High temperature ultrasonic sensor for fission gas characterization in MTR harsh environment O. Gatsa, P. Combette, E. Rozenkrantz, D. Fourmentel, C. Destouches and J.Y. Ferrandis EPJ Web Conf., 170 (2018) 04008 Published online: 10 January 2018 DOI: 10.1051/epjconf/201817004008