title: Continuous-scan capability at SSRL and applications to X-ray diffraction.
abstract: Typical X-ray diffraction measurements are made by moving a detector to discrete positions in space and then measuring the signal at each stationary position. This step-scanning method can be time-consuming, and may induce vibrations in the measurement system when the motors are accelerated and decelerated at each position. Furthermore, diffraction information between the data points may be missed unless a fine step-scanning is used, which further increases the total measurement time. To utilize beam time efficiently, the motor acceleration and deceleration time should be minimized, and the signal-to-noise ratio should be maximized. To accomplish this, an integrated continuous-scan system was developed at the Stanford Synchrotron Radiation Lightsource (SSRL). The continuous-scan system uses an in-house integrated motor controller system and counter/timer electronics. SPEC software is used to control both the hardware and data acquisition systems. The time efficiency and repeatability of the continuous-scan system were tested using X-ray diffraction from a ZnO powder and compared with the step-scan technique. Advantages and limitations of the continuous-scan system and a demonstration of variable-velocity continuous scan are discussed.
authors.affiliation: East China University of Science and Technology, Shanghai, People's Republic of China.
authors.forename: Chunlei
authors.initials: C
authors.lastname: Li
authors.affiliation: SLAC National Accelerator Laboratory, Menlo Park, CA, USA.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Kiss
authors.affiliation: SLAC National Accelerator Laboratory, Menlo Park, CA, USA.
authors.forename: Douglas G
authors.initials: DG
authors.lastname: Van Campen
authors.affiliation: SLAC National Accelerator Laboratory, Menlo Park, CA, USA.
authors.forename: Alex
authors.initials: A
authors.lastname: Garachtchenko
authors.affiliation: SLAC National Accelerator Laboratory, Menlo Park, CA, USA.
authors.forename: Yuriy
authors.initials: Y
authors.lastname: Kolotovsky
authors.affiliation: SLAC National Accelerator Laboratory, Menlo Park, CA, USA.
authors.forename: Kevin
authors.initials: K
authors.lastname: Stone
authors.affiliation: Donghua University, Shanghai, People's Republic of China.
authors.forename: Yahong
authors.initials: Y
authors.lastname: Xu
authors.affiliation: East China University of Science and Technology, Shanghai, People's Republic of China.
authors.forename: Wenjun
authors.initials: W
authors.lastname: Zhang
authors.affiliation: SLAC National Accelerator Laboratory, Menlo Park, CA, USA.
authors.forename: Jeff
authors.initials: J
authors.lastname: Corbett
keywords: X-ray diffraction; continuous scan; efficiency; step scan