| Paper | Title | Page |
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| THPPH036 | Design Study of RF Triode Structure for the KU-FEL Thermionic RF Gun | 656 |
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Thermionic rf guns show advantageous features compared with photocathode ones such as easy operation, low cost and high averaged current, which are suitable for their application to FELs for various uses. They however suffer from the back-bombardment effect, resulting in limited macro-pulse duration of severalμseconds. Against this adverse effect, we plan to introduce the triode structure*,** in the 4.5-cell rf gun for the KU-FEL by replacing the thermionic cathode by an assembly of a cathode with an additional coaxial cavity. Two-dimensional simulations have predicted a significant reduction of the back-bombardment power by 99% with a moderate rf power of several tens kW fed to the additional extraction cavity. Moreover an improved energy spread and peak current are expected at the same time with an optimal geometry and operating conditions.
* E. Tanabe et al., Proc. of 27th Linear Accelerator Meeting in Japan (2002) 57, in Japanese. ** K. Masuda et al., Proc. of 27th Intnl. FEL Conf. 2005 (2006) 588. |
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| THPPH039 | Experimental Study on Effect of Energy Distribution on Transverse Phase Space Tomography | 668 |
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Tomographic method * using a quadrupole magnet and a beam profile monitor is useful method of transverse phase space measurement. However the method is suffered from energy distribution. Therefore we have evaluated the effects numerically. As the result, the low energy tail of the beam distorted the result of tomographic method even with a small amount of the tail **.To confirm the numerical evaluation, measurements have been performed with single slit method, whose result is free from energy distribution. In this conference, the experimental result of two methods will be shown and a new tomographic analysis, which mitigates the effect of energy distribution, is proposed.
* C. B.McKee, et al, NIM A 358 (1995) 264** H. Zen, et al, Proc. of FEL2005 (2006) 592 |