LNLS, Campinas, Brazil
CARNAÚBA (Coherent X-ray Nanoprobe) and CATERETÊ (Coherent and Time Resolved Scattering) are the longest beamlines in Sirius - the 4th generation light source at the Brazilian Synchrotron Light Laboratory (LNLS). They comprise Four-Bounce Crystal Monochromators (4CM) for energy selection with strict stability and performance requirements. The motion control architecture implemented for this class of instruments was based on Omron Delta Tau Power Brick LV, controller with PWM amplifier. The 4CM was in-house designed and consists of two channel-cut silicon crystals whose angular position is given by two direct-drive actuators. A linear actuator mounted between the crystals moves a diagnostic device and a mask used to obstruct spurious diffractions and reflections. The system is assembled in an ultra-high vacuum (UHV) chamber onto a motorized granite bench that permits the alignment and the operation with pink-beam. This work details the motion control approach for axes coordination and depicts how the implemented methods led to the achievement of the desired stability, considering the impact of current control, in addition to benchmarking with manufacturer solution.
LNLS, Campinas, Brazil
TARUMÃ is the sub-microprobe station of the CARNAÚBA beamline at Sirius/LNLS*. Covering the range from 2.05 to 15keV, the probe consists of a fully-coherent monochromatic beam varying from 550 to 120nm with flux of up to 1e11ph/s/100mA after the achromatic focusing optics. Hence, positioning requirements span from nanometer-level errors for high-resolution experiments to fast continuous trajectories for high throughput, whereas a large flexibility is required for different sample setups and simultaneous multi-technique X-ray analyses, including tomography. To achieve this, the overall architecture of the station relies on a pragmatic sample positioning solution, with a rotation stage with a range of 220°, coarse stages for sub-micrometer resolution in a range of 20mm in XYZ and a fine piezo stage for nanometer resolution in a range of 0.3mm in XYZ. Typical scans consist of continuous raster 2D trajectories perpendicularly to the beam, over ranges that vary from tens to hundreds of micrometers, with acquisition times in range of milliseconds. Positioning is based on 4th order trajectories and feedforward, triggering includes the multiple detectors and data storage is addressed
* Geraldes, R.R., et al. ’Design and Commissioning of the TARUMÃ Station at the CARNAÚBA Beamline at Sirius/LNLS’ Proc. MEDSI20 (2020).