Désintégration de 95Ru

Mass measurements in the vicinity of ther p-process and theν p-process paths with the Penning trap facilities JYFLTRAP and SHIPTRAP

“…Since the positions of the ground and isomeric states are identical according to extrapolations (see Table I) a treatment for an unknown mixture of states [61] cannot be applied and our result is assigned as the ground state mass with an increased uncertainty of 87 keV. 90 Ru, 92 Ru, 92 Rh, and 93 Rh: The measurements reported here are the first experimental mass determinations of these nuclides. The even-even ruthenium isotopes have 0 + ground states and in 93 Rh no isomeric state was observed.…”

“…90 Tc: Prior to the Penning trap measurements, the radioactive nuclide 90 Tc was produced by a (p,3n) reaction on isotopically enriched 92 Mo at 43 MeV beam energy and studied by means of β-decay spectroscopy in two independent experiments at Foster Radiation Laboratory in Canada [63,64]. Two long-lived states were found in both experiments with (i) T 1/2 = 8.7 s and I π = 1 + and (ii) T 1/2 = 49.2 s and I π = 8 + [64].…”

“…A cyclotron resonance curve is obtained by the timeof-flight detection method: an increase in radial kinetic energy resulting from the resonant excitation of both radial ion motions with an RF-field at ν c is detected by a reduction in the time of flight of the ejected ions towards a detector [28,29]. Figure 2 shows examples of cyclotron resonance curves for singly-charged 91 Tc and 90 Ru ions from the SHIPTRAP and JYFLTRAP experiments, respectively. Figure 3 displays a section of the nuclear chart below the doubly-magic shell closure of 100 Sn.…”

“…In order to improve the detailed modeling of the reaction pathways even further, a continuation of the measurement programme is desired as follows: among the nuclides already studied open questions of ambigous massto-state assignments should be revisited. These include the nuclides 84 Y, 85 Nb, 88 Tc, 90 Tc, and 92 Rh. Furthermore, specific nuclides with uncertain spin assignments and/or long-lived isomeric states should be extensively searched for to assess their possible influence in the rp-or νp-process [127].…”

“…Similarly, the relative suppression of the flow through 88 Tc(p,γ) 89 Ru(n,p) 89 Tc in the calculation using the newly-determined mass values of this work leads to the observed lower abundance of 89 Y. The change in the mass of 90 Tc leads to a slight increase in the reaction rate for 90 Tc(γ,p) 89 Mo, thus shifting some mass of the A = 90 chain into the A = 89 chain. As a result, the final abundance of 90 Zr is lower for the calculation employing the newly-determined mass values of this work.…”