Leads To The Evolution Of The Ion, Electron Beam Ion Trap (ebtt)

An Electron Beam Ions Trap is a facility which can produce and trap high charged ions (HCIs). It can serve as a light source for spectrum studying. With the ions extraction system added to it, it becomes an ions source. Due to some unique property of HCIs, the extracted ions can be applied in many areas such as nano-science. Continuous method and pulsed method are used to extract ions from the trap. In the continuous method the trap potential is kept unchanged, ions escape from the trap by gaining enough energy through collisions with electrons and other ions. By applying the pulsed method, the trap is closed and opened in cycle to let the ions escape from the trap.The works presented in this thesis focus on the continuous method and establish a model to simulate the extracted ions evolution. The theoretical results are compared with experiment and the two are in agreement. Based on this, we study the disagreement of dielectronic recombination strength (DR strength) obtained by theory and experiment. In experiment, the continuous method is applied to extract ions and the relative intensity ratio of extracted ions with neighboring charge state (Nq-1/Nq) is assumed to equal relative density ratio of trapped ions (nq-1/nq). But this work reveals that (Nq-1/Nq) is larger than (nq-1/nq), the difference ranged from 13% to 34% under different experiment conditions. The variance between (Nq-1/Nq) and (nq-1/nq) leads to the disagreement of DR strength obtained by theory and experiment. By introducing an F factor to modify the experimental DR strength, the modified experimental DR strength and the theoretical results are in agreement. The property of F factor is also studied in this work. It is found that F factor is not sensitive to the trap depth, the energy and the current of electron beam. But it becomes less when reduce the density of neutral atoms in EBIT. Its value approaches one when the density of neutral atoms reaches 103cm-3. So the assumption made in the experiment of obtaining DR strength by continuous method is valid only when the density of neutral atoms in EBIT is very low.