Y. P. Zhang

THRESHOLD KINETIC ENERGY FOR GOLD X-RAY EMISSION INDUCED BY HIGHLY CHARGED IONS

The X-rays induced in the interaction of highly charged Argon ions with gold surface were investigated. We had altered the projectile kinetic energy from 150keV to about 400keV. The results show that, there is a threshold projectile kinetic energy for this excitation. Combining the colliding theory of classic electrodynamics with the concept of quantized orbits, we crudely give this threshold kinetic energy.

X-RAY EMISSION FROM THE METASTABLE COMPONENTS OF SLOW Ar16+ BEAM ON METALLIC SURFACES

K-shell X-ray emission was observed in the neutralization process of Ar16+ interacting with beryllium and molybdenum at slow speed (less than Bohr velocity). The K-shell X-ray emission came from the metastable component of Ar16+ beam with the configuration (1s2s) produced from electron cyclotron resonance ion source. The intensity ratio of Kβ X-ray emission to Kα X-ray emission (IKβ/IKα) in the neutralization process decreased when the kinetic energy of the projectile increased. This is closely related to the flight time the projectiles spend above the surface, which is dominated by both the work function of the metal and the normal velocity component of the incident ions to the surface according to the classical over-barrier model. As the relation between IKβ/IKα and the above-flight time shows, the longer time above the surface the larger ratio due to the above-surface contribution. Furthermore, the smaller work function leads to the smaller contribution from the above surface.

Kinetic Energy Effect in the X-Ray Emission of Mo Surface Induced by Xe28+ Ions

L-shell x-ray spectra of Mo surface induced by Xe28+ were measured with a Si(Li) detector. The x-ray intensity was found increased rapidly with the kinetic energy of the incident ions. The relation of x-ray intensity with kinetic energy of the projectile is discussed. There is a turning point of the intensity to the kinetic energy, and the explanation is given.

X-Ray Spectra of Hydrogen-Like and Helium-Like Argon Ions on Solid Surfaces

14-GHz electron cyclotron resonance ion source at the Heavy Ion Research Facility National Laboratory in Lanzhou has been used to investigate x-rays from the interaction of slow highly charged Ar17+and Ar16+ions for different energies with Be, Al, Ni, Mo and Au surfaces. Interaction of Ar17+ and Ar16+ ions with Metallic Surfaces for a wide range of energies has been studied by measuring the resulting x-ray emission. The characteristic features of the x-ray spectra have been explained.

INTERACTION OF HIGHLY CHARGED Xeq+ (q = 26, 27, 30) IONS WITH MOLYBDENUM SURFACE

Experimental investigation of Molybdenum L-shell X-ray emission is reported in the collision of highly charged Xeq+ (q = 26,27,30) ions with Molybdenum surface in the energy range 400 to 600 keV. Based on the X-ray spectra obtained and by the extrapolation of experimental data to the lower incident energy range, a limit was found for the energy of the incident ions. The influence of initial charge state on X-ray emission from the target L-shell was observed. The difference of the initial charge state and electron configuration of the incident ions may lead to observably different contribution to the target atom vacancy production and L-shell X-rays emission. Based on COB model, a simple explanation was presented to interpret the features of the experimental results.

X-RAYS EMISSION OF HYDROGEN-LIKE AND HELIUM-LIKE ARGON IN INTERACTION WITH Mo METALLIC SURFACE

14-GHz electron cyclotron resonance ion source (ECRIS) at the Heavy Ion Research Facility National Laboratory in Lanzhou has been used to investigate the radiative deexcitation of highly charged Ar17+ and Ar16+ ions as they interact with a molybdenum surface. The interaction of Ar17+ and Ar16+ ions above Mo Metallic Surface has been studied by looking at the X-rays with a Si (Li) detector. ECRIS is used in our work for the first time. As the experimental results, the X-ray spectra of Ar17+ and Ar16+ ions interacting with a Mo metal target have been given. The capture of many electrons by Ar17+ and Ar16+ ions, at low velocities, near a metallic surface, has been studied. Hollow atoms produced in the interaction of highly charged ions with a Mo metallic surface have been observed.