IPAC2018 - List of Authors (Fan, K.)

Paper	Title	Page
TUPAK010	The Development of a New Low Field Septum Magnet System for Fast Extraction in Main Ring of J-PARC	981
	T. Shibata, K. Ishii, H. 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 are conventional type have problem in durability of septum coil by its vibration, and large leakage field at the flange of the beam duct. 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 performance of the power supply and its magnetic field with the eddy septum magnet systems.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAK010
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TUPAK013	Geant4 Simulation of Radiation Effect on the Deflector of Extraction System in HUST SCC250	990
	S. Hu, K. Fan, L.X.F. Li, Z.Y. Mei, Z.J. Zeng, L.G. Zhang HUST, Wuhan, People's Republic of China
	China has payed extensive attention to the development of proton therapy in recent years. When design a compact, high energy superconducting cyclotron for proton therapy， radiation effect induced by beam losses is a crucial consideration. Since the proton beam is extracted out of HUST SCC250 by electrostatic deflectors, the fierce interaction between proton beam and the deflector septum is the main cause of beam losses, which will bring about radiation effect leading to activation and coil quench. This paper presents simulation results of radiation effect by utilizing Geant4 Monte Carlo code. The energy depositions of proton beam in various septum materials are compared. Meanwhile, the yields, the ener-gy and angular distributions of secondary particles are investigated. Those simulation results based on radiation effect will provide us with valuable implications for the design of this superconducting cyclotron.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAK013
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WEPML064	Design of the Trim Coil for the Superconducting Cyclotron Extraction	2840
	L.G. Zhang, K. Fan, S. Hu, Z.Y. Mei, Z.J. Zeng HUST, Wuhan, People's Republic of China
	A proton therapy system is being developed at Huazhong university of science and technology (HUST). A 250 MeV superconducting cyclotron with an average magnetic filed of 3.1 T in the extraction region is selected to reduce the machine size, which creates difficulties for beam extraction because of the small turn separation of the beam orbits in the extraction region. To obtain high extraction efficiency, a carefully controlled magnetic perturbation is introduced to excite resonance when beam passes through the νr =1 resonance. The first-order perturbation in the magnetic field is generated by trim coils within confined regions. The profile of the trim coil and the resultant perturbation fields are optimized iteratively with orbit tracking. Simulation shows that sufficient turn separation can be obtained with the proper setting of trim coils.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPML064
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Paper

Title

Page

The Development of a New Low Field Septum Magnet System for Fast Extraction in Main Ring of J-PARC

981

T. Shibata, K. Ishii, H. 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 are conventional type have problem in durability of septum coil by its vibration, and large leakage field at the flange of the beam duct. 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 performance of the power supply and its magnetic field with the eddy septum magnet systems.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAK010

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TUPAK013

Geant4 Simulation of Radiation Effect on the Deflector of Extraction System in HUST SCC250

990

S. Hu, K. Fan, L.X.F. Li, Z.Y. Mei, Z.J. Zeng, L.G. Zhang
HUST, Wuhan, People's Republic of China

China has payed extensive attention to the development of proton therapy in recent years. When design a compact, high energy superconducting cyclotron for proton therapy， radiation effect induced by beam losses is a crucial consideration. Since the proton beam is extracted out of HUST SCC250 by electrostatic deflectors, the fierce interaction between proton beam and the deflector septum is the main cause of beam losses, which will bring about radiation effect leading to activation and coil quench. This paper presents simulation results of radiation effect by utilizing Geant4 Monte Carlo code. The energy depositions of proton beam in various septum materials are compared. Meanwhile, the yields, the ener-gy and angular distributions of secondary particles are investigated. Those simulation results based on radiation effect will provide us with valuable implications for the design of this superconducting cyclotron.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAK013

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reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPML064

Design of the Trim Coil for the Superconducting Cyclotron Extraction

2840

L.G. Zhang, K. Fan, S. Hu, Z.Y. Mei, Z.J. Zeng
HUST, Wuhan, People's Republic of China

A proton therapy system is being developed at Huazhong university of science and technology (HUST). A 250 MeV superconducting cyclotron with an average magnetic filed of 3.1 T in the extraction region is selected to reduce the machine size, which creates difficulties for beam extraction because of the small turn separation of the beam orbits in the extraction region. To obtain high extraction efficiency, a carefully controlled magnetic perturbation is introduced to excite resonance when beam passes through the νr =1 resonance. The first-order perturbation in the magnetic field is generated by trim coils within confined regions. The profile of the trim coil and the resultant perturbation fields are optimized iteratively with orbit tracking. Simulation shows that sufficient turn separation can be obtained with the proper setting of trim coils.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPML064

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)