Application of a millimeter wave gyrotron for the pulsed ESR spectroscopy

In order to realize pulsed ESR measurements by using a gyrotron oscillator. 154 GHz gyrotron output had been successfully sliced to intense and short millimeter wave pulses. A quasi-optical transmission system has been developed to be led these short pulses to ESR measurement probe. Preliminary cw-ESR measurements had been successfully performed for DPPH from the room temperature down to the liquid helium temperature by using a MOU-II and VNA.