RESUMO
The results of the development of compact radiation module based on a 300 GHz continuous-wave (CW) clinotron are presented. The clinotron oscillator is proposed as a part of the module designated for high-field dynamic nuclear polarization (DNP) systems for applications in nuclear magnetic resonance (NMR) spectroscopy. The simulation results of clinotron radiation spectra considering the influence of accelerating voltage pulsations are compared with the requirements for THz radiation linewidth for efficient NMR signal enhancement. Based on the simulations, the 300 GHz CW clinotron oscillator was developed and tested together with the high-voltage (HV) power supply, providing the output voltage stability better than 20 ppm. The frequency stability of 33 ppm was observed during the clinotron operation within several hours. The spectral linewidth is better than 8 MHz at 300 GHz that satisfies the requirements for DNP-NMR spectroscopy.
RESUMO
We present the first experimental results of the study on a novel second harmonic THz-band double-beam gyrotron. The tube has demonstrated a stable single-mode operation with output parameters that are appropriate for the next-generation 1.2 GHz dynamic nuclear polarization-nuclear magnetic resonance spectroscopy. Besides the design mode (TE8,5), a series of other fundamental and second harmonic modes have been excited. This makes the new gyrotron a versatile radiation source, which can be used also in other applications of the high-power science and technologies.
