Muon Spin Echoes

Jess H. Brewer

Canadian Inst. for Advanced Research
and Dept. of Physics & Astronomy,
Univ. of British Columbia, Vancouver, BC, Canada V6T 1Z1

This page is under construction at     /~jess/musr/
  Muons which are initially longitudinally polarized can be rotated into the transverse plane by a burst of RF power at their resonant frequency. To do this at a continuous beam facility like TRIUMF required asynchronously triggered phase-locked RF amplification (every muon gets its own pulse).
At still higher RF power one can reverse the spins by 180o after they have lost all phase coherence due to random local fields, so that the original polarization returns (the ``direct echo'') after an equal time interval. In a simple spin system like the FµF complex, one can also use an RF pulse at the resonant frequency of the other spins (in this case 19F) to ``refocus'' the muon polarization (the ``indirect echo'').

Jess H. Brewer
Last modified: Fri Aug 14 15:09:06 PDT 1998