A new approach to monitor 13C-targets degradation in situ for 13C(alpha,n)16O cross-section measurements at LUNA

Abstract

Direct measurements of reaction cross-sections at astrophysical energies often require the use of solid targets able to withstand high ion beam currents for extended periods of time. Thus, monitoring target thickness, isotopic composition, and target stoichiometry during data taking is critical to account for possible target modifications and to reduce uncertainties in the final cross-section results. A common technique used for these purposes is the Nuclear Resonant Reaction Analysis (NRRA), which however requires that a narrow resonance be available inside the dynamic range of the accelerator used. In cases when this is not possible, as for example the 13C(alpha,n)16O reaction recently studied at low energies at the Laboratory for Underground Nuclear Astrophysics (LUNA) in Italy, alternative approaches must be found. Here, we present a new application of the shape analysis of primary gamma rays emitted by the 13C(p,g)14N radiative capture reaction. This approach was used to monitor 13C target degradation {\em in situ} during the 13C(alpha,n)16O data taking campaign. The results obtained are in agreement with evaluations subsequently performed at Atomki (Hungary) using the NRRA method. A preliminary application for the extraction of the 13C(alpha,n)16O reaction cross-section at one beam energy is also reported.

arXiv comment10 pages, 6 figures, to be published in EPJ A

References in corpus (8)

• S-factor of 14N(p,gamma)15O at astrophysical energies
• LUNA: Status and Prospects
• Improved Direct Measurement of the 64.5 keV Resonance Strength in the 17O(p,a)14N Reaction at LUNA
• The importance of the 13C(alpha,n)16O reaction in Asymptotic Giant Branch stars
• Preparation and characterisation of isotopically enriched Ta${}_2$O${}_5$ targets for nuclear astrophysics studies
• Revision of the 15N(p,γ)16O reaction rate and oxygen abundance in H-burning zones
• Constraining the S factor of 15N(p,g)16O at Astrophysical Energies
• Effect of beam energy straggling on resonant yield in thin gas targets: The cases ${}^{22}$Ne(p,γ)${}^{23}$Na and ${}^{14}$N(p,γ)${}^{15}$O

Cited by in corpus (9)

• Direct measurement of the 13C(α,n)16O cross section into the s-process Gamow peak
• New proton-capture rates on carbon isotopes and their impact on the astrophysical ${}^{12}\mathrm{C}/{}^{13}\mathrm{C}$ ratio
• Exploring Stars in Underground Laboratories: Challenges and Solutions
• The study of key reactions shaping the post main-sequence evolution of massive stars in underground facilities
• Improved $S$-factor of the ${}^{12}$C(p,$\gamma$)${}^{13}$N reaction at $E=$320-620~keV and the 422~keV resonance
• Underground Measurements of Nuclear Reaction Cross-Sections Relevant to AGB Stars
• Cross section measurement of the 12C(p,gamma)13N reaction with activation in a wide energy range
• Detectors and Shieldings: Past and Future at LUNA
• Status and future directions for direct cross-section measurements of the 13C(a,n)16O reaction for astrophysics