Data for the extraction of the critical temperature of niobium films deposited on copper produced at CERN for SRF applications

Each data set contains the voltage signal amplitude induced in a pickup coil by an alternating magnetic field, crossing the niobium-film-on-copper sample during its state transition from normal conducting to superconducting, the corresponding sample temperature and the estimated errors for the two measured quantities. File columns: #1 sample temperature in Kelvin, #2 estimated temperature error, #3 voltage amplitude in pickup coil in Volt, #4 estimated amplitude error. One data set corresponds to one sample. The critical temperature can be extracted as fit parameter by fitting the amplitude versus temperature data with a logistic function, where it corresponds to the half height of the state transition curve.每个数据集包含交变磁场在拾取线圈（pickup coil）中感应的电压信号幅值、对应样品温度，以及两项测量量的估计误差；其中该交变磁场在铜基底铌膜样品从正常导电态转变为超导态的过程中穿过该样品。 文件各列信息如下：第1列为以开尔文（Kelvin）为单位的样品温度，第2列为温度估计误差，第3列为拾取线圈中的电压幅值（单位为伏特（Volt）），第4列为幅值估计误差。 一个数据集对应一个样品。 可通过逻辑斯蒂函数（logistic function）对幅值-温度数据进行拟合，将临界温度（critical temperature）作为拟合参数提取得到，该临界温度对应于态转变曲线的半高位置。