Speaker
Description
The Virgo gravitational-wave detector is calibrated using two independent methods: the Photon Calibrator (PCal) and Newtonian Calibrator (NCal), that can validate h(t) with an accuracy of ~1% up to 2 kHz. A new independent technique that uses scattered light as a signal for the detector calibration was recently proposed and it is planned to be installed in Virgo for its fifth observing run.
Through this technique, scattered light is injected in the interferometer from the back of the end mirrors, using a scattering element that can be modulated in amplitude and frequency. This method will give an independent validation of h(t) in the range 50 Hz to few kHz with an accuracy of a few percent. The main advantage of this method is the possibility to validate h(t) also in the band 1.5 to 2 kHz, which is within the range of the standard GW data analysis. Furthermore, we will be able to inject a calibration signal in the detector without moving any ITF mirror, which will allow us to highlight systematic errors in the suspension modelisation.
In this talk we will explain the working principles of this method and we will give an update on the status of the project.