Positron annihilation lifetime measurements on polymethylmethacrylate (PMMA) at low temperature were performed. Different discrete fitting procedures have been used to analyze the experimental data. It shows that the extracted parameters depend strongly on the fitting procedure. The physical meaning of the results is discussed. The blob model seems to give the best annihilation parameters.
AbstractWe implement slow-light under electromagnetically induced transparency condition to measure the motion of cold atoms in an optical lattice undergoing Bloch oscillation. The motion of atoms is mapped out through the phase shift of light without perturbing the external and internal state of the atoms. Our results can be used to construct a continuous motional sensor of cold atoms.
Decoupling bulk and surface recombination properties in silicon by depth-dependent carrier lifetime measurements