The performance of superconducting radio-frequency (SRF) cavities depends on the niobium surface condition. Recently, various heat-treatment methods have been investigated to achieve unprecedented high quality factor (Q) and high accelerating field (E). We report the influence of a new baking process called furnace baking on the Q-E behavior of 1.3 GHz SRF cavities. Furnace baking is performed as the final step of the cavity surface treatment; the cavities are heated in a vacuum furnace for 3 h, followed by high-pressure rinsing and radio-frequency measurement. This method is simpler and potentially more reliable than previously reported heat-treatment methods, and it is therefore, easier to apply to the SRF cavities. We find that the quality factor is increased after furnace baking at temperatures ranging from 300 °C to 400 °C, while strong decreasing the quality factor at high accelerating field is observed after furnace baking at temperatures ranging from 600 °C to 800 °C. We find significant differences in the surface resistance for various processing temperatures.

中文翻译：

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炉内烘烤对超导加速腔QE行为的影响

超导射频 (SRF) 腔的性能取决于铌的表面条件。最近，已经研究了各种热处理方法以实现前所未有的高品质因数 (Q) 和高加速场 (E)。我们报告了一种称为炉烘烤的新烘烤工艺对 1.3 GHz SRF 腔的 QE 行为的影响。炉内烘烤作为型腔表面处理的最后一步；将型腔在真空炉中加热 3 小时，然后进行高压冲洗和射频测量。这种方法比以前报道的热处理方法更简单，可能更可靠，因此更容易应用于 SRF 腔。我们发现在 300 °C 到 400 °C 的温度范围内进行炉烘烤后品质因数增加，而在 600 °C 至 800 °C 的温度范围内进行炉烘烤后，在高加速场下的品质因数会显着降低。我们发现不同加工温度下的表面电阻存在显着差异。