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.
Non-statistical population of 1s2s2p4PJ states by charge transfer into multiply charged ions
The experimentally observed enhancement of (1s2s3s)ml4P to (1s2s3S)ml2P populations in collisions of He-like ions with H2 and He targets is discussed and explained by a state-selective cascade feeding mechanism. Continuum Distorted Wave (CDW) and Classical Trajectory Monte Carlo (CTMC) calculations show that large populations of higher lying (1s2s 3S)nl2'4L Rydberg states for l = L = 0, n-1 and n = 2 - 8 can be formed in 0.25-2 MeV/u collisions by direct capture to metastable F7+(1s2s3S) ions. These states subsequently decay through a cascade sequence of radiative or Auger transitions dictated by angular momentum and spin selection rules. All radiative (E1) and Auger transitions for n = 5 were evaluated using the Cowan package for Hartree-Fock calculations. The (1s2s3S)ml2L doublets were found to Auger decay rapidly to the 1s2 level allowing for negligible cascade feeding of lower lying doublets including the 1s2s2p2P±. Alternatively, Auger decay of the (1s2s3S)ml4L quartets is blocked by spin selection rules. Decay can proceed, however, through dipole transitions, but only to other quartets, including the lowest lying 1s2s2p4P state, which in this way acts as an "excited ground state" eventually collecting most cascade flux. This selective cascade feeding mechanism thus leads to the non-statistical enhancement of the 1s2s2p4P quartet population over those of the 1s2s2p2P± doublet populations providing an alternative explanation to the recently suggested novel mechanism of dynamical Pauli exchange.
Thermal-mechanical fully coupled analysis of high-speed angular contact ball bearings
The thermal and mechanical properties of angular contact ball bearings are critical to their operating accuracy and service life. On the basis of the theory of dynamics and frictional heat generation, this work establishes a thermal-mechanical fully coupled model. The high-speed motion characteristics, temperature, and dynamic stiffness are analyzed, and the simulation results are compared with the theoretical calculation and experimental results. Then, the temperature and axial deformation of the bearings under different rotation speeds are analyzed, and the laws of mechanical and thermal characteristics of the bearings are obtained. Results show that an increase in the rotation speed of the inner ring causes the temperature of each component to increase, with the contact area of the balls showing the greatest increase in temperature. An increase in rotation speed also increases the axial deformation of the inner ring.