IPAC2018 - List of Authors (Xiao, B. P.)

Paper	Title	Page
MOPMF016	Progress on RCS eRHIC Injector Design	115
	V.H. Ranjbar, M. Blaskiewicz, J.M. Brennan, S.J. Brooks, D.M. Gassner, H.-C. Hseuh, I. Marneris, F. Méot, M.G. Minty, C. Montag, V. Ptitsyn, K.S. Smith, S. Tepikian, F.J. Willeke, H. Witte, B. P. Xiao, A. Zaltsman BNL, Upton, Long Island, New York, USA I.V. Pogorelov Tech-X, Boulder, Colorado, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. We have refined the design for the Rapid Cycling Synchrotron (RCS) polarized electron injector for eRHIC. The newer design includes bypasses for the eRHIC detectors and definition of the lattice layout in the existing RHIC tunnel. Additionally, we provide more details on the RF, alignment and orbit control, and magnet specifications.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF016
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MOPMF020	Higher Order Mode Coupling Options for the eRHIC Crab Cavity	121
	Q. Wu, I. Ben-Zvi, S. Verdú-Andrés, B. P. Xiao BNL, Upton, Long Island, New York, USA I. Ben-Zvi Stony Brook University, Stony Brook, USA
	Funding: This work was supported by the US Department of Energy via Brookhaven Science Associates LLC under contract no. DE-SC0012704. The eRHIC crab cavity adopts the double quarter wave structure developed at Brookhaven National Lab for the LHC Hi-Lumi upgrade crab cavities. The cavity's fundamental mode is at 338 MHz with the first higher order mode more than 180 MHz above that. We looked into the higher order mode distribution up to 2 GHz, and considered various locations and geometries of the coupling scheme. The cylindrical outer shell of the cavity allowed various possibilities for coupler port openings on all the walls, which were difficult for the narrow waist of the LHC double quarter wave crab cavities. Beam pipe absorbers are also options for simpler high frequency modes damping. Some preliminary high pass filter design will also be discussed in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF020
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TUPMF032	RF Conceptual Design of Normal Conducting Cavity for an eRHIC Rapid Cycling Synchrotron	1316
	B. P. Xiao, M. Blaskiewicz, J.M. Brennan, D. Holmes, K.S. Smith, T. Xin, A. Zaltsman BNL, Upton, Long Island, New York, USA
	Funding: Work is supported by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 with the US DOE. The Rapid Cycling Synchrotron (RCS) for the eRHIC Ring-Ring design will provide on energy injection (up to 18 GeV) of high charge, polarized electron bunches to the eRHIC electron storage ring. The RF system comprises a large number of 563MHz fundamental cavities, providing up to 45MV per turn. The cavities will operate in pulsed mode with <20% duty factor, at a repetition rate of 1 Hz. In this paper we report the conceptual RF design of the cavity.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF032
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TUPMF034	Measuring the Electrical Center and Field Flatness of 704 MHz Deflecting Cavity for LEReC with Wire Stretching System	1320
	T. Xin, J.M. Brennan, J.C.B. Brutus, K. Mernick, K.S. Smith, B. P. Xiao, A. Zaltsman BNL, Upton, Long Island, New York, USA W. Johnson SBU, Stony Brook, New York, USA H. Wang JLab, Newport News, Virginia, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. 704 MHz deflecting cavity was designed for the Low Energy RHIC electron Cooling (LEReC) project. The cavity will serve as a major component in diagnostic line. In LEReC project the requirement on the energy spread of the electron beam is extremely high (better than 10^-4) and the diagnostic system has to to be designed accordingly. The 704 MHz transverse deflecting cavity provides the vertical kick to the beam after it passes through the dispersion dipole so that we can measure the energy spread of the core of the bunch. Traditional way of determining the electrical center of the cavity involves the needle pulling and integration of the signal which is prone to the cumulative error. We present the measurement result from a wire stretching system that is much more efficient and accurate compared to the bead/needle pulling method. Both simulation and experimental results are shown in this paper and the potential in further application is discussed at the end.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF034
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THPAL018	DQW HOM Coupler Design for the HL-LHC	3663
	J.A. Mitchell Lancaster University, Lancaster, United Kingdom G. Burt Cockcroft Institute, Lancaster University, Lancaster, United Kingdom R. Calaga CERN, Geneva, Switzerland S. Verdú-Andrés, B. P. Xiao BNL, Upton, Long Island, New York, USA
	HOMs in the DQW crab cavity can produce large heat loads and beam instabilities as a result of the high current HL-LHC beams. The DQW crab cavity has on-cavity, coaxial HOM couplers to damp the HOMs whilst providing a stop-band response to the fundamental mode. Manufacturing experience and further simulations give rise to a set of desirable coupler improvements. This paper will assess the performance of the current HOM coupler design, present operational improvements and propose an evolved design for HL-LHC.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL018
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THPML095	Improvement of Wire-Stretching Technique to the RF Measurements of E-Center and Multipole Field for the Dipole Cavities	4885
	G.-T. Park, J. Guo, H. Wang JLab, Newport News, Virginia, USA A. Overstreet ODU, Norfolk, Virginia, USA B. P. Xiao, T. Xin BNL, Upton, Long Island, New York, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. After the first publication* of wire-stretching technique from its principle to measure the electrical center of a deflecting cavity, more refinements of this techniques including the review of its analytical and simulation results, RF circuit improvement to improve the signal to noise ratio and its application to other cavities have been developed. These applications include the electrical center measurements for the LHC RFD and DQW crabbing cavity prototypes, multi-frequency harmonic kicker cavity for JLEIC electron cooler, TE011 cavity developed for the beam magnetization measurement, and a separator cavity at BNL**. Further development of measurement calibration, error reduction, alignment of cavity installation to the machine beam line, and multipole field analysis for the beam dynamics will be presented. H. Wang, Proceedings of NAPAC2016, pp225-228 S. A. Overstreet, BS Thesis 2017, Guilford College, Greensboro, NC J. Guo et al. these proceedings ***T. Xin et al, these proceedings
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML095
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Paper

Title

Page

Progress on RCS eRHIC Injector Design

115

V.H. Ranjbar, M. Blaskiewicz, J.M. Brennan, S.J. Brooks, D.M. Gassner, H.-C. Hseuh, I. Marneris, F. Méot, M.G. Minty, C. Montag, V. Ptitsyn, K.S. Smith, S. Tepikian, F.J. Willeke, H. Witte, B. P. Xiao, A. Zaltsman
BNL, Upton, Long Island, New York, USA
I.V. Pogorelov
Tech-X, Boulder, Colorado, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
We have refined the design for the Rapid Cycling Synchrotron (RCS) polarized electron injector for eRHIC. The newer design includes bypasses for the eRHIC detectors and definition of the lattice layout in the existing RHIC tunnel. Additionally, we provide more details on the RF, alignment and orbit control, and magnet specifications.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF016

Export •

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MOPMF020

Higher Order Mode Coupling Options for the eRHIC Crab Cavity

121

Q. Wu, I. Ben-Zvi, S. Verdú-Andrés, B. P. Xiao
BNL, Upton, Long Island, New York, USA
I. Ben-Zvi
Stony Brook University, Stony Brook, USA

Funding: This work was supported by the US Department of Energy via Brookhaven Science Associates LLC under contract no. DE-SC0012704.
The eRHIC crab cavity adopts the double quarter wave structure developed at Brookhaven National Lab for the LHC Hi-Lumi upgrade crab cavities. The cavity's fundamental mode is at 338 MHz with the first higher order mode more than 180 MHz above that. We looked into the higher order mode distribution up to 2 GHz, and considered various locations and geometries of the coupling scheme. The cylindrical outer shell of the cavity allowed various possibilities for coupler port openings on all the walls, which were difficult for the narrow waist of the LHC double quarter wave crab cavities. Beam pipe absorbers are also options for simpler high frequency modes damping. Some preliminary high pass filter design will also be discussed in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF020

Export •

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

TUPMF032

RF Conceptual Design of Normal Conducting Cavity for an eRHIC Rapid Cycling Synchrotron

1316

B. P. Xiao, M. Blaskiewicz, J.M. Brennan, D. Holmes, K.S. Smith, T. Xin, A. Zaltsman
BNL, Upton, Long Island, New York, USA

Funding: Work is supported by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 with the US DOE.
The Rapid Cycling Synchrotron (RCS) for the eRHIC Ring-Ring design will provide on energy injection (up to 18 GeV) of high charge, polarized electron bunches to the eRHIC electron storage ring. The RF system comprises a large number of 563MHz fundamental cavities, providing up to 45MV per turn. The cavities will operate in pulsed mode with <20% duty factor, at a repetition rate of 1 Hz. In this paper we report the conceptual RF design of the cavity.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF032

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TUPMF034

Measuring the Electrical Center and Field Flatness of 704 MHz Deflecting Cavity for LEReC with Wire Stretching System

1320

T. Xin, J.M. Brennan, J.C.B. Brutus, K. Mernick, K.S. Smith, B. P. Xiao, A. Zaltsman
BNL, Upton, Long Island, New York, USA
W. Johnson
SBU, Stony Brook, New York, USA
H. Wang
JLab, Newport News, Virginia, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
704 MHz deflecting cavity was designed for the Low Energy RHIC electron Cooling (LEReC) project. The cavity will serve as a major component in diagnostic line. In LEReC project the requirement on the energy spread of the electron beam is extremely high (better than 10^-4) and the diagnostic system has to to be designed accordingly. The 704 MHz transverse deflecting cavity provides the vertical kick to the beam after it passes through the dispersion dipole so that we can measure the energy spread of the core of the bunch. Traditional way of determining the electrical center of the cavity involves the needle pulling and integration of the signal which is prone to the cumulative error. We present the measurement result from a wire stretching system that is much more efficient and accurate compared to the bead/needle pulling method. Both simulation and experimental results are shown in this paper and the potential in further application is discussed at the end.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF034

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THPAL018

DQW HOM Coupler Design for the HL-LHC

3663

J.A. Mitchell
Lancaster University, Lancaster, United Kingdom
G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
R. Calaga
CERN, Geneva, Switzerland
S. Verdú-Andrés, B. P. Xiao
BNL, Upton, Long Island, New York, USA

HOMs in the DQW crab cavity can produce large heat loads and beam instabilities as a result of the high current HL-LHC beams. The DQW crab cavity has on-cavity, coaxial HOM couplers to damp the HOMs whilst providing a stop-band response to the fundamental mode. Manufacturing experience and further simulations give rise to a set of desirable coupler improvements. This paper will assess the performance of the current HOM coupler design, present operational improvements and propose an evolved design for HL-LHC.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL018

Export •

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

THPML095

Improvement of Wire-Stretching Technique to the RF Measurements of E-Center and Multipole Field for the Dipole Cavities

4885

G.-T. Park, J. Guo, H. Wang
JLab, Newport News, Virginia, USA
A. Overstreet
ODU, Norfolk, Virginia, USA
B. P. Xiao, T. Xin
BNL, Upton, Long Island, New York, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
After the first publication* of wire-stretching technique from its principle to measure the electrical center of a deflecting cavity, more refinements of this techniques including the review of its analytical and simulation results, RF circuit improvement to improve the signal to noise ratio and its application to other cavities have been developed. These applications include the electrical center measurements for the LHC RFD and DQW crabbing cavity prototypes, multi-frequency harmonic kicker cavity for JLEIC electron cooler**, TE011 cavity developed for the beam magnetization measurement***, and a separator cavity at BNL****. Further development of measurement calibration, error reduction, alignment of cavity installation to the machine beam line, and multipole field analysis for the beam dynamics will be presented.
*H. Wang, Proceedings of NAPAC2016, pp225-228
**S. A. Overstreet, BS Thesis 2017, Guilford College, Greensboro, NC
***J. Guo et al. these proceedings
****T. Xin et al, these proceedings

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML095

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