Gravitational Wave Group

Sapphier Test Mass Cooling using Spphire Fiber

Motivation

The only heat path to cool the sapphire test mass is suspension fibers. We investigated that sapphire fibers could be good heat paths, because of its drastic decrease of specific heat around 20[K]. In addition to this, we also investigated the thermal equilibrium between cooling and heating due to power absorption in the test mass.

Experimental setup


Result

The temperature of sapphire test mass was successfully cooled at 4 [K] ,using two wrapping sapphier fibers. The sapphier fibers proved to be a good heat path.The equilibrium temperature was 25 [K], which was low enough to decrease the thermal noise of a interferometer. The thermal distribution was less than 0.8 [K] in the test mass.