Design, assembly, programming, and testing of triaxially-nested Helmholtz coils, The

Abstract

This thesis entails the full development and testing of tri-axially nested square Helmholtz coils. A novel geometric approach is presented which enables the reader to reduce the overall size of the Helmholtz assembly without sacrificing any volume in the workspace. Included in the Appendix of this thesis are all of the mechanical and electrical drawings and bills of materials required for a full-scale reproduction of this project. There, the reader may also find a complete wiring schematic for the system. A comprehensive set of assembly and wiring instructions are provided. Two adaptations of the Biot-Savart law are developed in this paper which offer a means of calculating the B field, given the position of interest, the coil geometry, and the amount of current passing through the coil. The pseudoinverse is also used to calculate coefficients needed to calibrate the system. The Helmholtz system is capable of producing a field with a homogeneity of approximately 0.75% given a field strength to coil radius ratio of 0.219, exceeding performance criteria for typical Helmholtz coil assemblies. System performance is monitored using a three-axis hall magnetometer, the setup and results of which are presented and used to validate the system geometry and both approximation methods presented. For an outline of the overall system functionality, this paper details the structure of code written for system development and testing. This is accompanied by a discussion of the graphical user interface written for controlling and monitoring system performance.