A new small-angle X-ray scattering facility utilizing a rotating anode, pin-hole collimation and a position-sensitive proportional counter

A new small-angle X-ray scattering facility which utilizes a 6 kW rotating anode, pin-hole collimation, and a position-sensitive proportional counter has been developed. As presently constructed, the minimum scattering vector κ (= 4π sin θ/2) which can be reached with Cu Kα radiation is 5 × 10⁻³ Å⁻¹. Under these conditions the flux incident on the specimen has been found to be 6 × 10⁵ photons s⁻¹. The system has several advantages compared with traditional long-slit geometries; namely, (i) it can quantitatively measure anisotropic scattering distributions, (ii) it avoids large mathematical corrections of the data for slit-smearing effects, and (iii) it minimizes double Bragg scattering in crystalline materials and multiple diffuse scattering in amorphous or liquid materials. To illustrate the performance of this instrument, the scattering curves obtained from four widely different samples are shown. These are: polyethylene, a neutron-irradiated aluminium single-crystal containing voids, a dilute suspension of Ludox spheres, and duck tendon collagen. Quantitative comparisons of the performance with a Kratky camera and with the neutron small-angle scattering facility in Jülich are given.