IPAC2015 - List of Authors (Geng, H.)

Paper	Title	Page
MOPWA061	ADS Injector I Frequency Choice at IHEP	265
	F. Yan, H. Geng, C. Meng, H.F. Ouyang, S. Pei, Y.L. Zhao IHEP, Beijing, People's Republic of China
	Funding: Chinese Academy of Science (CAS) strategic Priority Research Program-Future Advanced Nuclear Fission Energy (Accelerator-Driven Sub-critical System) The China ADS driver linac is composed of two major parts: the injector and the main linac. There are two frequency choices for the injector: 325 MHz and 162.5 MHz. The former choice is benefit for the same frequency with the front end of the main linac. For half frequency choice, to obtain the same longitudinal acceptance of the main linac comparing with 325MHz injector, the tune depression of the beam reaches the lower design limit of 0.5, no current upgrade opportunity is reserved; contrarily to get the same space charge effect, 16 more cavities would be the cost to get the same acceptance. However the disadvantage of the 325MHz injector choice is the bigger power density of the copper structure CW RFQ and the smaller longitudinal acceptance of the SC section. The details of the comparing for the two frequency choices are introduced and presented. *Work supported by Chinese Academy of Science (CAS) strategic Priority Research Program-Future Advanced Nuclear Fission Energy (Accelerator-Driven Sub-critical System)
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA061
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MOPWA062	Optimization of the Momentum Bandwidth for Final Focus System in CEPC	269
	S. Bai, T.J. Bian, J. Gao, H. Geng, D. Wang, Y. Wang, M. Xiao IHEP, Beijing, People's Republic of China F. Su Institute of High Energy Physics (IHEP), People's Republic of China
	With the discovery of the higgs boson at around 125GeV, a circular higgs factory design with high luminosity (L ~ 10³⁴ cm^-2s^-1) is becoming more popular in the accelerator world. To achieve such high luminosity, a final focus system in non-local chromaticity correction scheme with very low β functions at the interaction point is designed. The narrow momentum bandwidth is a crucial problem of this kind of design. It is shown that by introducing additional sextupoles the momentum acceptance of the CEPC final focus system can be increased by about a factor of four.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA062
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TUPTY011	A Preliminary Design of the CEPC Interaction Region	2019
	Y. Wang, S. Bai, T.J. Bian, X. Cui, J. Gao, H. Geng, D. Wang, Y.S. Zhu IHEP, Beijing, People's Republic of China
	CEPC (Circular Electron and Positron Collider) is a circular Higgs Factory with optimized energy 240 GeV. In order to achieve luminosity as high as 2×10³⁴/cm²/s, CEPC calls for a small vertical beta function at IP (betay∗=1.2 mm) which was provided by the final focus of the interaction region. In this paper, a preliminary design of the CEPC interaction region was presented. The optimization of dynamic aperture with interaction region insertion and the machine detector interface was discussed as well.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY011
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TUPTY012	Orbit Correction in CEPC	2022
	S. Bai, J. Gao, H. Geng IHEP, Beijing, People's Republic of China
	With the discovery of the higgs boson at around 125GeV, a circular higgs factory design with high luminosity (L ~ 10³⁴ cm^-2s^-1) is becoming more popular in the accelerator world. The CEPC project in China is one of them. To reduce the cost, pretzel scheme was considered in CEPC orbit design. The presence of every kind of errors and misalignments will destroy the pretzel orbit. In this paper, we correct the distorted pretzel orbit in the CEPC main ring using the dipole correctors and beam position monitors. The pretzel orbit was recovered and the maximum corrector strengths are got.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY012
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WEBB3	Lattice and its Related Beam Dynamics Issues in the CEPC Storage Ring	2469
	H. Geng, S. Bai, Z. Duan, Y.M. Peng, Q. Qin, D. Wang, Y. Wang, G. Xu, Y. Yue, Y. Zhang IHEP, Beijing, People's Republic of China W. Chou Fermilab, Batavia, Illinois, USA
	The institute of High Energy Physics has proposed an electron positron collider ring with a circumference of 50-100km to study the Higgs boson. Since the proposal was made, the lattice design for CEPC has been carried out and a preliminary conceptual design report has been written at the end of 2014. In this paper, we will describe the philosophy and results of our lattice design. The procedure of dynamic aperture optimization will be shown. A specific issue for CEPC, the pretzel orbit, which has been found distorting the linear lattice for a considerable amount, will be examined. The ways that we are trying to correct the pretzel orbit effect and the result will be shown. We will also discuss the saw tooth effect on the linear lattice and dynamic aperture of the ring.
	Slides WEBB3 [2.599 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEBB3
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WEPMN003	The Magnetic Measurement for Low Magnetic Field Stability of Dipole Magnet for CEPC	2917
	Z. Zhang, F.S. Chen, H. Geng, B. Yin IHEP, Beijing, People's Republic of China
	The CEPC (China Electron-Positron Collider) project is in the pre-research stage. When the beam energy of booster is 120 GeV, the magnetic field of deflection magnet is 640 G. In order to save funds for scientific research, we are ready to select the injection energy for 6 GeV, this corresponds to a magnetic field about 32 G. In such a low magnetic field, the effects of earth's magnetic field and ambient temperature variations cannot be ignored. In this paper, first written the collection procedures for magnetic field value and ambient temperature values by Labview software, then used a one-dimensional probe to measure the background magnetic field for three directions (Bx, By, Bz) and the value of the ambient temperature values, the time of data collection for each direction are more than 24 hours (every minute collecting a set of values). Finally, plus the different currents (3A, 6A.. 15A) to the dipole magnet, the time of measured and the data collected by over 24 hours. Based on the results of the analysis of large amounts of data, summarized and analyzed the effect of Earth's magnetic field and ambient temperature for dipole magnet in a low magnetic field.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN003
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WEPMN004	Progress on the CSNS Power Supply System	2921
	X. Qi, H. Geng IHEP, Beijing, People's Republic of China
	The 1.6 GeV proton synchrotron proposed in the CSNS Project is a 25 Hz rapid-cycling synchrotron (RCS) with injection energy of 80 MeV. Beam power is aimed to 100 kW at 1.6 GeV. The power supply system consists of seven subsystems. Those power supplies have three operation modes: DC mode, AC plus DC mode and programmable pulse mode. This paper will introduce the Power supply system status in recent years. Power Supply, rapid-cycling synchrotron, serial resonant network
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN004
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THPF057	Beam Commissioning of C-ADS Injector-I RFQ Accelerator	3827
	C. Meng, J.S. Cao, Y.Y. Du, H. Geng, T.M. Huang, R.L. Liu, H.F. Ouyang, W.M. Pan, S. Pei, H. Shi, Y.F. Sui, J.L. Wang, S.C. Wang, F. Yan, Q. Ye, L. Yu, Y. Zhao IHEP, Beijing, People's Republic of China
	The C-ADS accelerator is a CW (Continuous-Wave) proton linac with 1.5 GeV in beam energy, 10 mA in beam current, and 15 MW in beam power. C-ADS Injector-I accelerator is a 10-mA 10-MeV CW proton linac, which uses a 3.2-MeV normal conducting 4-Vane RFQ and superconducting single-spoke cavities for accelerating. The frequency of RFQ accelerator is 325 MHz. The test stand composed of an ECR ion source, LEBT, RFQ, MEBT and beam dump have been installed and the first stage of beam commissioning have been finished at IHEP in 2014 mid-year. At 90% duty factor, we got 11 mA proton beam at RFQ exit with 90% beam transmission efficiency, while 95% beam transmission efficiency at 70% duty factor. The energy after RFQ was measured by TOF method with FCTs. The transverse emittance measured by double-slits emittance meter was 0.135 π mm-mrad, which of detailed data analysis will be presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF057
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Paper

Title

Page

ADS Injector I Frequency Choice at IHEP

265

F. Yan, H. Geng, C. Meng, H.F. Ouyang, S. Pei, Y.L. Zhao
IHEP, Beijing, People's Republic of China

Funding: Chinese Academy of Science (CAS) strategic Priority Research Program-Future Advanced Nuclear Fission Energy (Accelerator-Driven Sub-critical System)
The China ADS driver linac is composed of two major parts: the injector and the main linac. There are two frequency choices for the injector: 325 MHz and 162.5 MHz. The former choice is benefit for the same frequency with the front end of the main linac. For half frequency choice, to obtain the same longitudinal acceptance of the main linac comparing with 325MHz injector, the tune depression of the beam reaches the lower design limit of 0.5, no current upgrade opportunity is reserved; contrarily to get the same space charge effect, 16 more cavities would be the cost to get the same acceptance. However the disadvantage of the 325MHz injector choice is the bigger power density of the copper structure CW RFQ and the smaller longitudinal acceptance of the SC section. The details of the comparing for the two frequency choices are introduced and presented.
*Work supported by Chinese Academy of Science (CAS) strategic Priority Research Program-Future Advanced Nuclear Fission Energy (Accelerator-Driven Sub-critical System)

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA061

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

MOPWA062

Optimization of the Momentum Bandwidth for Final Focus System in CEPC

269

S. Bai, T.J. Bian, J. Gao, H. Geng, D. Wang, Y. Wang, M. Xiao
IHEP, Beijing, People's Republic of China
F. Su
Institute of High Energy Physics (IHEP), People's Republic of China

With the discovery of the higgs boson at around 125GeV, a circular higgs factory design with high luminosity (L ~ 10³⁴ cm^-2s^-1) is becoming more popular in the accelerator world. To achieve such high luminosity, a final focus system in non-local chromaticity correction scheme with very low β functions at the interaction point is designed. The narrow momentum bandwidth is a crucial problem of this kind of design. It is shown that by introducing additional sextupoles the momentum acceptance of the CEPC final focus system can be increased by about a factor of four.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA062

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TUPTY011

A Preliminary Design of the CEPC Interaction Region

2019

Y. Wang, S. Bai, T.J. Bian, X. Cui, J. Gao, H. Geng, D. Wang, Y.S. Zhu
IHEP, Beijing, People's Republic of China

CEPC (Circular Electron and Positron Collider) is a circular Higgs Factory with optimized energy 240 GeV. In order to achieve luminosity as high as 2×10³⁴/cm²/s, CEPC calls for a small vertical beta function at IP (betay∗=1.2 mm) which was provided by the final focus of the interaction region. In this paper, a preliminary design of the CEPC interaction region was presented. The optimization of dynamic aperture with interaction region insertion and the machine detector interface was discussed as well.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY011

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TUPTY012

Orbit Correction in CEPC

2022

S. Bai, J. Gao, H. Geng
IHEP, Beijing, People's Republic of China

With the discovery of the higgs boson at around 125GeV, a circular higgs factory design with high luminosity (L ~ 10³⁴ cm^-2s^-1) is becoming more popular in the accelerator world. The CEPC project in China is one of them. To reduce the cost, pretzel scheme was considered in CEPC orbit design. The presence of every kind of errors and misalignments will destroy the pretzel orbit. In this paper, we correct the distorted pretzel orbit in the CEPC main ring using the dipole correctors and beam position monitors. The pretzel orbit was recovered and the maximum corrector strengths are got.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY012

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WEBB3

Lattice and its Related Beam Dynamics Issues in the CEPC Storage Ring

2469

H. Geng, S. Bai, Z. Duan, Y.M. Peng, Q. Qin, D. Wang, Y. Wang, G. Xu, Y. Yue, Y. Zhang
IHEP, Beijing, People's Republic of China
W. Chou
Fermilab, Batavia, Illinois, USA

The institute of High Energy Physics has proposed an electron positron collider ring with a circumference of 50-100km to study the Higgs boson. Since the proposal was made, the lattice design for CEPC has been carried out and a preliminary conceptual design report has been written at the end of 2014. In this paper, we will describe the philosophy and results of our lattice design. The procedure of dynamic aperture optimization will be shown. A specific issue for CEPC, the pretzel orbit, which has been found distorting the linear lattice for a considerable amount, will be examined. The ways that we are trying to correct the pretzel orbit effect and the result will be shown. We will also discuss the saw tooth effect on the linear lattice and dynamic aperture of the ring.

Slides WEBB3 [2.599 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEBB3

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WEPMN003

The Magnetic Measurement for Low Magnetic Field Stability of Dipole Magnet for CEPC

2917

Z. Zhang, F.S. Chen, H. Geng, B. Yin
IHEP, Beijing, People's Republic of China

The CEPC (China Electron-Positron Collider) project is in the pre-research stage. When the beam energy of booster is 120 GeV, the magnetic field of deflection magnet is 640 G. In order to save funds for scientific research, we are ready to select the injection energy for 6 GeV, this corresponds to a magnetic field about 32 G. In such a low magnetic field, the effects of earth's magnetic field and ambient temperature variations cannot be ignored. In this paper, first written the collection procedures for magnetic field value and ambient temperature values by Labview software, then used a one-dimensional probe to measure the background magnetic field for three directions (Bx, By, Bz) and the value of the ambient temperature values, the time of data collection for each direction are more than 24 hours (every minute collecting a set of values). Finally, plus the different currents (3A, 6A.. 15A) to the dipole magnet, the time of measured and the data collected by over 24 hours. Based on the results of the analysis of large amounts of data, summarized and analyzed the effect of Earth's magnetic field and ambient temperature for dipole magnet in a low magnetic field.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN003

Export •

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

WEPMN004

Progress on the CSNS Power Supply System

2921

X. Qi, H. Geng
IHEP, Beijing, People's Republic of China

The 1.6 GeV proton synchrotron proposed in the CSNS Project is a 25 Hz rapid-cycling synchrotron (RCS) with injection energy of 80 MeV. Beam power is aimed to 100 kW at 1.6 GeV. The power supply system consists of seven subsystems. Those power supplies have three operation modes: DC mode, AC plus DC mode and programmable pulse mode. This paper will introduce the Power supply system status in recent years.
Power Supply, rapid-cycling synchrotron, serial resonant network

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN004

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THPF057

Beam Commissioning of C-ADS Injector-I RFQ Accelerator

3827

C. Meng, J.S. Cao, Y.Y. Du, H. Geng, T.M. Huang, R.L. Liu, H.F. Ouyang, W.M. Pan, S. Pei, H. Shi, Y.F. Sui, J.L. Wang, S.C. Wang, F. Yan, Q. Ye, L. Yu, Y. Zhao
IHEP, Beijing, People's Republic of China

The C-ADS accelerator is a CW (Continuous-Wave) proton linac with 1.5 GeV in beam energy, 10 mA in beam current, and 15 MW in beam power. C-ADS Injector-I accelerator is a 10-mA 10-MeV CW proton linac, which uses a 3.2-MeV normal conducting 4-Vane RFQ and superconducting single-spoke cavities for accelerating. The frequency of RFQ accelerator is 325 MHz. The test stand composed of an ECR ion source, LEBT, RFQ, MEBT and beam dump have been installed and the first stage of beam commissioning have been finished at IHEP in 2014 mid-year. At 90% duty factor, we got 11 mA proton beam at RFQ exit with 90% beam transmission efficiency, while 95% beam transmission efficiency at 70% duty factor. The energy after RFQ was measured by TOF method with FCTs. The transverse emittance measured by double-slits emittance meter was 0.135 π mm-mrad, which of detailed data analysis will be presented in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF057

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