Magnetic Field Measurement of the Extraction Kicker Magnet in J-PARC RCS

Kamiya, J.; Ueno, T.; Takayanagi, Tetsuya

doi:10.1109/tasc.2006.869982

Cited by 8 publications

(7 citation statements)

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“…Therefore, it is important to achieve the good uniformity of the magnetic field in the time direction and in the spatial distribution. The uniformity in the time direction was already reported in [3]. It was clarified that the disturbance of the temporal uniformity of the magnetic field was caused not only by the impedance mismatching between the load cable and the magnet, but also by the induced magnetic field from the other side of the ferrite cores.…”

Section: Introductionmentioning

confidence: 68%

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Magnetic Field Mapping and Excitation Test in Vacuum for the Kicker Magnet in J-PARC RCS

Kamiya

Kinsho

Kuramochi

et al. 2008

IEEE Trans. Appl. Supercond.

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Installation of the kicker magnets in the extraction section of the RCS in J-PARC facility was completed. They extract a proton beam accelerated up to 3GeV. Since high voltage of 30 kV, which corresponds to 60 kV for charging the pulse forming line, is applied to the magnet every 40 msec, they are installed in vacuum chambers to prevent the electrical breakdown. However, magnetic field mapping is difficult in vacuum. Therefore, we performed the mapping in the air with applying one third of the operational voltage after checking linear dependence of magnetic field to exciting current. A short search coil on the 3-axis stages was used in the magnetic field mapping. The results showed that the good uniformity was achieved in the whole aperture. The magnetic field distribution of the same type of kicker magnet was in good agreement with each other. The excitation test with the operational charging voltage of 60 kV was also performed in vacuum. At the first stage, we were bothered by the electric breakdown. It was noticed that the reduction of outgassing rate by baking was very effective to suppress the discharge. And the continuous excitation was found to have a conditioning effect for the stable operation.Index Terms-Accelerator magnet, magnetic field measurement, vacuum breakdown.

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Section: Introductionmentioning

confidence: 68%

“…Specification of the kicker magnet system and configuration of the magnet were reported in other papers [3], [5]. Therefore the structure and the whole composition of the kicker magnet system are briefly described here.…”

Section: Kicker Magnetmentioning

confidence: 98%

Magnetic Field Mapping and Excitation Test in Vacuum for the Kicker Magnet in J-PARC RCS

Kamiya

Kinsho

Kuramochi

et al. 2008

IEEE Trans. Appl. Supercond.

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“…1, the kicker at the 3-GeV RCS at J-PARC consists of a magnet and two pulse-forming lines (PFLs). Aluminum (Al) coils are embedded in the kicker magnet, which is a window-frame transmission-line type consisting of two ferrite cores, each of 9.8 Ω characteristic impedance (the mutual coupling between both cores is negligible at the RCS kicker [9]). The magnet has four terminals.…”

Section: Present Rcs Kicker At J-parcmentioning

confidence: 99%

Reducing the beam impedance of the kicker at the 3-GeV rapid cycling synchrotron of the Japan Proton Accelerator Research Complex

Shobuda

Chin

Hayashi

et al. 2018

Phys. Rev. Accel. Beams

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The present four-terminal kicker at the rapid cycling synchrotron (RCS) at the Japan Proton Accelerator Research Complex has the power-saving benefit that it allows beam extraction by doubling the excitation currents with two shorted ends. In this configuration, two terminals of the kicker are connected to the pulseforming line while the other two are terminated in a short circuit. On the other hand, beam instabilities are excited in the RCS by the kicker beam impedances, which result from the short-circuit termination of the kicker. In this paper, we describe a scheme to reduce the beam impedance of the kicker using diodes (nonlinear devices), while retaining the benefit of the doubled kicker excitation currents. We employ a simulation technique to determine the beam impedance of the kicker, even when such nonlinear devices and long cables are included. The characteristic of beam impedance measured using the accelerated beams is well explained by that obtained from the simulation.

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“…At JAEA, the measurement of the magneticˆeld distribution was performedˆrstly in the air 5) . After that, the magnet was baked out in vacuum to reduce the outgassing, mainly water which was absorbed on the surface.…”

Section: Conditioning By Continuous Excitation Testmentioning

confidence: 99%

Reduction of Outgassing for Suppressing Electrical Breakdown in the Kicker Magnet of J-PARC RCS

et al. 2007

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Magnetic Field Measurement of the Extraction Kicker Magnet in J-PARC RCS

Cited by 8 publications

References 1 publication

Magnetic Field Mapping and Excitation Test in Vacuum for the Kicker Magnet in J-PARC RCS

Magnetic Field Mapping and Excitation Test in Vacuum for the Kicker Magnet in J-PARC RCS

Reducing the beam impedance of the kicker at the 3-GeV rapid cycling synchrotron of the Japan Proton Accelerator Research Complex

Reduction of Outgassing for Suppressing Electrical Breakdown in the Kicker Magnet of J-PARC RCS

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