Advances in Radiative Capture Studies at LUNA with a Segmented BGO Detector

Abstract

Studies of charged-particle reactions for low-energy nuclear astrophysics require high sensitivity, which can be achieved by means of detection setups with high efficiency and low backgrounds, to obtain precise measurements in the energy region of interest for stellar scenarios. High-efficiency total absorption spectroscopy is an established and powerful tool for studying radiative capture reactions, particularly if combined with the cosmic background reduction by several orders of magnitude obtained at the Laboratory for Underground Nuclear Astrophysics (LUNA). We present recent improvements in the detection setup with the Bismuth Germanium Oxide (BGO) detector at LUNA, aiming to reduce high-energy backgrounds and to increase the summing detection efficiency. The new design results in enhanced sensitivity of the BGO setup, as we demonstrate and discuss in the context of the first direct measurement of the 65 keV resonance ($E_x=5672$ keV) of the ${}^{17}$O($p,\gamma$)${}^{18}$F reaction. Moreover, we show two applications of the BGO detector, which exploit its segmentation. In case of complex $\gamma$-ray cascades, e.g. the de-excitation of $E_x=5672$ keV in ${}^{18}$F, the BGO segmentation allows to identify and suppress the beam-induced background signals that mimic the sum peak of interest. We demonstrate another new application for such a detector in form of in-situ activation measurements of a reaction with ${\beta }^{+}$ unstable product nuclei, e.g., the ${}^{14}$N($p,\gamma$)${}^{15}$O reaction.

References in corpus (24)

• S-factor of 14N(p,gamma)15O at astrophysical energies
• Activation measurement of the 3He(alpha,gamma)7Be cross section at low energy
• First measurement of the 14N(p,gamma)15O cross section down to 70 keV
• LUNA: Status and Prospects
• Low energy neutron background in deep underground laboratories
• The 25Mg(p,g)Al reaction at low astrophysical energies
• Improved Direct Measurement of the 64.5 keV Resonance Strength in the 17O(p,a)14N Reaction at LUNA
• Three new low-energy resonances in the ${}^{22}$Ne(p,$\gamma$)${}^{23}$Na reaction
• The activation method for cross section measurements in nuclear astrophysics
• Feasibility of low energy radiative capture experiments at the LUNA underground accelerator facility
• Direct measurement of the 13C(α,n)16O cross section into the s-process Gamow peak
• First Direct Measurement of the ^{17}O(p,γ)^{18}F Reaction Cross-Section at Gamow Energies for Classical Novae
• Preparation and characterisation of isotopically enriched Ta${}_2$O${}_5$ targets for nuclear astrophysics studies
• Measurement of ${}^{19}$F($p$,$\gamma$)${}^{20}$Ne reaction suggests CNO break-out in first stars
• 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
• Direct capture cross section and the $E_p$ = 71 and 105 keV resonances in the ${}^{22}$Ne($p,\gamma$)${}^{23}$Na reaction
• The impact of the revised ${}^{17}$O$(p,\alpha {)}^{14}$N reaction rate on ${}^{17}$O stellar abundances and yields
• 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
• Resonance strengths in the 14N(p,gamma)15O astrophysical key reaction measured with activation
• Activation cross section measurement of the 14N(p,gamma)15O astrophysical key reaction
• Direct measurement of the low energy resonances in ${}^{22}\mathrm{Ne}(\alpha ,\gamma {)}^{26}\mathrm{Mg}$ reaction
• The new Felsenkeller 5 MV underground accelerator

Cited by in corpus (6)

• New proton-capture rates on carbon isotopes and their impact on the astrophysical ${}^{12}\mathrm{C}/{}^{13}\mathrm{C}$ ratio
• Improved $S$-factor of the ${}^{12}$C(p,$\gamma$)${}^{13}$N reaction at $E=$320-620~keV and the 422~keV resonance
• First direct measurement of the 64.5 keV resonance strength in ${}^{17}$O(p,$\gamma$)${}^{18}$F reaction
• Detectors and Shieldings: Past and Future at LUNA
• Study of the ${}^{20}$Ne($p,\gamma$)${}^{21}$Na reaction at LUNA
• The challenging first direct measurement of the 65 keV resonance strength in the ${}^{17}$O(p,$\gamma$)${}^{18}$F reaction at LUNA