Event Title

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

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Apr 22nd, 8:50 AM Apr 22nd, 9:05 AM

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