Refractometry of cryogenic condensed medium

Refractometry of cryogenic condensed medium is often impeded due to the limited vacuum cavity of cryodines. In our case the measurement of cryodeposit refraction index on the base of optical mirror placed into the vacuum space of cryodine were made. Solving the problem authors [1] used for the measurement of refraction two-beam interferometric method [2 ). They placed the interferometer into the vacuum cryodine space. Athors [3] placed cooling-down mirror in vacuum only. The rest of the device was situated out of cryodine. Moreover cooling-down mirror was placed in such a way that a structure of cryodepositn could not change. It required an arrangement of mirror deeply in the cavity of cryodine, decreasing of window area and a hole at the cryogenic screen. Refraction index measurement method of cryodeposit was developed and experimentally checked by the cryooptics laboratory of S.I.Vavilov Institute and "Engineering-Physical Laboratory" enterprise