Negative Ion Formation Process And Negative Ion Beam Test Study

Ion source is a rapidly evolving applied science and technology with wide applications. It is a important device in many fundamental sciences, such as nuclear physics, plasma chemistry, biological science, material science and so on. Now, in BTNL, there are three types of negative ion sources, they are off-axis duoplasamatron ion source, lithium charge exchange ion source and cesium sputter ion source.The research and development of negative ion sources in China came into being in 1980's. We haven't found the publications involving in theories of negative ion formation process to specific ion source in our country. Theoretic discussion of formation process and reaction is the first part of the treatise. This discussion will be beneficial to understand the principle of negative ion sources and to improve them.In some extent, ion source is the applied science and technology. Therefore, negative ion beam test is main part of all the work. We want to bring out three purposes: first is producing negative ion beams for specific research program; second is getting negative ion beams that have never been produced and accelerated on HI-13 Tandem Accelerator, the electron affinity of these elements are near to or less than zero that negative ion is difficult to form; the last one is increasing the beam intensity of those beam that had been used in BTNL. As a result of the beam test, 15 species of negative ions were produced.Analyzing of impurity in the composition of negative ion beam is other work we completed. Intensive impurity with the same mass number as needed beam will deeply effect physics study. In the modification of 200 Model Sputter Ion Source, metal shields were fixed on outside and inside of the insulated bushing between cathode and anode , which can effectively protect the target from deposit of unneeded materials particle . Purity and intensity of ion beam has been increasedafter improvement of the ion source.