Polarization and relaxation of radon

Investigations of the polarization and relaxation of $^{209}$Rn by spin exchange with laser optically pumped rubidium are reported. On the order of one million atoms per shot were collected in coated and uncoated glass cells. Gamma-ray anisotropies were measured as a signal of the alignment (second order moment of the polarization) resulting from the combination of polarization and quadrupole relaxation at the cell walls. The temperature dependence over the range 130$^\circ$C to 220$^\circ$C shows the anisotropies increasing with increasing temperature as the ratio of the spin exchange polarization rate to the wall relaxation rate increases faster than the rubidium polarization decreases. Polarization relaxation rates for coated and uncoated cells are presented. In addition, improved limits on the multipole mixing ratios of some of the main gamma-ray transitions have been extracted. These results are promising for electric dipole moment measurements of octupole-deformed $^{223}$Rn and other isotopes, provided sufficient quantities of the rare isotopes can be produced.Comment: 4 pages, 4 figure

Creatine kinase-MB elevation after percutaneous coronary intervention predicts adverse outcomes in patients with acute coronary syndromes.

AIM: To study the relationship between outcomes and peak creatine kinase (CK)-MB levels after percutaneous coronary intervention (PCI) in patients with non-ST-segment elevation acute coronar

Towards a Measurement of the Electric Dipole Moment of radon-223.

The observed baryon asymmetry in the universe requires a greater degree of CP violation than is contained in the CP-violating Standard Model processes discovered thus far. Since the permanent electric dipole moment (EDM) of a particle, atom, or molecule is a CP-odd observable, any nonzero measurement of an EDM above the small Standard Model background would indicate a new source of CP violation. The nuclear structure of 223Rn is expected to enhance its sensitivity to CP-violating interactions relative to 199Hg, currently the most sensitive atomic EDM result, motivating the development of the Radon EDM experiment. In anticipation of radon production at TRIUMF, we performed a series of studies to improve the design and predict the expected precision of the Radon EDM experiment. We designed and tested a prototype gas transfer apparatus that collects a sample of noble gas from a beam and transfers it to a measurement cell, achieving a transfer efficiency of about 40%. We recently improved this to greater than 90%. We studied the polarization and relaxation of radon using samples of 209Rn produced at SUNY Stony Brook's Nuclear Structure Laboratory and polarized it via spin-exchange with optically pumped rubidium. We constructed equations for the anisotropy of the gamma rays emitted by polarized 209Rn as a function of the rubidium polarization, the spin-exchange cross section sigmaSE, the wall-binding temperature T0, the quadrupole relaxation rate Ginfinity2 , and the cell temperature. Using rubidium polarization values measured by electron spin resonance, our radon polarization data indicated that a silane-based wall coating improved the relaxation rate in our cells. For T 0 = 350 K and sigmaSE = 2.5 x 10 -5A2, we found Ginfinity2 = 0.14 +/- 0.02 Hz in uncoated cells and Ginfinity2 = 0.042 +/- 0.012 Hz in coated cells. We used the coated-cell results to obtain a conservative estimate of the Radon EDM precision, 3 x 10-26e · cm at TRIUMF using gamma-ray anisotropies. Coupled with the enhancement effects, this indicates sensitivity to CP violation similar to that of 199Hg in the first phase of the Radon EDM experiment.Ph.D.Atomic physicsNuclear physicsPure SciencesUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/127179/2/3441653.pd

Polarization and relaxation of ^209Rn

The study of the nuclear polarization of radon is motivated by the expected large enhancement of sensitivity to a CP-violating electric dipole moment (EDM) in isotopes with octupole deformation or vibrational strength. In preparation for EDM measurements, the polarization of radon by spin exchange with laser-polarized alkali metals is studied. The measurement of the alignment of 209Rn using HPGe detectors to observe the resulting anisotropy in the 337 and 745 keV gamma rays emitted following electron-capture decay of 209Rn to 209At is demonstrated. Radon is polarized via spin-exchange collisions with rubidium atoms in an uncoated Pyrex optical pumping cell. Anisotropy measurements at several temperatures are used to study polarization and relaxation