RF resonance techniques for continuous muon beams

Abstract

RF excitation was first used in μSR in 1958 [1]. However, even with the advent of modern meson facilities the use of RF techniques in μSR has not flourished, in part due to the muon's short lifetime, but mainly because unlike NMR RF fields are simply not used to detect the muon's polarization. Nevertheless, a cursory survey of the relative power and sophistication of these two related fields leaves little doubt that the pursuit of RF resonance within μSR will add significantly to its analytical capability. At TRIUMF over the past few years we have worked toward developing RF capabilities suitable for use in a CW meson facility. Several spectroscopic applications utilizing time integral techniques have been tested. These include detection of final states in semiconductor and substituted radical systems, the very pretty two photon absorption (TPA) experiments, and the use of low field swept frequency excitation to measure nuclear hyperfine parameters in Mu like system. Of course, the most celebrated use of RF in magnetic resonance is its application to spin dynamics via various spin echo techniques. The adaptation of the spin echo to μSR is discussed and examples of both transverse and longitudinal field echoes are presented.