SRF2019 - List of Authors (Malyshev, O.B.)

Paper	Title	Page
THP048	Characterization of Flat Multilayer Thin Film Superconductors	968
SUSP037	use link to see paper's listing under its alternate paper code
	D. Turner, A.J. May STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom G. Burt, L. Gurran Cockcroft Institute, Lancaster University, Lancaster, United Kingdom K.D. Dumbell, N. Pattalwar, S.M. Pattalwar STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom T. Junginger, O.B. Malyshev Cockcroft Institute, Warrington, Cheshire, United Kingdom
	The maximum accelerating gradient of SRF cavities can be increased by raising the field of initial flux penetration, Hvp. Thin alternating layers of superconductors and insulators (SIS) can potentially increase Hvp. Magnetometry is commercially available but consists of limitations, such as SQUID measurements apply a field over both superconducting layers, so Hvp through the sample cannot be measured. If SIS structures are to be investigated a magnetic field must be applied locally, from one plane of the sample, with no magnetic field on the opposing side to allow Hvp to be measured. A magnetic field penetration experiment has been developed at Daresbury laboratory, where a VTI has been created for a cryostat where Hvp of a sample can be measured. The VTI has been designed to allow flat samples to be measured to reduce limitations such as edge effects by creating a DC magnetic field smaller than the sample. A small, parallel magnetic field is produced on the sample by the use of a ferrite yoke. The field is increased to determine Hvp by using 2 hall probes either side of the sample.
	Poster THP048 [0.327 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP048
About •	paper received ※ 23 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019
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TUP070	The SRF Thin Film Test Facility in LHe-Free Cryostat	610
	O.B. Malyshev, J.A. Conlon, P. Goudket, N. Pattalwar, S.M. Pattalwar STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom G. Burt Cockcroft Institute, Warrington, Cheshire, United Kingdom G. Burt Lancaster University, Lancaster, United Kingdom
	An ongoing programme of development superconducting thin film coating for SRF cavities requires a facility for a quick sample evaluation at the RF conditions. One of the key specifications is a simplicity of the testing procedure, allowing an easy installation and quick turnover of the testing samples. Choked test cavities operating at 7.8 GHz with three RF chokes have been designed and tested at DL in a LHe cryostat verifying that the system could perform as required. Having a sample and a cavity physically separate reduces the complexity involved in changing samples (major causes of low throughput rate and high running costs for other test cavities) and also allows direct measurement of the RF power dissipated in the sample via power calorimetry. However, changing a sample and preparation for a test requires about two-week effort per sample. In order to simplify the measurements and achieve a faster turnaround, a new cryostat cooled with a closed-cycle refrigerator has been designed, built and tested. Changing a sample, cooling down and testing can be reduced to 2-3 days per sample. Detailed design and results of testing of this facility will be reported at the conference.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP070
About •	paper received ※ 21 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)

THP041	Impact of the Cu Substrate Surface Preparation on the Morphological, Superconductive and RF Properties of the Nb Superconductive Coatings	935
	C. Pira, E. Chyhyrynets INFN/LNL, Legnaro (PD), Italy C.Z. Antoine CEA-IRFU, Gif-sur-Yvette, France X. Jiang, S.B. Leith, M. Vogel University Siegen, Siegen, Germany A. Katasevs, J. Kaupužs, A. Medvids, P. Onufrijevs Riga Technical University, Riga, Latvia O. Kugeler HZB, Berlin, Germany O.B. Malyshev, R. Valizadeh STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom R. Ries, E. Seiler Slovak Academy of Sciences, Institute of Electrical Engineering, Bratislava, Slovak Republic A. Sublet CERN, Meyrin, Switzerland
	Funding: This project has received funding from the European Union’s Horizon 2020 Research and Innovation programme under Grant Agreement No 730871. Nowadays, one of the main issues of the superconducting thin film resonant cavities is the Cu surface preparation. A better understanding of the impact of copper surface preparation on the morphological, superconductive (SC) and RF properties of the coating, is mandatory in order to improve the performances of superconducting cavities by coating techniques. ARIES H₂020 collaboration includes a specific work package (WP15) to study the influence of Cu surface polishing on the SRF performances of Nb coatings that involves a team of 8 research groups from 7 different countries. In the present work, a comparison of 4 different polishing processes for Cu (Tumbling, EP, SUBU, EP+SUBU) is presented through the evaluation of the SC and morphological properties of Nb thin film coated on Cu planar samples and QPR samples, polished with different procedures. Effects of laser annealing on Nb thin films have also been studied. Different surface characterizations have been applied: roughness measurements, SEM, EDS, XRD, AFM, and thermal and photo-stimulated exoelectrons measurements. SC properties were evaluated with PPMS, and QPR measurements will be carry out at HZB in the beginning of 2019.
	Poster THP041 [3.196 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP041
About •	paper received ※ 23 June 2019 paper accepted ※ 05 July 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

THP048

Characterization of Flat Multilayer Thin Film Superconductors

968

SUSP037

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

D. Turner, A.J. May
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
G. Burt, L. Gurran
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
K.D. Dumbell, N. Pattalwar, S.M. Pattalwar
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
T. Junginger, O.B. Malyshev
Cockcroft Institute, Warrington, Cheshire, United Kingdom

The maximum accelerating gradient of SRF cavities can be increased by raising the field of initial flux penetration, Hvp. Thin alternating layers of superconductors and insulators (SIS) can potentially increase Hvp. Magnetometry is commercially available but consists of limitations, such as SQUID measurements apply a field over both superconducting layers, so Hvp through the sample cannot be measured. If SIS structures are to be investigated a magnetic field must be applied locally, from one plane of the sample, with no magnetic field on the opposing side to allow Hvp to be measured. A magnetic field penetration experiment has been developed at Daresbury laboratory, where a VTI has been created for a cryostat where Hvp of a sample can be measured. The VTI has been designed to allow flat samples to be measured to reduce limitations such as edge effects by creating a DC magnetic field smaller than the sample. A small, parallel magnetic field is produced on the sample by the use of a ferrite yoke. The field is increased to determine Hvp by using 2 hall probes either side of the sample.

Poster THP048 [0.327 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP048

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)

TUP070

The SRF Thin Film Test Facility in LHe-Free Cryostat

610

O.B. Malyshev, J.A. Conlon, P. Goudket, N. Pattalwar, S.M. Pattalwar
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
G. Burt
Cockcroft Institute, Warrington, Cheshire, United Kingdom
G. Burt
Lancaster University, Lancaster, United Kingdom

An ongoing programme of development superconducting thin film coating for SRF cavities requires a facility for a quick sample evaluation at the RF conditions. One of the key specifications is a simplicity of the testing procedure, allowing an easy installation and quick turnover of the testing samples. Choked test cavities operating at 7.8 GHz with three RF chokes have been designed and tested at DL in a LHe cryostat verifying that the system could perform as required. Having a sample and a cavity physically separate reduces the complexity involved in changing samples (major causes of low throughput rate and high running costs for other test cavities) and also allows direct measurement of the RF power dissipated in the sample via power calorimetry. However, changing a sample and preparation for a test requires about two-week effort per sample. In order to simplify the measurements and achieve a faster turnaround, a new cryostat cooled with a closed-cycle refrigerator has been designed, built and tested. Changing a sample, cooling down and testing can be reduced to 2-3 days per sample. Detailed design and results of testing of this facility will be reported at the conference.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP070

About •

paper received ※ 21 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)

THP041

Impact of the Cu Substrate Surface Preparation on the Morphological, Superconductive and RF Properties of the Nb Superconductive Coatings

935

C. Pira, E. Chyhyrynets
INFN/LNL, Legnaro (PD), Italy
C.Z. Antoine
CEA-IRFU, Gif-sur-Yvette, France
X. Jiang, S.B. Leith, M. Vogel
University Siegen, Siegen, Germany
A. Katasevs, J. Kaupužs, A. Medvids, P. Onufrijevs
Riga Technical University, Riga, Latvia
O. Kugeler
HZB, Berlin, Germany
O.B. Malyshev, R. Valizadeh
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
R. Ries, E. Seiler
Slovak Academy of Sciences, Institute of Electrical Engineering, Bratislava, Slovak Republic
A. Sublet
CERN, Meyrin, Switzerland

Funding: This project has received funding from the European Union’s Horizon 2020 Research and Innovation programme under Grant Agreement No 730871.
Nowadays, one of the main issues of the superconducting thin film resonant cavities is the Cu surface preparation. A better understanding of the impact of copper surface preparation on the morphological, superconductive (SC) and RF properties of the coating, is mandatory in order to improve the performances of superconducting cavities by coating techniques. ARIES H₂020 collaboration includes a specific work package (WP15) to study the influence of Cu surface polishing on the SRF performances of Nb coatings that involves a team of 8 research groups from 7 different countries. In the present work, a comparison of 4 different polishing processes for Cu (Tumbling, EP, SUBU, EP+SUBU) is presented through the evaluation of the SC and morphological properties of Nb thin film coated on Cu planar samples and QPR samples, polished with different procedures. Effects of laser annealing on Nb thin films have also been studied. Different surface characterizations have been applied: roughness measurements, SEM, EDS, XRD, AFM, and thermal and photo-stimulated exoelectrons measurements. SC properties were evaluated with PPMS, and QPR measurements will be carry out at HZB in the beginning of 2019.

Poster THP041 [3.196 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP041

About •

paper received ※ 23 June 2019 paper accepted ※ 05 July 2019 issue date ※ 14 August 2019

Export •

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