Energy levels of light nuclei A = 13–15

High-resolution gamma ray spectroscopy measurements of the fast ion energy distribution in JET 4He plasmas

“…The fast ion energies, to which γ -ray spectroscopy is sensitive, are determined by the differential reactivity of each specific reaction, which comprises the combined product of the cross section and the ion energy distribution. When resonances in the cross sections appear [35,36], the evolution of the γ -ray counting rate can be dominated by ions with energies near resonance, despite those with energies off-resonance. For example, in the case of figure 15, a change in the fast deuteron population having E d ≈ 0.8 MeV would hardly be manifested in the observed γ -ray counting rate.…”

“…Although qualitative results could be derived by simple arguments based on the observed emission spectra, quantitative information was obtained only by considering the detailed nuclear physics behind the reaction in terms of differential cross section, energy levels and branching ratios of the emitting nuclei, which can be quite different depending on the emission process. In fact, the extremely varied properties of reactions between light nuclei and impurities (see for example [35,36] and references therein) can sometimes produce undesirable effects, such as limiting changes of an observable even over significant modifications in the plasma parameters. An example is given by the peak ratio of the 12 C( 3 He, pγ ) 14 N reaction, which is rather independent of the fast 3 He distribution as shown in [19], in clear contrast with the peak ratio from the 12 C(d, pγ ) 13 C reaction considered in this paper.…”

High-precision half-life and branching-ratio measurements for superallowed Fermiβ+emitters at TRIUMF – ISAC

“…In both cases, the half-life can be measured either by direct β counting or by measuring the γ activity since, with a branching-ratio of >99%, both decay to an excited state of their daughters, 10 B and 14 N, which then emit 718.4 and 2312.6 keV γ-rays, respectively [17,18]. An apparent systematic effect associated with the detection method used for previous half-life measurements calls into question the accuracy of the current average T 1/2 values for both 10 C and 14 O; resolving this issue motivated our 14 O half-life experiment that is described in Ref.…”

Determination of level widths in15N using nuclear resonance fluorescence

“…The proportionality factor contains the impinging flux, the number of target atoms, the detection efficiency, the angular correlation factor, the spin and energy of the level, and the branching ratio of the ground state transition. The first three are determined by the experiment, the angular correlation depends on the spin and parity of the involving states, which can be taken from the literature [3].…”