Characteristics of High Energy Ions Produced in Plasma Focus

Abstract

Characteristics of ion beams produced in the Mather type plasma focus (PF) were studied experimentally to apply the beam to materials processing. The plasma focus was pre-filled with H2 of 250 Pa, or mixture of H2 (270 Pa) and Ne (30 Pa). At 218 mm downstream from the top of the anode on the electrode axis, ion beam of current density ≈ 4 kA/cm2, pulse width ≈ 100 ns (FWHM) was observed when filling gas of H2 was used. The ion species and energy spectra were evaluated by a Thomson parabola spectrometer. Protons of energy in the range of 0.1-1.4 MeV were observed when PF was filled with H2. From the X-ray measurement pinch plasma column of 3-4 mm in diameter and 40 mm in length is observed and line emission of He-like and H-like K shell X-ray emissions were observed when PF was filled with mixture gas. From a particle pinhole image and an incident angle resolved proton energy spectrum ion production is found to be axial symmetry and the ion energy decreases with increasing incident angle. To evaluate the irradiation effect amorphous silicon thin films of thickness 500 nm was irradiated by the ion beam. By the X-ray diffraction measurement of the films before and after the irradiation we found that the film was poly-crystallized by the irradiation.