Fast 4$\pi$ track reconstruction in nuclear emulsion detectors based on GPU technology

Fast 4$\pi$ solid angle particle track recognition has been a challenge in particle physics for a long time, especially in using nuclear emulsion detectors. The recent advances in computing technology opened the way for its realization. A fast 4$\pi$ solid angle particle track reconstruction based on GPU technology combined with a multithread programming is reported here with a detailed comparison between GPU-based and CPU-based programming. A 60 times faster processing of 3D emulsion detector data, corresponding to processing of 15 cm$^2$ emulsion surface scanned per hour, has been achieved by GPUs with an excellent tracking performance.