SRF2013 - List of Authors (Iwashita, Y.)

Paper	Title	Page
TUP007	Vortex Penetration Field in the Multilayered Coating Model	430
	T. Kubo, T. Saeki KEK, Ibaraki, Japan Y. Iwashita Kyoto ICR, Uji, Kyoto, Japan
	A multilayered structure with a single superconductor layer and a single insulator layer deposited on a bulk superconductor is studied. General formulae for the vortex penetration-field of the superconductor layer and the magnetic field on the bulk superconductor which is shielded by the superconductor and insulator layers are derived with a rigorous calculation of the magnetic field attenuation in the multilayered structure. The formulae depend not only on the material and the thickness of the superconductor layer but also on the thickness of the insulator layer. The results can be applied to superconducting accelerating cavities with the multilayered structure. Using the formulae, a combination of the thicknesses of superconductor and insulator layers to enhance the RF breakdown field limits can be found for any given materials. (Submitted on 25 Apr 2013) T. Kubo, Y. Iwashita and T. Saeki, arXiv:1304.6876 [physics.acc-ph](Submitted on 25 Apr 2013); arXiv:1306.4823 [physics.acc-ph](Proc. of IPAC13); arXiv:1307.0583 [physics.acc-ph](Proc. of SRF2013)

TUP061	Update on Study of Welding Porosity in Nb EBW	567
	Y. Iwashita, Y. Fuwa, H. Tongu Kyoto ICR, Uji, Kyoto, Japan H. Hayano KEK, Ibaraki, Japan
	Voids have been found in the Nb EBW seams. Since the buried defects cannot be observed by the optical inspections, other techniques have to be applied to study their characteristics such as distributions. X-ray or neutron radiography have been tried for the purpose. The recent results will be presented.

TUP114	XT-map System for Locating SC Cavity Quench Position	747
	H. Tongu, Y. Iwashita Kyoto ICR, Uji, Kyoto, Japan H. Hayano, Y. Yamamoto KEK, Ibaraki, Japan
	XT-map system under development in collaboration between Kyoto University and KEK is a combined system of the temperature mapping (T-map) and X-ray mapping (X-map). High resolution T-map at quench detection will give more information for improving yield in production of high performance SC Cavities. The high-density sensor distribution of the XT-map gives the high resolution. Because the huge amount of sensor lines are multiplexed at a hi-speed scanning rate in the vicinity of the sensors, the small number of signal lines makes the installation process easy and reduces the system complexity. The scanning test of this XT-map system has been performed in the vertical test at KEK. The detected quench events will be reported.

Paper

Title

Page

Vortex Penetration Field in the Multilayered Coating Model

430

T. Kubo, T. Saeki
KEK, Ibaraki, Japan
Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan

A multilayered structure with a single superconductor layer and a single insulator layer deposited on a bulk superconductor is studied. General formulae for the vortex penetration-field of the superconductor layer and the magnetic field on the bulk superconductor which is shielded by the superconductor and insulator layers are derived with a rigorous calculation of the magnetic field attenuation in the multilayered structure. The formulae depend not only on the material and the thickness of the superconductor layer but also on the thickness of the insulator layer. The results can be applied to superconducting accelerating cavities with the multilayered structure. Using the formulae, a combination of the thicknesses of superconductor and insulator layers to enhance the RF breakdown field limits can be found for any given materials. (Submitted on 25 Apr 2013)
T. Kubo, Y. Iwashita and T. Saeki, arXiv:1304.6876 [physics.acc-ph](Submitted on 25 Apr 2013); arXiv:1306.4823 [physics.acc-ph](Proc. of IPAC13); arXiv:1307.0583 [physics.acc-ph](Proc. of SRF2013)

TUP061

Update on Study of Welding Porosity in Nb EBW

567

Y. Iwashita, Y. Fuwa, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan
H. Hayano
KEK, Ibaraki, Japan

Voids have been found in the Nb EBW seams. Since the buried defects cannot be observed by the optical inspections, other techniques have to be applied to study their characteristics such as distributions. X-ray or neutron radiography have been tried for the purpose. The recent results will be presented.

TUP114

XT-map System for Locating SC Cavity Quench Position

747

H. Tongu, Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan
H. Hayano, Y. Yamamoto
KEK, Ibaraki, Japan

XT-map system under development in collaboration between Kyoto University and KEK is a combined system of the temperature mapping (T-map) and X-ray mapping (X-map). High resolution T-map at quench detection will give more information for improving yield in production of high performance SC Cavities. The high-density sensor distribution of the XT-map gives the high resolution. Because the huge amount of sensor lines are multiplexed at a hi-speed scanning rate in the vicinity of the sensors, the small number of signal lines makes the installation process easy and reduces the system complexity. The scanning test of this XT-map system has been performed in the vertical test at KEK. The detected quench events will be reported.