Preliminary Design of a Hybrid Ion Source for 7Li3+ Generation

The p(Li-7,n)Be-7 reaction can be used to produce forward neutron beam based on the principle of inverse kinematics, which is useful to reduce the background of the measurement of prompt fission y-ray emission from fast neutron induced fission of U-235 and U-238. Based on inverse kinematics reaction, a hybrid Li-7(3+) ion source is going to be adopted to produce 10 e mu A beam for the project of CIFNEF (Compact Intense Fast NEutron Facility) proposed by Peking University (PKU) and China Institute of Atomic Energy (CIAE). To qualify the possibility of producing multi-charged ions with a 2.45 GlIz microwave source, a high B field 2.45 GHz ion source has been built at PKU. Oxygen gas was used for the source test. About 200 e mu A O3+ and 400 e mu A O2+ were produced with the high B field ion source. This indicates the feasibility of producing multi-charged state ions with lower frequency and high B field. Based on these results, a tandem type hybrid ion source with the combination of a 2.45 Gliz ECR ion source and a hot surface ionization source was developed for Li3+ ion generation at PKU. An oven will be used to produce lithium vapor and the surface ionization source converts the lithium atoms into Li+ ions. Then Li+ will be striped into Li3+. in ECR region. The configuration of magnetic field is min-B. Details will be presented in the paper.