21-25 July 2019
Connecticut Convention Center, Level 6
US/Eastern timezone

M3Or1C-01 [Invited]: Direct observation of nanometer scale niobium hydride (Nb1-xHx) on SRF Nb cavity surface using cryogenic atomic force microscopy (AFM)

24 Jul 2019, 09:30
30m
Level 6, Room 15-16

Level 6, Room 15-16

Speaker

Dr Zuhawn Sung (Fermi National Accelerator Laboratory)

Description

Cryogenic atomic force microscopy (AFM) allowed us to directly observe segregation morphology of nanometer size hydride phases (Nb1-xHx), which are responsible for Q degradation of superconducting radio frequency (SRF) Nb cavity at high RF field regime. Although niobium hydride has been recognized with cry-optical microscopy, electron diffraction or ion mass spectroscopy, identification of nm-scale Nb hydride segregation in terms of saturation temperature has never been accomplished due to difficulties on direct observation at cryogenic temperature. In this study, we address the first direct observation of nanometer size hydride segregation on the surface of superconducting RF niobium cavities as a function of cooling temperature, and quantitively compare its segregation morphology with respect to state of art cavity treatments.

Primary author

Dr Zuhawn Sung (Fermi National Accelerator Laboratory)

Co-authors

Dr Alexander Romanenko Dr Anna Grassellino (Fermi National Accelerator Laboratory) Daniel Bafia (Illinois Institute of Technology)

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