Speaker
Description
Our study of atomic beams passing through a static magnetic field, whose direction reverses along the axis of motion, gave rise to a new, versatile polarization method. For instance, a sinusoidal magnetic field entails a radial component, which is proportional to the gradient in the longitudinal direction. Such a field can be generated by two opposing solenoid coils. As a particle beam travels through the coils, it experiences the static field as an electromagnetic wave in its rest frame. The longitudinal component creates an energy splitting between the atomic hyperfine states and the radial component induces transitions between them. The hyperfine transitions can be described by the absorption of an odd multiple of the corresponding photon energy, so that the total photon energy is equal to the energy splitting between the states. The energy of the photons depends on the relative motion between the particle beam and the magnetic field (for a given wavelength of the sinusoidal field), and the number of the photons rises with increasing magnetic field strength. Therefore, oscillating transition rates are observed while ramping the magnetic field of the apparatus. As a result, it is feasible to achieve a high degree of polarization by adjusting the magnetic field strength. The produced polarization is higher for particles with simple hyperfine structures, e.g., H, D, $^{3}$He$^{+}$, etc. These species are required for the investigation of nuclear fusion with polarized fuel or polarized ion sources for accelerators. First measurements with metastable hydrogen beams will be presented. Furthermore, the applicability of this method to molecular samples (for medical applications) needs to be examined.
