Also, during a test series, scientists often need to quickly preselect samples with 2 meV resolution for more detailed tests at a very high energy resolution of 0.5 meV. This requires fast exchange of the monochromators with precise readjustment of the Bragg angle and the tilt angle of all four crystals.
To adjust the Bragg angle and the tilt angle of the crystals, they must be moved and positioned with high precision. Excellent long‑term stability and repeatability are also essential, while the space available for the positioning systems is very limited.
Positioning stages based on PiezoWalk drive technology show a number of advantages over conventional drive mechanisms. The closed-loop, self-clamping design provides the long-term stability required and the piezo effect delivers the resolution. Capacitive position feedback is used to close the loop with the motion controller. Long‑term repeatability of well under 0.1 µrad is achieved while the volume of the positioning stage is 95x78x32mm remains extremely compact.
NEXLINE piezo drives were originally developed for the semiconductor industry with extreme reliability and stability in mind. The technology is very mature and was selected for a Technology Innovation Showcase award by SEMI in 2005.