Measurement of theCa40(α,γ)

New measurement of the astrophysically important40Ca(α,γ)44Ti reaction

“…The measured strength for the 1.84 MeV resonance in this work (0.28 ± 0.04) eV agrees well with the documented (0.28 ± 0.03) eV value [35]. Review of the strong resonance triplet gives a fit value of integrated resonance ωγ int = 9.0 ± 1.2 eV, showing good agreement to the literature value of 8.5 ± 1.1 eV [36] and previous measurements of 7.6 ± 1.0 eV [13] and 8.8 ± 3.0 eV [12]. The ωγ value for this triplet is reliably consistent for all scans made during target degradation monitoring, giving increased confidence in the procedure.…”

“…As with more recent measurements this work gives a rate larger than that of the original PGS data, where a reaction rate has been calculated using resonances identified in the previously discussed studies of [11,[16][17][18][19][20]. This difference is due in part to the significant increase in identified resonance structure, previously also noted in [13]. In the temperature range >1.5 × 10 9 K there is good agreement (within quoted limits) between this work and the IKS work [13] which is smaller by a factor of 1.33.…”

“…Separate energy signals from the ion chamber were used for isobaric suppression, this was combined with γ-ray coincidence data from a BGO (bismuth germanate inorganic scintillator) array surrounding the 4 He gas cell. Two measurements were performed in this way, a preliminary activation over the strong triplet used to confirm the approach [28], then a wider range experiment covering E cm = 2110 -4190 keV (or T = 1 -2.8 K), where 50 resonances were identified and resonance strengths measured. The reaction rate was determined from the deduced resonance strengths.…”

“…The reaction was measured in inverse kinematics (in the following termed as IKS) using a 40 Ca beam incident on a windowless 4 He gas target [13]. The resultant recoils were separated by DRAGON and counted in a multi-anode ion chamber.…”

“…[11]), to the use of accelerator mass spectrometry (AMS) (e.g. [12]) and inverse kinematics techniques [13]. These experiments were complemented by a number of theoretical studies based on empirical [14] and statistical model approaches [15].…”