We extend our previous work of a classical over-barrier ionization （COBI） model to calculate the single ionization cross sections of noble gases ranging from He to Xe at strong perturbative energies. The calculation results are in good agreement with extensive experimental data. The scaling law of single ion-atom impact ionization cross sections of noble gases on projectile charge q and energy E, also on target ionization energy I is drawn from the model.
The values of cross-section ratio Rkl of direct k-fold ionization cross section （σk） to direct single ionization cross section （σ1） of Ne impacted by Cq＋ （q = 1-3） ions in an energy range of 10 keV/u-500 keV/u are measured in this work. The experimental data are compared with the results from our multi-electron classical over-barrier ionization （ME-COBI） model, showing that the model can give a good estimate to the experimental data.
There is no available theoretical description of electron transfer from negative projectiles at a velocity below 0.1 a.u.during grazing scattering on insulating surfaces.In this low-velocity range,electron-capture and electron-loss processes coexist.For electron capture,the Demkov model has been successfully used to explain the velocity dependence of the negative-ion fraction formed from fast atoms during grazing scattering on insulating surfaces.For electron loss,we consider that an electron may be transferred from the formed ionic diabatic quasi-molecular state to the formed covalent diabatic quasi-molecular state by the crossing of the potential curves of negative projectiles approaching the surface cations,which can be described by the Landau-Zener two-energy-level crossing model.Combining these two models,we obtain good agreement between the experimental and calculated data for the F-LiF（OOl） collision system,which is briefly discussed.
In this paper, we present a simple theoretical approach to calculate the multiple ionization of big atoms and molecules induced by very high-q fast projectiles in a strong coupling regime （q/v 〉 1）. The results obtained from this approach are in excellent agreement with the available experimental data. A probable scenario of molecular multiple ionization by fast and very high-q projectiles is discussed. The very small computational time required here and the good agreement with the existing experimental data make it a good candidate for studying the multiple ionization of complex molecules under high linear energy transfers.
When a A hyperon is embedded in a nucleus it can form a hypernucleus. The lifetime and its mass dependence of stable hypernuclei provide information about the AN interaction in the nuclear medium. This work will introduce the Jefferson Lab experiment （E02-017）, which aims to study the lifetime of the heavy hypernuclei using a specially developed fission fragment detection technique： a multi-wire proportional chamber operating under low gas pressure （LPMWPC）. The trajectory of the detected fragment is reconstructed and used to find the fission point on the target foil, the position resolution is less than I ram, which meets the original design, the separation of target materials and events mixture percentage in different regions are verified by Monte Carlo simulation.
