Determination of the solid angle and response function of a hemispherical spectrograph with injection lens for Auger electrons emitted from long lived projectile states.
We present SIMION 8.1 Monte Carlo type simulations of the response function and detection solid angle for long lived Auger states (lifetime τ ∼ 10(-9) - 10(-5) s) recorded by a hemispherical spectrograph with injection lens and position sensitive detector used for high resolution Auger spectroscopy of ion beams. Also included in these simulations for the first time are kinematic effects particular to Auger emission from fast moving projectile ions such as line broadening and solid angle limitations allowing for a more accurate and realistic line shape modeling. Our results are found to be in excellent agreement with measured electron line shapes of both long lived 1s2s2p(4)P and prompt Auger projectile states formed by electron capture in collisions of 25.3 MeV F(7+) with H2 and 12.0 MeV C(4+) with Ne recorded at 0° to the beam direction. These results are important for the accurate evaluation of the 1s2s2p (4)P/(2)P ratio of K-Auger cross sections whose observed non-statistical production by electron capture into He-like ions, recently a field of interesting interpretations, awaits further resolution.
Technique for the determination of the 1 s 2 s 3 S metastable fraction in two-electron ion beams
An experimental technique for the determination of the metastable 1s2s 3 S fraction f of two-electron ion beams is reported. The method utilizes the electron yields of the 1s2p 2 2 D and 1s2s2p 4 P doubly excited states, produced in collisions of two-electron ion beams with H 2 or He targets. The metastable beam fraction f is determined in two successive measurements at the same beam energy but having different metastable fractions. The technique is applied to the case of B 3 + ions in collisions with H 2 targets. The results are in good agreement with those from our recent paper on similar metastable fraction measurements [M. Zamkov et al., Phys. Rev. A 64, 052702 (2001)]. The method can be safely applied in cases where the two different metastable fractions differ significantly.
Mathematical Simulation of Combustion of Boron Powder Gas Suspension
Based on a two-phase two-velocity model of a reacting gas-dispersed medium, a mathematical model of combustion of a boron powder gas suspension has been formulated. The results of numerical solution of the problem are presented. The influence of the composition of the gas suspension, its size, size distribution of particles, mass concentration of particles, as well as of the presence of aluminum powder in the suspension on the visible and normal velocities of flame propagation in the gas suspension, is shown. A comparison of the results of calculation with the well-known experimental and theoretical data is carried out. Satisfactory agreement of the predicted results with experimental data is shown.