[en] The angle-dispersive neutron powder diffractometer, HRPD, installed at the JRR-3 in Japan Atomic Energy Agency (JAEA), can provide high-resolution data that meet the many users' needs until now. On the other hand, the demand of high-efficiency and high-intensity of measurements is growing in the recent years. However, HRPD is not suitable for high-intensity experiments because fine Soller slit-type collimators in front of detectors are fixed in an angular divergence of 6', so that users cannot choose the appropriate resolution for high-efficient measurements. In order to improve the source intensity of the monochromatic neutron beam, the authors tried to develop asymmetric reflection-type germanium monochromators. According to theoretical considerations, the asymmetric reflection in compression geometry has an effect on spatial condensation of the neutron beam, which leads to the enhancement of the flux density per unit area. We used germanium single crystals as neutron monochromators, introducing the crystal mosaic of 20' in the horizontal direction by hot pressing method. The mosaic crystals were cut at an angle of β=40deg relative to the Ge(3 3 1) reflection planes. The diffraction results of standard powder samples reveal that peak intensities by the asymmetric reflection-type monochromator are improved 1.2 times larger than those by the existing symmetric type one, but integrated intensities are almost comparable each other. For mosaic crystals, asymmetric reflections in compression geometry intensify the current density, but reflectivity is always less than that in symmetric reflections, and thus the suppression of the reflectivity just cancels out the enhancement of the current density. This is the reason why the asymmetric reflection has no practical effect on the beam enhancement. (author)