Electric field design of cold cathode Penning ion source for miniaturization neutron tube

Abstract

It is of great significance to study the optimum electric field strength of cold cathode Penning ion source (PIG), which is used on high yield neutron tube. The electric field in the ion source depends largely on the relationship between the voltage of anode and the thickness of anticathode. In the case of constant magnetic strength, the discharge modes of PIG can be distinguished by the relation between electric potential and pressure. Based on this relationship, we re-designed and optimized the PIG, and got the expected discharge mode. COMSOL was used to simulate the model, and a better extracted beam intensity (10.31μA) and a higher proton fraction (24 %) were obtained at an extracted voltage of −80 kV. It is estimated that the yield is higher under −80 kV than the previous design, which can reach 6×108n/s. This study can provide reference for the development of high yield neutron tube ion sources.