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Instrumentation, Particle Accelerators, and Particle and Radiation Detection
Published in Zeev B. Alfassi, Max Peisach, Elemental Analysis by Particle Accelerators, 2020
After passing through a series of collimators, the beam passes into a sextupole magnet. A thin-walled vacuum tube was inserted through the bore of the magnet so that the oven house and magnet system are separate. Two 6-poles are used in the source. The first one polarizes the atomic electrons and the second one, which follows the weak-field transition, serves as a polarization detector. One 6-pole is a conventional electromagnet, while the other is a permanent 6-pole constructed of SmCo5 pole pieces. The permanent magnet was produced in four separate sections of 15-cm length with a pole tip strength of 7 kG. The Li+ beam currents are between 7 and 10 μA. To obtain a Li– beam, needed for acceleration by the tandem, the Li+ beam passes through a heated charge exchange canal containing a Cs vapor. The charge exchange efficiency is about 1%.
Beams and Beam Physics
Published in Martin Berz, Kyoko Makino, Weishi Wan, An Introduction to Beam Physics, 2014
Martin Berz, Kyoko Makino, Weishi Wan
In order to produce sufficient quantities of multiply charged ions, the ion confinement has to relatively long (~ 10 ms). The major improvement in this aspect is the addition of a sextupole magnet, which ensures that the magnetic field at the center of the chamber is at the minimum, which prevents the ions from drifting to the side wall. Another consequence of this configuration of the magnetic field is that the surface on which electron cyclotron resonance heating takes place is now closed, which significantly reduces hot electron loss. This configuration of the magnetic field also makes ion production more efficient, since electrons are confined longer and can collide with ions and be reheated many times. The fact that the ECR ion source does not use a cathode to generate electrons makes it a much more reliable source compared to other varieties.
Synergies between Accelerators, Lasers and Plasma
Published in Andrei Seryi, Unifying Physics of Accelerators, Lasers and Plasma, 2015
The sextupole magnet produces the following effect (kick) on the angle of the beam trajectory x′=x′+S(x2−y2)andy′=y′−S2xy
Design and actual performance of J-PARC 3 GeV rapid cycling synchrotron for high-intensity operation
Published in Journal of Nuclear Science and Technology, 2022
Kazami Yamamoto, Michikazu Kinsho, Naoki Hayashi, Pranab Kumar Saha, Fumihiko Tamura, Masanobu Yamamoto, Norio Tani, Tomohiro Takayanagi, Junichiro Kamiya, Yoshihiro Shobuda, Masahiro Yoshimoto, Hiroyuki Harada, Hiroki Takahashi, Yasuhiro Watanabe, Kota Okabe, Masahiro Nomura, Taihei Shimada, Takamitsu Nakanoya, Ayato Ono, Katsuhiro Moriya, Yoshio Yamazaki, Kazuaki Suganuma, Kosuke Fujirai, Nobuhiro Kikuzawa, Shin-Ichiro Meigo, Motoki Ooi, Shuichiro Hatakeyama, Tomohito Togashi, Kaoru Wada, Hideaki Hotchi, Masahito Yoshii, Chihiro Ohmori, Takeshi Toyama, Kenichirou Satou, Yoshiro Irie, Tomoaki Ueno, Koki Horino, Toru Yanagibashi, Riuji Saeki, Atsushi Sato, Osamu Takeda, Masato Kawase, Takahiro Suzuki, Kazuhiko Watanabe, Tatsuya Ishiyama, Shinpei Fukuta, Yuki Sawabe, Yuichi Ito, Yuko Kato, Kazuo Hasegawa, Hiromitsu Suzuki, Fumiaki Noda
The RCS was originally able to switch certain operating parameters: the RF excitation pattern, COD correction, and sextupole magnet excitation pattern. However, it was impossible to change the injection trajectory to meet the requirements of both MLF and MR at the same time owing to the capacity limitation of the power supply of the original injection bump magnets. Furthermore, when we sought to create a no-paint orbit (so-called center injection) for the study that did not involve the painting magnets, the circulating orbit and the injection orbit should come near each other by only the shift bump magnet. In this case, the required capacity of the power supply for the shift bump magnet, which was redesigned at the same time for a 400 MeV upgrade, would be extremely large and was deemed impossible. Therefore, two additional horizontal pulse magnets were designed and installed in the L-3BT line [101–103]. The power supplies for the additional magnets had two operation modes: the pulse current mode and the DC mode. The center injection was only used for the beam study, and we did not require to switch the excitation current pulse by pulse. Thus, the power supplies were operated with DC mode to generate a high current. On contrast, at the simultaneous user operation for MLF and MR, excitation current was changed when the destination was switched between MLF and MR.