A method for rapidly estimating the thickness of nanometer film targets and its application in experiments on generation of picosecond X-ray pulses

A method for rapidly determining the thickness of nanometer dielectric films accurate to $\pm$2-3 nm is suggested. The method is a modification of the ellipsometric method and is based on Brewster angle measurements for light passing through film-substrate systems. The results are used in experiments on effective generation of soft X-rays in dangling superthin films exposed to $10^{16}$ W /cm$^2$ laser pulses.