IPAC2018 - List of Authors (He, X.)

Paper	Title	Page
TUPMF042	Design of a High Dose Rate Micro-Focused X-Ray Source	1346
	X. He, S.Q. Liao, J. Long, J. Shi, W. Wang, L. Yang CAEP/IFP, Mainyang, Sichuan, People's Republic of China
	High energy X-ray computer tomography has wide application in industry, especially in quality control of complicated high-tech equipment. In many applications, higher spatial resolution is needed to discover smaller defects. Decreasing the spot size of the X-Ray source is a promising way to get higher spatial resolution. Rhodotron have been used to produce high power CW electron beam in hundreds of kilowatts level. In this paper, we propose to use an improved Rhodotron to generate high brightness electron beam with high average power. Beam dynamics study shows that when producing tens of kilowatts electron beam, the normalized RMS emittance can be lower than 10 μm, and the relative RMS energy spread can be lower than 0.2%. The beam can be focused to a spot size of about 100μm by using a series of quadruple, and converted to X-Ray by using a rotating target within several kilowatts beam power. Improved Rhodotron proposed in this paper is a good candidate of X-ray source for high resolution high energy industrial CT systems.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF042
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WEPAF027	Low Q Cavity BPM Study for the Beam Position Measurement of Nanosecond Spaced Electron Bunches	1881
	L. Yang, X. He, L.W. Zhang CAEP/IFP, Mainyang, Sichuan, People's Republic of China S.S. Cao, Y.B. Leng, L.Y. Yu, R.X. Yuan SINAP, Shanghai, People's Republic of China
	Funding: National natural science foundation of China, 11705184 Low Q cavity BPM is a key to distinguish closely spaced electron bunches allowing precise beam handling for XFEL facilities operating in a multi-bunch mode at high repetition rate up to hundreds MHz. The inter-bunch signal pollution issue becomes significant when bunch separation is down to nanosecond and causes the position detection to be increasingly overestimated. Solely relying on extreme low Q to achieve sufficient decay within bunch interval leads to appreciable interference from non-signal modes due to strong overcoupling of antenna design is required. The error imposed on measured position raises a challenge to meet the goal of high resolution. Alternatively, a concept is proposed to remove the dominant part of signal pollution at the moment of sampling by intentionally shifting the phase of the last bunch signal 90degree respect to that of current bunch signal, where signal sampling is normally taken for nanosecond spaced bunches. This quadrature phase shift is defined by properly choosing the operational frequency of dipole mode regarding to the bunch frequency. A low Q cavity BPM prototype to identify technical challenges and verify this concept is under development in the R&D plan for future XFEL with high repetition rate
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF027
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WEPMF022	Coulped Multiphysics Simulation for the Water Cooling Layout of a Rhodotron Cavity	2416
	L. Yang, X. He, H. Li, S.Q. Liao CAEP/IFP, Mainyang, Sichuan, People's Republic of China
	A Rhodotron-based electron accelerator served as micro-focused X-ray source is under development at IFP, CAEP. The RF-cavity, running in long pulse/ CW mode, will deliver 9 MeV energy to electron beams after multiple accelerations within the same field at a frequency of 10⁷.5MHz. A substantial amount of average power loss with tens of kW will be dissipated on the RF surface of the cavity to maintain the operational field level. Efficient water cooling is critical to prevent large scale temperature rise for stable operation sake. Reasonable prediction of temperature rise becomes essential to assess a certain cooling layout in the design phase. The frequency drift and thermal stress on account of temperature variation and gradient on cavity wall respectively, could be computed accordingly. This paper presents a comprehensive coupled simulation involving electromagnetic, thermal and structural for the RF-cavity of Rhodotron.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF022
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THPAF011	Design of 4 Ampere S-Band LINAC Using Slotted Iris Structure for HOM Damping	2965
	J. Pang, S. Chen, X. He, L.W. Zhang CAEP/IFP, Mainyang, Sichuan, People's Republic of China S. Pei, H. Shi, J.R. Zhang IHEP, Beijing, People's Republic of China
	Funding: Key Laboratory of Pulsed Power, CAEP (Contract NO. PPLF2014PZ05) Key Laboratory of Particle Acceleration Physics &Technology，IHEP, CAS (Contract Y5294109TD) An S-band LINAC with the operating frequency of 2856 MHz and beam current of 4 A was designed for flash X-ray radiography for hydrodynamic test. The optimization of the parameters of the LINAC was processed to obtain the minimum beam radius and the maximum energy efficiency. For the purpose of reducing the beam orbits offset at the exit of LINAC, a slotted iris accelerating structure would be employed to suppress the transverse Higher Order Modes (HOMs) by cutting four radial slots in the iris to couple the HOMs to SiC loads. In this paper, we present the design of the LINAC and the results of beam dynamic analysis.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF011
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Paper

Title

Page

Design of a High Dose Rate Micro-Focused X-Ray Source

1346

X. He, S.Q. Liao, J. Long, J. Shi, W. Wang, L. Yang
CAEP/IFP, Mainyang, Sichuan, People's Republic of China

High energy X-ray computer tomography has wide application in industry, especially in quality control of complicated high-tech equipment. In many applications, higher spatial resolution is needed to discover smaller defects. Decreasing the spot size of the X-Ray source is a promising way to get higher spatial resolution. Rhodotron have been used to produce high power CW electron beam in hundreds of kilowatts level. In this paper, we propose to use an improved Rhodotron to generate high brightness electron beam with high average power. Beam dynamics study shows that when producing tens of kilowatts electron beam, the normalized RMS emittance can be lower than 10 μm, and the relative RMS energy spread can be lower than 0.2%. The beam can be focused to a spot size of about 100μm by using a series of quadruple, and converted to X-Ray by using a rotating target within several kilowatts beam power. Improved Rhodotron proposed in this paper is a good candidate of X-ray source for high resolution high energy industrial CT systems.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF042

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

WEPAF027

Low Q Cavity BPM Study for the Beam Position Measurement of Nanosecond Spaced Electron Bunches

1881

L. Yang, X. He, L.W. Zhang
CAEP/IFP, Mainyang, Sichuan, People's Republic of China
S.S. Cao, Y.B. Leng, L.Y. Yu, R.X. Yuan
SINAP, Shanghai, People's Republic of China

Funding: National natural science foundation of China, 11705184
Low Q cavity BPM is a key to distinguish closely spaced electron bunches allowing precise beam handling for XFEL facilities operating in a multi-bunch mode at high repetition rate up to hundreds MHz. The inter-bunch signal pollution issue becomes significant when bunch separation is down to nanosecond and causes the position detection to be increasingly overestimated. Solely relying on extreme low Q to achieve sufficient decay within bunch interval leads to appreciable interference from non-signal modes due to strong overcoupling of antenna design is required. The error imposed on measured position raises a challenge to meet the goal of high resolution. Alternatively, a concept is proposed to remove the dominant part of signal pollution at the moment of sampling by intentionally shifting the phase of the last bunch signal 90degree respect to that of current bunch signal, where signal sampling is normally taken for nanosecond spaced bunches. This quadrature phase shift is defined by properly choosing the operational frequency of dipole mode regarding to the bunch frequency. A low Q cavity BPM prototype to identify technical challenges and verify this concept is under development in the R&D plan for future XFEL with high repetition rate

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF027

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

WEPMF022

Coulped Multiphysics Simulation for the Water Cooling Layout of a Rhodotron Cavity

2416

L. Yang, X. He, H. Li, S.Q. Liao
CAEP/IFP, Mainyang, Sichuan, People's Republic of China

A Rhodotron-based electron accelerator served as micro-focused X-ray source is under development at IFP, CAEP. The RF-cavity, running in long pulse/ CW mode, will deliver 9 MeV energy to electron beams after multiple accelerations within the same field at a frequency of 10⁷.5MHz. A substantial amount of average power loss with tens of kW will be dissipated on the RF surface of the cavity to maintain the operational field level. Efficient water cooling is critical to prevent large scale temperature rise for stable operation sake. Reasonable prediction of temperature rise becomes essential to assess a certain cooling layout in the design phase. The frequency drift and thermal stress on account of temperature variation and gradient on cavity wall respectively, could be computed accordingly. This paper presents a comprehensive coupled simulation involving electromagnetic, thermal and structural for the RF-cavity of Rhodotron.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF022

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

THPAF011

Design of 4 Ampere S-Band LINAC Using Slotted Iris Structure for HOM Damping

2965

J. Pang, S. Chen, X. He, L.W. Zhang
CAEP/IFP, Mainyang, Sichuan, People's Republic of China
S. Pei, H. Shi, J.R. Zhang
IHEP, Beijing, People's Republic of China

Funding: Key Laboratory of Pulsed Power, CAEP (Contract NO. PPLF2014PZ05) Key Laboratory of Particle Acceleration Physics &Technology，IHEP, CAS (Contract Y5294109TD)
An S-band LINAC with the operating frequency of 2856 MHz and beam current of 4 A was designed for flash X-ray radiography for hydrodynamic test. The optimization of the parameters of the LINAC was processed to obtain the minimum beam radius and the maximum energy efficiency. For the purpose of reducing the beam orbits offset at the exit of LINAC, a slotted iris accelerating structure would be employed to suppress the transverse Higher Order Modes (HOMs) by cutting four radial slots in the iris to couple the HOMs to SiC loads. In this paper, we present the design of the LINAC and the results of beam dynamic analysis.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF011

Export •

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