Subcriticality estimation by extended Kalman filter technique in transient experiment with external neutron source at Kyoto University Critical AssemblyMasao Yamanaka, Kenichi Watanabe and Cheol Ho PyeonEur. Phys. J. Plus, 135 2 (2020) 256DOI: https://doi.org/10.1140/epjp/s13360-020-00270-6