Applications of an amorphous silicon-based area detector for high-resolution, high-sensitivity and fast time-resolved pair distribution function measurements

Abstract

The application of a large-area (41 × 41 cm, 2048 × 2048 or 1024 × 1024 pixel) high-sensitivity (detective quantum efficiency > 65%) fast-readout (up to 7.5 or 30 Hz) flat-panel detector based on an amorphous silicon array system to the collection of high-energy X-ray scattering data for quantitative pair distribution function (PDF) analysis is evaluated and discussed. Data were collected over a range of exposure times (0.13 s–7 min) for benchmark PDF samples: crystalline nickel metal and amorphous silica (SiO 2 ). The high real-space resolution of the resultant PDFs (with Q max up to ∼40 Å −1 ) and the high quality of fits to data [ R Ni(0.13s) = 10.5%, R Ni(1.3s) = 6.3%] obtained in short measurement times indicate that this detector is well suited to studies of materials disorder. Further applications of the detector to locate weakly scattering H 2 molecules within the porous Prussian blue system, {\rm Mn}^{\rm II}_{\,3}[Co III (CN) 6 ] 2 · x H 2 , and to follow the in situ reduction of Pt IV O 2 to Pt 0 at 30 Hz, confirm the high sensitivity of the detector and demonstrate a new potential for fast time-resolved studies.