A high-efficiency gas target setup for underground experiments, and redetermination of the branching ratio of the 189.5 keV ${}^{22}\mathbf{Ne}(\mathbf{p},\gamma {)}^{23}\mathbf{Na}$ resonance

Abstract

The experimental study of nuclear reactions of astrophysical interest is greatly facilitated by a low-background, high-luminosity setup. The Laboratory for Underground Nuclear Astrophysics (LUNA) 400 kV accelerator offers ultra-low cosmic-ray induced background due to its location deep underground in the Gran Sasso National Laboratory (INFN-LNGS), Italy, and high intensity, 250-500 $\mu$A, proton and $\alpha$ ion beams. In order to fully exploit these features, a high-purity, recirculating gas target system for isotopically enriched gases is coupled to a high-efficiency, six-fold optically segmented bismuth germanate (BGO) $\gamma$-ray detector. The beam intensity is measured with a beam calorimeter with constant temperature gradient. Pressure and temperature measurements have been carried out at several positions along the beam path, and the resultant gas density profile has been determined. Calibrated $\gamma$-intensity standards and the well-known $E_p$ = 278 keV ${}^{14}\mathrm{N}(\mathrm{p},\gamma {)}^{15}\mathrm{O}$ resonance were used to determine the $\gamma$-ray detection efficiency and to validate the simulation of the target and detector setup. As an example, the recently measured resonance at $E_p$ = 189.5 keV in the ${}^{22}$Ne(p,$\gamma$)${}^{23}$Na reaction has been investigated with high statistics, and the $\gamma$-decay branching ratios of the resonance have been determined.

arXiv comment11 pages, 11 figures, accepted in Eur. Phys. Journal A

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• First measurement of the 14N(p,gamma)15O cross section down to 70 keV
• LUNA: a Laboratory for Underground Nuclear Astrophysics
• LUNA: Nuclear Astrophysics Deep Underground
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• Three new low-energy resonances in the ${}^{22}$Ne(p,$\gamma$)${}^{23}$Na reaction
• Feasibility of low energy radiative capture experiments at the LUNA underground accelerator facility
• Activation measurement of the 3He(a,g)7Be reaction cross section at high energies
• Direct measurement of low-energy ${}^{22}$Ne(p,$\gamma$)${}^{23}$Na resonances
• Preparation and characterisation of isotopically enriched Ta${}_2$O${}_5$ targets for nuclear astrophysics studies
• A new study of the ${}^{22}$Ne(p,$\gamma$)${}^{23}$Na reaction deep underground: Feasibility, setup, and first observation of the 186 keV resonance
• Direct measurement of the 15N(p,gamma)16O total cross section at novae energies
• ${}^{22}$Ne and ${}^{23}$Na ejecta from intermediate-mass stars: The impact of the new LUNA rate for ${}^{22}$Ne(p,$\gamma$)${}^{23}$Na
• Revision of the 15N(p,γ)16O reaction rate and oxygen abundance in H-burning zones
• Strengths of the resonances at 436, 479, 639, 661, and 1279 keV in the ${}^{22}$Ne(p,$\gamma$)${}^{23}$Na reaction

Cited by in corpus (13)

• Direct capture cross section and the $E_p$ = 71 and 105 keV resonances in the ${}^{22}$Ne($p,\gamma$)${}^{23}$Na reaction
• Setup commissioning for an improved measurement of the D(p,gamma)3He cross section at Big Bang Nucleosynthesis energies
• Advances in Radiative Capture Studies at LUNA with a Segmented BGO Detector
• First direct limit on the 334 keV resonance strength in the ${}^{22}$Ne(α,γ)${}^{26}$Mg reaction
• 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
• 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
• Underground Measurements of Nuclear Reaction Cross-Sections Relevant to AGB Stars
• First direct measurement of the 64.5 keV resonance strength in ${}^{17}$O(p,$\gamma$)${}^{18}$F reaction
• Experimental determination of the ${}^3$He($\alpha$,$\gamma$)${}^7$Be reaction cross section above the ${}^7$Be proton separation threshold
• Development of a jet gas target system for the Felsenkeller underground accelerator
• Gas-jet target with online interferometric thickness measurement for nuclear astrophysics
• Study of the ${}^{20}$Ne($p,\gamma$)${}^{21}$Na reaction at LUNA