Since the heat links are mechanical

Since the heat links are mechanically connected to the cryostat, which is firmly fixed to the ground, extra vibration from the cryostat is introduced to the suspension system through the heat links. Although the heat links are loosely connected so that they do not provide much DC stiffness, the vibration transmissivity is enhanced at high frequencies by the internal resonances of the wires. Figure 4.16 shows the calculated vibration transmissivity of an aluminum wire configured in a semi-ellipsoidal shape, assuming that the wire is attached to a 50-kg mass. The resonant peaks appearing above 4 Hz affect the transmissivity and result in 10 −3 -10 −4 vibration transmission in the detection band of gravitational waves.