射频超导腔性能测量平台的设计与实现

Design and Implementation of RF Superconducting Cavity Performance Measurement Platform

摘要:

射频超导腔的无载品质因数Q0和加速梯度Ea是评价腔性能的重要指标。为了得到铌溅射超导腔的性能参数，研制了一套射频超导腔性能测量平台实现Q0和Ea的测量。测量平台由单腔低温柜和超导腔性能测量设备信号源、功率计和数据采集卡组成，其中单腔低温柜由PLC控制真空计、压力传感器、温度传感器和步进电机等设备建立4.2K低温环境；超导腔性能测试程序基于图形化编程语言LabVIEW开发，由计算机远程操作测试过程，通过接受信号源和功率计的USB通讯接口传送的数据以及采集PCI总线上数据采集卡的信号，经过数据处理后实时显示测量值和Q0和Ea的测试结果，并存入数据库随时调用。测量结果表明，测量平台实现了对铌溅射射频超导腔的性能评价，性能参数达到了设计要求。

Abstract:

The unloaded quality factor Q0 and accelerated gradient Ea of RF superconducting cavity are important parameters for evaluating the performance of the cavity. In order to obtain the performance parameters of Nb sputtered superconducting cavity, a RF superconducting cavity performance measurement platform was developed to measure Q0 and Ea. The measurement platform is composed of a single-cavity cryogenic cabinet and a set of superconducting cavity performance measurement equipments such as signal source, power meter and data acquisition card. The single-cavity cryogenic cabinet provides 4.2K cryogenic environment by PLC controlled vacuum gauge, pressure sensor, temperature sensor and stepper motor. The superconducting cavity performance test program is developed based on graphical programming language LabVIEW and computer-operated remote control operation is realized. Through receiving the data transmitted by the USB communication interface of signal source and power meter, and collecting the signal of data acquisition card on PCI bus, the measured values and the test results of Q0 and Ea are displayed promptly after data processing. These data is stored in the database and can invoke them at any time. Result from the test proves that the measurement platform realizes the evaluation of Nb sputtered RF superconducting cavity, and the performance parameters meet the design requirements.