Progress in the development of low-voltage gyrotron for integration with NMR spectrometerV.L. Bratman, A.E. Fedotov, Yu. K. Kalynov, V.N. Manuilov and I.V. OsharinEPJ Web Conf., 149 (2017) 04039DOI: https://doi.org/10.1051/epjconf/201714904039