| Paper | Title | Page |
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| TUPMA042 | Beam Parameters of the SCSS Prototype Accelerator Designed by PARMELA and Comparison with Measured Values | 169 |
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The 250 MeV prototype facility of the SCSS X-FEL project was constructed in the Octorber 2005 and the machine commissioning was started in May 2006. One month later, we have succeeded in confirming the amplification of the synchrotron radiation. The electron beam parameters, such as peak current and emittance, have been designed and estimated using PARMELA. In contrast to other X-FEL projects, the SCSS injector uses a thermionic pulsed electron gun [1]. Compared with RF photocathode guns, the thermionic gun is stable and easy to handle. Its peak current, however, is smaller, and the compression of the electron bunch is necessary at early stage of the low beam energy injector. In this report, we compare the simulation and measured values, such as a bunch length and projected emittance, on the SCSS prototype accelerator. The measured beam parameters, after the bunch compression procedure and emittance degradation due to space charge, show fairly good agreement with the simulation.
[1] K. Togawa, et al., “Emittance Measurement on the CeB6 Electron Gun for the SPring-8 Compact SASE Source”, Proceedings of the 2004 FEL Conference, (2004)351-354, URL: http://www. JACoW.org. |
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| WEPMA105 | High Power Test of C-band Accelerating System for Japanese XFEL Project | 470 |
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| ?The C-band (5712 MHz) choke-mode type accelerating structure will be used for SCSS: SPring-8 Compact SASE Source project. Since the C-band accelerator generates higher accelerating gradient than traditional S-band accelerator, it makes the machine size compact and the cost low. In order to confirm the performance of the C-band accelerating system for the 8 GeV XFEL machine, the system including the same accelerating structure and RF system have been installed in the SCSS prototype accelerator. The first SASE amplification was observed at 49 nm on June 2006. In the prototype machine, four 1.8 m long C-band accelerating structures are used to accelerate electron up to 250 MeV. The C-band accelerator?unit has one 50 MW klystron and pulse compressor, where two types of pulse compressors: SKIP and SLED were adapted. After 300-hour RF conditioning, accelerating gradient up to 32 MV/m was achieved and we confirmed there is no serious problem. Now we continue the RF conditioning to get higher accelerating gradient and find the practical limit. In this paper, we would like to report on the RF conditioning and the achieved performance of the C-band accelerator. |