Multi-speckle X-ray photon correlation spectroscopyin the ultra-small-angle X-ray scatteringrange.

Johannes Möller,Yuriy Chushkin,Sylvain Prevost,Theyencheri Narayanan

doi:10.1107/s1600577516008092

Abstract

Multi-speckle X-ray photon correlation spectroscopy (XPCS) measurements in the ultra-small-angle range are performed using a long pinhole collimation instrument in combination with two-dimensional photon-counting and high-sensitivity imaging detectors. The feasibility of the presented setup to measure dynamics on different time and length scales pertinent to colloidal systems is shown. This setup offers new research opportunities, such as for example in the investigation of non-equilibrium dynamics in optically opaque, complex systems over length scales from tens of nanometres to several micrometres. In addition, due to the short duration of the X-ray exposure involved in the ultra-small-angle range, possible radiation-induced effects are alleviated. Furthermore, the performance of two different detectors, a photon-counting Pilatus 300K and an integrating FReLoN CCD, are compared, and their applicability for accurate XPCS measurements is demonstrated.

Highlights

For nearly half a century, complex dynamics and relaxations in various condensed matter systems have been studied by using coherent visible-light scattering techniques, most prominently dynamic light scattering (DLS) (Berne & Pecora, 2000)
X-ray photon correlation spectroscopy (XPCS) has been well established as a technique to probe slow dynamics in complex systems (Grubel et al, 2008; Sutton, 2008; Madsen et al, 2010)
We have demonstrated the feasibility of performing highquality XPCS measurements in the ultra-small-angle X-ray scattering (USAXS) range using a high-resolution pinhole collimation instrument with 1 A X-ray wavelength

Summary

Introduction

For nearly half a century, complex dynamics and relaxations in various condensed matter systems have been studied by using coherent visible-light scattering techniques, most prominently dynamic light scattering (DLS) (Berne & Pecora, 2000). In this method, the dynamics within the material are manifested by the fluctuations in the coherent scattering intensity. The same principle holds when the dynamics are probed by using a coherent X-ray beam This technique is known as X-ray photon correlation spectroscopy (XPCS) (Mainville et al, 1997; Grubel et al, 2008; Sutton, 2008). XPCS has been well established as a technique to probe slow dynamics in complex systems (Grubel et al, 2008; Sutton, 2008; Madsen et al, 2010)

Methods

Results

Conclusion