ABSTRACT
In the early 1990s, the instruments at the Institut Laue-Langevin (ILL), Grenoble, were out of action due to refurbishment of the reactor. Hence, small-angle neutron scattering (SANS) experiments were moved to the LOQ (low Q) instrument at ISIS, Didcot, UK ISIS is a spallation, or pulsed, source and so time-of-flight instrumentation is used to measure the neutron wavelengths. The standard of the canteen lunches went down when neutron-scattering experiments moved from Grenoble to Didcot, but the LOQ instrument and the new, bigger cells turned out to be perfect for studying the sol-concentration effect in n-butylammonium vermiculite swelling. The neutron-diffraction experiments were done using the LOQ small-angle scattering diffractometer at the ISIS spallation neutron source. The salt fractionation effect has been presented in terms of painstaking experimental results and cold theoretical comparisons. The chapter concludes that establishing a new theory is a bit of a slog, and wild speculation which gives way to cautious progress.
