SRF2013 - List of Authors (Junginger, T.)

Paper

Title

Page

Nb Coating Developments with HIPIMS for SRF Applications

627

G. Terenziani, I. Aviles Santillana, S. Calatroni, T. Junginger
CERN, Geneva, Switzerland
A.P. Ehiasarian
SHU, Sheffield, United Kingdom

In the last few years the interest of the thin film science and technology community on High Impulse Power Magnetron Sputtering (HIPIMS) coatings has steadily increased. HIPIMS literature shows that better thin film morphology, denser and smoother films can be achieved when compared with standard dc Magnetron Sputtering (dcMS) coating technology. Furthermore the capability of HIPIMS to produce a high quantity of ionized species can allow conformal coatings also for complex geometries. A study is under way at CERN to apply this technology for the Nb coating of SRF 1.3-1.5 GHz Cu cavities, and in parallel at SHU the plasma physics and its correlation with film morphology are being investigated. Recent results achieved with this technique are presented in the paper.

WEIOC01

High Resolution Surface Resistance Studies

785

S. Aull, S. Döbert, T. Junginger
CERN, Geneva, Switzerland
S. Aull, J. Knobloch
University of Siegen, Siegen, Germany
J. Knobloch
HZB, Berlin, Germany

Funding: Work supported by the German Doctoral Students program of the Federal Ministry of Education and Research (BMBF).
The attempt to reach quality factors beyond 10¹¹ and pushing the accelerating gradients of SRF cavities to the theoretical limit, the treatment depending loss mechanisms in niobium need better understanding. CERNs Quadrupole Resonator enables sub-nΩ-resolution measurements of the surface resistance. The available parameters cover resonant modes at 400, 800 and 1200 MHz, any temperature up to 15 K and rf fields up to 60 mT. Recently the setup has been extended with a coil creating a dc magnetic field for trapped flux studies. Overall, much more information about the rf performance is accessible compared to regular cavity measurements. Since the samples are flat disks of 75 mm diameter geometric fabrication issues are simplified which makes the Quadrupole Resonator also the perfect tool to study alternative materials or new coating techniques. In this contribution in depth studies of a heat treated bulk niobium sample exploiting the complete parameter range of the setup are presented.

Slides WEIOC01 [2.724 MB]

FRIOB04

CERN Developments for 704 MHz Superconducting Cavities

1198

O. Capatina, G. Arnau-Izquierdo, S. Atieh, I. Aviles Santillana, R. Bonomi, S. Calatroni, J.K. Chambrillon, R. Garoby, F. Gerigk, M. Guinchard, T. Junginger, M. Malabaila, L. Marques Antunes Ferreira, S. Mikulas, V. Parma, T. Renaglia, K.M. Schirm, T. Tardy, M. Therasse, A. Vacca, N. Valverde Alonso, A. Vande Craen
CERN, Geneva, Switzerland
F. Pillon
Kraftanlagen Nukleartechnik GmbH, Heidelberg, Germany

The Superconducting Proton Linac (SPL) is an R&D effort coordinated by CERN in partnership with other international laboratories. It is aiming at developing key technologies for the construction of a multi-megawatt proton linac based on state-of-the-art RF superconducting technology, which would serve as a driver in new physics facilities for neutrinos and/or Radioactive Ion Beam (RIB). Amongst the main objectives of this R&D effort, is the development of 704 MHz bulk niobium β=1 elliptical cavities, operating at 2 K with a maximum accelerating gradient of 25 MV/m, and the testing of a string of cavities integrated in a machine-type cryomodule. The cavity together with its helium tank had to be carefully designed in coherence with the innovative design of the cryomodule. New fabrication methods have also been explored. Five such niobium cavities and two copper cavities are in fabrication. The key design aspects are discussed, the results of the alternative fabrication methods presented and the status of the cavity manufacturing and surface preparation is detailed.

Slides FRIOB04 [8.677 MB]

Paper	Title	Page
TUP078	Nb Coating Developments with HIPIMS for SRF Applications	627
	G. Terenziani, I. Aviles Santillana, S. Calatroni, T. Junginger CERN, Geneva, Switzerland A.P. Ehiasarian SHU, Sheffield, United Kingdom
	In the last few years the interest of the thin film science and technology community on High Impulse Power Magnetron Sputtering (HIPIMS) coatings has steadily increased. HIPIMS literature shows that better thin film morphology, denser and smoother films can be achieved when compared with standard dc Magnetron Sputtering (dcMS) coating technology. Furthermore the capability of HIPIMS to produce a high quantity of ionized species can allow conformal coatings also for complex geometries. A study is under way at CERN to apply this technology for the Nb coating of SRF 1.3-1.5 GHz Cu cavities, and in parallel at SHU the plasma physics and its correlation with film morphology are being investigated. Recent results achieved with this technique are presented in the paper.

WEIOC01	High Resolution Surface Resistance Studies	785
	S. Aull, S. Döbert, T. Junginger CERN, Geneva, Switzerland S. Aull, J. Knobloch University of Siegen, Siegen, Germany J. Knobloch HZB, Berlin, Germany
	Funding: Work supported by the German Doctoral Students program of the Federal Ministry of Education and Research (BMBF). The attempt to reach quality factors beyond 10¹¹ and pushing the accelerating gradients of SRF cavities to the theoretical limit, the treatment depending loss mechanisms in niobium need better understanding. CERNs Quadrupole Resonator enables sub-nΩ-resolution measurements of the surface resistance. The available parameters cover resonant modes at 400, 800 and 1200 MHz, any temperature up to 15 K and rf fields up to 60 mT. Recently the setup has been extended with a coil creating a dc magnetic field for trapped flux studies. Overall, much more information about the rf performance is accessible compared to regular cavity measurements. Since the samples are flat disks of 75 mm diameter geometric fabrication issues are simplified which makes the Quadrupole Resonator also the perfect tool to study alternative materials or new coating techniques. In this contribution in depth studies of a heat treated bulk niobium sample exploiting the complete parameter range of the setup are presented.
	Slides WEIOC01 [2.724 MB]

FRIOB04	CERN Developments for 704 MHz Superconducting Cavities	1198
	O. Capatina, G. Arnau-Izquierdo, S. Atieh, I. Aviles Santillana, R. Bonomi, S. Calatroni, J.K. Chambrillon, R. Garoby, F. Gerigk, M. Guinchard, T. Junginger, M. Malabaila, L. Marques Antunes Ferreira, S. Mikulas, V. Parma, T. Renaglia, K.M. Schirm, T. Tardy, M. Therasse, A. Vacca, N. Valverde Alonso, A. Vande Craen CERN, Geneva, Switzerland F. Pillon Kraftanlagen Nukleartechnik GmbH, Heidelberg, Germany
	The Superconducting Proton Linac (SPL) is an R&D effort coordinated by CERN in partnership with other international laboratories. It is aiming at developing key technologies for the construction of a multi-megawatt proton linac based on state-of-the-art RF superconducting technology, which would serve as a driver in new physics facilities for neutrinos and/or Radioactive Ion Beam (RIB). Amongst the main objectives of this R&D effort, is the development of 704 MHz bulk niobium β=1 elliptical cavities, operating at 2 K with a maximum accelerating gradient of 25 MV/m, and the testing of a string of cavities integrated in a machine-type cryomodule. The cavity together with its helium tank had to be carefully designed in coherence with the innovative design of the cryomodule. New fabrication methods have also been explored. Five such niobium cavities and two copper cavities are in fabrication. The key design aspects are discussed, the results of the alternative fabrication methods presented and the status of the cavity manufacturing and surface preparation is detailed.
	Slides FRIOB04 [8.677 MB]