SRF2011 - List of Authors (Vollenberg, W.)

Paper

Title

Page

New Approaches to Nb Thin Film Coating

331

S. Calatroni, A.E. Gustafsson, M. Scheubel, W. Vollenberg
CERN, Geneva, Switzerland

Funding: The research leading to these results has received funding from the European Commission under the FP7 Research Infrastructures grant agreement no.227579.
Niobium films are widely used at CERN and several other Laboratories for the coating of superconducting cavities. The performances of these cavities are highly influenced by the thin film properties, and in particular its microstructure. Energetic condensation, and in particular High Power Impulse Magnetron Sputtering (HIPIMS) gives new opportunities for conventional magnetron sputtering equipment. In this talk we will review the background on thin film performance, the motivations of the study, illustrate the experience that has been gained at CERN during the first months of operation and present the results obtained so far.

THPO026

Second Sound Measurement for SPL Cavity Diagnostics

767

K.C. Liao, C. Balle, J. Bremer, T. Junginger, W. Vollenberg, W. Weingarten
CERN, Geneva, Switzerland
H. Vennekate
University of Göttingen, Georg-August University of Göttingen, Göttingen, Germany

Second sound is a temperature wave which travels at a speed of ≈ 20m/s in superfluid helium. The second sound detector used is a so-called oscillating superleak transducer (OST), initially provided by Cornell-CLASSE, and thereafter manufactured at CERN. It contains a flexible porous membrane for transmitting and blocking the movement of the superfluid and normal fluid components of the second sound wave. From the measured speed of this wave and by determining the travel time between the quench event and several OSTs, an alternative method is offered to localise the quench site by triangulation. Several surface mount devices (SMDs) – thick film chip resistors – are used to simulate the quench spot in a cavity. Given the heat pulse and the location of the installed OSTs, the temperature dependence of the second sound velocity is determined under different experimental conditions and compared with previous results and theoretical expectations. The second sound triangulation will eventually be used to determine quench locations on the Superconducting Proton Linac (SPL) test cavities (704MHz) at CERN.

Poster THPO026 [2.544 MB]

Paper	Title	Page
TUIOB05	New Approaches to Nb Thin Film Coating	331
	S. Calatroni, A.E. Gustafsson, M. Scheubel, W. Vollenberg CERN, Geneva, Switzerland
	Funding: The research leading to these results has received funding from the European Commission under the FP7 Research Infrastructures grant agreement no.227579. Niobium films are widely used at CERN and several other Laboratories for the coating of superconducting cavities. The performances of these cavities are highly influenced by the thin film properties, and in particular its microstructure. Energetic condensation, and in particular High Power Impulse Magnetron Sputtering (HIPIMS) gives new opportunities for conventional magnetron sputtering equipment. In this talk we will review the background on thin film performance, the motivations of the study, illustrate the experience that has been gained at CERN during the first months of operation and present the results obtained so far.

THPO026	Second Sound Measurement for SPL Cavity Diagnostics	767
	K.C. Liao, C. Balle, J. Bremer, T. Junginger, W. Vollenberg, W. Weingarten CERN, Geneva, Switzerland H. Vennekate University of Göttingen, Georg-August University of Göttingen, Göttingen, Germany
	Second sound is a temperature wave which travels at a speed of ≈ 20m/s in superfluid helium. The second sound detector used is a so-called oscillating superleak transducer (OST), initially provided by Cornell-CLASSE, and thereafter manufactured at CERN. It contains a flexible porous membrane for transmitting and blocking the movement of the superfluid and normal fluid components of the second sound wave. From the measured speed of this wave and by determining the travel time between the quench event and several OSTs, an alternative method is offered to localise the quench site by triangulation. Several surface mount devices (SMDs) – thick film chip resistors – are used to simulate the quench spot in a cavity. Given the heat pulse and the location of the installed OSTs, the temperature dependence of the second sound velocity is determined under different experimental conditions and compared with previous results and theoretical expectations. The second sound triangulation will eventually be used to determine quench locations on the Superconducting Proton Linac (SPL) test cavities (704MHz) at CERN.
	Poster THPO026 [2.544 MB]