铜铌溅射型低β超导腔的研制及初步实验

Researches and Preliminary Experiments on Copper-Niobium Sputtered Low-β Superconducting Resonator

超导谐振腔是超导加速器的关键部件 .用于重离子超导加速器的低β加速腔的最佳选择是四分之一波长谐振腔 (QWR) .目前 ,利用无氧铜为基底 ,溅射一层几微米厚的铌膜 ,可以获得极好的超导性能和加速离子性能 .但是 ,四分之一波长谐振腔的内表面复杂 ,溅射均匀的铌膜比较困难 .针对此难题 ,发展了一种多参数可调节的溅射方法 ,在 64 0×2 2 0的大型腔体内 ,成功地生成了一层均匀的、超导性能优异的铌膜 .超导腔的低温实验表明铌膜的性能良好 .

Superconducting resonator is the important component of a superconducting accelerator. The best choice of the acceleration cavity for heavy ion superconducting accelerator is quarter wave resonator (QWR). By sputtering a layer of niobium films of several microns on the OFHC copper substrate, good superconducting properties and acceleration properties of the cavity can be obtained. However, it is very difficult to get uniform niobium films by sputtering because the inner surface of the QWR is complicated. To deal with this problem, we developed a multiparameter adjusting method to control the sputtering process of different parts of the QWR. A layer of uniform niobium film with nice superconducting performance is obtained. The low temperature experiments with liquid helium show that the Cu Nb QWR has good superconducting characters. The Q value of the cavity is about 5×10 8.