EN
We present the possibility of using magnetic field to enhance responsivity and to tune spectral range of far-infrared InSb detector (based on photoconductivity effect) beyond its standard range limited to about 30 cm^{-1}. We show that due to cyclotron resonance assisted transitions we can use it as a tunable detector working up to energies about 180 cm^{-1} (22 meV). We have used such a detector as a spectrometer for measurements of the Landau emission from GaAs emitter.