Thesis
Magnetometer temperature calibration facility
University of Iowa
Master of Science (MS), University of Iowa
Summer 2023
DOI: 10.25820/etd.006973
Abstract
Fluxgate magnetometers are important tools for space plasma studies, but these instruments are sensitive to temperature changes in their calibrations due to the wide temperature range that be experienced during orbit. It is critical to characterize their calibration over temperature changes prior to flight. However, building a facility that can maintain a stable magnetic and thermal environment is difficult due to temperature sensitivity of magnetic shielding and building materials. A new calibration facility is desired to span the broad range of positive and negative temperatures experienced in space missions, while providing accurate control for test instruments and producing a three-axis vector magnetic field that can be used for calibration.
This temperature testing device was built to accurately calibrate the magnetometers with temperature control for both heating and cooling in the range of -80 to +80 °C. Current calibration methods are limited to an improvised cooling-only system constructed with dry ice. There is a limited number of comparable apparatuses available worldwide, and unlike these similar apparatuses the new facility introduces the additional ability to obtain orthogonality measurements of the relative angles between the three components measured by the magnetometer. The apparatus produces a known and highly stable three-axis magnetic field that is isolated from time-varying external fields that can confound the calibration. A three-layer MuMETAL shield provides this protection from time-varying external fields. A custom-sized Helmholtz coil was designed and built to fit within the shield and generate the necessary magnetic field to which to calibrate the magnetometer. The instrument is housed inside a dewar into which nitrogen is supplied. This insulates the Helmholtz coil and shield from changes in performance that occur when exposed to temperature fluxes. A thermal conditioning unit iv supplies controlled flows of liquid and gaseous nitrogen to the dewar, creating a controlled thermal environment. Additional insulation prevents condensation. The design of the facility was verified using heat transfer analysis and ANSYS simulations. Structural analysis on the Helmholtz coil was performed using CREO Simulate. The multi-layered build allows for the complete three-axis calibration of magnetometers up to 5.5 inches in width within a temperature range of -80 to +80 °C. The facility is currently being built and commissioned for potential use for the TRACERS satellite mission.
Details
- Title: Subtitle
- Magnetometer temperature calibration facility
- Creators
- Kate Morris
- Contributors
- Sharif Rahman (Advisor)David Miles (Committee Member)Justin Garvin (Committee Member)Albert Ratner (Committee Member)
- Resource Type
- Thesis
- Degree Awarded
- Master of Science (MS), University of Iowa
- Degree in
- Mechanical Engineering
- Date degree season
- Summer 2023
- Publisher
- University of Iowa
- DOI
- 10.25820/etd.006973
- Number of pages
- xii, 86 pages
- Copyright
- Copyright 2023 Kate Morris
- Language
- English
- Date submitted
- 06/29/2023
- Description illustrations
- illustrations, tables, graphs
- Description bibliographic
- Includes bibliographical references (pages 73-75).
- Public Abstract (ETD)
- Fluxgate magnetometers are important tools used to study space plasma by measuring the intensity and directions of local magnetic fields. It is critical to understand the changes in their readings with temperature fluxes as their geometries and materials are sensitive to thermal changes which are commonly felt in orbit. However, building this type of facility is difficult because the magnetometer must be under the influence of a known and stable magnetic field while isolated from other confounding external magnetic fields, all while heating and cooling within a broad temperature range. This controlled temperature region must also be insulated to prevent propagation of its thermal effects to temperature-sensitive building and data collection materials.
Current calibration methods are limited to an improvised cooling-only system constructed with dry ice, capping the upper temperature limit at room temperature. A new temperature testing device was built to accurately calibrate the magnetometers with temperature control for both heating and cooling in the range of -80 to +80 °C using controlled nitrogen. The setup is comprised of an insulating test chamber to house the test instrument, a Helmholtz coil to induce a known magnetic field, and an outer shield to prevent external magnetic interference. The facility is currently being built and commissioned for potential use for the TRACERS satellite mission. This calibration aids in studying thermal effects on these instruments and provides corrections against errors introduced by temperature changes to be applied during post-processing.
- Academic Unit
- Mechanical Engineering
- Record Identifier
- 9984454643902771
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