Search

Abstract: A measurement of the neutrino asymmetry is presented which represents the first search for new physics using polarized radioactive atoms initially cooled and confined in a magneto-optical trap. Optical pumping and photoionization techniques are used to generate and measure, in situ, a highly spin-polarized sample of the short-lived -emitter 37K. The angular distribution of neutrinos from this polarized decay, inferred from the daughter recoil asymmetry, is used to search for a hypothetical current in the weak interaction. We find the ν asymmetry parameter to be , in agreement with the standard model''s purely interaction. [Copyright &y& Elsevier]

Abstract: A compact -ray detecting nuclear magnetic/quadrupole resonance system with a permanent magnet was developed at ISAC/TRIUMF to measure ground-state electromagnetic moments of short-lived nuclei. Polarized Na beams produced using the collinear optical-pumping technique were used to demonstrate the properties of the system. The degree of nuclear polarization and the spin–lattice relaxation times of the 20,21,26,27,28Na isotopes in NaF, TiO2, LiNbO3, MgF2, ZnO, Pt, and Mg single crystals at room temperature are reported. The electric-quadrupole coupling constants of 20,21Na in TiO2, ZnO and Mg, and that of 27Na in ZnO are also reported. The quadrupole moments of 20,21Na were extracted from the electric-quadrupole coupling constants in ZnO, using the known quadrupole moment of 27Na. [Copyright &y& Elsevier]

The polarized beam line at ISAC relies on the well known technique of collinear optical pumping to polarize the nuclear spins of a low energy (10–60 keV) radioactive beam. Alkali-metal beams are longitudinally polarized by optical pumping of a fast atomic beam, which is created by charge exchange of the incident ion beam in a Na vapour cell. At ISAC, the beam is then reionized in a He gas target and directed to the experiments. To date, 30 keV beams of 8Li and 9Li have been polarized, and 11Li and 20Na beams are scheduled immediately following this conference. The polarization of the 8Li beam, using a dual frequency, standing wave Ti:sapphire laser, is up to ∼80%. High polarization is achieved by matching the laser bandwidth to the energy spread in the beam. The status of the facility is reported. [Copyright &y& Elsevier]