New progress on DC ${\mathrm{H}}_2^{+}$ beam generation: Tens of mA output and 70% fraction from a 2.45 GHz microwave driven ion source

Recently ${\mathrm{H}}_2^{+}$ ion beam finds widespread use in many fields, and the demand of high-current ${\mathrm{H}}_2^{+}$ ion sources is urgent for numerous applications. However, there are currently almost no reported ion sources capable of generating a direct-current (DC) ${\mathrm{H}}_2^{+}$ beam with tens of mA current. In previous work at Peking University (PKU), ${\mathrm{H}}_2^{+}$ ion beams with a current of over 40 mA have been obtained in pulse mode, and a current of 16 mA was achieved in DC mode. In this paper, we report the generation of a DC ${\mathrm{H}}_2^{+}$ ion beam with a current of 22 mA extracted from an improved miniaturized microwave driven ion source (MMDIS). Beam analysis shows that the ${\mathrm{H}}_2^{+}$ fraction in the extracted beam is about 70%. The emittance of the mixed hydrogen beam is about 0.12 π ⋅ mm⋅ mrad. These results provide references for the applications of ${\mathrm{H}}_2^{+}$ beam and the design of ${\mathrm{H}}_2^{+}$ ion source.