IPAC2021 - List of Authors (Wenskat, M.)

Paper	Title	Page
MOPAB376	Design and Fabrication of a Quadrupole Resonator for SRF R&D	1158
	R. Monroy-Villa, W. Hillert, M. Wenskat University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany S. Gorgi Zadeh, P. Putek Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany R. Monroy-Villa, D. Reschke, J.H. Thie DESY, Hamburg, Germany
	As Nb superconducting radio-frequency (SRF) cavities are now approaching the theoretical limits of the material, a variety of different surface treatments have been developed to further improve their performance; although no fully understood theory is yet available. Small superconducting samples are studied to characterize their material properties and their evolution under different surface treatments. To study the RF properties of such samples under realistic SRF conditions at low temperatures, a test cavity called quadrupole resonator (QPR) is currently being fabricated. In this work we report the status of the QPR at Universität Hamburg in collaboration with DESY. Our device is based on the QPRs operated at CERN and at HZB and its design will allow for testing samples under cavity-like conditions, i.e., at temperatures between 2K and 8 K, under magnetic fields up to 120mT and with operating frequencies of 433 MHz, 866 MHz and 1300 MHz. Fabrication tolerance studies on the electromagnetic field distributions and simulations of the static detuning of the device, together with a status report on the current manufacturing process, will be presented.
	Poster MOPAB376 [1.119 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB376
About •	paper received ※ 26 May 2021 paper accepted ※ 09 June 2021 issue date ※ 17 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB320	ALD-Based NbTiN Studies for SIS R&D	4420
	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 Tc by 87.5% after thermal annealing and a maximum Tc 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 ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB320
About •	paper received ※ 24 May 2021 paper accepted ※ 23 July 2021 issue date ※ 18 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Design and Fabrication of a Quadrupole Resonator for SRF R&D

1158

R. Monroy-Villa, W. Hillert, M. Wenskat
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
S. Gorgi Zadeh, P. Putek
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
R. Monroy-Villa, D. Reschke, J.H. Thie
DESY, Hamburg, Germany

As Nb superconducting radio-frequency (SRF) cavities are now approaching the theoretical limits of the material, a variety of different surface treatments have been developed to further improve their performance; although no fully understood theory is yet available. Small superconducting samples are studied to characterize their material properties and their evolution under different surface treatments. To study the RF properties of such samples under realistic SRF conditions at low temperatures, a test cavity called quadrupole resonator (QPR) is currently being fabricated. In this work we report the status of the QPR at Universität Hamburg in collaboration with DESY. Our device is based on the QPRs operated at CERN and at HZB and its design will allow for testing samples under cavity-like conditions, i.e., at temperatures between 2K and 8 K, under magnetic fields up to 120mT and with operating frequencies of 433 MHz, 866 MHz and 1300 MHz. Fabrication tolerance studies on the electromagnetic field distributions and simulations of the static detuning of the device, together with a status report on the current manufacturing process, will be presented.

Poster MOPAB376 [1.119 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB376

About •

paper received ※ 26 May 2021 paper accepted ※ 09 June 2021 issue date ※ 17 August 2021

Export •

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

THPAB320

ALD-Based NbTiN Studies for SIS R&D

4420

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 Tc by 87.5% after thermal annealing and a maximum Tc 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 ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB320

About •

paper received ※ 24 May 2021 paper accepted ※ 23 July 2021 issue date ※ 18 August 2021

Export •

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