Energy loss around the stopping power maximum of Ne, Mg and Na ions in hydrogen gas

Greife, U.; Bishop, S.; Buchmann, L.; Chatterjee, M. L.; Chen, A.A; D’Auria, J.M.; Engel, Sabine; Gigliotti, D.; Hunter, D.; Hutcheon, D.A.; Hussein, A.; Jewett, C.; Laird, A. M.; Lamey, M; Liu, W; Olin, Å.; Ottewell, D.; Rogers, J.G.; Wrede, C.

doi:10.1016/j.nimb.2003.09.042

Cited by 14 publications

(12 citation statements)

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“…Consequently, reaction rates involving 34 S and 38 Ar will influence final abundances of mid-mass elements (28 A 62) [2]. Experimentally, there exist broad uncertainties in the literature values for two strong resonances within the astrophysically relevant energy range for oxygenburning temperatures that result in significant uncertainties in the stellar reaction rates at these temperatures.…”

Section: Introductionmentioning

confidence: 99%

“…Experimentally, there exist broad uncertainties in the literature values for two strong resonances within the astrophysically relevant energy range for oxygenburning temperatures that result in significant uncertainties in the stellar reaction rates at these temperatures. Additionally, there are several states in 38 Ar within the relevant energy range for which no 34 S + α resonance strength or energy measurements have been performed [6]. The astrophysical 34 S(α,γ ) 38 Ar reaction rate is expected to be dominated by resonant capture to natural parity states in 38 Ar lying above the α separation energy within the astrophysically relevant energy range, so accurate and precise calculation of the reaction rate depends strongly on experimental knowledge of the strength of these resonances.…”

Section: Introductionmentioning

confidence: 99%

“…The astrophysical 34 S(α,γ ) 38 Ar reaction rate is expected to be dominated by resonant capture to natural parity states in 38 Ar lying above the α separation energy within the astrophysically relevant energy range, so accurate and precise calculation of the reaction rate depends strongly on experimental knowledge of the strength of these resonances. 34 S(α,γ ) 38 Ar reaction. Values marked with an asterisk are those for which there exists a broad uncertainty in the published values.…”

Section: Introductionmentioning

confidence: 99%

“…Sinha et al [9] Erne and Van Der Leun [10] Clarke et al [ 34 S and subsequently 38 Ar are synthesized mainly through α capture on 30 Si, a product of the heavy-ion reactions ( 16 O + 16 O) that occur during oxygen burning. Oxygen burning occurs in M>8 M ⊙ stars near the end of their evolution during the blue supergiant phase.…”

Section: Introductionmentioning

confidence: 99%

“…Core oxygen burning typically occurs at temperatures of T = 1.5-2.7 GK, whereas shell oxygen burning occurs at somewhat higher temperatures [1]. At a nominal temperature of T = 2.2 GK (typical for core oxygen burning), the astrophysically relevant energy range for radiative α capture on 34 S spans 1.94-3.42 MeV in the center of momentum (CM) frame [7]. The primary ashes of oxygen burning are 28 Si and 32,34 S [8].…”

Section: Introductionmentioning

confidence: 99%

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Direct measurement of resonance strengths inS34(α,γ)Ar38at astrophysically relevant energies using the DRAGO

et al. 2018

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Background: Nucleosynthesis of mid-mass elements is thought to occur under hot and explosive astrophysical conditions. Radiative α capture on 34 S has been shown to impact nucleosynthesis in several such conditions, including core and shell oxygen burning, explosive oxygen burning, and type Ia supernovae. Purpose: Broad uncertainties exist in the literature for the strengths of three resonances within the astrophysically relevant energy range (E CM = 1.94-3.42 MeV at T = 2.2 GK). Further, there are several states in 38 Ar within this energy range which have not been previously measured. This work aimed to remeasure the resonance strengths of states for which broad uncertainty existed as well as to measure the resonance strengths and energies of previously unmeasured states. Methods: Resonance strengths and energies of eight narrow resonances (five of which had not been previously studied) were measured in inverse kinematics with the DRAGON facility at TRIUMF by impinging an isotopically pure beam of 34 S ions on a windowless 4 He gas target. Prompt γ emissions of de-exciting 38 Ar recoils were detected in an array of bismuth germanate scintillators in coincidence with recoil nuclei, which were separated from unreacted beam ions by an electromagnetic mass separator and detected by a time-of-flight system and a multianode ionization chamber. Results: The present measurements agree with previous results. Broad uncertainty in the resonance strength of the E CM = 2709 keV resonance persists. Resonance strengths and energies were determined for five low-energy resonances which had not been studied previously, and their strengths were determined to be significantly weaker than those of previously measured resonances. Conclusions:The five previously unmeasured resonances were found not to contribute significantly to the total thermonuclear reaction rate. A median total thermonuclear reaction rate calculated using data from the present work along with existing literature values using the STARLIB rate calculator agrees with the NON-SMOKER statistical model calculation as well as the REACLIB and STARLIB library rates at explosive and nonexplosive oxygen-burning temperatures (T = 3-4 GK and T = 1.5-2.7 GK, respectively).

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Section: Introductionmentioning

confidence: 99%