Noise Reduction in the Low-Frequency LIGO Detectors
Faculty Mentor Name
Michele Zanolin, Joshua Freed
Format Preference
Poster
Abstract
The U.S. National Science Foundation Laser Interferometer Gravitational-Wave Observatory (NSF LIGO) was the first to detect gravitational waves, back in 2015. By increasing the sensitivity in the detectors, scientists can observe more gravitational waves, and of various types; however, increasing the sensitivity also makes the equipment more susceptible to detecting external noise, which interferes with the results. For that reason, the objective of this research project is to reduce the noise in the LIGO detectors while maintaining their high sensitivity. We are especially interested in low-frequency range gravitational waves (below 10Hz). This band is the frequency band where our group's interest, the core collapse supernovae memory, is prominent.
In place of the LIGO quadruple pendulum, we are using a Cavendish torsional pendulum. A laser that can periodically be switched on and off is used to apply a small force caused by radiation pressure to one side of the pendulum. By varying the period that the laser is applied to our pendulum, the pendulum's natural frequency can be determined. The natural frequency is then used to add control systems to further alter the behavior of the pendulum. This portion of the project aims to use software, specifically MATLAB and Simulink, to develop a virtual model of the system that can be used to test different system configurations and control architecture. The virtual model will be used to find the constraints of the system (such as the allowable time delay), as well as help determine the physical characteristics of the physical pendulum control architecture (such as the moment arms for the auxiliary mirrors). When we have installed the control systems in our model successfully, we will replace the torsional pendulum we are currently using with alternative designs to determine which ones give us the optimal performance in the low-frequency range.
Noise Reduction in the Low-Frequency LIGO Detectors
The U.S. National Science Foundation Laser Interferometer Gravitational-Wave Observatory (NSF LIGO) was the first to detect gravitational waves, back in 2015. By increasing the sensitivity in the detectors, scientists can observe more gravitational waves, and of various types; however, increasing the sensitivity also makes the equipment more susceptible to detecting external noise, which interferes with the results. For that reason, the objective of this research project is to reduce the noise in the LIGO detectors while maintaining their high sensitivity. We are especially interested in low-frequency range gravitational waves (below 10Hz). This band is the frequency band where our group's interest, the core collapse supernovae memory, is prominent.
In place of the LIGO quadruple pendulum, we are using a Cavendish torsional pendulum. A laser that can periodically be switched on and off is used to apply a small force caused by radiation pressure to one side of the pendulum. By varying the period that the laser is applied to our pendulum, the pendulum's natural frequency can be determined. The natural frequency is then used to add control systems to further alter the behavior of the pendulum. This portion of the project aims to use software, specifically MATLAB and Simulink, to develop a virtual model of the system that can be used to test different system configurations and control architecture. The virtual model will be used to find the constraints of the system (such as the allowable time delay), as well as help determine the physical characteristics of the physical pendulum control architecture (such as the moment arms for the auxiliary mirrors). When we have installed the control systems in our model successfully, we will replace the torsional pendulum we are currently using with alternative designs to determine which ones give us the optimal performance in the low-frequency range.