Development of a Compact Molecular Hydrogen Ion Source for Low-Energy Surface Scattering Experiments

A compact ion source with the extraction energy less than 300 eV has been developed to study low-energy ion reflection from a metal surface. Extraction characteristics of atomic and molecular hydrogen ion beams were investigated by changing the wall materials of the discharge chamber to Ti, Ni, Mo, and stainless steel. The discharge chamber surface of the stainless steel produced the currents of 45 nA H+ and 550 nA H-2(+) beams. The latter current corresponds to particle flux of 1100 pnA(particle nanoamperes) of protons. The 300 eV H-3(+) ion beam with the Ti surface formed the particle flux of 1300 pnA of protons. The production of hydrogen atom particle flux was more efficient in the order from Ti, Mo, stainless steel to Ni. The 50 eV/u and 630 pnA of protons were extracted for the H-3(+) ion beam with the Ti surface.