IPAC2019 - List of Authors (Chang, C.-C.)

Paper	Title	Page
TUPMP041	Preliminary Design of RF-Shielded Bellows	1341
	Y.T. Huang, C.K. Chan, C.-C. Chang, C.M. Cheng, P.J. Chou, Y.C. Yang NSRRC, Hsinchu, Taiwan
	A new design of RF-shielded bellows is proposed for the TPS to alleviate wake field effects and Joule heating resulting from contact resistance at the contact interface of sliding two dissimilar metals. Most efforts are put into controlling corrosion which is regarded as the main cause of electrical contact degradation. Rh-Au is chosen as a mating interface because they are stable under high temperature condition. Experimental tests are made to find an effective plating thickness of Rh and Au and to determine a suitable normal load applicable on the Rh-Au interface. A preliminary design of RF-shielded bellows that can sustain thousands of cycles during their lifetime is under testing.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP041
About •	paper received ※ 06 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPMP042	The Beam Cleaning Analysis for the TPS Vacuum System	1344
	Y.C. Yang, C.K. Chan, C.-C. Chang, A.Y. Chen, J.-Y. Chuang, C.H. Huang NSRRC, Hsinchu, Taiwan
	Commissioning for the TPS, a low-emittance 3-GeV synchrotron ring, started in December 2014 and is now currently operating in top-up mode at 400mA for users. Until the last machine shut down in December 2018, a total beam dose of 4919 Ah was accumulated and the beam cleaning effect decreased the dynamic pressure to 1.5×10^-11 Pa/mA. During past years operation, several vacuum chambers were replaced to improve vacuum performance and avoid exposure to synchrotron radiation from insertion devices. In this paper, the beam cleaning evolution of new vacuum sections will be discussed and compared with experience in the rest of the storage ring. A particular cleaning evolution could be predicted and can be referenced for machine shutdown planning in the future.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP042
About •	paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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THPRB092	Reduction of Beam Induced RF-Heating in the Horizontal Stripline Kicker at the TPS	4035
	P.J. Chou, C.K. Chan, C.-C. Chang, K.T. Hsu, K.H. Hu, C.K. Kuan, I.C. Sheng NSRRC, Hsinchu, Taiwan
	In preparation for 500 mA operation at the Taiwan Pho-ton Source (TPS), we redesigned the horizontal stripline kicker for the beam feedback system to gain a smaller loss factor with higher shunt impedance. We introduced ground fenders (see Fig. 1) to this new design which resulted in the reduction of the loss factor and substantial increase of the kicker shunt impedance. The transverse profile of the kicker electrodes was matched to the race-track beam pipe in the straight sections to minimize broadband impedance. The ground fenders can reduce the leakage of image currents through the gaps between the two strip line electrodes and also help to achieve a better impedance matching for the TEM modes in the transmission lines formed by the stripline electrodes and beam pipe in the kicker. The RF design and analysis of trapped resonant modes in the kicker were simulated by the 3-D electromagnetic code GdfidL [1]. Results of the RF design and analysis of trapped resonant modes will be discussed together with analytical estimates of coupled bunch instabilities at a beam current of 500 mA.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB092
About •	paper received ※ 17 April 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019
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THPTS072	Field Measurements for a Superconducting Magnet at Room Temperature	4281
	J.C. Jan, C.-C. Chang, Y.L. Chu, J.C. Huang, C.-S. Hwang, C.Y. Kuo, F.-Y. Lin NSRRC, Hsinchu, Taiwan
	A superconducting multipole wiggler (SMPW) was fabricated at the National Synchrotron Radiation Research Center (NSRRC) and was installed in the Synchrotron Light Research Institute (SLRI). A 3.5 T field strength could be generated by the NbTi coils and the magnetic arrays are immersed in a liquid helium (LHe) bath. A removable mapping chamber, made from thin stainless steel sheets, was developed to allow field mapping in the narrow aperture of the SMPW. The mapping chamber provides a room temperature environment for the magnetic field mapping and enables an easier field scan in the cryostat. The design for the mapping chamber includes a blockage of heat transfer from room temperature to the LHe bath and is strong enough to resist deformations during evacuation. The mechanical design, strain simulation, thermal simulation, dummy test and measurement results with the mapping chamber will be discussed in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS072
About •	paper received ※ 10 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Preliminary Design of RF-Shielded Bellows

1341

Y.T. Huang, C.K. Chan, C.-C. Chang, C.M. Cheng, P.J. Chou, Y.C. Yang
NSRRC, Hsinchu, Taiwan

A new design of RF-shielded bellows is proposed for the TPS to alleviate wake field effects and Joule heating resulting from contact resistance at the contact interface of sliding two dissimilar metals. Most efforts are put into controlling corrosion which is regarded as the main cause of electrical contact degradation. Rh-Au is chosen as a mating interface because they are stable under high temperature condition. Experimental tests are made to find an effective plating thickness of Rh and Au and to determine a suitable normal load applicable on the Rh-Au interface. A preliminary design of RF-shielded bellows that can sustain thousands of cycles during their lifetime is under testing.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP041

About •

paper received ※ 06 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

Export •

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

TUPMP042

The Beam Cleaning Analysis for the TPS Vacuum System

1344

Y.C. Yang, C.K. Chan, C.-C. Chang, A.Y. Chen, J.-Y. Chuang, C.H. Huang
NSRRC, Hsinchu, Taiwan

Commissioning for the TPS, a low-emittance 3-GeV synchrotron ring, started in December 2014 and is now currently operating in top-up mode at 400mA for users. Until the last machine shut down in December 2018, a total beam dose of 4919 Ah was accumulated and the beam cleaning effect decreased the dynamic pressure to 1.5×10^-11 Pa/mA. During past years operation, several vacuum chambers were replaced to improve vacuum performance and avoid exposure to synchrotron radiation from insertion devices. In this paper, the beam cleaning evolution of new vacuum sections will be discussed and compared with experience in the rest of the storage ring. A particular cleaning evolution could be predicted and can be referenced for machine shutdown planning in the future.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP042

About •

paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

Export •

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

THPRB092

Reduction of Beam Induced RF-Heating in the Horizontal Stripline Kicker at the TPS

4035

P.J. Chou, C.K. Chan, C.-C. Chang, K.T. Hsu, K.H. Hu, C.K. Kuan, I.C. Sheng
NSRRC, Hsinchu, Taiwan

In preparation for 500 mA operation at the Taiwan Pho-ton Source (TPS), we redesigned the horizontal stripline kicker for the beam feedback system to gain a smaller loss factor with higher shunt impedance. We introduced ground fenders (see Fig. 1) to this new design which resulted in the reduction of the loss factor and substantial increase of the kicker shunt impedance. The transverse profile of the kicker electrodes was matched to the race-track beam pipe in the straight sections to minimize broadband impedance. The ground fenders can reduce the leakage of image currents through the gaps between the two strip line electrodes and also help to achieve a better impedance matching for the TEM modes in the transmission lines formed by the stripline electrodes and beam pipe in the kicker. The RF design and analysis of trapped resonant modes in the kicker were simulated by the 3-D electromagnetic code GdfidL [1]. Results of the RF design and analysis of trapped resonant modes will be discussed together with analytical estimates of coupled bunch instabilities at a beam current of 500 mA.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB092

About •

paper received ※ 17 April 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019

Export •

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

THPTS072

Field Measurements for a Superconducting Magnet at Room Temperature

4281

J.C. Jan, C.-C. Chang, Y.L. Chu, J.C. Huang, C.-S. Hwang, C.Y. Kuo, F.-Y. Lin
NSRRC, Hsinchu, Taiwan

A superconducting multipole wiggler (SMPW) was fabricated at the National Synchrotron Radiation Research Center (NSRRC) and was installed in the Synchrotron Light Research Institute (SLRI). A 3.5 T field strength could be generated by the NbTi coils and the magnetic arrays are immersed in a liquid helium (LHe) bath. A removable mapping chamber, made from thin stainless steel sheets, was developed to allow field mapping in the narrow aperture of the SMPW. The mapping chamber provides a room temperature environment for the magnetic field mapping and enables an easier field scan in the cryostat. The design for the mapping chamber includes a blockage of heat transfer from room temperature to the LHe bath and is strong enough to resist deformations during evacuation. The mechanical design, strain simulation, thermal simulation, dummy test and measurement results with the mapping chamber will be discussed in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS072

About •

paper received ※ 10 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

Export •

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