IPAC2022 - List of Authors (Simakov, E.I.)

Paper	Title	Page
TUPOMS057	Design Study of HOM Couplers for the C-Band Accelerating Structure	1561
	D. Kim, E.I. Simakov LANL, Los Alamos, New Mexico, USA S. Biedron UNM-ECE, Albuquerque, USA Z. Li SLAC, Menlo Park, California, USA
	Funding: High Energy Physics (HEP) at the U.S. Department of Energy (DOE) A cold copper distributed coupling accelerator, with a high accelerating gradient at cryogenic temperatures (~77 K), is proposed as a baseline structure for the next generation of linear colliders. This novel technology improves accelerator performance and allows more degrees of freedom for optimization of individual cavities. It has been suggested that C-band accelerating structures at 5.712 GHz may allow to maintain high efficiency, achieve high accelerating gradient, and be suitable beam dynamics with wakefield damping and detuning of the cavities. The optimization of the cavity shape was performed and we computed quality factor, shunt impedance, and beam kick factor for each of the proposed cavity geometries using CST microwave studio. Next, we proposed a configuration for higher order mode (HOM) suppression that includes waveguide slots running parallel to the axis of the accelerator. This presentation will report details of the parametric study of performance of the HOM suppression waveguide, and the dependence of HOM Q-factors and kick-factors on the cavity’s and HOM waveguide’s geometries.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS057
About •	Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 09 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOMS058	C-Band High Gradient Testing of the Benchmark a/λ=0.105 Cavity	1564
	E.I. Simakov, V. Gorelov, T. Tajima, M.R.A. Zuboraj LANL, Los Alamos, New Mexico, USA S. Biedron Element Aero, Chicago, USA S. Biedron UNM-ECE, Albuquerque, USA M.E. Middendorf ORNL RAD, Oak Ridge, Tennessee, USA
	Funding: Los Alamos National Laboratory LDRD Program This poster will report the results of high gradient testing of the benchmark C-band RF cavity. Modern applications such as X-ray sources require accelerators with optimized cost of construction and operation, naturally calling for high-gradient acceleration. At LANL we commissioned a test stand (CERF-NM) powered by a 50 MW, 5.712 GHz Canon klystron. The test stand is capable of conditioning accelerating cavities for operation at surface electric fields in excess of 300 MV/m. CERF-NM is the first high gradient C-band test facility in the United States. An important milestone for this test stand is to demonstrate conditioning and high gradient testing of the most basic high gradient RF cavity with a geometry that has been extensively studied at other frequencies, such as X-band. The cavity is the three-cell structure with the highest gradient in the central cell and two coupling cells, and the ratio of the radius of the coupling iris to the wavelength a/\lamda=0.105. This presentation will report achieved gradients, breakdown probabilities, and other characteristics measured during the high power operation of this cavity.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS058
About •	Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 17 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOMS060	High Gradient Conditioning and Performance of C-Band ß=0.5 Proton Normal- Conducting Copper and Copper-Silver Radio-Frequency Accelerating Cavities	1567
	M.R.A. Zuboraj, R.L. Fleming, V. Gorelov, J.W. Lewellen, M.E. Middendorf, E.I. Simakov LANL, Los Alamos, New Mexico, USA S.V. Baryshev, M.E. Schneider Michigan State University, East Lansing, Michigan, USA V.A. Dolgashev, E.A. Nanni, E.J.C. Snively, S.G. Tantawi SLAC, Menlo Park, California, USA E. Jevarjian MSU, East Lansing, Michigan, USA
	Funding: LANL-LDRD This work presents the results of high gradient testing of the two C-band (5.712 GHz) normal conducting ß=0.5 accelerating cavities. The first cavity was made of copper and second was made of copper-silver alloy with 0.08% silver concentration. The tests were conducted at the C-Band Engineering Research Facility of New Mexico (CERF-NM) located at Los Alamos National Laboratory Both cavities achieved gradients in excess of 200 MV/m and surface electric fields in excess of 300 MV/m. The breakdown rates were mapped as functions of the gradient and peak surface fields. The gradients and peak surface fields observed in the copper-silver cavity were about 20% higher than those in the pure copper cavity with the same breakdown rate. It was concluded that the dominant breakdown mechanism in these cavities was not the pulse heating but the breakdown due to very high surface electric fields.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS060
About •	Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 19 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Design Study of HOM Couplers for the C-Band Accelerating Structure

1561

D. Kim, E.I. Simakov
LANL, Los Alamos, New Mexico, USA
S. Biedron
UNM-ECE, Albuquerque, USA
Z. Li
SLAC, Menlo Park, California, USA

Funding: High Energy Physics (HEP) at the U.S. Department of Energy (DOE)
A cold copper distributed coupling accelerator, with a high accelerating gradient at cryogenic temperatures (~77 K), is proposed as a baseline structure for the next generation of linear colliders. This novel technology improves accelerator performance and allows more degrees of freedom for optimization of individual cavities. It has been suggested that C-band accelerating structures at 5.712 GHz may allow to maintain high efficiency, achieve high accelerating gradient, and be suitable beam dynamics with wakefield damping and detuning of the cavities. The optimization of the cavity shape was performed and we computed quality factor, shunt impedance, and beam kick factor for each of the proposed cavity geometries using CST microwave studio. Next, we proposed a configuration for higher order mode (HOM) suppression that includes waveguide slots running parallel to the axis of the accelerator. This presentation will report details of the parametric study of performance of the HOM suppression waveguide, and the dependence of HOM Q-factors and kick-factors on the cavity’s and HOM waveguide’s geometries.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS057

About •

Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 09 July 2022

Cite •

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

TUPOMS058

C-Band High Gradient Testing of the Benchmark a/λ=0.105 Cavity

1564

E.I. Simakov, V. Gorelov, T. Tajima, M.R.A. Zuboraj
LANL, Los Alamos, New Mexico, USA
S. Biedron
Element Aero, Chicago, USA
S. Biedron
UNM-ECE, Albuquerque, USA
M.E. Middendorf
ORNL RAD, Oak Ridge, Tennessee, USA

Funding: Los Alamos National Laboratory LDRD Program
This poster will report the results of high gradient testing of the benchmark C-band RF cavity. Modern applications such as X-ray sources require accelerators with optimized cost of construction and operation, naturally calling for high-gradient acceleration. At LANL we commissioned a test stand (CERF-NM) powered by a 50 MW, 5.712 GHz Canon klystron. The test stand is capable of conditioning accelerating cavities for operation at surface electric fields in excess of 300 MV/m. CERF-NM is the first high gradient C-band test facility in the United States. An important milestone for this test stand is to demonstrate conditioning and high gradient testing of the most basic high gradient RF cavity with a geometry that has been extensively studied at other frequencies, such as X-band. The cavity is the three-cell structure with the highest gradient in the central cell and two coupling cells, and the ratio of the radius of the coupling iris to the wavelength a/\lamda=0.105. This presentation will report achieved gradients, breakdown probabilities, and other characteristics measured during the high power operation of this cavity.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS058

About •

Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 17 June 2022

Cite •

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

TUPOMS060

High Gradient Conditioning and Performance of C-Band ß=0.5 Proton Normal- Conducting Copper and Copper-Silver Radio-Frequency Accelerating Cavities

1567

M.R.A. Zuboraj, R.L. Fleming, V. Gorelov, J.W. Lewellen, M.E. Middendorf, E.I. Simakov
LANL, Los Alamos, New Mexico, USA
S.V. Baryshev, M.E. Schneider
Michigan State University, East Lansing, Michigan, USA
V.A. Dolgashev, E.A. Nanni, E.J.C. Snively, S.G. Tantawi
SLAC, Menlo Park, California, USA
E. Jevarjian
MSU, East Lansing, Michigan, USA

Funding: LANL-LDRD
This work presents the results of high gradient testing of the two C-band (5.712 GHz) normal conducting ß=0.5 accelerating cavities. The first cavity was made of copper and second was made of copper-silver alloy with 0.08% silver concentration. The tests were conducted at the C-Band Engineering Research Facility of New Mexico (CERF-NM) located at Los Alamos National Laboratory Both cavities achieved gradients in excess of 200 MV/m and surface electric fields in excess of 300 MV/m. The breakdown rates were mapped as functions of the gradient and peak surface fields. The gradients and peak surface fields observed in the copper-silver cavity were about 20% higher than those in the pure copper cavity with the same breakdown rate. It was concluded that the dominant breakdown mechanism in these cavities was not the pulse heating but the breakdown due to very high surface electric fields.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS060

About •

Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 19 June 2022

Cite •

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