  For thermal noise considerations of LIGO suspensions, the sources of
dissipation in the suspending fibers must be analyzed. To determine the
dissipation induced by the surface of fused silica fibers, we measured the
quality factor of fibers having various diameters. We measured a maximum
quality factor of 21 million and extrapolated to obtain an intrinsic quality
factor for fused silica of 30 million. Dissipation in the surface dominated at
diameters less than about 1 mm. We developed a method for characterizing
surface-induced dissipation that is independent of sample geometry or mode
shape.
