ARIADNE: A Technique to Model Superconducting and Mu-metal Magnetic Shielding
Session Number
Project ID: PHYS 14
Advisor(s)
Andrew Geraci; Northwestern University
Nancy Aggarwal; Northwestern University
Chloe Lohmeyer; Northwestern University
Discipline
Physical Science
Start Date
22-4-2020 8:50 AM
End Date
22-4-2020 9:05 AM
Abstract
The Axion Resonant InterAction Detection Experiment (ARIADNE) searches for the axion, a theoretical particle arising from Charge-conjugation & Parity symmetry violation. To do so it mediates a spin-dependent force extending beyond the standard model. ARIADNE uses nuclear magnetic resonance to detect an axion exerting a spin-dependent force in a cryostat between a sample of laser-polarized 3Helium nuclei and a rotating tungsten source mass. If the axion is present and acting as a fictitious magnetic field, a transverse magnetization may be detected. To do so, incredible precision must go toward shielding background magnetic noise, requiring superconducting shielding around the sample cell and possibly µmetal shielding around the motor rotating the mass. My work evaluates the shielding effect of a µmetal box around the motor by using Comsol Multiphysics to determine the way it alters the magnetic flux and gradients in a uniform magnetic field. The gradients at a critical position were calculated below 20 μTesla/cm, signaling that 3He must be pumped down quickly to avoid depolarization. A second set of models found that the superconducting shield around the sample cell distorted the field at critical areas. My calculations for the gradients around this shield provide constraints on the experimental project
ARIADNE: A Technique to Model Superconducting and Mu-metal Magnetic Shielding
The Axion Resonant InterAction Detection Experiment (ARIADNE) searches for the axion, a theoretical particle arising from Charge-conjugation & Parity symmetry violation. To do so it mediates a spin-dependent force extending beyond the standard model. ARIADNE uses nuclear magnetic resonance to detect an axion exerting a spin-dependent force in a cryostat between a sample of laser-polarized 3Helium nuclei and a rotating tungsten source mass. If the axion is present and acting as a fictitious magnetic field, a transverse magnetization may be detected. To do so, incredible precision must go toward shielding background magnetic noise, requiring superconducting shielding around the sample cell and possibly µmetal shielding around the motor rotating the mass. My work evaluates the shielding effect of a µmetal box around the motor by using Comsol Multiphysics to determine the way it alters the magnetic flux and gradients in a uniform magnetic field. The gradients at a critical position were calculated below 20 μTesla/cm, signaling that 3He must be pumped down quickly to avoid depolarization. A second set of models found that the superconducting shield around the sample cell distorted the field at critical areas. My calculations for the gradients around this shield provide constraints on the experimental project