Title: CRYSTAL OPTICAL METHOD FOR TEMPERATURE MEASURING
Author(s): M.O.Romanyuk, B.Andriyevsky (The Ivan Franko National University of Lviv, 8 Kyryla i Mefodiya Str., 79005 Lviv, Ukraine), O.Kostetsky (Lviv State Agrarian University, 80381 Dublyany, Ukraine), M.M.Romanyuk (The National University ``Lviv Politekhnika'', 12 Stepana Bandery Str., 79013 Lviv, Ukraine), V.Stadnyk (The Ivan Franko National University of Lviv, 8 Kyryla i Mefodiya Str., 79005 Lviv, Ukraine)

A new crystal optical method for temperature measuring based on the sign inversion of birefringence $\Delta n$ and temperature dependence of $\Delta n (T)$ is substantiated. The respective characteristics of some crystals are presented, which confirm good metrological and exploitation properties of the method. It is noted that the method solves some problems which arise in thermometry based on thermoelectricity and thermoresistance. The proposed method also gives better possibilities for measuring the temperature in hard conditions (in the region of high electric and magnetic fields, rotating workpieces etc.).

Key words: temperature, inversion of birefringence sign, scale of temperature
PACS: 78.20.Nv, 07.20.Dt