How High a Field Can Be and Has Been Achieved in Superconducting Bulk Niobium Cavities Across Different RRR Values?

Fuente: arXiv
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Autore principale: Kubo, Takayuki
Natura: Preprint
Pubblicazione: 2024
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author Kubo, Takayuki
author_facet Kubo, Takayuki
contents This Brief Note explores the relationship between residual resistivity ratio (RRR) and the maximum surface magnetic field in superconducting bulk niobium (Nb) cavities. Data from the 1980s to 2020s, covering RRR values from 30 to 500, are compared with theoretical performance limits, including the lower critical field (Bc1), superheating field (Bsh), and thermal runaway field (Brun). The results show that modern Nb cavities are approaching Brun and the metastability region above Bc1 across the entire RRR range but remain below the fundamental limit at Bsh. Achieving Bsh requires not only advanced high-gradient surface processing but also improved thermal stability with low surface resistance, ultra-pure Nb, and optimized Kapitza conductance to ensure Brun > Bsh.
format Preprint
id arxiv_https___arxiv_org_abs_2410_18365
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle How High a Field Can Be and Has Been Achieved in Superconducting Bulk Niobium Cavities Across Different RRR Values?
Kubo, Takayuki
Superconductivity
Accelerator Physics
Quantum Physics
This Brief Note explores the relationship between residual resistivity ratio (RRR) and the maximum surface magnetic field in superconducting bulk niobium (Nb) cavities. Data from the 1980s to 2020s, covering RRR values from 30 to 500, are compared with theoretical performance limits, including the lower critical field (Bc1), superheating field (Bsh), and thermal runaway field (Brun). The results show that modern Nb cavities are approaching Brun and the metastability region above Bc1 across the entire RRR range but remain below the fundamental limit at Bsh. Achieving Bsh requires not only advanced high-gradient surface processing but also improved thermal stability with low surface resistance, ultra-pure Nb, and optimized Kapitza conductance to ensure Brun > Bsh.
title How High a Field Can Be and Has Been Achieved in Superconducting Bulk Niobium Cavities Across Different RRR Values?
topic Superconductivity
Accelerator Physics
Quantum Physics
url https://arxiv.org/abs/2410.18365