Application of magnetic markers for precise measurement of magnetic fieldsin ramped accelerators

For precise measurements of the magnetic field in ramped machines, differen t magnetic markers are in use. The best known are peaking strips, Nuclear M agnetic Resonance (NMR) probes and Electron Spin Resonance (ESR) probes. Th eir operational principles and limitations are explained and some examples of recent and new applications are given. A fuller theoretical description is given of the lesser-known Ferrimagnetic Resonance (FMR) probe and its pr actical application. The essential purpose of these magnetic markers is the in situ calibration of either on-line magnetic field measurements (e.g. vi a a magnetic pick-up coil) or field predictions (e.g. using a magnetic mode l).