Study Of Secondary Electron Emission Coefficient From Targets Induced By Medium-low Energy Ions

When energetic ion beams interact with solid materials, phenomenas such as ions sputtering, electron and photon emission from solid surface occurs. Since it was fonud, secondary electron emission phenomenon has been extensively studied because of its important fundamental research significance in the production and the direct great value in life.The physical mechanism of secondary electron emission and several mainstream theoretical research model on the secondary electron emission in abroad, is contained in this theses,and also introduces secondary electron emission coefficient measurements principle and something need to pay attention to the part.Combining the theory and experimental menthod of particle-matter interaction, analysed the slowing down of energetic ions in matter, interaction process of ions with the target nucleus and the electrons, discussed the mechanism of ion-beam-induced secondary electron emission from targets. On the basis of existed international theory models, derived theory in the low-energy light-ion-induced secondary electron emission coefficient of the target, and get the specific expression of the ratio factor; combines theory of secondary electron emission coefficient induced by low-energy heavy ion, finished theoretical results for low energy heavy ion induced secondary electron emission coefficient.Combined with existed laboratory equipment, design and processing a simple experimental setup for the measure of ion beam induced secondary electron emission coefficient, and tested. carried out the measurements On the320kV Ion source in the Chinese Academy of Sciences Institute of Modern Physics,which is about secondary electron emission coefficient from metal molybdenum, zirconium, titanium, and deuterated titanium deuteride induced by low-energy proton. carried out the measurement on the ion implanter In the Beijing Normal University, which is about a low-energy titanium beam induced secondary electron emission coefficient for each sample, and achieved good results.Combined with theoretical calculations, the experimental results were in-depth analysis. When20nA/cm2low energy proton beam irradiate each sample,the secondary electron emission coefficient and electron energy loss is approximately proportional to the scale factor (?),but about50%larger than the Sternglass theoretical value. Adsorption layer on the surface affect the secondary electron emission coefficient. proton beam of current density7μA/cm2and energy100keV irradiate a sample for a long time, the secondary electron emission coefficient γ proportional factor A gradually decreased rapidly within the first100second and stable until the theoretical value, the first sample emission coefficient is large, then the rapid decay, and showing the proton beam strikes the sample thought the secondary electron emission similar trend to further illustrate the radiation beam with the sample to continuously improve the surface cleanliness, decreased emission coefficient, eventually stabilize. Same incident energy, the same material as titanium ion-induced proton emission coefficient than many large, mainly due to the titanium ions and electrons in the material to prevent large induced nuclear stopping.Finally, given the improvement direction for further research on the improvement of the measuring device made practical proposals, I believe, based on existing research, the study of ion-beam-induced secondary electron emission from targets will achieve more fruitful results. Domestic beam-induced secondary electron emission research is still relatively rough, compared with foreign counterparts,the gap is not small, I hope this thesis research can be helpful in this area on domestic research.