Double-K-shell ionization of Mg and Si induced in collisions with C and Ne ions
- J. Stefan Institute, P.O. Box 3000, SI-1001 Ljubljana (Slovenia)
The satellite and hypersatellite K x-ray emission of a thin Mg foil and thick polycrystalline Si target bombarded by 34-MeV C and 50-MeV Ne ions was measured using high-resolution crystal diffractometry. The corresponding projectile reduced velocities v/v{sub K} were 1.09 and 0.92 for C ions and 1.02, 0.86 for Ne ions in case of Mg and Si targets, respectively. An energy resolution of approximately 0.5 eV enabled separation of contributions corresponding to states with different numbers of K- and L-shell vacancies. The relative intensities of satellite and hypersatellite lines were determined by fitting the measured spectra with line shapes calculated using the GRASP92 computer code. To determine the production yields of initial states from the measured x-ray yields, the total decay schemes of initial states were considered. The decay schemes were also used to determine the relative intensities of components contributing to the observed K{alpha} satellites and hypersatellites and K{beta} satellite intensities. Including theoretical predictions in the fitted model is crucial to analyze properly the K{alpha} hypersatellite region which overlaps the K{beta} satellites. The initial-state production yields were then used to determine the L-shell ionization probabilities and the double- to single-K-shell ionization ratio corresponding to the four investigated collisions. The experimental values were compared to the theoretical predictions obtained within the independent electron model using single-electron ionization probabilities calculated by the three-body classical trajectory Monte Carlo (CTMC) method. Since the targets used were thick enough, the equilibrium projectile charge-state distributions in the solid media were assumed. While for the double- to single-K-shell ionization ratios a satisfactory agreement was observed between the CTMC predictions and our experimental results, the L-shell ionization probabilities were found to be overestimated by the CTMC calculations by a factor of about 2.
- OSTI ID:
- 20649951
- Journal Information:
- Physical Review. A, Vol. 70, Issue 6; Other Information: DOI: 10.1103/PhysRevA.70.062720; (c) 2004 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CARBON IONS
CHARGE STATES
ELECTRONS
EMISSION SPECTRA
ENERGY RESOLUTION
EV RANGE
FOILS
INNER-SHELL IONIZATION
ION-ATOM COLLISIONS
K SHELL
L SHELL
MAGNESIUM
MEV RANGE
MONTE CARLO METHOD
NEON IONS
POLYCRYSTALS
PROBABILITY
SILICON
THREE-BODY PROBLEM
VACANCIES
X RADIATION
X-RAY SPECTRA
YIELDS