On-the-fly sample mapping with integrated x-ray diffraction


HPCAT recently developed and commissioned a compact, high precision, high speed sample positioning system.  The core components of the system include four precision DC servomotor stages with encoder resolutions ranging from 50 to 100 nm.  Sample motion profiles are executed by an advanced motion control system that uses real-time positioning feedback for accurate, on-the-fly triggering of external hardware components, viz., imaging detectors and photon counters. Custom control software has been written to enable high-speed, high-resolution sample mapping using x-ray transmission intensity while simultaneously collecting angle-dispersive x-ray diffraction images.  The basic hardware and software control principles have been extended to bring on-the-fly measurement capabilities to existing open-loop stepper assemblies at several HPCAT end-stations.  The recently developed capability enables high-speed, high-resolution sample mapping using x-ray transmission intensity while simultaneously collecting angle-dispersive x-ray diffraction images. The commissioning of this development has been very successful. The new capability is now widely used by users at one of the four stations at HPCAT. We have made components ready to implement similar capabilities in other experimental stations as well, scheduled in early 2016, including the laser heating table in 16-ID-B and 16-BM-D.

Near-future developments will include novel data reduction techniques based on composite x-ray diffraction images from the noise-free Pilatus imaging detector. (key personnel: Jesse Smith, Eric Rod, Stas Sinogeikin)