Yuanbo Sun

Trends in heavy ion interaction with plasma

In this work, we review current trends in China to investigate beam plasma interaction phenomena. Recent progresses in China on low energy heavy ions and plasma interaction, ion beam-plasma interactions under the influences of magnetic fields, high energy heavy ion radiography through marginal range method, energy deposition of highly charged ions on surfaces and Raman spectroscopy of surfaces after irradiation of highly charged ions are presented.

K-shell ionization of Al induced by ions near the threshold energy

The K-shell ionization cross sections of Al induced by H+ and Ne7+ were studied. The ionization cross sections obtained are compared with the predictions of ECPSSR theory (based on the perturbed-stationary-state approach including Coulomb deflection, energy loss and relativistic corrections), BEA (binary encounter approximation) and 1sσ molecular-orbital ionization. It is found that the ECPSSR theoretical results agree with the experimental data very well for proton impact, while the BEA model with correction of Coulomb deflection shows good agreement with experimental results.

Effects of multiple ionization on total L X-ray emission by proton impact

The effects of multiple ionization on L X-ray emission by proton with energy from 100 keV to 250 keV on iron target was studied. The total L X-ray production cross sections were measured. A multiple ioniza-tion model and an average fluorescence yield were used together. The theoretical predictions with the correction of atomic parameter were obtained.

A study of highly charged ions interacting with a plasma target at the Institute of Modern Physics

A new experimental area for the investigation of ion beam matter interaction and ion beam plasma interaction was completed at the Institute of Modern Physics (Lanzhou, China). We report the details of this low-energy setup and first results on ion beam matter interaction, where we measured the charge state of O5+ ions at 1 MeV passing through a hydrogen gas target. The data were compared with the Monte-Carlo simulation results for cold hydrogen gas and hydrogen plasma.

Cross-sections of single & double electron capture in the interaction of highly charged ions with N2 gas

Electron capture of Xe20+ ions from the N2 molecules in a gas cell was measured. A parallel plate and a position sensitive detector were combined to distinguish Xe ions with different charge states. The cross section of single and double electron capture were deduced.

Target Z dependence of Xe L x-ray emission in heavy ion–atom collision near the Bohr velocity: influence of level matching

X-ray yields for the projectile L-shell have been measured for collisions between Xe20+ and thick solid targets throughout the periodic table with incident energies near the Bohr velocity. The yields show a very pronounced cyclic dependence on the target atomic number. This result indicates that Xe L x-ray emission intensity is greatly enhanced either in near-symmetric collisions or if the binding energy of the Xe M-shell matches the L- or N-shell binding energy of the target.

X-ray emission from 424-MeV/u C ions impacting on selected target*

The K-shell x-rays of Ti, V, Fe, Co, Ni, Cu, and Zn induced by 424-MeV/u C6+ ion impact are measured. It is found that the K x-ray shifts to the high energy side and the intensity ratio of K beta/K alpha is larger than the atomic data, owing to the L-shell multiple-ionization. The x-ray production cross sections are deduced from the experimental counts and compared with the binary encounter approximation (BEA), plane wave approximation (PWBA) and energy-loss Coulomb-repulsion perturbed-stationary-state relativistic (ECPSSR) theoretical predictions. The BEA model with considering the multipleionization fluorescence yield is in better consistence with the experimental results. In addition, the cross section as a function of target atomic K-shell binding energy is presented.

Fluorescence emission from CsI(Tl) crystals induced by high-energy heavy ions

The fluorescence radiation from a CsI(Tl) scintillator induced by high-energy carbon ions was investigated. The structures of the emission spectra in the ultraviolet and visible bands as well as their intensity dependence on the projectile energy are reported.

Charge state effect on Si K X-ray emission induced by Iq+ ions impacting

K X-ray emission of Si induced by Iq+ (q=20, 22, 25) ion impact has been investigated. The results show a much higher intensity of X-ray emission for I25+ ions bombardment compared to I20+ and I22+ ions. The experimental data are explained within the framework of 3dπ, δ-3dσ rotational coupling.

Study of the slow ion beam penetrating the low density plasma target

Energy loss of the slow ion beam impacting on a low density hydrogen gas target was measured. A good agreement between the experimental and theoretical results is found. The result of the ion beam passing through a fully ionized hydrogen plasma target is shown too.