Portable atom interferometry: investigation on magnetic shielding techniques for compact quantum sensors

[摘要] Focus of this thesis are the magnetic shielding aspects of a mobile atom interferometer, developed under the Gravity Gradient Technologies and Opportunities Programme (GGtop). This system has been used as a test bed for new compact technologies with the aim to perform outdoor gravity gradient measurements. A finite element analysis model was used for optimising magnetic shielding design, aiming to reach a field attenuation factor of the order of 103, by mu-metal. The research was extended to alternative shielding techniques with the intention to push current technology towards next generation portable atomic sensors. Initially, Metglas foil was used to create lightweight cylindrical shielding housings. The performance goal was approached by a total of 37 foil wrappings around two coaxial cylinders. However, material inhomogeneities affected the magnetic field uniformity. The second approach exploits additive manufacturing of permalloy-80 for 3D-printing compact shielding structures. Process optimisation was undertaken by fabricating approximately 70 small bulk samples under different printing parameters, while 6 cylindrical shield prototypes were produced for preliminary shielding tests. Application of post heat treatments enhanced shielding effectiveness by a factor of up to ~ 15, indicating that a performance closer to mu-metal could potentially be reached by further process optimisation.

[发布机构] University:University of Birmingham;Department:School of Physics and Astronomy

[关键词] Q Science;QC Physics