Speaker
Description
The sensitivity of gravitational wave (GW) detectors is constrained by various sources of
noise. Quantum noise pervades the entire frequency band of the current detectors (10
Hz - 10 kHz), while magnetic noise will significantly constrain the sensitivity of future
GW detectors, such as the Einstein Telescope (ET), especially at low frequencies (a few
Hz to around 100 Hz).
This poster highlights strategies to mitigate magnetic noise, including emission
reduction from critical sources and shielding sensitive coupling locations. Additionally, it
presents a thorough examination of phase noise causes, employing software
simulations to identify methods for addressing these issues in future detectors such as
the ET.
In particular, quantum noise manifests in fluctuations in phase (shot-noise) and in
amplitude (radiation-pressure noise), in accordance with Heisenberg's Uncertainty
Principle. One approach to reduce quantum noise is injecting squeezed light states into
the dark port of the interferometer, although degradation can occur due to losses and
phase noise. Phase noise can be generated by both the squeezing system and the
interferometer itself.
Magnetic noise results from coupling of environmental fields with magnetized elements,
such as magnet-coil actuators and Faraday isolators. Sources of environmental fields
include the natural background associated with Schumann Resonances, on the order of
pT/sqrt(Hz), and “self-inflicted” noise. The latter involves any device carrying an electric
current, such as power grid cables, motors, pumps or conductive materials, which are
part of the detector infrastructure. Ambient magnetic fields exert forces on permanent
magnets or ferromagnetic materials, creating field gradients and induced currents in
sensitive electronics and within conductive objects, thereby amplifying the field
gradients. Leveraging experience from Virgo and KAGRA, efforts have been made to
identify the contributors to magnetic noise, aiming to optimize them in the future ET
infrastructure.
| Role of Submitter | I am the presenter |
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