Study of the dependence of mechanical losses in silicon disc resonators caused by electric field on the silicon resistivity

Silicon is considered as perspective material for test masses in some projects of future gravitational-wave detectors. Electrostatic actuators are suggested for precise correction of test masses' position. Electric field of actuators will cause additional mechanical loss and corresponding thermal noise of their position, because of finite value of silicon resistivity. The experimental setup developed allows us to investigate this loss in temperature range 100-300 K via a model comprises silicon disc resonator and an electrode plate situated nearby. The dependence of additional mechanical losses induced by electrostatic field on the resistivity of silicon was obtained. These results would be useful while estimating additional losses, arising from action of actuator's electric field on test masses and corresponding noise.