Online perception on the performance of YBCO tapes via intelligent video-aided PLD system

Second generation HTS tape has entered the stage of mass production. The biggest bottleneck in stable production and consistently high-quality superconducting coatings lies in the control of deposition temperature during superconducting coatings. It is very challenging to effectively monitor the temperature in the dynamic process of roll-to-roll coating. Through observation, it is found that the color of superconducting surface is very sensitive to the change of coating temperature. In this study, a real-time video analysis technology has been developed to obtain the grayness scale of the surface of the superconducting layer during coating. The relationship between grayness scale, temperature and the final critical current of superconducting tape has been established through short sample experiments. These relationships are also clearly demonstrated in the long tape production process, which can significantly detect any abnormal trends of tape products by capturing the surface temperatures through grayness scale. The region of interest was tracked, by dividing it into three parts and calculating the average grayness level of each part. The results obtained can be used to determine PLD temperature setting and provide a reference for the subsequent slitting of superconducting tapes. This work also provides a potential quality improvement technique for superconducting tape production.