Abstract: As a technique for enhancing the output from an X-ray source, poly-capillary parallel beams can be used to increase the count rate so effectively over a certain range that the same efficiency can be obtained as with a rotor target X-ray diffractometer. Furthermore, the results measured via parallel beam irradiation is insensitive to the sample position, and symmetrical peaks may be easily obtained over the entire angular range. Due to these advantages certain problems that occurr frequently in traditional X-ray diffractometry may be solved by using poly-capillary parallel beams.