SRF2017 - List of Authors (Ben-Zvi, I.)

Paper	Title	Page
MOPB002	eRHIC Crab Cavity Choice for Ring-ring Design	43
	Q. Wu, I. Ben-Zvi, Y. Hao, S. Verdú-Andrés, B. P. Xiao BNL, Upton, Long Island, New York, USA
	Funding: This work was supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE. The future electron ion collider eRHIC adopts large crossing angle (22 mrad) to allow fast separation of two beams in the ring-ring scheme. Crab cavities are required to recover the luminosity from geometric losses. Initial calculation shows that the frequency of the cavities for the ion beam is no more than 336MHz. In this paper, we discuss the crab cavity related lattice parameters for both ion and electron beams in ring-ring design, the frequency choice, and the cavity design considerations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB002
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MOPB009	Progress of 650 MHz SRF Cavity for eRHIC SRF Linac	64
	W. Xu, I. Ben-Zvi, Y. Gao, D. Holmes, P. Kolb, G.T. McIntyre, C. Pai, R. Porqueddu, K.S. Smith, R. Than, J.E. Tuozzolo, F.J. Willeke, A. Zaltsman BNL, Upton, Long Island, New York, USA I. Ben-Zvi Stony Brook University, Stony Brook, USA
	Funding: This work is supported by LDRD program of Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE. eRHIC ERL SRF requires 160 5-cell 650 MHz SRF cavities. The 650 MHz cavity has been designed and two prototypes have been fabricated, one Cu cavity for HOM study and one Nb cavity for cavity performance study. This paper will describe cavity design and the progress of prototyping.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB009
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MOPB053	RF Energy Harvesting of HOM Power	180
	C. Xu, I. Ben-Zvi, Q. Wu, T. Xin BNL, Upton, Long Island, New York, USA I. Ben-Zvi Stony Brook University, Stony Brook, USA
	In an accelerator cavity, Higher Order Modes (HOM) are generated by the current of the beam. The HOM power can reach tens of kilowatts in a high current accelerator, depending on the details of the beam and cavity design. In this report, we propose a novel RF harvesting system to recover the HOM power into DC power which can further used for various purposes such as driving a solid state or klystron RF amplifier to supply fundamental RF power at other frequencies, charge batteries etc. The efficiency would be a product of the energy recovery and regeneration efficiencies, where the state of art is 90%. The proposed HOM power recycling system contains a multiple band harmonic RF coupler, broadband RF antenna system, a high power rectifier diode circuit and a DC load. 1) Collider-Accelerator Department, Brookhaven National Lab, Upton, NY 11973, USA 2) Physics & Astronomy Department, Stony Brook University, Stony Brook, NY 11794, USA
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB053
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TUPB001	338 MHz Crab Cavity Design for the eRHIC Hadron Beam	382
	S. Verdú-Andrés, I. Ben-Zvi, Q. Wu, B. P. Xiao BNL, Upton, Long Island, New York, USA I. Ben-Zvi Stony Brook University, Stony Brook, USA
	Funding: Work supported by the US Department of Energy via Brookhaven Science Associates LLC under contract no. DE-AC02-98CH10886. Crab crossing is an essential mechanism to restore high luminosity and avoid synchro-betatron resonances in the electron-hadron collider eRHIC. The current ring-ring eRHIC design envisages a set of crab cavities operating at 338 MHz. This set of cavities will provide the crabbing kick to the hadron beam of eRHIC. Double-Quarter Wave (DQW) cavities are compact, superconducting RF deflecting cavities appropriate for crab crossing. This paper summarizes the main design requirements and presents an optimized RF design of a DQW cavity for the crabbing system of the ring-ring eRHIC hadron beam.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUPB001
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TUPB002	Novel HOM Damper Design for High Current SRF Cavities	385
	W. Xu, I. Ben-Zvi, M. Blaskiewicz, Y. Gao, D. Holmes, P. Kolb, G.T. McIntyre, R. Porqueddu, K.S. Smith, R. Than, F.J. Willeke, B. P. Xiao, T. Xin, C. Xu, A. Zaltsman BNL, Upton, Long Island, New York, USA I. Ben-Zvi Stony Brook University, Stony Brook, USA Y. Gao PKU, Beijing, People's Republic of China
	Funding: This work is supported by LDRD program of Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE. ERL-Ring eRHIC aims to build a new high current (50 mA), multi-pass (6 passes) ERL to provide 3-18 GeV electron beams to collide with proton beams from existing RHIC. One critical challenge for eRHIC is to damp HOMs. The average HOM power is up to 8 kW per cavity, and it will get worse when the electron beam spectrum overlaps with cavity HOM spectrum. A novel HOM damping scheme by employing ridge waveguides has been worked out at BNL, which is able to well damp both longitudinal and transversal modes. This paper will describe the design of the HOM damping scheme, including RF design, HOM damping results, progress of prototyping.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUPB002
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TUPB014	In-situ Bulk Residual Resistivity Ratio Measurement on Double Quarter Wave Crab Cavities	415
	N.C. Shipman, A. Castilla, K.G. Hernández-Chahín, A. Macpherson CERN, Geneva, Switzerland I. Ben-Zvi BNL, Upton, Long Island, New York, USA G. Burt, N.C. Shipman Cockcroft Institute, Lancaster University, Lancaster, United Kingdom K.G. Hernández-Chahín Universidad de Guanajuato, División de Ciencias e Ingenierías, León, Mexico J.A. Mitchell Lancaster University, Lancaster, United Kingdom N.C. Shipman UMAN, Manchester, United Kingdom
	A four wire measurement was used to measure the bulk RRR on two DQW Crab Cavities. The measurement procedure is explained and the values obtained for each cavity are compared together with the values obtained from Niobium samples of the same stock from which the cavities were manufactured. Measurement errors and carefully analysed and further improvements to the measurement procedure are suggested.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUPB014
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THPB059	Simulation and Measurements of Crab Cavity HOMs and HOM Couplers for HL-LHC	881
	J.A. Mitchell, T.J. Jones Lancaster University, Lancaster, United Kingdom R. Apsimon, G. Burt, N.C. Shipman Cockcroft Institute, Lancaster University, Lancaster, United Kingdom I. Ben-Zvi, S. Verdú-Andrés, B. P. Xiao BNL, Upton, Long Island, New York, USA R. Calaga, A. Castilla, A. Macpherson, N.C. Shipman, A. Zwozniak CERN, Geneva, Switzerland T. Powers, H. Wang JLab, Newport News, Virginia, USA N.C. Shipman UMAN, Manchester, United Kingdom
	Two Superconducting Radio-Frequency (SRF) crab cavities are foreseen for the High Luminosity LHC (HL-LHC) upgrade. Preliminary beam tests of the Double Quarter Wave (DQW) crab cavity will take place in the Super Proton Synchrotron (SPS) in 2018. For damping of the cavity's Higher Order Modes (HOMs) the DQW has three identical on-cell, superconducting HOM couplers. The couplers are actively cooled by liquid heluim. In this paper, electromagnetic simulations of the HOMs and HOM couplers are presented. A novel approach to pre-installation spectral analysis of the HOM couplers is then presented, detailing both simulated and measured data. Measurements of the cavity HOMs at warm and in Vertical Test Facilities (VTFs) at both JLAB and CERN are detailed, comparing the measured characteristics of each mode to that of the simulated data-sets. Finally, the measured cavity data is compared with the test box measurements to see by what extent any reduction in damping can be predicted.
	Poster THPB059 [8.192 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-THPB059
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Paper

Title

Page

eRHIC Crab Cavity Choice for Ring-ring Design

43

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

Funding: This work was supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
The future electron ion collider eRHIC adopts large crossing angle (22 mrad) to allow fast separation of two beams in the ring-ring scheme. Crab cavities are required to recover the luminosity from geometric losses. Initial calculation shows that the frequency of the cavities for the ion beam is no more than 336MHz. In this paper, we discuss the crab cavity related lattice parameters for both ion and electron beams in ring-ring design, the frequency choice, and the cavity design considerations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB002

Export •

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

MOPB009

Progress of 650 MHz SRF Cavity for eRHIC SRF Linac

64

W. Xu, I. Ben-Zvi, Y. Gao, D. Holmes, P. Kolb, G.T. McIntyre, C. Pai, R. Porqueddu, K.S. Smith, R. Than, J.E. Tuozzolo, F.J. Willeke, A. Zaltsman
BNL, Upton, Long Island, New York, USA
I. Ben-Zvi
Stony Brook University, Stony Brook, USA

Funding: This work is supported by LDRD program of Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
eRHIC ERL SRF requires 160 5-cell 650 MHz SRF cavities. The 650 MHz cavity has been designed and two prototypes have been fabricated, one Cu cavity for HOM study and one Nb cavity for cavity performance study. This paper will describe cavity design and the progress of prototyping.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB009

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MOPB053

RF Energy Harvesting of HOM Power

180

C. Xu, I. Ben-Zvi, Q. Wu, T. Xin
BNL, Upton, Long Island, New York, USA
I. Ben-Zvi
Stony Brook University, Stony Brook, USA

In an accelerator cavity, Higher Order Modes (HOM) are generated by the current of the beam. The HOM power can reach tens of kilowatts in a high current accelerator, depending on the details of the beam and cavity design. In this report, we propose a novel RF harvesting system to recover the HOM power into DC power which can further used for various purposes such as driving a solid state or klystron RF amplifier to supply fundamental RF power at other frequencies, charge batteries etc. The efficiency would be a product of the energy recovery and regeneration efficiencies, where the state of art is 90%. The proposed HOM power recycling system contains a multiple band harmonic RF coupler, broadband RF antenna system, a high power rectifier diode circuit and a DC load.
1) Collider-Accelerator Department, Brookhaven National Lab, Upton, NY 11973, USA 2) Physics & Astronomy Department, Stony Brook University, Stony Brook, NY 11794, USA

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reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB053

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TUPB001

338 MHz Crab Cavity Design for the eRHIC Hadron Beam

382

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

Funding: Work supported by the US Department of Energy via Brookhaven Science Associates LLC under contract no. DE-AC02-98CH10886.
Crab crossing is an essential mechanism to restore high luminosity and avoid synchro-betatron resonances in the electron-hadron collider eRHIC. The current ring-ring eRHIC design envisages a set of crab cavities operating at 338 MHz. This set of cavities will provide the crabbing kick to the hadron beam of eRHIC. Double-Quarter Wave (DQW) cavities are compact, superconducting RF deflecting cavities appropriate for crab crossing. This paper summarizes the main design requirements and presents an optimized RF design of a DQW cavity for the crabbing system of the ring-ring eRHIC hadron beam.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUPB001

Export •

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

TUPB002

Novel HOM Damper Design for High Current SRF Cavities

385

W. Xu, I. Ben-Zvi, M. Blaskiewicz, Y. Gao, D. Holmes, P. Kolb, G.T. McIntyre, R. Porqueddu, K.S. Smith, R. Than, F.J. Willeke, B. P. Xiao, T. Xin, C. Xu, A. Zaltsman
BNL, Upton, Long Island, New York, USA
I. Ben-Zvi
Stony Brook University, Stony Brook, USA
Y. Gao
PKU, Beijing, People's Republic of China

Funding: This work is supported by LDRD program of Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
ERL-Ring eRHIC aims to build a new high current (50 mA), multi-pass (6 passes) ERL to provide 3-18 GeV electron beams to collide with proton beams from existing RHIC. One critical challenge for eRHIC is to damp HOMs. The average HOM power is up to 8 kW per cavity, and it will get worse when the electron beam spectrum overlaps with cavity HOM spectrum. A novel HOM damping scheme by employing ridge waveguides has been worked out at BNL, which is able to well damp both longitudinal and transversal modes. This paper will describe the design of the HOM damping scheme, including RF design, HOM damping results, progress of prototyping.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUPB002

Export •

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

TUPB014

In-situ Bulk Residual Resistivity Ratio Measurement on Double Quarter Wave Crab Cavities

415

N.C. Shipman, A. Castilla, K.G. Hernández-Chahín, A. Macpherson
CERN, Geneva, Switzerland
I. Ben-Zvi
BNL, Upton, Long Island, New York, USA
G. Burt, N.C. Shipman
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
K.G. Hernández-Chahín
Universidad de Guanajuato, División de Ciencias e Ingenierías, León, Mexico
J.A. Mitchell
Lancaster University, Lancaster, United Kingdom
N.C. Shipman
UMAN, Manchester, United Kingdom

A four wire measurement was used to measure the bulk RRR on two DQW Crab Cavities. The measurement procedure is explained and the values obtained for each cavity are compared together with the values obtained from Niobium samples of the same stock from which the cavities were manufactured. Measurement errors and carefully analysed and further improvements to the measurement procedure are suggested.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUPB014

Export •

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

THPB059

Simulation and Measurements of Crab Cavity HOMs and HOM Couplers for HL-LHC

881

J.A. Mitchell, T.J. Jones
Lancaster University, Lancaster, United Kingdom
R. Apsimon, G. Burt, N.C. Shipman
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
I. Ben-Zvi, S. Verdú-Andrés, B. P. Xiao
BNL, Upton, Long Island, New York, USA
R. Calaga, A. Castilla, A. Macpherson, N.C. Shipman, A. Zwozniak
CERN, Geneva, Switzerland
T. Powers, H. Wang
JLab, Newport News, Virginia, USA
N.C. Shipman
UMAN, Manchester, United Kingdom

Two Superconducting Radio-Frequency (SRF) crab cavities are foreseen for the High Luminosity LHC (HL-LHC) upgrade. Preliminary beam tests of the Double Quarter Wave (DQW) crab cavity will take place in the Super Proton Synchrotron (SPS) in 2018. For damping of the cavity's Higher Order Modes (HOMs) the DQW has three identical on-cell, superconducting HOM couplers. The couplers are actively cooled by liquid heluim. In this paper, electromagnetic simulations of the HOMs and HOM couplers are presented. A novel approach to pre-installation spectral analysis of the HOM couplers is then presented, detailing both simulated and measured data. Measurements of the cavity HOMs at warm and in Vertical Test Facilities (VTFs) at both JLAB and CERN are detailed, comparing the measured characteristics of each mode to that of the simulated data-sets. Finally, the measured cavity data is compared with the test box measurements to see by what extent any reduction in damping can be predicted.

Poster THPB059 [8.192 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-THPB059

Export •

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