A novel parafocusing X-ray diffractometer operates by irradiating a thin ring of fine crystals with a point source of monochromatic X-rays and passing the cone of diffracted X-rays at each focal point through a pinhole to an X-ray sensor, thereby obtaining optimum values for both line intensity and resolution...http://www.google.es/patents/US4247771?utm_source=gb-gplus-sharePatente US4247771 - Parafocusing diffractometer
