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An implanted target ( 14 N on Ta ) is prepared and characterized via surface and bulk characterization processes. The depth profile of the implanted ions is obtained experimentally by populating a narrow resonance state of 15 O through 14 N(p,γ) reaction induced with a laboratory proton energy of 278 keV. The experimental profile is then compared with devoted simulations to understand the locations of the implantated ions in the lattice structure. Later, the lifetimes of a few excited states of 15 O, relevant for applications in astrophysical scenario, have been determined using Doppler Shift Attenuation Method (DSAM).

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We have calculated rates of β − decay to both continuum and bound states separately for some astrophysically important fully ionized (bare) atoms in the mass range A ≈ 60-240. Most of these nuclei are on the s-process path. One of the motivations of this work is that the previous theoretical calculations were very old and/or informatically incomplete. Probably no theoretical study on this subject has been done in the last three decades. For the calculation, we have derived a framework from the usual β − decay theory used by previous authors. Dependence of the calculated rates on the nuclear radius and neutral atom Q-value have been examined. We have used latest experimental data for nuclear and atomic observables, such as β − decay Q-value, ionization energy, neutral atom β − decay branchings, neutral atom half-lives etc. Results of β − decay rates for decay to continuum and bound states and the enhancement factor due to the bound state decay for 114 transition cases in 27 different nuclei (33 parent levels) have been tabulated and compared with the previously calculated values, if available. The effective rate or half-life calculated for bare atom might be helpful to set a limit for the maximum enhancement due to bound state decay. Finally, β − decay branching for bare atom has been calculated and for the first time, the change in branching in bare atom, compared to that in neutral atom, has been found. Reason for this branching change has been understood in terms of Q-values of the transitions in the neutral and bare atoms. Verification of this branching change phenomenon in bare atom decay might be of interest for future experiments.

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