レイリー散乱を用いたパルス管内温度計測法の検討

抄録

Temperature measurement in a pulse tube is important to understand the gas behavior in particular. However, it has not been measured with few exceptions. In this paper, we propose temperature measurement in a pulse tube with Rayleigh scattering. Rayleigh scattering is elastic scattering of light quanta from molecules or small particles. The gas temperature can be calculated from Rayleigh-scattering light if the gas behaves according to the ideal gas law and the pressure of the gas is known. This method has the following advantages: (1) Temperature is measured without disturbing the flow in the pulse tube; (2) there is little time delay for measurement; and (3) a two-dimensional temperature image is presented. The disadvantages are: (1) Stray light interferences cause some errors in measurement; and (2) an excimer laser is needed. We installed an experimental system in a clean room and measured Rayleigh-scattering light using a CCD camera. A new energy-monitoring method contributed to improvement in measurement precision. We demonstrated that the temperature under static pressure conditions can be measured with a standard deviation of less than 1.7%. Furthermore temperature measurement under a steady flow with a thermocouple agrees approximately with that measured by Rayleigh scattering. Moreover, it was demonstrated that the temperature can be measured under oscillating pressure conditions.