上海光源500MHz超导腔水平测试

上海光源是能量为3.5 GeV的第三代先进中能同步辐射光源，其储存环上安装了三台超导高频腔补偿电子因同步辐射等原因丢失的能量。为保障上海光源的长期稳定高效运行，中国科学院上海应用物理研究所和上海市低温超导高频腔技术重点实验室共同研制了具备低高次模损失参数和可承受更高入射功率的新型500 MHz超导腔，作为上海光源在线运行超导高频腔的备用腔。超导铌腔经低温垂直测试达到所需加速性能后，需要与高功率输入耦合器、高次模吸收器、低温恒温器等集成并完成水平测试，获得超导腔模组的加速性能、低温性能和真空性能。介绍了超导腔备用腔的研制、集成和测试过程，采用文丘里(Venturi)校准法获得模组的静态功耗反应模组的低温性能，并通过高功率测试获得了超导腔备用腔模组的加速性能。测试结果表明:自主研制的500 MHz超导腔备用腔满足上海光源的工作需求，在超导腔的加速腔压为2.0 MV时，无载品质因数为1.2×109 @4.2 K，且低温模组的静态热损耗为36.1 W。

Horizontal test of 500 MHz superconducting cavity for SSRF

The Shanghai Synchrotron Radiation Facility (SSRF) is a third-generation synchrotron radiation source with an energy of 3.5 GeV. The superconducting radio frequency cavities have been used to compensate the energy dissipation during synchrotron radiation. A 500 MHz superconducting niobium cavity which adopts the one side fluted beam pipe for higher order modes propagation has been developed to provide support for the operation of SSRF. To make sure this superconducting cavity can be used as a substitution in SSRF, it is necessary to complete the horizontal test after the vertical test was completed successfully. The cavity have been assembled into the cryogenic module with high-power input couplers, high-order mode absorbers, etc.This paper presents the development and installation process of horizontal test module. The high power test of the superconducting cavity have been performed and the static heat loss of the superconducting cavity cryogenic module have been calculated by Venturi tube calibration method. The results show that the performance of 500 MHz superconducting cavity developed by Shanghai Institute of Applied Physics exceeds the working needs of SSRF. When the cavity accelerating voltage of the superconducting cavity is up to 2 MV, the unloaded quality factor Q₀ is 1.2×109 at 4.2 K, and the static loss power of the cryogenic module is 36.1 W. The horizontal test for the 500MHz superconducting cavity have been completed in Shanghai Institute of Applied Physics (SINAP).