponds to a temporal resolution of 58 fs (rms) (250 fs/mm on the profile monitor) with 750 kW input rf-power, drift length L of 1 m and initial size σoff of 230 μm. These results indicate that we have successfully achieved our target: temporal resolution of less than 100 fs with an electron bunch with energy of 4.5 MeV and charge of 100 pC.
AB - For a longitudinal characterization of an ultra-short electron bunch, an rf-deflector cavity is the best resolution technique that can directly convert longitudinal distribution to transverse. This paper describes the principle of longitudinal diagnostics using an rf-deflector cavity, the design details of an rf-deflector cavity and the results of rf-characteristics for a manufactured cavity. The cavity is based on a rectangular two-cell structure operating on standing wave π-mode, dipole (TM120) mode at 2856 MHz. We have confirmed using HFSS simulation that this cavity can produce a deflecting voltage of 1.63 MV with an input rf-power of 750 kW. The results of low power rf-measurement of the manufactured cavity show an effective deflecting voltage of 1.00 MV which corresponds to a temporal resolution of 58 fs (rms) (250 fs/mm on the profile monitor) with 750 kW input rf-power, drift length L of 1 m and initial size σoff of 230 μm. These results indicate that we have successfully achieved our target: temporal resolution of less than 100 fs with an electron bunch with energy of 4.5 MeV and charge of 100 pC.
KW - Ultra-short electron bunch measurement
KW - rf deflector cavity
KW - rf electron gun
UR - http://www.scopus.com/inward/record.url?scp=84906565398&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84906565398&partnerID=8YFLogxK
U2 - 10.1016/j.nima.2014.07.035
DO - 10.1016/j.nima.2014.07.035
M3 - Article
AN - SCOPUS:84906565398
VL - 764
SP - 291
EP - 298
JO - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
JF - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
SN - 0168-9002
ER -