Usage of heterodyne and resonant wavemeter to analyse 4-mm radiation generated at ELMI-device

This paper presents the description of two spectral diagnostics employed to analyse spectral characteristics of powerful 4-mm radiation pulses generated in a planar free electron maser with hybrid resonator at the ELMI-device. To create this diagnostics we have applied heterodyne and resonant wavemeter that give us possibilities to obtain spectrum bandwidth, mode composition and width of single lines in spectrum of generated radiation.