Figure 1

Gas-filled magnet separation of the ${}^{63}\mathrm{C}\mathrm{u}$-${}^{63}\mathrm{N}\mathrm{i}$ isobaric pair: (a)–(c) Two-dimensional time-of-flight vs focal-plane position spectra for (a),(b) a ${}^{nat}\mathrm{N}\mathrm{i}$ (nickelocene) sample in the ECR ion source, (c) activated ${}^{nat}\mathrm{N}\mathrm{i}$. In (a), the ion beam was attenuated by a factor of 125 to permit the counting of the full ${}^{63}\mathrm{C}\mathrm{u}$ isobaric group. In (b) and (c), most of the ${}^{63}\mathrm{C}\mathrm{u}$ group is blocked before the detector by a movable shield. (d) Identification spectrum of ${}^{63}\mathrm{N}\mathrm{i}$ ions in the detector blocked as in (c), measured for the fast-neutron activated sample. The $x$ ($y$) axis represents the energy loss measured in the second (third) anode of the focal-plane ionization chamber.Reuse & Permissions

Figure 2

(a) Beam transmission through the accelerator during the experiment. The solid and dashed lines are the unweighted mean and standard deviation of the measured values, respectively. (b) Repeated measurements of the ${}^{63}\mathrm{N}\mathrm{i}/{}^{58}\mathrm{N}\mathrm{i}$ ratio for the fast-neutron activated sample (solid dots) and the calibration thermal-neutron activated sample (open dots). The error bars include (in quadrature) statistical counting error, standard deviation of the mean beam transmission (a) and an estimated error on the ${}^{58}\mathrm{N}\mathrm{i}^{15+}$ mean current during each run (see text). The solid lines indicate the weighted mean of the measurements. (c) Comparison of the present experimental value of the total Maxwellian-averaged ${}^{62}\mathrm{N}\mathrm{i}(n,\gamma ){}^{63}\mathrm{N}\mathrm{i}$ cross section ($kT=25\mathrm{k}\mathrm{e}\mathrm{V}$) (solid dot) with evaluations from 8, 9 (open dots) and of 10 (open box). The values from 8, 9 were corrected for a thermal energy of 25 keV, using the temperature dependence of 9, in order to compare them with the experimental value.Reuse & Permissions

Figure 3

Nucleosynthesis yields as a function of the mass number calculated for different values of the ${}^{62}\mathrm{N}\mathrm{i}(n,\gamma ){}^{63}\mathrm{N}\mathrm{i}$ cross section at $kT=30\mathrm{k}\mathrm{e}\mathrm{V}$ and normalized to the yields at a cross section of 12.5 mb [3], for a $15M_{\odot }$ (top) and a $25M_{\odot }$ (bottom) star. Solid dots represent the ratios between the yields calculated using 26.1 mb (this work, extrapolated from 28.4 mb at $kT=25\mathrm{k}\mathrm{e}\mathrm{V}$) to that using 12.5 mb [9]. Open dots represent the ratios between yields for 35.5 mb [8, 10] and 12.5 mb [9]. Solid (open) dots corresponding to isotopes of a given element are connected by solid (dashed) lines.Reuse & Permissions