Chunlei Li, Andrew Kiss, Alex Garachtchenko, Yuriy Kolotovsky, Kevin Stone, Doug Van Campen, Jeff Corbett

East China University of Science and Technology

Typical x-ray diffraction measurements are made by moving the detector to discrete positions in space and then measuring beam intensity at each stationary position. However, this discrete-step scanning method is time consuming,and may induce vibrations into the measurement system because the motors have to be accelerated and decelerated. Furthermore, information between the data points may be missed unless fine scanning is performed which further increases the total scan time. In order to improve the data acquisition efficiency, improve signal-to-noise ratio, and reduce vibration, an integrated continuous-scan system was developed at Stanford Synchrotron Radiation Light Source (SSRL). The continuous-scan system uses an in-house motor controller with integrated counter/timer, and commercially available signal detection hardware.
The SPEC language was used to control the whole system. The repeatability and efficiency of the continuous-scan system were tested based on a ZnO crystal diffraction experiment, and compared with the step scan technique. Limitations of the continuous-scan system are discussed.