SRF2021 - List of Keywords (plasma)

Paper	Title	Other Keywords	Page
SUPFDV020	ALD-Based NbIiN Studies for SIS R&D	cavity, site, vacuum, SRF	109
	I. González Díaz-Palacio, R.H. Blick, R. Zierold University of Hamburg, Hamburg, Germany W. Hillert, M. Wenskat University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
	Superconductor-Insulator-Superconductor multilayers improve the performance of SRF cavities providing magnetic screening of the bulk cavity and lower surface resistance. In this framework NbTiN mixtures stand as a potential material of interest. Atomic layer deposition (ALD) allows for uniform coating of complex geometries and enables tuning of the stoichiometry and precise thickness control in sub-nm range. In this talk, we report about NbTiN thin films deposited by plasma-enhanced ALD on insulating AlN buffer layer. The deposition process has been optimized by studying the superconducting electrical properties of the films. Post-deposition thermal annealing studies with varying temperatures, annealing times, and gas atmospheres have been performed to further improve the thin film quality and the superconducting properties. Our experimental studies show an increase in T_c by 87.5% after thermal annealing and a maximum T_c of 13.9 K has been achieved for NbTiN of 23 nm thickness. Future steps include lattice characterization, using XRR/XRD/EBSD/PALS, and SRF measurements to obtain Hc1 and the superconducting gap.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2021-SUPFDV020
About •	Received ※ 22 June 2021 — Revised ※ 17 August 2021 — Accepted ※ 17 August 2021 — Issue date ※ 19 January 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

SUPTEV002	Application of Plasma Electrolytic Polishing onto SRF Substrates	cathode, SRF, cavity, power-supply	116
	E. Chyhyrynets, O. Azzolini, R. Caforio, V.A. Garcia Diaz, G. Keppel, C. Pira, F. Stivanello, M. Zanierato INFN/LNL, Legnaro (PD), Italy
	Funding: Work supported by the INFN CSNV experiment TEFEN. This project has received funding from the Euro-pean Union’s Horizon 2020 Research and Innovation programme under GA No 101004730. A new promising approach of SRF substrates surface treatment has been studied - Plasma Electrolytic Polishing (PEP). The possible application of PEP can be used not only on conventional elliptical resonators, but also on other components of SRF such as, for example, couplers or Quadrupole resonators (QPRs). However, SRF application of PEP represents a challenge since it requires a different approach to treat the inner surface of elliptical cavities respect to electropolishing. In this work, the main problematics and possible solutions, the equipment, and the polishing system requirements will be shown. A proposed polishing system for 6 GHz elliptical cavities and QPRs will be shown and discussed.
	Poster SUPTEV002 [2.715 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2021-SUPTEV002
About •	Received ※ 21 June 2021 — Revised ※ 08 July 2021 — Accepted ※ 12 August 2021 — Issue date ※ 22 April 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

SUPTEV007	Development of a System for Coating SRF Cavities Using Remote Plasma CVD	cavity, SRF, controls, vacuum	129
	G. Gaitan, P. Bishop, A.T. Holic, G. Kulina, M. Liepe, J. Sears, Z. Sun Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: This work was supported by the National Science Foundation under Grant No. PHY-1549132. Next-generation, thin-film surfaces employing Nb₃Sn, NbN, NbTiN, and other compound superconductors are destined to allow reaching superior RF performance levels in SRF cavities. Optimized, advanced deposition processes are required to enable high-quality films of such materials on large and complex-shaped cavities. For this purpose, Cornell University is developing a remote plasma-enhanced chemical vapor deposition (CVD) system that facilitates coating on complicated geometries with a high deposition rate. This system is based on a high-temperature tube furnace with a clean vacuum and furnace loading system. The use of plasma alongside reacting precursors will significantly reduce the required processing temperature and promote precursor decomposition. A vacuum quality monitor (VQM) is used to characterize the residual gases before coating. The CVD system has been designed and is currently under assembly and commissioning.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2021-SUPTEV007
About •	Received ※ 09 July 2021 — Accepted ※ 21 August 2021 — Issue date ※ 10 February 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTEV004	In Situ Plasma Processing of Superconducting Cavities at Jefferson Lab	cavity, cryomodule, HOM, software	485
	T. Powers, N.C. Brock, T.D. Ganey JLab, Newport News, Virginia, USA
	Funding: Funding provided by SC Nuclear Physics Program through DOE SC Lab funding announcement Lab-20-2310 Jefferson Lab began a plasma processing program starting in the spring of 2019. Plasma processing is a common technique for removing hydrocarbons from surfaces, which increases the work function and reduces the secondary emission coefficient. Unlike helium processing which relies on ion bombardment of the field emitters, plasma processing uses free oxygen produced in the plasma to break down the hydrocarbons on the surface of the cavity. The residuals of the hydrocarbons in the form of water, carbon monoxide and carbon dioxide are removed from the cryomodule as part of the process gas flow. The initial focus of the effort is processing C100 cavities by injecting RF power into the HOM coupler ports. We will then start investigating processing of C50 cavities by introducing RF into the fundamental power coupler. The plan is to start processing cryomodules in the CEBAF tunnel in the mid-term future, with a goal of improving the operational gradients and the energy margin of the linacs. This work will describe the systems and methods used at JLAB for processing cavities using an argon oxygen gas mixture. Before and after plasma processing results will also be presented.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2021-TUPTEV004
About •	Received ※ 21 June 2021 — Accepted ※ 05 October 2021 — Issue date ※ 02 May 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPFDV006	Activities at NCBJ Towards Development of the Future, Fully-Superconducting, XFEL-Type, RF Electron Gun	cathode, gun, electron, cavity	566
	J. Lorkiewicz, P.J. Czuma, A.M. Kosińska, P. Krawczyk, R. Mirowski, R. Nietubyć, M. Staszczak, K. Szamota-Leandersson NCBJ, Świerk/Otwock, Poland J.K. Sekutowicz DESY, Hamburg, Germany
	Our group at NCBJ works on upgrade of 1.6-cell, SRF, XFEL-type injector in collaboration with DESY and other laboratories. The work is focused on preparation of lead-on-niobium photocathode, its positioning in the gun cavity and on the UV laser system for photocurrent excitation. RF focusing effect was used to minimize the predicted emittance and transverse size of accelerated e^- beam. Following beam dynamics computation, it has been proposed that the photocathode be recessed 0.45 mm into the rear wall of the gun cavity. It helps focusing e^- beam in its low-energy part. Preparation of sc cathodes of Pb layer on Nb plugs (, ) is reported, aimed at reaching clean, planar and uniform Pb films. The laser system will consist of commercially available Pharos laser and a 4-th harmonic generator. A gaussian, 300 fs long, 257 nm in wavelength UV pulse will be transformed in time by a pulse stretcher/stacker and in space by pi-shaper. The planned optical system will generate cylindrical photoelectron bunch 2 - 30 ps long and 0.2 - 3 mm wide. J. Lorkiewicz et al., Vacuum 179 (2020) 109524 ** R. Nietubyc et al., NIM A891 (2018) pp. 78-86
	Poster WEPFDV006 [2.018 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2021-WEPFDV006
About •	Received ※ 21 June 2021 — Accepted ※ 13 April 2022 — Issue date ※ 03 May 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPCAV001	Study of the Niobium Oxide Structure and Microscopic Effect of Plasma Processing on the Niobium Surface	niobium, cavity, background, ECR	585
	B. Giaccone, M. Martinello Fermilab, Batavia, Illinois, USA B. Giaccone, J. Zasadzinski IIT, Chicago, Illinois, USA
	A study of the niobium oxide structure is presented here, with particular focus on the niobium suboxides. Multiple steps of argon sputtering and XPS measurements were carried out until the metal surface was exposed. The sample was then exposed to air and the oxide regrowth was studied. In addition, three Nb samples prepared with different surface treatments were studied before and after being subjected to plasma processing. The scope is investigating the microscopic effect that the reactive oxygen contained in the glow discharge may have on the niobium surface. This study suggests that the Nb₂O₅ thickness may increase, although no negative change in the cavity performance is measured since the pentoxide is a dielectric.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2021-WEPCAV001
About •	Received ※ 22 June 2021 — Revised ※ 13 September 2021 — Accepted ※ 13 January 2022 — Issue date ※ 16 May 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPTEV011	Development of In-Situ Plasma Cleaning for the FRIB SRF Linac	cavity, electron, cryomodule, operation	657
	C. Zhang, W. Chang, K. Elliott, W. Hartung, S.H. Kim, J.T. Popielarski, K. Saito, T. Xu FRIB, East Lansing, Michigan, USA
	Development of techniques for in-situ plasma cleaning of quarter-wave and half-wave resonator cryomodules is underway at the Facility for Rare Isotope Beams (FRIB) at Michigan State University. If SRF cavity performance degradation is seen during future FRIB linac operation, in-situ plasma cleaning may help to restore performance without disassembly of the cavities from the cryomodules for off-line cleaning. A plasma cleaning feasibility study for FRIB cryomodules indicates that plasma cleaning can be done on-line without modifications to the RF couplers or cryomodules. Initial bench measurements have been performed on a FRIB half-wave resonator using noble gases (Ne, Ar), with and without added oxygen gas. The plasma ignition threshold has been measured as a function of gas pressure and composition. Studies of plasma cleaning efficacy are underway. Results will be presented.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2021-WEPTEV011
About •	Received ※ 04 July 2021 — Revised ※ 08 November 2021 — Accepted ※ 24 December 2021 — Issue date ※ 01 March 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THOTEV06	Plasma Electrolytic Polishing as a Promising Treatment Replacement of Electropolishing in the Copper and Niobium Substrate Preparation for SRF	cavity, SRF, niobium, cathode	718
	C. Pira, O. Azzolini, R. Caforio, E. Chyhyrynets, V.A. Garcia, G. Keppel, F. Stivanello INFN/LNL, Legnaro (PD), Italy
	Superconducting radio frequency (SRF) cavities performances strongly depend on the substrate preparation. Currently, the conventional protocol of SRF surface preparation includes electropolishing (EP) as the main treatment achieving low roughness, clean and non-contaminated surfaces, both for bulk Nb and Cu substrates. Harsh and non-environmentally friendly solutions are typically used: HF and H₂SO₄ mixture for Nb, and H3PO4 with Butanol mixtures for EP of Cu. This research is focused on the application of a relatively new technique "Plasma Electrolytic Polishing" (PEP) for the SRF needs. PEP technology is an evolution of EP with a list of advantages that SRF community can benefit from. PEP requires diluted salt solutions moving to a greener approach in respect to EP. PEP can in principle substitute, or completely eliminate, intermediate steps, like mechanical and/or (electro) chemical polishing. Thanks to the superior removing rate in the field (up to 3.5 µm/min of Nb, and 10 µm/min of Cu) in one single treatment roughness below 100 nm Ra has been obtained both for Nb and Cu. In the present work a proof of concept is shown on Nb and Cu planar samples.
	Slides THOTEV06 [7.202 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2021-THOTEV06
About •	Received ※ 21 June 2021 — Accepted ※ 18 October 2021 — Issue date ※ 01 May 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

SUPFDV020

ALD-Based NbIiN Studies for SIS R&D

cavity, site, vacuum, SRF

109

I. González Díaz-Palacio, R.H. Blick, R. Zierold
University of Hamburg, Hamburg, Germany
W. Hillert, M. Wenskat
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany

Superconductor-Insulator-Superconductor multilayers improve the performance of SRF cavities providing magnetic screening of the bulk cavity and lower surface resistance. In this framework NbTiN mixtures stand as a potential material of interest. Atomic layer deposition (ALD) allows for uniform coating of complex geometries and enables tuning of the stoichiometry and precise thickness control in sub-nm range. In this talk, we report about NbTiN thin films deposited by plasma-enhanced ALD on insulating AlN buffer layer. The deposition process has been optimized by studying the superconducting electrical properties of the films. Post-deposition thermal annealing studies with varying temperatures, annealing times, and gas atmospheres have been performed to further improve the thin film quality and the superconducting properties. Our experimental studies show an increase in T_c by 87.5% after thermal annealing and a maximum T_c of 13.9 K has been achieved for NbTiN of 23 nm thickness. Future steps include lattice characterization, using XRR/XRD/EBSD/PALS, and SRF measurements to obtain Hc1 and the superconducting gap.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2021-SUPFDV020

About •

Received ※ 22 June 2021 — Revised ※ 17 August 2021 — Accepted ※ 17 August 2021 — Issue date ※ 19 January 2022

Cite •

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

SUPTEV002

Application of Plasma Electrolytic Polishing onto SRF Substrates

cathode, SRF, cavity, power-supply

116

E. Chyhyrynets, O. Azzolini, R. Caforio, V.A. Garcia Diaz, G. Keppel, C. Pira, F. Stivanello, M. Zanierato
INFN/LNL, Legnaro (PD), Italy

Funding: Work supported by the INFN CSNV experiment TEFEN. This project has received funding from the Euro-pean Union’s Horizon 2020 Research and Innovation programme under GA No 101004730.
A new promising approach of SRF substrates surface treatment has been studied - Plasma Electrolytic Polishing (PEP). The possible application of PEP can be used not only on conventional elliptical resonators, but also on other components of SRF such as, for example, couplers or Quadrupole resonators (QPRs). However, SRF application of PEP represents a challenge since it requires a different approach to treat the inner surface of elliptical cavities respect to electropolishing. In this work, the main problematics and possible solutions, the equipment, and the polishing system requirements will be shown. A proposed polishing system for 6 GHz elliptical cavities and QPRs will be shown and discussed.

Poster SUPTEV002 [2.715 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2021-SUPTEV002

About •

Received ※ 21 June 2021 — Revised ※ 08 July 2021 — Accepted ※ 12 August 2021 — Issue date ※ 22 April 2022

Cite •

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

SUPTEV007

Development of a System for Coating SRF Cavities Using Remote Plasma CVD

cavity, SRF, controls, vacuum

129

G. Gaitan, P. Bishop, A.T. Holic, G. Kulina, M. Liepe, J. Sears, Z. Sun
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: This work was supported by the National Science Foundation under Grant No. PHY-1549132.
Next-generation, thin-film surfaces employing Nb₃Sn, NbN, NbTiN, and other compound superconductors are destined to allow reaching superior RF performance levels in SRF cavities. Optimized, advanced deposition processes are required to enable high-quality films of such materials on large and complex-shaped cavities. For this purpose, Cornell University is developing a remote plasma-enhanced chemical vapor deposition (CVD) system that facilitates coating on complicated geometries with a high deposition rate. This system is based on a high-temperature tube furnace with a clean vacuum and furnace loading system. The use of plasma alongside reacting precursors will significantly reduce the required processing temperature and promote precursor decomposition. A vacuum quality monitor (VQM) is used to characterize the residual gases before coating. The CVD system has been designed and is currently under assembly and commissioning.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2021-SUPTEV007

About •

Received ※ 09 July 2021 — Accepted ※ 21 August 2021 — Issue date ※ 10 February 2022

Cite •

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

TUPTEV004

In Situ Plasma Processing of Superconducting Cavities at Jefferson Lab

cavity, cryomodule, HOM, software

485

T. Powers, N.C. Brock, T.D. Ganey
JLab, Newport News, Virginia, USA

Funding: Funding provided by SC Nuclear Physics Program through DOE SC Lab funding announcement Lab-20-2310
Jefferson Lab began a plasma processing program starting in the spring of 2019. Plasma processing is a common technique for removing hydrocarbons from surfaces, which increases the work function and reduces the secondary emission coefficient. Unlike helium processing which relies on ion bombardment of the field emitters, plasma processing uses free oxygen produced in the plasma to break down the hydrocarbons on the surface of the cavity. The residuals of the hydrocarbons in the form of water, carbon monoxide and carbon dioxide are removed from the cryomodule as part of the process gas flow. The initial focus of the effort is processing C100 cavities by injecting RF power into the HOM coupler ports. We will then start investigating processing of C50 cavities by introducing RF into the fundamental power coupler. The plan is to start processing cryomodules in the CEBAF tunnel in the mid-term future, with a goal of improving the operational gradients and the energy margin of the linacs. This work will describe the systems and methods used at JLAB for processing cavities using an argon oxygen gas mixture. Before and after plasma processing results will also be presented.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2021-TUPTEV004

About •

Received ※ 21 June 2021 — Accepted ※ 05 October 2021 — Issue date ※ 02 May 2022

Cite •

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

WEPFDV006

Activities at NCBJ Towards Development of the Future, Fully-Superconducting, XFEL-Type, RF Electron Gun

cathode, gun, electron, cavity

566

J. Lorkiewicz, P.J. Czuma, A.M. Kosińska, P. Krawczyk, R. Mirowski, R. Nietubyć, M. Staszczak, K. Szamota-Leandersson
NCBJ, Świerk/Otwock, Poland
J.K. Sekutowicz
DESY, Hamburg, Germany

Our group at NCBJ works on upgrade of 1.6-cell, SRF, XFEL-type injector in collaboration with DESY and other laboratories. The work is focused on preparation of lead-on-niobium photocathode, its positioning in the gun cavity and on the UV laser system for photocurrent excitation. RF focusing effect was used to minimize the predicted emittance and transverse size of accelerated e^- beam. Following beam dynamics computation, it has been proposed that the photocathode be recessed 0.45 mm into the rear wall of the gun cavity. It helps focusing e^- beam in its low-energy part. Preparation of sc cathodes of Pb layer on Nb plugs (*, **) is reported, aimed at reaching clean, planar and uniform Pb films. The laser system will consist of commercially available Pharos laser and a 4-th harmonic generator. A gaussian, 300 fs long, 257 nm in wavelength UV pulse will be transformed in time by a pulse stretcher/stacker and in space by pi-shaper. The planned optical system will generate cylindrical photoelectron bunch 2 - 30 ps long and 0.2 - 3 mm wide.
* J. Lorkiewicz et al., Vacuum 179 (2020) 109524
** R. Nietubyc et al., NIM A891 (2018) pp. 78-86

Poster WEPFDV006 [2.018 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2021-WEPFDV006

About •

Received ※ 21 June 2021 — Accepted ※ 13 April 2022 — Issue date ※ 03 May 2022

Cite •

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

WEPCAV001

Study of the Niobium Oxide Structure and Microscopic Effect of Plasma Processing on the Niobium Surface

niobium, cavity, background, ECR

585

B. Giaccone, M. Martinello
Fermilab, Batavia, Illinois, USA
B. Giaccone, J. Zasadzinski
IIT, Chicago, Illinois, USA

A study of the niobium oxide structure is presented here, with particular focus on the niobium suboxides. Multiple steps of argon sputtering and XPS measurements were carried out until the metal surface was exposed. The sample was then exposed to air and the oxide regrowth was studied. In addition, three Nb samples prepared with different surface treatments were studied before and after being subjected to plasma processing. The scope is investigating the microscopic effect that the reactive oxygen contained in the glow discharge may have on the niobium surface. This study suggests that the Nb₂O₅ thickness may increase, although no negative change in the cavity performance is measured since the pentoxide is a dielectric.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2021-WEPCAV001

About •

Received ※ 22 June 2021 — Revised ※ 13 September 2021 — Accepted ※ 13 January 2022 — Issue date ※ 16 May 2022

Cite •

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

WEPTEV011

Development of In-Situ Plasma Cleaning for the FRIB SRF Linac

cavity, electron, cryomodule, operation

657

C. Zhang, W. Chang, K. Elliott, W. Hartung, S.H. Kim, J.T. Popielarski, K. Saito, T. Xu
FRIB, East Lansing, Michigan, USA

Development of techniques for in-situ plasma cleaning of quarter-wave and half-wave resonator cryomodules is underway at the Facility for Rare Isotope Beams (FRIB) at Michigan State University. If SRF cavity performance degradation is seen during future FRIB linac operation, in-situ plasma cleaning may help to restore performance without disassembly of the cavities from the cryomodules for off-line cleaning. A plasma cleaning feasibility study for FRIB cryomodules indicates that plasma cleaning can be done on-line without modifications to the RF couplers or cryomodules. Initial bench measurements have been performed on a FRIB half-wave resonator using noble gases (Ne, Ar), with and without added oxygen gas. The plasma ignition threshold has been measured as a function of gas pressure and composition. Studies of plasma cleaning efficacy are underway. Results will be presented.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2021-WEPTEV011

About •

Received ※ 04 July 2021 — Revised ※ 08 November 2021 — Accepted ※ 24 December 2021 — Issue date ※ 01 March 2022

Cite •

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

THOTEV06

Plasma Electrolytic Polishing as a Promising Treatment Replacement of Electropolishing in the Copper and Niobium Substrate Preparation for SRF

cavity, SRF, niobium, cathode

718

C. Pira, O. Azzolini, R. Caforio, E. Chyhyrynets, V.A. Garcia, G. Keppel, F. Stivanello
INFN/LNL, Legnaro (PD), Italy

Superconducting radio frequency (SRF) cavities performances strongly depend on the substrate preparation. Currently, the conventional protocol of SRF surface preparation includes electropolishing (EP) as the main treatment achieving low roughness, clean and non-contaminated surfaces, both for bulk Nb and Cu substrates. Harsh and non-environmentally friendly solutions are typically used: HF and H₂SO₄ mixture for Nb, and H3PO4 with Butanol mixtures for EP of Cu. This research is focused on the application of a relatively new technique "Plasma Electrolytic Polishing" (PEP) for the SRF needs. PEP technology is an evolution of EP with a list of advantages that SRF community can benefit from. PEP requires diluted salt solutions moving to a greener approach in respect to EP. PEP can in principle substitute, or completely eliminate, intermediate steps, like mechanical and/or (electro) chemical polishing. Thanks to the superior removing rate in the field (up to 3.5 µm/min of Nb, and 10 µm/min of Cu) in one single treatment roughness below 100 nm Ra has been obtained both for Nb and Cu. In the present work a proof of concept is shown on Nb and Cu planar samples.

Slides THOTEV06 [7.202 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2021-THOTEV06

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Received ※ 21 June 2021 — Accepted ※ 18 October 2021 — Issue date ※ 01 May 2022

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