Speaker
Description
Calculation of thermoelastic noise in the suspension fiber in the vertical direction is not only a good exercise to use fluctuation-dissipation theorem in a 1-dimensional solid but also an interesting platform to consider an influence of heat flow at the boundaries. In KAGRA or ET-LF, the heat from the laser absorbed by the test mass is transferred via the suspension fiber. The fiber temperature is not uniform, and the heat flow at the top and bottom ends of fiber is apparently non-zero. In LIGO or Virgo, with monolithic silica fibers, the fiber temperature is uniform, but the heat flow at the ends can be non-zero. In NEMO or Voyager, the both ends of the fiber is to be thermally insulated if the fiber temperature needs to be uniformly 120K. We perform the calculation with the different boundary conditions and compare the results.