| Paper |
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| THP010 |
Low-level RF system for STF
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586 |
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- T. Matsumoto, S. Fukuda, H. Katagiri, S. Michizono, Y. Yano
KEK, Ibaraki
- Z. Geng
IHEP Beijing, Beijing
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The Super-conducting RF Test Facility (STF) has been constructed to establish the production technique of a cavity having a high gradient and operated for the high power testing of the klystron and couplers being installed in the superconducting cavities. An accelerating electric field stability of 0.3% (rms) in amplitude and 0.3 degree (rms) in phase is also required for the RF system in STF. In order to satisfy these requirements, a digital LLRF control system using FPGA is adopted, and the components required for the digital LLRF system have been developed.
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| THP022 |
Status of RF Sources in Super-Conducting RF Test Facility (STF) at KEK
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613 |
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- S. Fukuda, M. Akemoto, H. Hayano, H. Katagiri, S. Kazakov, S. Matsumoto, T. Matsumoto, S. Michizono, H. Nakajima, K. Nakao, T. Shidara, T. Takenaka, Y. Yano, M. Yoshida
KEK, Ibaraki
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Super-conducting rf test facility (STF) has been progessing in KEK since 2005. In this paper, we describe the current status of rf sources in STF. STF rf sources comprise of a long pulse modulator with bouncer circuit, a pulse transformer, an L-band 5MW klystron, power distribution system and low level rf system. We have completed the construction of the first rf system and have been testing for the system evaluation and for the coupler test of the super-conducting cavity. We have a schedule to feed a power to the cryomodule with 8 super-conducting cavities in December of 2006. We also describe the plan of the second rf sources of STF.
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| THP027 |
Study of PPM-Focused X-band Pulse Klystron
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628 |
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- S. Matsumoto, M. Akemoto, S. Fukuda, T. Higo, H. Honma, S. Kazakov, N. K. Kudo, H. Nakajima, T. Shidara, M. Yoshida
KEK, Ibaraki
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The R&D of PPM (Periodic Permanent Magnet)-focused X-band pulse klystrons has been conducted since 1999, originally for Global Linear Collider (GLC) project. So far six prototype tubes have been tested. Some of them successfully produce the power required in GLC (75MW, 1.6μsec pulse width). However their performance was not perfect as a GLC tube. The problems are the stability of RF output and the gun performance. Since GLC programs were terminated in 2004, some limited work on the improvement of the PPM tubes continues at X-Band Test Facility (XTF) in KEK. The work includes the test to evaluate the performance of revised (rebuilt) tubes as well as disassembling these tubes after the test for further inspection. Recent results are reported.
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| THP036 |
Long-Pulse Modulator for the Superconducting RF Test Facility at KEK
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655 |
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- M. Akemoto, S. Fukuda, H. Honma, H. Nakajima, T. Shidara
KEK, Ibaraki
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A long-pulse modulator for the Superconducting RF Test Facility(STF) at KEK is under development now. The modulator is a direct-switched type design with a bouncer circuit to compensate the output pulse droop, and operates the klystron up to 5 MW peak power, 1.5 ms rf pulse width and up to 5 pps repetition rate. The modulator is built by improving a klystron modulator system inherited from Power Reactor and Nuclear Fuel Corp. The design and specifications of the modulator as well as R&D status for ILC modulator are described.
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| THP038 |
Normal Conducting High-Gradient Studies at KEK
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661 |
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- T. Higo, M. Akemoto, S. Fukuda, Y. Higashi, N. K. Kudo, S. Matsumoto, K. Takata, T. T. Takatomi, K. Ueno, K. Yokoyama
KEK, Ibaraki
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Normal-conducting high field studies have been pursued at XTF, a high power X-band RF facility of KEK developed for linear collider. Three traveling-wave structures developed for X-band linear collider were studied in high field of more than 70MV/m level. High-field characteristic such as field emission properties and trip rate, etc. are studied carefully as the processing proceeds. Operation at 50MV/m level was found very stable while breakdowns happened once an hour or so at more than 70MV/m, indicating the approach to some critical point. This characteristics is discussed in conjunction with various author’s trials to make a scaling law of severe breakdowns among power, pulse width and so on. Further basic studies on field/power limitation or robustness against breakdowns in various materials are planned using narrowed waveguide configuration. Unique features related to this study is also described.
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