Development of Gyrotron for 300 MHz and 600 MHz DNP-NMR

Dynamic Nuclear Polarization (DNP) could open sensitivity enhancement of Nuclear Magnetic Resonance (NMR) for application of analysis of complicated protein molecules. The so-colled DNP-NMR is well known method in low field and low frequency NMR. However, high frequency DNP-NMR is needed for high spacial resolution of the measurement. We have developed a sub-THz Grotron FU CW VII for 300 MHz and 600 MHz DNP-NMR. The cavity radius is 2.175 mm, length is 19 mm. Designed cavity mode are TE_<421> (f=203.75 GHz)for 300 MHz DNP-NMR and TE_<161> (f=395.28 GHz)for 600 MHz DNP-NMR. The output power are 200 W (I_b = 350 mA) and 50 W (I_b = 200 mA) respectively. In this report, operation results of Gyrotron FU CW VII are presented