Area detector based photon correlation in the regime of short data batches: Data reduction for dynamic x-ray scattering

Abstract

A method for reducing time sequences of raw scattering images to intensity time-autocorrelation functions is presented. The procedure is based on the use of a charge coupled device ͑CCD͒ area detector, and optimized for operating in the regime of short data batches. Its application to x-ray photon correlation spectroscopy ͑XPCS͒ measurements is described in detail. Using a slow-scan CCD, we explain how to achieve data acquisition on a 30 ms or faster time scale, while simultaneously acquiring data from many coherence areas in parallel. The statistical uncertainties of the acquired XPCS data are quantified experimentally, and compared to the theoretically expected noise levels of the correlation functions.

Beyond simple exponential correlation functions and equilibrium dynamics in x-ray photon correlation spectroscopy

“…In a multi-speckle time-correlation scheme [51,52], the age dependence of the dynamics can be captured by replacing the time-averaged correlation function with a two-time correlation function,…”

Surface and Interface Analyses of Polymer Brushes by Synchrotron Radiation

“…Various detectors have been used and developed. Up to now, considerable numbers of experiments have been conducted with various types of 2D detectors, such as the directly illuminated X-ray CCD, 49) the indirectly illuminated X-ray CCD, 50) and photon counting 2D detectors such as Medipix2 detector, 51) the PILATUS detector 52) and Maxipix detector. 53) The correlation functions mentioned above are taken by homodyne experiments, thus the phase information of the scattered electric fields are lost.…”

Slow dynamics, aging, and glassy rheology in soft and living matter

“…For example, for a dilute suspension of monodisperse colloidal beads with purely diffusive dynamics, f (q, t) ∼ exp( −t τ• ) , where τ • is the characteristic time scale for scatterer diffusion and is related to the self-diffusion coefficient D • according to the formula τ • = (D • q 2 ) −1 . X-ray photon correlation spectroscopy (XPCS) uses synchrotron radiation to probe very high values of q that are inaccessible by PCS methods involving visible light [53,54]. For example, XPCS has been employed in [24] to study the particle scale dynamics in an aging clay suspension, where each particle is a disc approximately 15 nm in radius and 1 nm in thickness.…”