X-Ray Scattering Studies of Critical Opalescence in Argon at Constant Density

Small-angle x-ray scattering techniques have been used to investigate the temperature dependence of the isothermal compressibility of argon at its critical density for temperatures in the critical region and above the critical temperature. The coexistence curve and the long-range correlation length have also been studied. Within experimental uncertainty the results are in agreement with the scaling laws.