No abstract

Time-differential recoil-into-vacuum measurements have been performed with a plunger on the first-excited 1 ~ = 2 + states of 24Mg and 2°Ne. The states were populated by the reactions 12C(t60, ct)2'*Mg and ~2C(~ 2C, ct)2°Ne. The measured anisotropy of the :t-7 angular correlation was greatly increased by means of a vertical slit on the annular particle detector. ionic electron configurations. Natural targets.

Time-differential perturbed gamma-ray angular correlations have been measured for 148'15~ recoiling into vacuum and into helium (v/c= 1.3 ~o) in the pressure region from 0.75 to 25Torr. A model is presented of the perturbation mechanism for recoils travelling in vacuum, which allows for the hitherto hidden fact that a hard core of the attenuation exists. In addition, a higher order modification of the first order Abragam and Pound theory for random perturbations has to be taken into account at very low pressure.