Author: Ishii, K.
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TUPMR039 The Development of a New High Field Injection Septum Magnet System for Main Ring of J-Parc 1337
 
  • T. Shibata, K. Ishii, H. Matsumoto, N. Matsumoto, T. Sugimoto
    KEK, Ibaraki, Japan
  • K. Fan
    HUST, Wuhan, People's Republic of China
 
  We are improving the Main Ring (MR) for beam power of 750 kw which is the first goal of J-PARC. The repetition period of the fast extraction must be short to 1.3 second from the current period of 2.48 second for the improvement of the beam power. It is necessary to exchange a high field injection septum magnet which will be installed at the injection line from RCS to MR and its power supply, because the current injection septum system can not be operated with 1.3 second repetition. Since confirmed the large leakage field around current circling beam line of the injection magnet, we must improve the shielding structure which make low leakage field. We started the development of the new injection septum magnet and its power supply in 2013. It can operate with 1 Hz repetition and the low leakage field which its order is 10-4 of the gap field. The new Injection septum magnet and the new power supply were constructed in Winter of 2014. We had many improvement of the magnet and power supply. We will install the new injection septum magnet system in this summer. In this presentation, we will report the detail of the results of its performance.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR039  
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TUPMR040 The Development of a New Low Field Septum Magnet System for Fast Extraction in Main Ring of J-PARC 1340
 
  • T. Shibata, K. Ishii, H. Matsumoto, N. Matsumoto, T. Sugimoto
    KEK, Ibaraki, Japan
  • K. Fan
    HUST, Wuhan, People's Republic of China
 
  The J-PARC Main Ring (MR) is being upgraded to improve its beam power to the design goal of 750 kW. One important way is to reduce the repetition period from 2.48 s to 1.3 s so that the beam power can be nearly doubled. We need to improve the septum magnets for fast extraction. We are improving the magnets and their power supplies. The present magnets which is conventional type have problem in durability of septum coil by its vibration, and large leakage field. The new magnets are eddy current type. The eddy current type does not have septum coil, but has a thin plate. We expect that there is no problem in durability, we can construct the thin septum plate, the leakage field can be reduced. The output of the present power supply are pattern current which of flat top is 10 ms width, the new one is short pulse which of one is 10 us. The short pulse consists of 1st and 3rd higher harmonic. We can expect that the flatness and reproducibility of flat top current can be improved. The calorific power can be also reduced. This paper will report the field measurement results with the eddy septum magnet systems.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR040  
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THPMW021 Performance of a Compensation Kicker Magnet for J-PARC Main Ring 3588
 
  • T. Sugimoto, K. Ishii, H. Matsumoto, T. Shibata
    KEK, Ibaraki, Japan
  • K. Fan
    HUST, Wuhan, People's Republic of China
 
  Four lumped-type kicker magnets have been equipped in the J-PARC MR (Main Ring) to inject 8 proton bunches. To increase beam power, the bunch length will be increased up to 350 ns that will restricts the rise time of the injection kicker to be less than 250 ns. We have already developed a method to improve the rising time to 200 ns*. However, two reflection pulses are appeared at the waveform tail, which will kick the circulating bunches and induce coherent oscillation leading to beam loss. To compensate reflection pulses, we decide to install two new lumped-type kicker magnets, which are excited independently making operation flexible. A ceramic vacuum duct with TiN coating is inserted in the compensation kickers. Magnetic field measurement and coupling impedance measurement have been carried. In this paper, the results of both these measurements and performance study using proton beam will be discussed.
* T.Sugimot et.al, "Upgrade of the Injection Kicker System for J-PARC Main Ring", MOPME069, IPAC14, Dresden, Germany, 2014.
 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMW021  
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