A fast one coordinate X-ray detector of a new design has been developed at INP for angular measurements in diffraction experiments. The detector is based on a multiwire proportional chamber with an X-ray absorption drift volume. It allows one to accept photons in the energy range of 6 to 20 keV at angles of up to ±15° and a maximum rate of 10 MHz. The coordinate resolution is about 100 μm (r.m.s.) on a linear scale. The first test of the chamber together with its front-end electronics has shown a good performance.