No abstract

No abstract

We present cranking model calculations of mass parameters for the Asymmetric Two Center Shell Model. It is shown, that terms that are small in a One Center Shell Model and for this reason have been neglected in previous calculations become important in the late stages of the fission process. We extend these investigations to the case of finite temperature and point out that the inclusion of dissipative effects can help to overcome some difficulties which arise in cranking type calculations in the limit of vanishing pairing gap due to pseudo crossings in the single particle spectrum.

No abstract

The force on microparticles in an energetic ion beam is investigated experimentally. Hollow glass microspheres are injected into the vertically upward directed beam and their trajectories are recorded with a charge-coupled device camera. The net force on the particles is determined by means of the measured vertical acceleration. The resulting beam pressures are compared with Faraday cup measurements of the ion current density and calorimetric measurements of the beam power density. Due to the neutral gas background, the beam consists, besides the ions, of energetic neutral atoms produced by charge-exchange collisions. It is found that the measured composition of the drag force by an ion and a neutral atom component agrees with a beam model that takes charge-exchange collisions into account. Special attention is paid to the momentum contribution from sputtered atoms, which is shown to be negligible in this experiment, but should become measurable in case of materials with high sputtering yields.