Vacancy-Hydrogen Interaction in Niobium during Low-Temperature Baking

Marc Wenskat; Jakub Cizek; Maciej Oskar Liedke; Maik Butterling; Christopher Bate; Peter Hausild; Eric Hirschmann; Andreas Wagner; Hans Weise

arXiv · 2004.13450

Vacancy-Hydrogen Interaction in Niobium during Low-Temperature Baking

Marc Wenskat·Jakub Cizek·Maciej Oskar Liedke·Maik Butterling·Christopher Bate·Peter Hausild·Eric Hirschmann·Andreas Wagner·Hans Weise

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Abstract

A recently discovered modified low-temperature baking leads to reduced surface losses and an increase of the accelerating gradient of superconducting TESLA shape cavities. We will show that the dynamics of vacancy-hydrogen complexes at low-temperature baking lead to a suppression of lossy nanohydrides at 2\,K and thus a significant enhancement of accelerator performance. Utilizing Doppler broadening Positron Annihilation Spectroscopy, Positron Annihilation Lifetime Spectroscopy and instrumented nanoindentation, samples made from European XFEL niobium sheets were investigated. We studied the evolution of vacancies in bulk samples and in the sub-surface region and their interaction with hydrogen at different temperature levels during {\it in-situ} and {\it ex-situ} annealing.

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Marc Wenskat, Jakub Cizek, Maciej Oskar Liedke, Maik Butterling, Christopher Bate, Peter Hausild, Eric Hirschmann, Andreas Wagner, Hans Weise. 2020-04-28. Vacancy-Hydrogen Interaction in Niobium during Low-Temperature Baking. https://arxiv.org/abs/2004.13450

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