High current He− injector for tandem accelerators

Measurement of theH2(p,γ)He3STurkat1, Hammer2, Masha3 et al. 2021Phys. Rev. C70200View full textAdd to dashboardCite

“…For the in situ measurement of the deuterium areal density of the targets by the 2 H( 3 He, p) 4 He reaction, a Toroidal Volume Ion Source (TORVIS [27]) fed with a mixture of 4 He and 3 He gas was connected to the 3 MV Tandetron, and a 3 He 2+ beam of 1987 keV energy and 30-40 nA intensity was incident on the target.…”

“…For the NRA run, a TORVIS-type ion source [27] was fed with a special mixture of 3 He (5% by volume) and 4 He gas (95% by volume) and connected to the 3 MV Tandetron accelerator. Using this gas mixture, a tuneable beam intensity of typically 1 μA He − was extracted from the ion source.…”

“…The full-energy detection efficiency curve was then extended to high energies using the well-known E p = 991 keV resonance in the 27 Al(p, γ ) 28 Si reaction [39,40], applying the two-line method following a procedure used before [28][29][30][31][32][33]. The resulting full energy γ -ray detection efficiency in the relevant energy range of E γ = 5800 -6600 keV was between 7.7 − 6.7 × 10 −4 for the 90 • detector and between 2.6 − 2.3 × 10 −4 for the 55 • detector.…”

“…The resulting full energy γ -ray detection efficiency in the relevant energy range of E γ = 5800 -6600 keV was between 7.7 − 6.7 × 10 −4 for the 90 • detector and between 2.6 − 2.3 × 10 −4 for the 55 • detector. The final uncertainty of the detection efficiency was 3%, taking into account the branching ratios in 27 Al(p, γ ) 28 Si, the statistics of the 27 Al(p, γ ) 28 Si and offline runs, the calibration of the activity standards, and the fit uncertainty of the efficiency curve.…”

“…The laboratory background is given by 40 K (E γ = 1461 keV) and the natural decay chains, most prominently by 208 Tl decay 045805-6 (E γ = 2615 keV). The weak 1779 keV line is likely caused by the 27 Al(p, γ ) 28 Si reaction on the target holder. It has been used to place an experimental upper limit of 0.5% on beam protons that are elastically scattered off the copper tube and hit the aluminum target holder.…”