| Paper |
Title |
Page |
| MOP025 |
Study on High-Current Multi-Bunch Beam Acceleration for KEKB Injector Linac
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91 |
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- M. Yoshida, H. Katagiri, Y. Ogawa
KEK, Ibaraki
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The KEKB injector linac is usually operated to accelerate only two 10 nC electron bunches to generate positron, since more bunch cannot be equalized the beam energy using the conventional pulse compressor (SLED) and the simple phase modulation. The aim of this study is to find how to accelerate more bunches without any modification of high power RF distribution. One way is that a part of the acceleration units is used to compensate the beam energy difference. On the other hand, the recent electron linac is designed for the multi-bunch operation by compensating the beam loading. And this beam loading compensation method is usually realized by combining the output power of two or more klystrons. However our linac system consists of one 50 MW klystron in one acceleration unit, and eight klystrons are driven by a 100kW klystron. Another way to realize the multi-bunch acceleration in our linac is using the amplitude modulation of the klystron. This is realized using the I-Q modulation of the low level RF considering the non-linear characteristics of the total amplification system including klystrons. Further we developed a FPGA board with 100 MHz DACs and ADCs to realize this.
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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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| THP040 |
New Concept of Small Delay Line Type RF Pulse Compressor Using Coupled Cavities
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667 |
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I propose a new concept for the RF pulse compressor using the coupled cavities to make a small delay line. This new concept is a hybrid scheme of a cavity type and a delay line type of the RF pulse compressor. The delay line produces the pulse compression outputs through resultant RF beat between two inputs connected both ports of the coupled cavities. The time constant of the beat is matched to the time constant of the power flow of the coupled cavities. Further the special test stand for the coupled cavities was developed to easily adjust the resonant frequency of such high-Q coupled cavities.
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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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