SRF2015 - List of Keywords (framework)

Paper	Title	Other Keywords	Page
MOPB008	Theoretical Field Limit and Cavity Surface Conditions: Nano-Scale Topography and Sub-millimeter Pit	cavity, factory, simulation, radio-frequency	86
	T. Kubo KEK, Ibaraki, Japan
	The recent two theoretical papers,* are briefly introduced. The former addresses the superheating field (Bs) suppression due to nano-defects distributing almost continuously on the cavity surface. We introduce a model of the nano-defect. An analytical formula for Bs suppression factor is derived. By using the formula, suppression factors of bulk or multilayer superconductors and those after various surface processing technologies can be evaluated. An application to the dirty Nb processed by EP is also presented as an example. The latter address the magnetic field enhancement (MFE) at the sub-millimeter pit on the surface of cavity, which is thought to cause quench. There exists the famous well-type pit model, but many of pits are not well-type but have gentle slopes. Impacts of the slope angle on MFE have not been well understood. We introduce a model that can describe a pit with an arbitrary slope angle. A formula to evaluate the MFE factor is derived. A pit with a gentle slope angle yields a much smaller MFE factor than the well-type pit. The formula can be applied to the calculation of MFE factors of real pits with arbitrary slope angles. T. Kubo, Prog. Theor. Exp. Phys. 2015,063G01(2015). ** T. Kubo, Prog. Theor. Exp. Phys. 2015,073G01(2015).
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MOPB009	Model of Flux Trapping in Cooling Down Process	target, cavity, interface, experiment	90
	T. Kubo KEK, Ibaraki, Japan
	Recent findings that cooling conditions affect an amount of trapped magnetic flux attract much attention as a way to achieve a high-Q0 by SRF cavity,,*. Q0~210¹¹ has already been achieved by the full flux expulsion***. While much experimental studies have been conducted, not much theoretical progress followed on it. In this paper, I introduce a simple model that can explain how trapped fluxoids are expelled in cooling process. J.M.Vogt et al., PRSTAB 16, 102002 (2013) A.Romanenko et al., JAP 115, 184903 (2014) J.M.Vogt et al., PRSTAB 18, 042001 (2015) ***A.Romanenko et al., APL 105, 234103 (2014)
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Paper

Title

Other Keywords

Page

MOPB008

Theoretical Field Limit and Cavity Surface Conditions: Nano-Scale Topography and Sub-millimeter Pit

cavity, factory, simulation, radio-frequency

86

T. Kubo
KEK, Ibaraki, Japan

The recent two theoretical papers*,** are briefly introduced. The former addresses the superheating field (Bs) suppression due to nano-defects distributing almost continuously on the cavity surface*. We introduce a model of the nano-defect. An analytical formula for Bs suppression factor is derived. By using the formula, suppression factors of bulk or multilayer superconductors and those after various surface processing technologies can be evaluated. An application to the dirty Nb processed by EP is also presented as an example. The latter address the magnetic field enhancement (MFE) at the sub-millimeter pit on the surface of cavity, which is thought to cause quench**. There exists the famous well-type pit model, but many of pits are not well-type but have gentle slopes. Impacts of the slope angle on MFE have not been well understood. We introduce a model that can describe a pit with an arbitrary slope angle. A formula to evaluate the MFE factor is derived. A pit with a gentle slope angle yields a much smaller MFE factor than the well-type pit. The formula can be applied to the calculation of MFE factors of real pits with arbitrary slope angles.
* T. Kubo, Prog. Theor. Exp. Phys. 2015,063G01(2015).
** T. Kubo, Prog. Theor. Exp. Phys. 2015,073G01(2015).

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

MOPB009

Model of Flux Trapping in Cooling Down Process

target, cavity, interface, experiment

90

T. Kubo
KEK, Ibaraki, Japan

Recent findings that cooling conditions affect an amount of trapped magnetic flux attract much attention as a way to achieve a high-Q0 by SRF cavity*,**,***. Q0~2*10¹¹ has already been achieved by the full flux expulsion****. While much experimental studies have been conducted, not much theoretical progress followed on it. In this paper, I introduce a simple model that can explain how trapped fluxoids are expelled in cooling process.
*J.M.Vogt et al., PRSTAB 16, 102002 (2013)
**A.Romanenko et al., JAP 115, 184903 (2014)
***J.M.Vogt et al., PRSTAB 18, 042001 (2015)
****A.Romanenko et al., APL 105, 234103 (2014)

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