STEP卫星加速度计测量头线圈的超导特性测试及改进

Test of superconductivity of pick-up coils for STEP accelerometer and their modification

为确保STEP卫星超高精度加速度计的测量头线圈三维超导膜在设计的工作电流范围内完全超导,以实现10-18g精度的加速度测量,对测量头线圈进行了低温超导测试,测试证明三维超导膜存在不完全超导缺陷。利用分段测试法对三维膜线圈的二维组成部分进行了测试,确定了测量头线圈超导缺陷的位置,并分析了造成超导缺陷的原因。根据测试和分析结果改进了线圈设计,实现了测量头线圈的完全超导,并标定线圈的最大工作电流为-40～40mA,满足STEP卫星加速度计对超导电流要求的-10～10mA,设计裕度达到300%。通过测试、分析与改进设计,定型了STEP卫星超高精度加速度计测量头线圈的研制,为完成STEP任务奠定了技术基础。同时,实现了三维超导膜线圈的制造与工程应用。

To ensure the fully superconductivity of a 3D superconducting film in the range of working current required by an accelerometer in the STEP mission and to realize the acceleration measurement in an accuracy of 10^-18 g, the cryo superconductivity of pick-up coils was tested by several experiments. Tested results show that there are uperconductivity failures in the 3D film coils. A subsection method was used to test the 2D composition of the 3D film coils separately, by which the locations of superconductivity failures were determined and the reasons why the failures were happened were obtained. Finally, the method to improve the coil design was presented. After modification according to the method, the film coils have turned to be fully superconducting and their allowable superconducting currents are demarcated from -40 mA to 40 mA. With a 300% margin, they satisfy the requirement of the STEP mission for the working current range from -10 mA to 10 mA. Through the test, analysis and modification, the design and manufacture of pick-up coils are finalized, which lays the technical foundation for STEP mission, and completes engineering applications of 3-D superconducting film coils.