SRF2015 - List of Keywords (superconducting-cavity)

Paper	Title	Other Keywords	Page
MOPB013	Simulation of Geometry Dependent Flux Trapping	cavity, simulation, factory, focusing	105
	J. May-Mann, R.G. Eichhorn Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Trapping or expulsion of ambient magnetic field has become an important factor in the performance of superconducting cavities with very high Q. As experimental data is limited, we set up a numerical field calculation model to study this effect in more details. We will report, how the cavity orientation, the movement of the transition to superconductivity front, and the orientation of the magnetic field contributes to the amount of magnetic field being vulnerable for trapping.
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TUPB091	Systematic Uncertainties in RF-Based Measurement of Superconducting Cavity Quality Factors	cavity, coupling, resonance, factory	814
	W. Schappert, J.P. Holzbauer, Y.M. Pischalnikov, D.A. Sergatskov Fermilab, Batavia, Illinois, USA
	Measurements of cavity quality factor measurements are subject to at least three potentially large sources of systematic error that have not been previously recognized. Imperfect coupler directivity (cross-talk) can lead to large errors in the cavity coupling factor when the cavity coupling factor is significantly different than unity. Energy re-reflected from the circulator can systematically bias the measured cavity decay time which is used to determine the loaded quality factor. Use of the peak probe power or the minimum of the reflected power to determine the cavity resonance frequency rather than the peak of the probe/forward transfer function may lead to errors in the resonance frequency that can also affect quality factors. Each effect is illustrated with measurements in the Fermilab VTS, simulations and analytic calculations. If the magnitude and phase of the cavity RF signals are measured, these effects can be measured and corrected for. If only signal magnitudes are recorded or these effects are not measured, they must be treated as sources of systematic uncertainty.
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Paper

Title

Other Keywords

Page

MOPB013

Simulation of Geometry Dependent Flux Trapping

cavity, simulation, factory, focusing

105

J. May-Mann, R.G. Eichhorn
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Trapping or expulsion of ambient magnetic field has become an important factor in the performance of superconducting cavities with very high Q. As experimental data is limited, we set up a numerical field calculation model to study this effect in more details. We will report, how the cavity orientation, the movement of the transition to superconductivity front, and the orientation of the magnetic field contributes to the amount of magnetic field being vulnerable for trapping.

Export •

reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text, ※ RIS/RefMan, ※ EndNote (xml)

TUPB091

Systematic Uncertainties in RF-Based Measurement of Superconducting Cavity Quality Factors

cavity, coupling, resonance, factory

814

W. Schappert, J.P. Holzbauer, Y.M. Pischalnikov, D.A. Sergatskov
Fermilab, Batavia, Illinois, USA

Measurements of cavity quality factor measurements are subject to at least three potentially large sources of systematic error that have not been previously recognized. Imperfect coupler directivity (cross-talk) can lead to large errors in the cavity coupling factor when the cavity coupling factor is significantly different than unity. Energy re-reflected from the circulator can systematically bias the measured cavity decay time which is used to determine the loaded quality factor. Use of the peak probe power or the minimum of the reflected power to determine the cavity resonance frequency rather than the peak of the probe/forward transfer function may lead to errors in the resonance frequency that can also affect quality factors. Each effect is illustrated with measurements in the Fermilab VTS, simulations and analytic calculations. If the magnitude and phase of the cavity RF signals are measured, these effects can be measured and corrected for. If only signal magnitudes are recorded or these effects are not measured, they must be treated as sources of systematic uncertainty.

Export •

reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text, ※ RIS/RefMan, ※ EndNote (xml)