Structure of hard-sphere colloid observed in real space by spin-echo small-angle neutron scattering

Spin-echo small-angle neutron scattering (SESANS) opens a wide range of potential applications. One of them is the study of colloids. Using SESANS we measured the structure of hard-sphere colloidal suspensions at two concentrations. We show that SESANS measures real-space correlations due to the particle shape as well as interactions between them. The dilute suspension showed no correlations exceeding the particle diameter. For a concentrated colloid the effect of the excluded volume is observed as a minimum in correlation function. Experimental correlation functions are compared with theoretical ones for noninteracting spheres and a hard-sphere liquid. The scattering density, volume fraction and the radius of particles are also determined from SESANS correlation function.