Magnetic Field Mapping

Abstract

Magnetic field mapping is the production of maps or images of magnetic fields in space. Magnetic field maps are needed for designing and optimizing of magnets used in particle accelerators, spectrometers (mass, nuclear magnetic resonance, and electron paramagnetic resonance), and magnetic resonance imaging systems. Magnetic field maps are also used in geologic exploration where the variations in the magnitude and direction of the earth's magnetic field are indicative of subsurface features and objects. Field mapping relies on various methods of measuring the magnetic field, generally one point at a time. These measurement methods are the main focus of this article. It is curious to note that most measurement methods have remained virtually unchanged for a very long period, but the equipment has been subject to continual development. In this article, only the more commonly used methods are discussed. These methods are complementary and a wide variety of the equipment is readily available from industry. For the many other existing measurement methods, a more complete discussion can be found in two classical bibliographical reviews. Much of the material was presented at the CERN Accelerator School on Measurement and Alignment of Accelerator and Detector Magnets.