FEL2009 - List of Authors (Shiiyama, T.)

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Shiiyama, T.

Paper	Title	Page
TUPC18	Development of a Thermionic Triode RF Gun	281
	K. Masuda, T. Kii, H. Ohgaki, T. Shiiyama Kyoto IAE, Kyoto K. Kanno, E. Tanabe AET Japan, Inc., Kawasaki-City
	A triode rf gun* is being developed, which is aimed at drastic reduction of electrons back-streaming and hitting the thermionic cathode. Thermionic rf guns in general show advantages over photocathode guns such as low cost, easy operation and high averaged current (high repetition rate), which are suitable for FELs for various uses. They however suffer from the electron back-bombardment resulting in limited macro-pulse duration of severalμseconds. In order to reduce the back-streaming electrons, the triode rf gun employs an rf cavity much shorter (e.g. ~2 mm) than the rf wavelength as the first cell with a thermionic cathode. The phase and amplitude of the rf field in the first short cell are then controlled independent from the successive cells. We have designed a triode rf gun and fabricated the additional short rf cavity which is to be installed in the S-band 4.5-cell rf gun used in the KU-FEL. The results from PIC simulations showed that the back-bombardment power is expected to reduce drastically by more than 80% without loss of beam brightness. Preliminary results from the cold testing and rf conditioning of the additional cavity will be also presented. *K. Kanno et al., Japanese J. Applied Physics 41 (2002) 62-64, and K. Masuda et al., Proc. of 27th Intnl. FEL Conf. 2005 (2006) 588.

Paper

Title

Page

TUPC18

Development of a Thermionic Triode RF Gun

281

K. Masuda, T. Kii, H. Ohgaki, T. Shiiyama
Kyoto IAE, Kyoto
K. Kanno, E. Tanabe
AET Japan, Inc., Kawasaki-City

A triode rf gun* is being developed, which is aimed at drastic reduction of electrons back-streaming and hitting the thermionic cathode. Thermionic rf guns in general show advantages over photocathode guns such as low cost, easy operation and high averaged current (high repetition rate), which are suitable for FELs for various uses. They however suffer from the electron back-bombardment resulting in limited macro-pulse duration of severalμseconds. In order to reduce the back-streaming electrons, the triode rf gun employs an rf cavity much shorter (e.g. ~2 mm) than the rf wavelength as the first cell with a thermionic cathode. The phase and amplitude of the rf field in the first short cell are then controlled independent from the successive cells. We have designed a triode rf gun and fabricated the additional short rf cavity which is to be installed in the S-band 4.5-cell rf gun used in the KU-FEL. The results from PIC simulations showed that the back-bombardment power is expected to reduce drastically by more than 80% without loss of beam brightness. Preliminary results from the cold testing and rf conditioning of the additional cavity will be also presented.

*K. Kanno et al., Japanese J. Applied Physics 41 (2002) 62-64, and
K. Masuda et al., Proc. of 27th Intnl. FEL Conf. 2005 (2006) 588.