The Initial State of Optically Polarized 8Li+ from the β-NMR in Bismuth

[摘要] Unlike the positive muon, β-NMR probe nuclei must be actively polarized. At the TRIUMF ISAC facility this is accomplished by in-flight collinear optical pumping with resonant circularly polarized laser light. This reliably produces a high degree of polarization, but the detailed state populations in the beam emerging from the optical polarizer are not well known. These populations are significant as they represent the initial state of the ensemble of probe spins implanted in a β-NMR experiment. Here we use the well-resolved quadrupolar split spectrum of8Li+in a high purity single crystal of bismuth to extract the sublevel populations under typical polarizer operating conditions, accounting for the spin relaxation in this semimetal.

[发布机构] Chemistry Department, University of British Columbia, Vancouver; BC; V6T 1Z1, Canada^1;TRIUMF, Vancouver; BC; V6T 2A3, Canada^2;Department of Physics, University of British Columbia, Vancouver; BC; V6T 1Z1, Canada^3;Department of Physics, University of Alberta, Edmonton; AB; T6G 2E1, Canada^4;Department of Physics and Astrophysics, University of Delhi, Delhi; 110007, India^5

[关键词] Circularly polarized lasers;Degree of polarization;NMR experiments;Operating condition;Optical polarizers;Positive muons;Spin relaxation;State population