SRF2019 - List of Keywords (factory)

Paper	Title	Other Keywords	Page
MOP011	High Frequency Nb₃Sn Cavities	cavity, SRF, niobium, radio-frequency	44
	R.D. Porter, M. Liepe, J.T. Maniscalco Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Niobium-3 Tin (Nb₃Sn) is an alternative material to Nb for SRF cavities. This material is capable of higher temperature operation and has high theoretical maximum accelerating gradients. Cornell University is a leader in the development of this material for SRF applications, and current Nb₃Sn 1.3 GHz single cells produced at Cornell achieve quality factors above 10^zEhNZeHn at 4.2 K at medium fields, far above what can be reached with niobium. Most of the recent Nb₃Sn cavity development has been done at 1.3 GHz. In this paper, we present new results from Nb₃Sn cavities at 2.6 GHz and 3.9 GHz. We compare relative cavity performance and flux trapping sensitivities, and extract frequency dependencies. Results show that the frequency can be increased without degrading the performance of the cavities, opening the path towards a new generation of compact and efficient SRF cavities for a wide range of future applications.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP011
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)

MOP015	RF Performance Sensitivity to Tuning of Nb₃Sn Coated CEBAF Cavities	cavity, simulation, SRF, experiment	55
	G.V. Eremeev, W. Crahen, J. Henry, F. Marhauser, C.E. Reece JLab, Newport News, Virginia, USA U. Pudasaini The College of William and Mary, Williamsburg, Virginia, USA
	Funding: Co-Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics. Nb₃Sn has the potential to surpass niobium as the material of choice for SRF applications. The potential of this material stems from a larger superconducting energy gap, which leads to expectations of a higher RF critical field and a lower RF surface resistance. The appeal of better superconducting properties is offset by the relative complexity of producing practical Nb₃Sn structures, and Nb₃Sn sensitivity to lattice disorder challenges the use of the material for practical applications. Such sensitivity is indirectly probed during SRF cavity development, when the cavity is tuned to match the desired accelerator frequency. In the course of recent experiments we have coated and tuned several multi-cell cavities. Cold RF measurements before and after tuning showed degradation in cavity performance after tuning. The results of RF measurement were compared against strain evolution on Nb₃Sn surface during tuning based on CST and ANSYS models.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP015
About •	paper received ※ 26 June 2019 paper accepted ※ 01 July 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOP018	Recent Results From Nb₃Sn Single Cell Cavities Coated at Jefferson Lab	cavity, SRF, experiment, niobium	65
	U. Pudasaini, M.J. Kelley The College of William and Mary, Williamsburg, Virginia, USA G. Ciovati, G.V. Eremeev, M.J. Kelley, C.E. Reece JLab, Newport News, Virginia, USA I.P. Parajuli, Md.N. Sayeed ODU, Norfolk, Virginia, USA
	Funding: Partially authored by Jefferson Science Associates under contract no. DE¬AC05¬06OR23177. Supported by Office of High Energy Physics under grants DE-SC-0014475 to the College of William and DE-SC-0018918 to Virginia Tech Because of superior superconducting properties (Tc ~ 18.3K, Hs h ~ 425 mT and delta ~ 3.1 meV) compared to niobium, Nb₃Sn promise better RF performance (Q₀ and E_acc) and/or higher operating temperature (2 K Vs 4.2 K) for SRF cavities. Nb₃Sn-coated SRF cavities are produced routinely by depositing a few micron-thick Nb₃Sn films on the interior surface of Nb cavities via tin vapor diffusion technique. Early results from Nb₃Sn cavities coated with this technique exhibited precipi-tous low field Q-slope, also known as Wuppertal slope. Several Nb₃Sn single cell cavities coated at JLab ap-peared to exhibit similar Q-slope. RF testing of cavi-ties and materials study of witness samples were con-tinuously used to modify the coating protocol. At best condition, we were able to produce Nb₃Sn cavity with Q₀ in excess of ~ 5×10¹⁰ at 2 K and ~ 2×1010 at 4 K up the accelerating gradient of ~15 MV/m, without any significant Q-slope. In this presentation, we will dis-cuss recent results from several Nb₃Sn coated single-cell cavities linked with material studies of witness samples, coating process modifications and the possi-ble causative factors to Wuppertal slope.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP018
About •	paper received ※ 23 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)

MOP026	A Cross-Lab Qualification of Modified 120°C Baked Cavities	cavity, shielding, multipactoring, niobium	90
	M. Wenskat, D. Reschke, J. Schaffran, L. Steder, M. Wiencek DESY, Hamburg, Germany D. Bafia, A. Grassellino, O.S. Melnychuk Fermilab, Batavia, Illinois, USA A.D. Palczewski JLab, Newport News, Virginia, USA M. Wiencek IFJ-PAN, Kraków, Poland
	Funding: This work was supported by the Helmholtz Association within the topic Accelerator Research and Development (ARD) of the Matter and Technologies (MT) Program and by the BMBF under the research grant 05H18GURB1. Within a global effort to understand and standardize the nitrogen-infusion and the low T bake procedure, one large grain and two fine grain single-cell cavity were treated and tested at FNAL and then send to other labs including DESY and JLab for further studies.
	Poster MOP026 [0.813 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP026
About •	paper received ※ 20 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)

TUP016	Quarter-wave Resonator with the Optimized Shape for Quantum Information Systems	cavity, niobium, photon, shielding	430
	S.V. Kutsaev, R.B. Agustsson, P.R. Carriere, A. Moro, A.Yu. Smirnov, K.V. Taletski RadiaBeam, Santa Monica, California, USA A.N. Cleland, É. Dumur The University of Chicago, Chicago, Illinois, USA Z.A. Conway ANL, Lemont, Illinois, USA K.V. Taletski MEPhI, Moscow, Russia
	Funding: This work was supported by the U.S. Department of Energy, Office of High Energy Physics, under SBIR grant DE-SC0018753 Quantum computers (QC), if realized, could disrupt many computationally intense fields of science. The building block element of a QC is a quantum bit (qubit). Qubits enable the use of quantum superposition and multi-state entanglement in QC calculations, allowing a QC to simultaneously calculate millions of computations at once. However, quantum states stored in a qubit degrade with decreased quality factors and interactions with the environment. One technical solution to improve qubit lifetimes and network interactions is a circuit comprised of a Josephson junction located inside of a high Q-factor superconducting 3D cavity. RadiaBeam, in collaboration with Argonne National Laboratory and The University of Chicago, has developed a superconducting radio-frequency quarter-wave resonant cavity (QWR) for quantum computation. Here a 6 GHz QWR was optimized to include tapering of the inner and outer conductors, a toroidal shape for the resonator shorting plane, and the inner conductor to reduce parasitic capacitance. In this paper, we present the results of the qubit cavity design optimization, fabrication, processing and testing in a single-photon regime at mK temperatures.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP016
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)

TUP046	Low Frequency, Low Beta Cavity Performance Improvement Studies	cavity, niobium, SRF, vacuum	527
	P. Kolb, R.E. Laxdal, Z.Y. Yao TRIUMF, Vancouver, Canada
	In recent years, new discoveries such as N₂ doping and infusion lead to a significant increases in Q₀ and accelerating gradient for 1.3 GHz, β=1 elliptical cavities. To understand and to adapt these treatments for lower frequency, \beta < 1 cavities, two coaxial test cavities, one quarter-wave resonator (QWR) and one half-wave resonator (HWR), have been built and put through a systematic study of these new treatments to show the effectiveness of these treatments at different frequencies. These cavities are tested in their fundamental mode and several higher order modes to study the frequency dependence of new cavity treatments such as N₂ doping and infusion. Results of these studies are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP046
About •	paper received ※ 22 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)

TUP062	New Insights in the Quench Mechanisms in Nitrogen Doped Cavities	cavity, SRF, accelerating-gradient, niobium	592
	D. Bafia, J. Zasadzinski IIT, Chicago, Illinois, USA D. Bafia, D.J. Bice, A. Grassellino, O.S. Melnychuk, A.S. Romanenko, D.A. Sergatskov Fermilab, Batavia, Illinois, USA D. Gonnella SLAC, Menlo Park, California, USA A.D. Palczewski JLab, Newport News, Virginia, USA
	This paper will cover a systematic study of the quench in nitrogen doped cavities: three cavities were sequentially treated/reset with different doping recipes which are known to produce different levels of quench field. Analysis of mean free path and TMAP coupled with sample analysis reveals new insights on the physics of the premature quench in nitrogen doped cavities; new recipes demonstrate the possibility to increase quench fields well beyond 30 MV/m.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP062
About •	paper received ※ 23 June 2019 paper accepted ※ 02 July 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

MOP011

High Frequency Nb₃Sn Cavities

cavity, SRF, niobium, radio-frequency

44

R.D. Porter, M. Liepe, J.T. Maniscalco
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Niobium-3 Tin (Nb₃Sn) is an alternative material to Nb for SRF cavities. This material is capable of higher temperature operation and has high theoretical maximum accelerating gradients. Cornell University is a leader in the development of this material for SRF applications, and current Nb₃Sn 1.3 GHz single cells produced at Cornell achieve quality factors above 10^zEhNZeHn at 4.2 K at medium fields, far above what can be reached with niobium. Most of the recent Nb₃Sn cavity development has been done at 1.3 GHz. In this paper, we present new results from Nb₃Sn cavities at 2.6 GHz and 3.9 GHz. We compare relative cavity performance and flux trapping sensitivities, and extract frequency dependencies. Results show that the frequency can be increased without degrading the performance of the cavities, opening the path towards a new generation of compact and efficient SRF cavities for a wide range of future applications.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP011

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)

MOP015

RF Performance Sensitivity to Tuning of Nb₃Sn Coated CEBAF Cavities

cavity, simulation, SRF, experiment

55

G.V. Eremeev, W. Crahen, J. Henry, F. Marhauser, C.E. Reece
JLab, Newport News, Virginia, USA
U. Pudasaini
The College of William and Mary, Williamsburg, Virginia, USA

Funding: Co-Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics.
Nb₃Sn has the potential to surpass niobium as the material of choice for SRF applications. The potential of this material stems from a larger superconducting energy gap, which leads to expectations of a higher RF critical field and a lower RF surface resistance. The appeal of better superconducting properties is offset by the relative complexity of producing practical Nb₃Sn structures, and Nb₃Sn sensitivity to lattice disorder challenges the use of the material for practical applications. Such sensitivity is indirectly probed during SRF cavity development, when the cavity is tuned to match the desired accelerator frequency. In the course of recent experiments we have coated and tuned several multi-cell cavities. Cold RF measurements before and after tuning showed degradation in cavity performance after tuning. The results of RF measurement were compared against strain evolution on Nb₃Sn surface during tuning based on CST and ANSYS models.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP015

About •

paper received ※ 26 June 2019 paper accepted ※ 01 July 2019 issue date ※ 14 August 2019

Export •

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

MOP018

Recent Results From Nb₃Sn Single Cell Cavities Coated at Jefferson Lab

cavity, SRF, experiment, niobium

65

U. Pudasaini, M.J. Kelley
The College of William and Mary, Williamsburg, Virginia, USA
G. Ciovati, G.V. Eremeev, M.J. Kelley, C.E. Reece
JLab, Newport News, Virginia, USA
I.P. Parajuli, Md.N. Sayeed
ODU, Norfolk, Virginia, USA

Funding: Partially authored by Jefferson Science Associates under contract no. DE¬AC05¬06OR23177. Supported by Office of High Energy Physics under grants DE-SC-0014475 to the College of William and DE-SC-0018918 to Virginia Tech
Because of superior superconducting properties (Tc ~ 18.3K, Hs h ~ 425 mT and delta ~ 3.1 meV) compared to niobium, Nb₃Sn promise better RF performance (Q₀ and E_acc) and/or higher operating temperature (2 K Vs 4.2 K) for SRF cavities. Nb₃Sn-coated SRF cavities are produced routinely by depositing a few micron-thick Nb₃Sn films on the interior surface of Nb cavities via tin vapor diffusion technique. Early results from Nb₃Sn cavities coated with this technique exhibited precipi-tous low field Q-slope, also known as Wuppertal slope. Several Nb₃Sn single cell cavities coated at JLab ap-peared to exhibit similar Q-slope. RF testing of cavi-ties and materials study of witness samples were con-tinuously used to modify the coating protocol. At best condition, we were able to produce Nb₃Sn cavity with Q₀ in excess of ~ 5×10¹⁰ at 2 K and ~ 2×1010 at 4 K up the accelerating gradient of ~15 MV/m, without any significant Q-slope. In this presentation, we will dis-cuss recent results from several Nb₃Sn coated single-cell cavities linked with material studies of witness samples, coating process modifications and the possi-ble causative factors to Wuppertal slope.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP018

About •

paper received ※ 23 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)

MOP026

A Cross-Lab Qualification of Modified 120°C Baked Cavities

cavity, shielding, multipactoring, niobium

90

M. Wenskat, D. Reschke, J. Schaffran, L. Steder, M. Wiencek
DESY, Hamburg, Germany
D. Bafia, A. Grassellino, O.S. Melnychuk
Fermilab, Batavia, Illinois, USA
A.D. Palczewski
JLab, Newport News, Virginia, USA
M. Wiencek
IFJ-PAN, Kraków, Poland

Funding: This work was supported by the Helmholtz Association within the topic Accelerator Research and Development (ARD) of the Matter and Technologies (MT) Program and by the BMBF under the research grant 05H18GURB1.
Within a global effort to understand and standardize the nitrogen-infusion and the low T bake procedure, one large grain and two fine grain single-cell cavity were treated and tested at FNAL and then send to other labs including DESY and JLab for further studies.

Poster MOP026 [0.813 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP026

About •

paper received ※ 20 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)

TUP016

Quarter-wave Resonator with the Optimized Shape for Quantum Information Systems

cavity, niobium, photon, shielding

430

S.V. Kutsaev, R.B. Agustsson, P.R. Carriere, A. Moro, A.Yu. Smirnov, K.V. Taletski
RadiaBeam, Santa Monica, California, USA
A.N. Cleland, É. Dumur
The University of Chicago, Chicago, Illinois, USA
Z.A. Conway
ANL, Lemont, Illinois, USA
K.V. Taletski
MEPhI, Moscow, Russia

Funding: This work was supported by the U.S. Department of Energy, Office of High Energy Physics, under SBIR grant DE-SC0018753
Quantum computers (QC), if realized, could disrupt many computationally intense fields of science. The building block element of a QC is a quantum bit (qubit). Qubits enable the use of quantum superposition and multi-state entanglement in QC calculations, allowing a QC to simultaneously calculate millions of computations at once. However, quantum states stored in a qubit degrade with decreased quality factors and interactions with the environment. One technical solution to improve qubit lifetimes and network interactions is a circuit comprised of a Josephson junction located inside of a high Q-factor superconducting 3D cavity. RadiaBeam, in collaboration with Argonne National Laboratory and The University of Chicago, has developed a superconducting radio-frequency quarter-wave resonant cavity (QWR) for quantum computation. Here a 6 GHz QWR was optimized to include tapering of the inner and outer conductors, a toroidal shape for the resonator shorting plane, and the inner conductor to reduce parasitic capacitance. In this paper, we present the results of the qubit cavity design optimization, fabrication, processing and testing in a single-photon regime at mK temperatures.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP016

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)

TUP046

Low Frequency, Low Beta Cavity Performance Improvement Studies

cavity, niobium, SRF, vacuum

527

P. Kolb, R.E. Laxdal, Z.Y. Yao
TRIUMF, Vancouver, Canada

In recent years, new discoveries such as N₂ doping and infusion lead to a significant increases in Q₀ and accelerating gradient for 1.3 GHz, β=1 elliptical cavities. To understand and to adapt these treatments for lower frequency, \beta < 1 cavities, two coaxial test cavities, one quarter-wave resonator (QWR) and one half-wave resonator (HWR), have been built and put through a systematic study of these new treatments to show the effectiveness of these treatments at different frequencies. These cavities are tested in their fundamental mode and several higher order modes to study the frequency dependence of new cavity treatments such as N₂ doping and infusion. Results of these studies are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP046

About •

paper received ※ 22 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)

TUP062

New Insights in the Quench Mechanisms in Nitrogen Doped Cavities

cavity, SRF, accelerating-gradient, niobium

592

D. Bafia, J. Zasadzinski
IIT, Chicago, Illinois, USA
D. Bafia, D.J. Bice, A. Grassellino, O.S. Melnychuk, A.S. Romanenko, D.A. Sergatskov
Fermilab, Batavia, Illinois, USA
D. Gonnella
SLAC, Menlo Park, California, USA
A.D. Palczewski
JLab, Newport News, Virginia, USA

This paper will cover a systematic study of the quench in nitrogen doped cavities: three cavities were sequentially treated/reset with different doping recipes which are known to produce different levels of quench field. Analysis of mean free path and TMAP coupled with sample analysis reveals new insights on the physics of the premature quench in nitrogen doped cavities; new recipes demonstrate the possibility to increase quench fields well beyond 30 MV/m.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP062

About •

paper received ※ 23 June 2019 paper accepted ※ 02 July 2019 issue date ※ 14 August 2019

Export •

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