Effect Of Charge State Research Articles

Effect of atomic charge state on nuclear lifetimes:Au197

The mean life of the 77.3-keV level in $^{197}\mathrm{Au}$ has been measured simultaneously in neutral gold atoms and in atoms with a mean charge of $\overline{q}=+9.5\ifmmode\pm\else\textpm\fi{}1.5$. Mean lives of ${\ensuremath{\tau}}^{0}=2.76\ifmmode\pm\else\textpm\fi{}0.03$ nsec and ${\ensuremath{\tau}}^{+9.5}=2.84\ifmmode\pm\else\textpm\fi{}0.12$ nsec were obtained. These results indicate that even the removal of 10 electrons from this atom does not affect the electronic structure of the inner shells, and therefore has little effect on the internal-conversion coefficients and lifetime of this nuclear state. These results are in good agreement with both relativistic and nonrelativistic calculations.[RADIOACTIVITY $^{197}\mathrm{Au}$; ${E}_{x}=77.3$ keV, measured ${T}_{\frac{1}{2}}$ in neutral and ionized atoms, $^{197}\mathrm{Au}$($^{16}\mathrm{O}$, $^{16}\mathrm{O}$\ensuremath{'}), $E=45$ MeV, $^{16}\mathrm{O}\ensuremath{-}\ensuremath{\gamma}$ delayed coin; calculated ICC.]

A gated ion source for time-of-flight spectroscopy

A gated ion source using tetrode geometry and having 100% gating efficiency for all ion species is described. Static transfer characteristics and gating characteristics are presented, and the effect of other charge states on the space charge limited current of a given ion species is discussed.

Charge-State Effects in Displacement Damage Invited Paper

Charge-state effects in displacement damage in covalent semiconductors are reviewed. Specifically the influence on defect production mechanisms, configurations, mobility, annealing kinetics, interaction and dissociation are discussed. The recent theoretical work on the split-interstitial is mentioned, as is the new athermal migration mechanism.

Effects of Metastable Charge States on Short-Term Annealing in p-Type Silicon

In contrast to n-type material, short-term annealing of neutron-induced lifetime damage in p-type silicon is strongly dependent upon minority carrier density. While physical reordering is an important process, and may be somewhat dependent upon excess electron density in p-type material, arguments presented here indicate that this difference between n- and p-type material is primarily an electronic effect having to do with neutralization of metastable charge states induced during defect production. A qualitative model is presented which appears to be more consistent with experimental observations than those which depend upon physical defect motion alone.

Nuclear spectroscopy measurements employing modulation of target potential

Precision measurements which may be obtained by applying voltage modulation to a target bombarded with a fixed energy beam are discussed. Examples are given for studies of beam and resonance parameters, target thickness measurements, d E/d x determinations, the observation of Symon-Landau energy distributions, excitation function measurements and charge state effects of reaction products.