| Paper | Title | Page |
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| MOPLT066 | Induction Accelerating Cavity for a Circular Ring Accelerator | 704 |
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This paper reports details of an induction accelerating cavity employed for induction synchrotron POP experiments [*] using the KEK 12GeV PS. This cavity is the first induction cavity in the history of accelerator that is used in a circular ring. We focus our attention on crucial aspects distinguished from well-know properties of RF cavity. The single cavity is capable of generating an acceleration voltage of 2.5kV with a pulse width of 250ns, which is operated at a repetition rate in the range of 667kHz - 882kHz. The cavity is driven by its own pulse modulator through a 25m long transmission cable of 125W, the end of which is connected with a matching resistance so as to minimize reflection in a wide range of frequency. Accelerating field characteristics are discussed and matching features of the cavity as a one-to-one transformer are presented. A longitudinal and transverse coupling impedance have been measured using a net-work analyzer.
* K.Takayama et al., 'POP Experiments of the Induction Synchrotron' in this conference |
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| TUPLT077 | R&D Status of the Fast Extraction Kicker Magnets for the KEK/JAERI 50 GeV Synchrotron | 1333 |
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| The 50 GeV proton synchrotron composes the final stage of the high intensity proton accelerator complex now on construction at JAERI/Tokai site as a joint project by KEK and JAERI. In this ring, the proton beam is accelerated from 3 GeV to 50 GeV, and delivered to the experimental facilities through the fast and slow extraction lines. The distinctive feature of the fast extraction line is that the bipolar extraction function will be provided. In normal operations, the beam is extracted toward the inner side of the ring and transported to the facility for the long baseline neutrino oscillation experiment using the Super-Kamiokande detector. In case of emergency, for example, quenches of the superconducting magnets of the neutrino line or malfunctioning of the ring RF systems, the beam is extracted toward the outer side of the ring and sent directly to the abort line with a beam dump at the end. In the current kicker design, the bipolar function will be achieved by the Symmetric Blumlein PFN (SBPFN) system with two switches on both ends. The designed parameters of the fast extraction kicker magnets and the recent hardware R&D status will be described in this paper. | ||
| WEPKF041 | Permanent Magnet Generating High and Variable Septum Magnetic Field and its Deterioration by Radiation | 1696 |
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| Conventional high field septum magnet is fed by DC current or pulse current. In the case of DC, the problem of coil support is not very important, but the cooling of the coil is serious problem. While, in the case of pulse, the problem of support is much important than that of cooling. However, if the septum magnet is made of permanent magnet, those problems are dissolved. And the cost for electricity and cooling water can be exceedingly decreased. Therefore, we made the model septum magnet which has 1/4 scale of the real size and generates 1[T] with the variable range of ± 10%. The magnetic field distribution in the gap by changing the representative field is reported. When this permanent magnet is set in an accelerator, the deterioration of the permanent magnet by radiation will be serious problem. We also report the dependence of the magnetic fields generated by permanent magnet samples on accumulated radiation by various types of radiation source. | ||
| WEPLT110 | Specific Beam Dynamics in Super-bunch Acceleration | 2107 |
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| Proof-of-principle experiments on the induction synchrotron concept using the KEK 12-GeV PS makes progress, in which RF bunches and a super-bunch will be accelerated with a long step voltage generated in the induction accelerating gaps. In order to give a guide for super-bunch acceleration, the beam stabilities against a droop and a fluctuation of the accelerating voltage have been examined by using a simulation. The droop voltage gives an additional focusing or defocusing force in the longitudinal direction, which leads the mismatching beyond the transition energy. Furthermore, the extremely slow fluctuation of the accelerating voltage causes a lowest-order resonance near the transition. These induce a serious emittance blow-up in the longitudinal, so that the compensating manners will be presented. Moreover, the other issues such as head-tail instability and intra beam scattering will be discussed. |