SRF2023 - List of Keywords (higher-order-mode)

Paper	Title	Other Keywords	Page
TUPTB026	Measurements of High Values of Dielectric Permittivity Using Transmission Lines	GUI, resonance, simulation, cavity	447
	V.D. Shemelin, M. Liepe Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: DOE Usage of lossy materials is necessary for absorption of higher order modes excited in the RF cavities. Presently, measurements of lossy materials with usage of transmission lines give errors rapidly increasing with increase of the dielectric permittivity. A method is presented for measurements of high values of dielectric permittivity epsilon in a waveguide at high frequencies with lower errors. This method supplements the method of measurements evolved for low values of epsilon and is close to resonant methods, when a sample is placed into a cavity and the measurement is done at one only frequency. The new approach with use of Microwave Studio simulations makes possible to measure this value in several frequency points at one measurement.
	Poster TUPTB026 [0.872 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB026
About •	Received ※ 20 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 02 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, impedance, niobium	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)

WEPWB047	Higher Order Mode Analysis of a 915 MHz 2-Cell Cavity for a Prototype Industrial Accelerator	cavity, impedance, HOM, SRF	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)

Paper

Title

Other Keywords

Page

TUPTB026

Measurements of High Values of Dielectric Permittivity Using Transmission Lines

GUI, resonance, simulation, cavity

447

V.D. Shemelin, M. Liepe
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: DOE
Usage of lossy materials is necessary for absorption of higher order modes excited in the RF cavities. Presently, measurements of lossy materials with usage of transmission lines give errors rapidly increasing with increase of the dielectric permittivity. A method is presented for measurements of high values of dielectric permittivity epsilon in a waveguide at high frequencies with lower errors. This method supplements the method of measurements evolved for low values of epsilon and is close to resonant methods, when a sample is placed into a cavity and the measurement is done at one only frequency. The new approach with use of Microwave Studio simulations makes possible to measure this value in several frequency points at one measurement.

Poster TUPTB026 [0.872 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB026

About •

Received ※ 20 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 02 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, impedance, niobium

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)

WEPWB047

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

cavity, impedance, HOM, SRF

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)