Calibration of high order integral diffraction coefficient for X-ray PET flat crystal on the automatic X-ray diffractometer

On the automatic X-ray diffractometer (XRD), based on the stability and precision control of θ and 2θ goniometer, special plane crystal holder was made. Bremsstrahlung and Cu Kβ line are attenuated for 5 orders by 40 μm-thick pure Nickel filter in 15 kilo-voltage and 20 mA supply to X-ray Cu tube, X-ray source of Cu target is to be Cu Kα monochromatic source, transmission coefficient of Nickel filter is the criterion of Cu Kα monochromatic source. For X-ray Pentaerythritol (002) crystal, integral diffraction coefficient of 1-3 order diffraction on Cu Kα energy were calibrated. The results show that the 2nd order and the 3rd order is only 14.36% and 4.07%, the Cu Kα1 intensity ratio of 2nd order and the 3rd order is only 7.7% and 1.3%, comparing the 1st order diffraction. This kind of calibration is efficient and convenient on XRD in common laboratory. (authors)