Fe K-shell ionization cross sections induced by 2.4-6.0 MeV Xe^20＋ are measured and compared with different binary- encounter-approximation （BEA） models. The results indicate that the BEA model corrected both by the Coulomb repulsion and by the effective nuclear charge （Zeff） agrees well with the experimental data. Comparison of Fe K-shell X-ray emission induced by 5 MeV xenon ions with different initial charge states （20＋, 22＋, 26＋, 30＋） verifies the applicability of the effective nuclear charge （Zeff） correction for the BEA model. It is found that Zeff correction is reasonable to describe direct ionization induced by xenon ions with no initial M-shell vacancies. However, when the M shell is opened, the Zeff corrected BEA model is unable to explain the inner-shell ionization, and the electron transfer by molecular-orbital promotion should be considered.
Simulations of guiding of low-energy ions through a single nanocapillary in insulating polymers are reported. The nanocapillary has a diameter of 100 nm and a length of 10 μm. Different from previous work, in our simulations a hyperbolic function is used to describe the decay of the charges deposited on the capillary surface. The present simulations reproduce the self-organized charge-up process occurring in the capillary. It is shown that lower-energy ions undergo more oscillations to get guiding equilibrium than those of higher-energy ions, resulting in a longer charging time, which is in good agreement with previous experimental results. Moreover, the experimentally observed mass independence of ion guiding is proved in our simulations. In particular, it is found that the maximum of the repulsive field within the capillary is independent of the ion energy as well as the tilt angle. To counterbalance the increasing of the transversal energy caused by increasing the tilt angle or incident energy, the effective length of the repulsive field is expanded in a self-organizing manner.
The K-shell x-rays of Ti, V, Fe, Co, Ni, Cu, and Zn induced by 424-MeV/u C^（6＋） ion impact are measured. It is found that the K x-ray shifts to the high energy side and the intensity ratio of Kβ/Kα 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.
The interaction process of ions and plasmas is an important topic in Ion-Beam-Driven High Energy DensityPhysics and Inertial Confinement Fusion research. Due to the strong non-linear effects and the special importancein ICF research, more and more emphasis has been given to the investigations for ion beam in low energy rangeand/or for plasma with high intensity[1;2]. Here, we address the newly measured results of the energy loss by slowions penetrating the fully ionized hydrogen plasma target.
Highly charged ions (HCIs) carrying amount of potential energy will produce some new physical phenomenabecause the potential energy will be deposited into a very small volume within a very short time. We wouldapply the calorimetric method to study the energy deposition of HCIs [1;2]. Herein we introduce the new setup forcalorimetric measurement for the potential energy deposition of highly charged ions at 320 kV Highly Charged IonsPhysics Experimental Platform.The setup was constructed by 3 parts: the Dewar, the electrical temperature controller and the main part. Thediamond target was connected to the LN2 cooled heat sink by 4 copper wires and a Platinum temperature sensorwas glued to the rear side of the target. As shown in Fig. 1.
Graphene is two dimensional materials which is made of honeycombed carbon atoms. It attracts extensiveinterests for its wonderful characteristics that make the graphene a potential candidate in fields of microelectronicsproduction, molecule detection, desalination and DNA sequencing. Highly charged ion (HCI) has huge potentialenergy for peeling off electrons. When interacting with solid surface, the HCI distorted the solid lattice via potentialdeposition and then the nanostructures were formed on the solid surface. The HCI was expected as a tool for surfacemodification. In this work, HOPG and grapheme were irradiated with Xeq+ and Arq+ ions. The typical Ramanspectra of graphene and HOPG irradiated with highly charged ions were shown in Fig. 1. The D peak appeared at1 335 cm??1 on the spectra of graphene irradiated with highly charged ions. The intensity of D peak increased withfluence. The ratio of intensity of D peak to that of G peak varied with fluence in Fig. 2. The ratio rose linearlywith the square root of fluence when fluence was low. The ratio saturated when the irradiation fluence was high.The critical fluence depended on the charge state of ion. The higher charge state it was, the lower critical fluenceit would be.
High energy density is generally defined as a state with energy content larger than 1011 J/m3,or equivalently with pressure higher than 1 Mbar.High energy density matter widely exists in the universe,like the cores of Jupiter,Sun and Earth,as well as inertial confinement fusion.The creation of high energy density state in the laboratory and the research on its properties are very important in astrophysics,planetary sciences,geophysics,inertial fusion sciences and so on.Related to high energy density physics,we carried out a series of research activities including simulation of the state of warm dense matter at HIAF,ion-plasma interaction,highly charged ions induced nanoscale defect on surface and X-ray emission,as well as developing a new multi-channel pyrometer and high energy electron radiography.
Warm dense matter,an intermediate state of matter between a solid and an ideal plasma,has a density as a solid,a temperature of a few eV,and a pressure of some Mbar,which exists in the cores of large planets and the path to inertial confinement fusion.However,in this state,because of the strongly coupled particles,the assumptions of both condensed matter theory and ideal-plasma theory break down,the quantum mechanics and other effects become of the importance as well.
The research activities on warm dense matter driven by intense heavy ion beams at the new project High Intensity heavy-ion AcceleratorFacility (HIAF) are presented. The ion beam parameters and the simulated accessible state of matter at HIAF are introduced, respectively. Theprogresses of the developed diagnostics for warm dense matter research including high energy electron radiography, multiple-channel pyrometer,in-situ energy loss and charge state of ion detector are briefly introduced.
