IPAC2016 - List of Authors (Romanenko, A.)

Paper	Title	Page
TUOAA03	Long Term Plans to Increase Fermilab's Proton Intensity to Meet the Needs of the Long Baseline Neutrino Program	1010
	E. Prebys, P. Adamson, S.C. Childress, P. Derwent, S.D. Holmes, I. Kourbanis, V.A. Lebedev, W. Pellico, A. Romanenko, V.D. Shiltsev, E.G. Stern, A. Valishev, R.M. Zwaska Fermilab, Batavia, Illinois, USA
	Funding: This work is supported by the US Department of Energy under contract No. De-AC02-07CH11359. The flagship of Fermilab's long term research program is the Deep Underground Neutrino Experiment (DUNE), located Sanford Underground Research Facility (SURF) in Lead, South Dakota, which will study neutrino oscillations with a baseline of 1300 km. The neutrinos will be produced in the Long Baseline Neutrino Facility (LBNF), a proposed new beam line from Fermilab's Main Injector. The physics goals of the DUNE require a proton beam with a power of roughly 2.5 MW at 120 GeV, which is roughly five times the current maximum power. This poster outlines the staged plan to achieve the required power over the next 15 years.
	Slides TUOAA03 [4.129 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUOAA03
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WEPMR002	Ultimate Gradient Limitation in Niobium Superconducting Accelerating Cavities	2254
SUPSS091	use link to see paper's listing under its alternate paper code
	M. Checchin, A. Grassellino, M. Martinello, S. Posen, A. Romanenko Fermilab, Batavia, Illinois, USA M. Checchin, M. Martinello Illinois Institute of Technology, Chicago, Illlinois, USA J. Zasadzinski IIT, Chicago, Illinois, USA
	Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. The present study is addressed to the theoretical description of the ultimate gradient limitation in SRF cavities. Our intent is to exploit experimental data to confirm models which provide feed-backs on how to improve the current state-of-art. New theoretical insight on the cavities limiting factor can be suitable to improve the quench field of N-doped cavities, and therefore to take advantage of high Q0 at high gradients.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMR002
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WEPMR003	Tailoring Surface Impurity Content to Maximize Q-factors of Superconducting Resonators	2258
SUPSS094	use link to see paper's listing under its alternate paper code
	M. Martinello, M. Checchin, A. Grassellino, O.S. Melnychuk, S. Posen, A. Romanenko, D.A. Sergatskov Fermilab, Batavia, Illinois, USA M. Checchin, M. Martinello Illinois Institute of Technology, Chicago, Illlinois, USA J. Zasadzinski IIT, Chicago, Illinois, USA
	Funding: Fermilab is operated by Fermi Research Alliance, LLC under contract No. DE-AC02-07CH11359 with the United States Department of Energy. Quality factor of superconducting radio-frequency (SRF) cavities is degraded whenever magnetic flux is trapped in the cavity walls during the cooldown. In this contribution we study how the trapped flux sensitivity, defined as the trapped flux surface resistance normalized for the amount of flux trapped, depends on the mean free path. A variety of 1.3 GHz cavities with different surface treatments (EP, 120 C bake and different N-doping) were studied in order to cover the largest range of mean free path nowadays achievable, from few to thousands of nanometers. A bell shaped trend appears for the range of mean free path studied. Over doped cavities falls at the maximum of this curve defining the largest values of sensitivity. In addition, we have also studied the trend of the BCS surface resistance contribution as a function of mean free path, revealing that N-doped cavities follow close to the theoretical minimum of the BCS surface resistance as a function of the mean free path. Adding these results together we unveil that optimal N-doping treatment allows to maximize Q-factor at 2 K and 16 MV/m until the magnetic field fully trapped during the cavity cooldown stays below 10 mG.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMR003
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WEPMR009	Magnetic Flux Expulsion Studies in Niobium SRF Cavities	2277
	S. Posen, M. Checchin, A.C. Crawford, A. Grassellino, M. Martinello, O.S. Melnychuk, A. Romanenko, D.A. Sergatskov, Y. Trenikhina Fermilab, Batavia, Illinois, USA
	With the recent discovery of nitrogen doping treatment for SRF cavities, ultra-high quality factors at medium accelerating fields are regularly achieved in vertical RF tests. To preserve these quality factors into the cryomodule, it is important to consider background magnetic fields, which can become trapped in the surface of the cavity during cooldown and cause Q₀ degradation. Building on the recent discovery that spatial thermal gradients during cooldown can significantly improve expulsion of magnetic flux, a detailed study was performed of flux expulsion on two cavities with different furnace treatments that are cooled in magnetic fields amplitudes representative of what is expected in a realistic cryomodule. In this contribution, we summarize these cavity results, in order to improve understanding of the impact of flux expulsion on cavity performance.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMR009
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Long Term Plans to Increase Fermilab's Proton Intensity to Meet the Needs of the Long Baseline Neutrino Program

1010

E. Prebys, P. Adamson, S.C. Childress, P. Derwent, S.D. Holmes, I. Kourbanis, V.A. Lebedev, W. Pellico, A. Romanenko, V.D. Shiltsev, E.G. Stern, A. Valishev, R.M. Zwaska
Fermilab, Batavia, Illinois, USA

Funding: This work is supported by the US Department of Energy under contract No. De-AC02-07CH11359.
The flagship of Fermilab's long term research program is the Deep Underground Neutrino Experiment (DUNE), located Sanford Underground Research Facility (SURF) in Lead, South Dakota, which will study neutrino oscillations with a baseline of 1300 km. The neutrinos will be produced in the Long Baseline Neutrino Facility (LBNF), a proposed new beam line from Fermilab's Main Injector. The physics goals of the DUNE require a proton beam with a power of roughly 2.5 MW at 120 GeV, which is roughly five times the current maximum power. This poster outlines the staged plan to achieve the required power over the next 15 years.

Slides TUOAA03 [4.129 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUOAA03

Export •

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

WEPMR002

Ultimate Gradient Limitation in Niobium Superconducting Accelerating Cavities

2254

SUPSS091

use link to see paper's listing under its alternate paper code

M. Checchin, A. Grassellino, M. Martinello, S. Posen, A. Romanenko
Fermilab, Batavia, Illinois, USA
M. Checchin, M. Martinello
Illinois Institute of Technology, Chicago, Illlinois, USA
J. Zasadzinski
IIT, Chicago, Illinois, USA

Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
The present study is addressed to the theoretical description of the ultimate gradient limitation in SRF cavities. Our intent is to exploit experimental data to confirm models which provide feed-backs on how to improve the current state-of-art. New theoretical insight on the cavities limiting factor can be suitable to improve the quench field of N-doped cavities, and therefore to take advantage of high Q0 at high gradients.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMR002

Export •

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

WEPMR003

Tailoring Surface Impurity Content to Maximize Q-factors of Superconducting Resonators

2258

SUPSS094

use link to see paper's listing under its alternate paper code

M. Martinello, M. Checchin, A. Grassellino, O.S. Melnychuk, S. Posen, A. Romanenko, D.A. Sergatskov
Fermilab, Batavia, Illinois, USA
M. Checchin, M. Martinello
Illinois Institute of Technology, Chicago, Illlinois, USA
J. Zasadzinski
IIT, Chicago, Illinois, USA

Funding: Fermilab is operated by Fermi Research Alliance, LLC under contract No. DE-AC02-07CH11359 with the United States Department of Energy.
Quality factor of superconducting radio-frequency (SRF) cavities is degraded whenever magnetic flux is trapped in the cavity walls during the cooldown. In this contribution we study how the trapped flux sensitivity, defined as the trapped flux surface resistance normalized for the amount of flux trapped, depends on the mean free path. A variety of 1.3 GHz cavities with different surface treatments (EP, 120 C bake and different N-doping) were studied in order to cover the largest range of mean free path nowadays achievable, from few to thousands of nanometers. A bell shaped trend appears for the range of mean free path studied. Over doped cavities falls at the maximum of this curve defining the largest values of sensitivity. In addition, we have also studied the trend of the BCS surface resistance contribution as a function of mean free path, revealing that N-doped cavities follow close to the theoretical minimum of the BCS surface resistance as a function of the mean free path. Adding these results together we unveil that optimal N-doping treatment allows to maximize Q-factor at 2 K and 16 MV/m until the magnetic field fully trapped during the cavity cooldown stays below 10 mG.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMR003

Export •

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

WEPMR009

Magnetic Flux Expulsion Studies in Niobium SRF Cavities

2277

S. Posen, M. Checchin, A.C. Crawford, A. Grassellino, M. Martinello, O.S. Melnychuk, A. Romanenko, D.A. Sergatskov, Y. Trenikhina
Fermilab, Batavia, Illinois, USA

With the recent discovery of nitrogen doping treatment for SRF cavities, ultra-high quality factors at medium accelerating fields are regularly achieved in vertical RF tests. To preserve these quality factors into the cryomodule, it is important to consider background magnetic fields, which can become trapped in the surface of the cavity during cooldown and cause Q₀ degradation. Building on the recent discovery that spatial thermal gradients during cooldown can significantly improve expulsion of magnetic flux, a detailed study was performed of flux expulsion on two cavities with different furnace treatments that are cooled in magnetic fields amplitudes representative of what is expected in a realistic cryomodule. In this contribution, we summarize these cavity results, in order to improve understanding of the impact of flux expulsion on cavity performance.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMR009

Export •

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