[en] The source of ionizing radiation based on relativistic charged particle channeling in a bent crystal is described. With the purpose of increasing the monochromaticity of radiation the monocrystal is realized in two sections with uniform bending of crystallographic planes divided by a controlled gap; each of the planes is oriented in such a manner that the tangent line in the output crystallographic plane of the first section of the crystal coincides with the tangential line to the inlet crystallographic plane of the second section of the crystal. The output collimator is mounted along the direction of this tangent line. The radiation interference results in improvement of monochromaticity and increase of intensity of the generated radiation more than two times. Two variants of sources are described. The spectra of quasi-synchronous radiation of 1 GeV positrons during channeling in the silicon uniformly bent crystal are given