SRF2019 - List of Keywords (collider)

Paper	Title	Other Keywords	Page
MOP028	Materials Science Investigations of Nitrogen-Doped Niobium for SRF Cavities	cavity, niobium, SRF, superconducting-RF	99
	M. Major, L. Alff, M. Arnold, J. Conrad, S. Flege, R. Grewe, N. Pietralla TU Darmstadt, Darmstadt, Germany
	Funding: Work supported by the German Federal Ministry for Education and Research (BMBF) through grant 05H18RDRB2. Niobium is the standard material for superconducting RF (SRF) cavities for particle acceleration. Superconducting materials with higher critical temperature or higher critical magnetic field allow cavities to work at higher operating temperatures or higher accelerating fields, respectively. Enhancing the surface properties of the superconducting material in the range of the penetration depth is also beneficial. One direction of search for new materials with better properties is the modification of bulk niobium by nitrogen doping. In the Nb-N phase diagram, the cubic delta-phase of NbN has the highest critical temperature. Niobium samples were annealed and N-doped in the high-temperature furnace at TU Darmstadt and investigated at its Materials Research Department with respect to structural modifications. Secondary ion mass spectrometry showed at which conditions N-diffusion takes place. X-ray diffraction (XRD) confirmed the appearance of NbN and Nb₂N phases for the optimized doping process. XRD pole figures also showed grain growth during sample annealing.
	Poster MOP028 [2.555 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP028
About •	paper received ※ 05 July 2019 paper accepted ※ 12 July 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOP078	Adjustable Power Coupler for NICA HWR Cavities	cavity, vacuum, simulation, coupling	260
	S.V. Matsievskiy, M.V. Lalayan MEPhI, Moscow, Russia D. Bychanok INP BSU, Minsk, Belarus M. Gusarova JINR, Dubna, Moscow Region, Russia
	Current results on input power coupler development for Half-Wave superconducting accelerating cavity proposed for Nuclotron-based Ion Collider fAcility (NICA) collider injector upgrade are discussed. Two coupler designs are considered, first one is a low-power coupler for cavity tests and the second one is a high-power operational coupler. Both devices are of coaxial type with capacitive coupling; high-power coupler utilizes single ceramic vacuum window. NICA is designed to accelerate different types of ions. Due to the variable intensity of ion sources, beam current will vary in wide range. In order to ensure efficient acceleration, power coupler must be highly adjustable in terms of coupling coefficient. This introduces excessive mechanical stress in the ceramic RF window due to the bellows deformation. In order to mitigate this effect bellows were substituted with sliding contacts. This paper discusses new coupler design and its electrical, mechanical and thermal properties.
	Poster MOP078 [1.296 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP078
About •	paper received ※ 23 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THP070	CEPC HOM Coupler R&D	HOM, cavity, SRF, cryomodule	1050
	H.J. Zheng, F. Meng, P. Sha, J.Y. Zhai IHEP, Beijing, People’s Republic of China
	The conceptual design report (CDR) for the Circular Electron Positron Collider (CEPC) has been published in September 2018. In this talk, the CDR design and prototyping of the HOM coupler for the CEPC Collider ring cavity will be given. Each cavity has two detachable coaxial HOM couplers mounted on the cavity beam pipe with HOM power handling capacity of 1 kW. A double notch coupler is chosen due to its wide bandwidth for the fundamental mode. A prototype of this HOM coupler and a coaxial line test bench have been fabricated and tested under low power. The low power test results agree well with the simulation results. The high power test was also carried out in room temperature.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP070
About •	paper received ※ 19 June 2019 paper accepted ※ 29 June 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THP071	HOM Measurement Results for CEPC 650 MHz 2-cell Cavity	HOM, cavity, damping, cryomodule	1055
	H.J. Zheng, F. Meng, J.Y. Zhai IHEP, Beijing, People’s Republic of China
	CEPC will use a 650 MHz RF system with 240 2-cell cavities for the Collider. The Collider is a double-ring with shared cavities for Higgs operation and separate cavities for W and Z operations. The higher order modes (HOM) excited by the intense beam bunches must be damped to avoid additional cryogenic loss and multi-bunch instabilities. In this paper, the impedance budget and HOM damping and HOM power requirement for the CEPC Collider ring are given. This HOM power limit and the fast-growing longitudinal coupled-bunch instabilities (CBI) driven by both the fundamental and higher order modes impedance of the RF cavities determine to a large extent the highest beam current and luminosity obtainable in the Z mode. Two prototypes of HOM coupler have been fabricated and installed on the 650 MHz 2-cell cavity. The higher order modes were verified by bead pulling method. The Qe for the HOMs were also measured. A test bench with two 2-cell cavities was used to measure the real damping results and HOM propagating properties for a cavity string.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP071
About •	paper received ※ 19 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

FRCAA1	Overview of SRF Deflecting and Crabbing Cavities	cavity, HOM, cryomodule, luminosity	1192
	S.U. De Silva ODU, Norfolk, Virginia, USA
	Developments over the past few years on novel superconducting deflecting and crabbing cavities have introduced advanced rf geometries with improved performance, in comparison to the typical squashed elliptical cavities operating in TM110 type mode. These new structures are compact geometries operating in either TEM type or TE11-like mode. One of the key applications of such cavities is the use of crabbing systems for circular colliders in increasing the luminosity. Crabbing systems are an essential component in future colliders with intense beams and proposed electron-ion colliders. High luminosity upgrade of LHC is planned to implement crabbing systems at two interaction points. Recently, a two-cavity cryomodule with double quarter wave crabbing cavity was installed in SPS at CERN and successfully tested with the proton beam. We present the details of different superconducting deflecting and crabbing cavities and their applications, as well as the recent results of the crabbing systems test at SPS.
	Slides FRCAA1 [14.149 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-FRCAA1
About •	paper received ※ 04 July 2019 paper accepted ※ 14 August 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

MOP028

Materials Science Investigations of Nitrogen-Doped Niobium for SRF Cavities

cavity, niobium, SRF, superconducting-RF

99

M. Major, L. Alff, M. Arnold, J. Conrad, S. Flege, R. Grewe, N. Pietralla
TU Darmstadt, Darmstadt, Germany

Funding: Work supported by the German Federal Ministry for Education and Research (BMBF) through grant 05H18RDRB2.
Niobium is the standard material for superconducting RF (SRF) cavities for particle acceleration. Superconducting materials with higher critical temperature or higher critical magnetic field allow cavities to work at higher operating temperatures or higher accelerating fields, respectively. Enhancing the surface properties of the superconducting material in the range of the penetration depth is also beneficial. One direction of search for new materials with better properties is the modification of bulk niobium by nitrogen doping. In the Nb-N phase diagram, the cubic delta-phase of NbN has the highest critical temperature. Niobium samples were annealed and N-doped in the high-temperature furnace at TU Darmstadt and investigated at its Materials Research Department with respect to structural modifications. Secondary ion mass spectrometry showed at which conditions N-diffusion takes place. X-ray diffraction (XRD) confirmed the appearance of NbN and Nb₂N phases for the optimized doping process. XRD pole figures also showed grain growth during sample annealing.

Poster MOP028 [2.555 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP028

About •

paper received ※ 05 July 2019 paper accepted ※ 12 July 2019 issue date ※ 14 August 2019

Export •

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

MOP078

Adjustable Power Coupler for NICA HWR Cavities

cavity, vacuum, simulation, coupling

260

S.V. Matsievskiy, M.V. Lalayan
MEPhI, Moscow, Russia
D. Bychanok
INP BSU, Minsk, Belarus
M. Gusarova
JINR, Dubna, Moscow Region, Russia

Current results on input power coupler development for Half-Wave superconducting accelerating cavity proposed for Nuclotron-based Ion Collider fAcility (NICA) collider injector upgrade are discussed. Two coupler designs are considered, first one is a low-power coupler for cavity tests and the second one is a high-power operational coupler. Both devices are of coaxial type with capacitive coupling; high-power coupler utilizes single ceramic vacuum window. NICA is designed to accelerate different types of ions. Due to the variable intensity of ion sources, beam current will vary in wide range. In order to ensure efficient acceleration, power coupler must be highly adjustable in terms of coupling coefficient. This introduces excessive mechanical stress in the ceramic RF window due to the bellows deformation. In order to mitigate this effect bellows were substituted with sliding contacts. This paper discusses new coupler design and its electrical, mechanical and thermal properties.

Poster MOP078 [1.296 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP078

About •

paper received ※ 23 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019

Export •

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

THP070

CEPC HOM Coupler R&D

HOM, cavity, SRF, cryomodule

1050

H.J. Zheng, F. Meng, P. Sha, J.Y. Zhai
IHEP, Beijing, People’s Republic of China

The conceptual design report (CDR) for the Circular Electron Positron Collider (CEPC) has been published in September 2018. In this talk, the CDR design and prototyping of the HOM coupler for the CEPC Collider ring cavity will be given. Each cavity has two detachable coaxial HOM couplers mounted on the cavity beam pipe with HOM power handling capacity of 1 kW. A double notch coupler is chosen due to its wide bandwidth for the fundamental mode. A prototype of this HOM coupler and a coaxial line test bench have been fabricated and tested under low power. The low power test results agree well with the simulation results. The high power test was also carried out in room temperature.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP070

About •

paper received ※ 19 June 2019 paper accepted ※ 29 June 2019 issue date ※ 14 August 2019

Export •

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

THP071

HOM Measurement Results for CEPC 650 MHz 2-cell Cavity

HOM, cavity, damping, cryomodule

1055

H.J. Zheng, F. Meng, J.Y. Zhai
IHEP, Beijing, People’s Republic of China

CEPC will use a 650 MHz RF system with 240 2-cell cavities for the Collider. The Collider is a double-ring with shared cavities for Higgs operation and separate cavities for W and Z operations. The higher order modes (HOM) excited by the intense beam bunches must be damped to avoid additional cryogenic loss and multi-bunch instabilities. In this paper, the impedance budget and HOM damping and HOM power requirement for the CEPC Collider ring are given. This HOM power limit and the fast-growing longitudinal coupled-bunch instabilities (CBI) driven by both the fundamental and higher order modes impedance of the RF cavities determine to a large extent the highest beam current and luminosity obtainable in the Z mode. Two prototypes of HOM coupler have been fabricated and installed on the 650 MHz 2-cell cavity. The higher order modes were verified by bead pulling method. The Qe for the HOMs were also measured. A test bench with two 2-cell cavities was used to measure the real damping results and HOM propagating properties for a cavity string.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP071

About •

paper received ※ 19 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019

Export •

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

FRCAA1

Overview of SRF Deflecting and Crabbing Cavities

cavity, HOM, cryomodule, luminosity

1192

S.U. De Silva
ODU, Norfolk, Virginia, USA

Developments over the past few years on novel superconducting deflecting and crabbing cavities have introduced advanced rf geometries with improved performance, in comparison to the typical squashed elliptical cavities operating in TM110 type mode. These new structures are compact geometries operating in either TEM type or TE11-like mode. One of the key applications of such cavities is the use of crabbing systems for circular colliders in increasing the luminosity. Crabbing systems are an essential component in future colliders with intense beams and proposed electron-ion colliders. High luminosity upgrade of LHC is planned to implement crabbing systems at two interaction points. Recently, a two-cavity cryomodule with double quarter wave crabbing cavity was installed in SPS at CERN and successfully tested with the proton beam. We present the details of different superconducting deflecting and crabbing cavities and their applications, as well as the recent results of the crabbing systems test at SPS.

Slides FRCAA1 [14.149 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-FRCAA1

About •

paper received ※ 04 July 2019 paper accepted ※ 14 August 2019 issue date ※ 14 August 2019

Export •

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