SRF2023 - List of Keywords (impedance)

Paper	Title	Other Keywords	Page
TUPTB044	Compact Multicell Superconducting Crab Cavity for ILC	cavity, HOM, dipole, SRF	521
	A. Lunin, S.A. Belomestnykh, I.V. Gonin, T.N. Khabiboulline, Y.M. Orlov, V. Poloubotko, V.P. Yakovlev Fermilab, Batavia, Illinois, USA
	Funding: Work supported by the Fermi National Accelerator Laboratory; managed by Fermi Research Alliance, LLC under Contract No. DEAC02-07CH11359 with the U.S. Department of Energy We propose a novel design of a deflecting cavity for the ILC project with low parasitic HOM losses and preserving the beam emittance, which is critical for operation with high beam current intensity. Multiple electrodes immersed in the hollow waveguide form a trapped-mode resonator. The transverse components of the electromagnetic field of the trapped dipole mode induce a transverse kick and efficiently deflect charged particles passing through the cavity. We present a scalable design of a superconducting Quasi-waveguide Multicell Resonator (QMiR) seamlessly connected with a beam vacuum chamber. The cavity is completely open at both ends, which significantly reduces the maximum loaded quality factor of the higher order modes (HOM), avoids complex HOM couplers and thus simplifies the mechanical design of the cavity. The same port is used to feed RF power to the operating mode and to extract the same order modes (SOM). Finally, we estimate the expected cryogenic losses, HOM impedance limits, RF input power required, and frequency tuning for a QMiR cavity designed to operate at 2.6 GHz.
	Poster TUPTB044 [6.975 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB044
About •	Received ※ 19 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 16 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTB046	Development and Performance of RFD Crab Cavity Prototypes for HL-LHC AUP	cavity, HOM, niobium, higher-order-mode	531
	L. Ristori, P. Berrutti, M. Narduzzi Fermilab, Batavia, Illinois, USA A. Castilla JLAB, Newport News, USA S.U. De Silva, J.R. Delayen ODU, Norfolk, Virginia, USA N.A. Huque JLab, Newport News, Virginia, USA Z. Li, A. Ratti SLAC, Menlo Park, California, USA
	Funding: Operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the U.S. DOE The US will be contributing to the HL-LHC upgrade at CERN with the fabrication and qualification of RFD crabbing cavities in the framework of the HL-LHC Accelerator Upgrade Project (AUP) managed by Fermilab. AUP received Critical Decision 3 (CD-3) approval by DOE in December 2020 launching the project into the production phase. The electro-magnetic design of the cavity was inherited from the LHC Accelerator Research Program (LARP) but needed to be revised to meet new project requirements and to prevent issues encountered during beam tests performed at CERN in the R&D phase. Two prototype cavities were manufactured in industry and cold tested. Challenges specific to the RFD cavity were the stringent interface tolerances, the pole symmetry and the higher-order-mode impedance spectrum. Chemical processing and heat treatments were performed initially at FNAL/ANL and are now being transferred to industry for the production phase. HOM dampers are manufactured and validated by JLAB. A summary of cold test results with and without HOM dampers is presented.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB046
About •	Received ※ 20 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 11 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTB068	EIC 197 MHz Crab Cavity RF Optimization	cavity, HOM, multipactoring, GUI	584
	Z. Li SLAC, Menlo Park, California, USA S.U. De Silva, J.R. Delayen ODU, Norfolk, Virginia, USA R.A. Rimmer JLab, Newport News, Virginia, USA Q. Wu, B.P. Xiao, W. Xu BNL, Upton, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under U.S. DOE K No. DE-SC0012704, by Jefferson Science Associates, LLC under U.S. DOE K No. DE-SC0002769, and by DOE K No. DE-AC02-76SF00515. Crab cavities, operating at 197 MHz and 394 MHz respectively, will be used to compensate the loss of luminosity due to a 25 mrad crossing angle at the interaction point in the Electron Ion Collider (EIC). Both crab cavities are of the RF Dipole (RFD) shape. To meet the machine design requirements, there are a few important cavity design considerations that need to be addressed. First, to achieve stable cavity operation at the design voltages, cavity geometry details must be optimized to suppress potential multipacting. Incorporating strong HOM damping in the cavity design is required for the beam stability and quality. Furthermore, due to the finite pole width, the multipole fields, especially the sextupole and the decapole terms, need to be minimized to maintain an acceptable beam dynamic aperture. This paper will present the RF optimization details of the 197 MHz cavity.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB068
About •	Received ※ 16 June 2023 — Revised ※ 29 June 2023 — Accepted ※ 03 July 2023 — Issue date ※ 08 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPWB047	Higher Order Mode Analysis of a 915 MHz 2-Cell Cavity for a Prototype Industrial Accelerator	cavity, HOM, SRF, higher-order-mode	667
	A. Castilla JLAB, Newport News, USA G. Ciovati, J. Guo, G.-T. Park, R.A. Rimmer, H. Vennekate JLab, Newport News, Virginia, USA
	A possible solution to reduce the complexity posed by the cryogenic systems in a superconducting RF accelerator for industrial applications, is to capitalize on the advances achieved by the Nb₃Sn superconducting RF technology, as well as the feasibility of a reliable 4 K cooling system, based on commercial cryocoolers. Following this philosophy, the conceptual design for a prototype, conduction-cooled, 4 MeV, 20 kW SRF electron linac, is being developed at Jefferson Lab. Such design is based on a 915 MHz two-cell Nb₃Sn cavity. In this contribution, we present the proposed cavity design, including the fundamental power coupler, and the preliminary analysis of the Higher Order Modes, using numerical simulations to estimate the potentially dangerous modes as a starting point to evaluate the requirements for damping for reliable operations with a cryocooler. Finally, different methods to calculate the Higher Order Modes’ Impedances are briefly discussed.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB047
About •	Received ※ 25 June 2023 — Revised ※ 29 June 2023 — Accepted ※ 04 July 2023 — Issue date ※ 16 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

FRIBA03	Heavily Damped Crab Cavities for High Luminosity Collisions	cavity, GUI, HOM, collider	986
	B.P. Xiao BNL, Upton, New York, USA S.U. De Silva ODU, Norfolk, Virginia, USA
	Funding: Work supported by BSA under U.S. DOE contract No. DE-SC0012704, by JSA under U.S. DOE Contract No. DE-SC0002769, and by DOE Contract No. DE-AC02-76SF00515. Next generation colliders require crab cavities to mitigate parasitic collisions caused by finite crossing angle for luminosity leveling and detector data pile up reduction. The Electron Ion Collider (EIC) crab cavity designs will be introduced as an example to fulfill the geometrical constraints, crabbing voltages, multipole components, Higher Order Mode (HOM) power and impedance budgets. Operational challenges such as tuning, high gain low delay control loop, amplitude and phase noises control will be discussed.
	Slides FRIBA03 [3.666 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-FRIBA03
About •	Received ※ 19 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 06 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

FRIBA04	Crab Cavities for ILC	cavity, HOM, SRF, operation	990
	P.A. McIntosh STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom S.A. Belomestnykh, I.V. Gonin, T.N. Khabiboulline, A. Lunin, Y.M. Orlov, V.P. Yakovlev Fermilab, Batavia, Illinois, USA G. Burt Cockcroft Institute, Lancaster University, Lancaster, United Kingdom R. Calaga CERN, Meyrin, Switzerland S.U. De Silva JLab, Newport News, Virginia, USA J.R. Delayen ODU, Norfolk, Virginia, USA T. Okugi, A. Yamamoto KEK, Ibaraki, Japan S. Verdú-Andrés, B.P. Xiao BNL, Upton, New York, USA
	For the 14 mrad crossing angle proposed, crab cavity systems are fundamentally anticipated for the viable operation of the International Linear Collider (ILC), in order to maximise its luminosity performance. Since 2021, a specialist development team have been defining optimum crab cavity technologies which can fulfil the operational requirements for ILC, both for its baseline centre-of-mass energy of 250 GeV, but also extending those requirements out to higher beam collision intensities. Five design teams have established crab cavity technology solutions, which have the capability to also operate up to 1 TeV centre-of-mass. This presentation showcases the key performance capabilities of these designs and their associated benefits for both manufacture and integration into the ILC Interaction Region. The recommended outcome of the recently conducted crab cavity technology down-selection, will also be highlighted.
	Slides FRIBA04 [2.526 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-FRIBA04
About •	Received ※ 19 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 20 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

TUPTB044

Compact Multicell Superconducting Crab Cavity for ILC

cavity, HOM, dipole, SRF

521

A. Lunin, S.A. Belomestnykh, I.V. Gonin, T.N. Khabiboulline, Y.M. Orlov, V. Poloubotko, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

Funding: Work supported by the Fermi National Accelerator Laboratory; managed by Fermi Research Alliance, LLC under Contract No. DEAC02-07CH11359 with the U.S. Department of Energy
We propose a novel design of a deflecting cavity for the ILC project with low parasitic HOM losses and preserving the beam emittance, which is critical for operation with high beam current intensity. Multiple electrodes immersed in the hollow waveguide form a trapped-mode resonator. The transverse components of the electromagnetic field of the trapped dipole mode induce a transverse kick and efficiently deflect charged particles passing through the cavity. We present a scalable design of a superconducting Quasi-waveguide Multicell Resonator (QMiR) seamlessly connected with a beam vacuum chamber. The cavity is completely open at both ends, which significantly reduces the maximum loaded quality factor of the higher order modes (HOM), avoids complex HOM couplers and thus simplifies the mechanical design of the cavity. The same port is used to feed RF power to the operating mode and to extract the same order modes (SOM). Finally, we estimate the expected cryogenic losses, HOM impedance limits, RF input power required, and frequency tuning for a QMiR cavity designed to operate at 2.6 GHz.

Poster TUPTB044 [6.975 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB044

About •

Received ※ 19 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 16 July 2023

Cite •

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

TUPTB046

Development and Performance of RFD Crab Cavity Prototypes for HL-LHC AUP

cavity, HOM, niobium, higher-order-mode

531

L. Ristori, P. Berrutti, M. Narduzzi
Fermilab, Batavia, Illinois, USA
A. Castilla
JLAB, Newport News, USA
S.U. De Silva, J.R. Delayen
ODU, Norfolk, Virginia, USA
N.A. Huque
JLab, Newport News, Virginia, USA
Z. Li, A. Ratti
SLAC, Menlo Park, California, USA

Funding: Operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the U.S. DOE
The US will be contributing to the HL-LHC upgrade at CERN with the fabrication and qualification of RFD crabbing cavities in the framework of the HL-LHC Accelerator Upgrade Project (AUP) managed by Fermilab. AUP received Critical Decision 3 (CD-3) approval by DOE in December 2020 launching the project into the production phase. The electro-magnetic design of the cavity was inherited from the LHC Accelerator Research Program (LARP) but needed to be revised to meet new project requirements and to prevent issues encountered during beam tests performed at CERN in the R&D phase. Two prototype cavities were manufactured in industry and cold tested. Challenges specific to the RFD cavity were the stringent interface tolerances, the pole symmetry and the higher-order-mode impedance spectrum. Chemical processing and heat treatments were performed initially at FNAL/ANL and are now being transferred to industry for the production phase. HOM dampers are manufactured and validated by JLAB. A summary of cold test results with and without HOM dampers is presented.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB046

About •

Received ※ 20 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 11 July 2023

Cite •

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

TUPTB068

EIC 197 MHz Crab Cavity RF Optimization

cavity, HOM, multipactoring, GUI

584

Z. Li
SLAC, Menlo Park, California, USA
S.U. De Silva, J.R. Delayen
ODU, Norfolk, Virginia, USA
R.A. Rimmer
JLab, Newport News, Virginia, USA
Q. Wu, B.P. Xiao, W. Xu
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under U.S. DOE K No. DE-SC0012704, by Jefferson Science Associates, LLC under U.S. DOE K No. DE-SC0002769, and by DOE K No. DE-AC02-76SF00515.
Crab cavities, operating at 197 MHz and 394 MHz respectively, will be used to compensate the loss of luminosity due to a 25 mrad crossing angle at the interaction point in the Electron Ion Collider (EIC). Both crab cavities are of the RF Dipole (RFD) shape. To meet the machine design requirements, there are a few important cavity design considerations that need to be addressed. First, to achieve stable cavity operation at the design voltages, cavity geometry details must be optimized to suppress potential multipacting. Incorporating strong HOM damping in the cavity design is required for the beam stability and quality. Furthermore, due to the finite pole width, the multipole fields, especially the sextupole and the decapole terms, need to be minimized to maintain an acceptable beam dynamic aperture. This paper will present the RF optimization details of the 197 MHz cavity.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB068

About •

Received ※ 16 June 2023 — Revised ※ 29 June 2023 — Accepted ※ 03 July 2023 — Issue date ※ 08 July 2023

Cite •

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

WEPWB047

Higher Order Mode Analysis of a 915 MHz 2-Cell Cavity for a Prototype Industrial Accelerator

cavity, HOM, SRF, higher-order-mode

667

A. Castilla
JLAB, Newport News, USA
G. Ciovati, J. Guo, G.-T. Park, R.A. Rimmer, H. Vennekate
JLab, Newport News, Virginia, USA

A possible solution to reduce the complexity posed by the cryogenic systems in a superconducting RF accelerator for industrial applications, is to capitalize on the advances achieved by the Nb₃Sn superconducting RF technology, as well as the feasibility of a reliable 4 K cooling system, based on commercial cryocoolers. Following this philosophy, the conceptual design for a prototype, conduction-cooled, 4 MeV, 20 kW SRF electron linac, is being developed at Jefferson Lab. Such design is based on a 915 MHz two-cell Nb₃Sn cavity. In this contribution, we present the proposed cavity design, including the fundamental power coupler, and the preliminary analysis of the Higher Order Modes, using numerical simulations to estimate the potentially dangerous modes as a starting point to evaluate the requirements for damping for reliable operations with a cryocooler. Finally, different methods to calculate the Higher Order Modes’ Impedances are briefly discussed.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB047

About •

Received ※ 25 June 2023 — Revised ※ 29 June 2023 — Accepted ※ 04 July 2023 — Issue date ※ 16 July 2023

Cite •

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

FRIBA03

Heavily Damped Crab Cavities for High Luminosity Collisions

cavity, GUI, HOM, collider

986

B.P. Xiao
BNL, Upton, New York, USA
S.U. De Silva
ODU, Norfolk, Virginia, USA

Funding: Work supported by BSA under U.S. DOE contract No. DE-SC0012704, by JSA under U.S. DOE Contract No. DE-SC0002769, and by DOE Contract No. DE-AC02-76SF00515.
Next generation colliders require crab cavities to mitigate parasitic collisions caused by finite crossing angle for luminosity leveling and detector data pile up reduction. The Electron Ion Collider (EIC) crab cavity designs will be introduced as an example to fulfill the geometrical constraints, crabbing voltages, multipole components, Higher Order Mode (HOM) power and impedance budgets. Operational challenges such as tuning, high gain low delay control loop, amplitude and phase noises control will be discussed.

Slides FRIBA03 [3.666 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-FRIBA03

About •

Received ※ 19 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 06 July 2023

Cite •

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

FRIBA04

Crab Cavities for ILC

cavity, HOM, SRF, operation

990

P.A. McIntosh
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
S.A. Belomestnykh, I.V. Gonin, T.N. Khabiboulline, A. Lunin, Y.M. Orlov, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA
G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
R. Calaga
CERN, Meyrin, Switzerland
S.U. De Silva
JLab, Newport News, Virginia, USA
J.R. Delayen
ODU, Norfolk, Virginia, USA
T. Okugi, A. Yamamoto
KEK, Ibaraki, Japan
S. Verdú-Andrés, B.P. Xiao
BNL, Upton, New York, USA

For the 14 mrad crossing angle proposed, crab cavity systems are fundamentally anticipated for the viable operation of the International Linear Collider (ILC), in order to maximise its luminosity performance. Since 2021, a specialist development team have been defining optimum crab cavity technologies which can fulfil the operational requirements for ILC, both for its baseline centre-of-mass energy of 250 GeV, but also extending those requirements out to higher beam collision intensities. Five design teams have established crab cavity technology solutions, which have the capability to also operate up to 1 TeV centre-of-mass. This presentation showcases the key performance capabilities of these designs and their associated benefits for both manufacture and integration into the ILC Interaction Region. The recommended outcome of the recently conducted crab cavity technology down-selection, will also be highlighted.

Slides FRIBA04 [2.526 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-FRIBA04

About •

Received ※ 19 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 20 July 2023

Cite •

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