Recently, heat treatment in the range of 250 C–500 C has been attempted with the aim of improving the quality factor (Q) of superconducting radio-frequency (SRF) cavities worldwide. Herein, medium-temperature (mid-T) furnace baking experiments were conducted at the Institute of High Energy Physics to obtain higher Q values. First, 1.3 GHz 1-cell cavities received mid-T furnace baking at different temperatures, resulting in not only the improvement of Q but also an anti-Q-slope behavior. Furthermore, mid-T furnace baking was applied to six 1.3 GHz 9-cell cavities, all of which indicated higher Q and anti-Q-slope behavior. The average Q was 3.8 10¹⁰ at 16 MV m⁻¹. The maximum gradients of the 9-cell cavities were 22.7–26.5 MV m⁻¹. Finally, the mid-T furnace baked 1.3 GHz 9-cell cavities were welded with helium vessel, with no degradation in the vertical tests. In addition, the mid-T furnace baking process was simplified in comparison with European X-ray Free Electron Laser and Linear Coherent Light Source because of the cancellation of light electro-polishing. This simplification is beneficial in the mass production of SRF cavities with high Q, which are widely adopted in free electron lasers and high-energy colliders.

最近，已尝试在 250 C-500 C 范围内进行热处理，目的是提高全球超导射频 (SRF) 腔的品质因数 ( Q )。在此，高能物理研究所进行了中温（mid-T）炉烘烤实验，以获得更高的Q值。首先，1.3 GHz 1 单元腔在不同温度下接受中 T 炉烘烤，不仅导致Q的提高，而且还具有抗Q斜率行为。此外，中 T 炉烘烤应用于六个 1.3 GHz 9 电池腔，所有这些都显示出更高的Q和反Q斜率行为。平均Q为 3.8 10¹⁰在 16 MV m ^-1。9 单元腔的最大梯度为 22.7-26.5 MV m ^-1。最后，中 T 炉烘烤的 1.3 GHz 9 单元腔与氦容器焊接，在垂直测试中没有退化。此外，由于取消了光电抛光，中T炉烘烤工艺与欧洲X射线自由电子激光器和线性相干光源相比得到了简化。这种简化有利于大规模生产高Q 值的 SRF 腔，这些腔被广泛用于自由电子激光器和高能对撞机。