Fourier-analyzing coil arrays for pulsed relativistic electron beam experiments

Arrays of flux detection coils can be used in pulsed relativistic electron beam experiments to Fourier analyze in azimuth the magnetic fields resulting from beam or net currents. In propagation experiments using the beam generated with the IBEX accelerator the displacement perturbations of the initially injected beam were determined using arrays sensitive to the first azimuthal harmonic of the azimuthal magnetic field. These arrays were found to be capable of easily resolving 120-MHz oscillations of the beam centroid with amplitude less than 0.1 mm.