LUNA: a laboratory for underground nuclear astrophysics

Costantini, H.; Formicola, A.; Imbriani, G.; Junker, M.; Rolfs, C.; Strieder, F.

doi:10.1088/0034-4885/72/8/086301

Cited by 148 publications

(238 citation statements)

References 154 publications

(545 reference statements)

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“…In the past ten years there have been several experiments that measured this cross section using both direct and indirect methods. In particular, the experiment performed by the LUNA collaboration (Imbriani et al 2005;Costantini et al 2009) has reached the lowest energy, about 70 keV, which corresponds to a stellar temperature of about 50 MK. It is worth noting that a reliable extrapolation of the LUNA data to the solar Gamow peak requires combining low-energy with high-energy data, namely the results of the LENA experiment at TUNL (Runkle et al 2005).…”

Section: Reaction Rate Uncertaintiesmentioning

confidence: 99%

Effects of nuclear cross sections on¹⁹F nucleosynthesis at low metallicities

Cristallo

Leva

Imbriani

et al. 2014

A&A

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Context. The origin of fluorine is a longstanding problem in nuclear astrophysics. It is widely recognized that asymptotic giant branch (AGB) stars are among the most important contributors to the Galactic fluorine production. Aims. In general, extant nucleosynthesis models overestimate the fluorine production by AGB stars with respect to observations. Although those differences are rather small at solar metallicity, low metallicity AGB stellar models predict fluorine surface abundances up to one order of magnitude larger than the observed ones. Methods. As part of a project devoted to reducing the uncertainties in the nuclear physics that affect the nucleosynthesis in AGB stellar models, we review the relevant nuclear reaction rates involved in the fluorine production or destruction. We perform this analysis on a model with initial mass M = 2 M and Z = 0.001. Results. We found that the major uncertainties are due to the 13 C(α,n) 16 O, the 19 F(α,p) 22 Ne, and the 14 N(p,γ) 15 O reactions. A change in the corresponding reaction rates within the present experimental uncertainties implies surface 19 F variations at the AGB tip lower than 10%, thus much smaller than observational uncertainties. For some α capture reactions, however, cross sections at astrophysically relevant energies are determined on the basis of nuclear models, in which some low-energy resonance parameters are very poorly known. Thus, larger variations in the rates of those processes cannot be excluded. That being so, we explore the effects of the variation in some α capture rates well beyond the current published uncertainties. The largest 19 F variations are obtained by varying the 15 N(α,γ) 19 F and the 19 F(α,p) 22 Ne reactions. Conclusions. The currently estimated uncertainties of the nuclear reaction rates involved in the production and destruction of fluorine produce minor 19 F variations in the ejecta of AGB stars. Analysis of some α capture processes that assume a wider uncertainty range determines 19 F abundances in better agreement with recent spectroscopic fluorine measurements at low metallicity. In the framework of this scenario, the 15 N(α,γ) 19 F and the 19 F(α,p) 22 Ne reactions show the strongest effects on fluorine nucleosynthesis. The presence of poorly known low-energy resonances make such a scenario possible, even if it is unlikely. We plan to measure these resonances directly.

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Section: Reaction Rate Uncertaintiesmentioning

confidence: 99%

Effects of nuclear cross sections on¹⁹F nucleosynthesis at low metallicities

Cristallo

Leva

Imbriani

et al. 2014

A&A

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“…The accelerator at LUNA (more precisely: LUNA2 [6]) provides a proton beam with energies up to 400 keV. The setup used for these studies employs solid targets, which are bombarded with beam currents typically about 100 µA.…”

Section: Setupmentioning

confidence: 99%

Status of Direct ²³Na(p, \(\gamma \))²⁴Mg and ¹⁸O(p, \(\gamma \))¹⁹F Cross Section Measurements Underground at LUNA

Boeltzig¹,

Pantaleo²,

Best³

et al. 2017

Proceedings of the 14th International Symposium on Nuclei in the Cosmos (NIC2016)

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The reactions 23 Na(p, γ) 24 Mg and 18 O(p, γ) 19 F are currently under study at the Laboratory for Underground Nuclear Astrophysics (LUNA) at the Gran Sasso National Laboratory. The reaction rates of the two reactions in the temperature range up to several hundred MK are determined by the direct capture process and few narrow resonances. For both reactions the strength of some of these resonances are known only with a large uncertainty, or with upper limits that do not exclude their relevance for astrophysics. The measurements at LUNA aim at a direct detection of these reactions at low energies, to provide data to decrease the uncertainty of the reaction rates. The two reactions are studied in parallel with the same two detector setups. We present the setups as well as the status of the measurements.

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“…The basic processes are by now well understood, leading to the so-called standard solar model [13] that explains both helioseismological data and neutrino observations. LUNA started its work studying the 3 He( 3 He,2p) 4 He reaction. This is a key reaction of the hydrgen burning proton proton chain and at the beginning of the seventies it was believed to exist a possible resonance in the 3 He( 3 He,2p) 4 He Gamow peak that could have explained the low measured neutrino flux measured by the Homestake experiment [14].…”

Section: Solar Hydrogen Burningmentioning

confidence: 99%

“…As a matter of fact the natural shielding provided by an underground site will guarantee a reduction of the cosmic flux of orders of magnitude leading to the success of experimental nuclear physics. LUNA (Laboratory for Underground Nuclear Physics) [4,5] is placed under the Gran Sasso National Laboratories of INFN. Two accelerators were used during years.…”

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confidence: 99%

Nuclear Astrophysics in underground laboratories: the LUNA experiment

Simpson¹,

Simenel²,

Cook³

et al. 2017

EPJ Web Conf.

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Abstract. One of the main ingredients of nuclear astrophysics is the knowledge of the thermonuclear reactions responsible for powering the stellar engine and for the synthesis of the chemical elements. At astrophysical energies the cross section of nuclear processes is extremely reduced by the effect of the Coulomb barrier. The low value of cross sections prevents their measurement at stellar energies on Earth surface and often extrapolations are needed. The Laboratory for Underground Nuclear Astrophysics (LUNA) is placed under the Gran Sasso mountain and thanks to the cosmic-ray background reduction provided by its position can investigate cross sections at energies close to the Gamow peak in stellar scenarios. Many crucial reactions involved in hydrogen burning has been measured directly at astrophysical energies with both the LUNA-50kV and the LUNA-400kV accelerators, and this intense work will continue with the installation of a MV machine able to explore helium and carbon burnings. Based on this progress, currently there are efforts in several countries to construct new underground accelerators. In this talk, the typical techniques adopted in underground nuclear astrophysics will be described and the most relevant results achieved by LUNA will be reviewed. The exciting science that can be probed with the new facilities will be highlighted.

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LUNA: a laboratory for underground nuclear astrophysics

Cited by 148 publications

References 154 publications

Effects of nuclear cross sections on¹⁹F nucleosynthesis at low metallicities

Effects of nuclear cross sections on¹⁹F nucleosynthesis at low metallicities

Status of Direct ²³Na(p, \(\gamma \))²⁴Mg and ¹⁸O(p, \(\gamma \))¹⁹F Cross Section Measurements Underground at LUNA

Nuclear Astrophysics in underground laboratories: the LUNA experiment

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LUNA: a laboratory for underground nuclear astrophysics

Cited by 148 publications

References 154 publications

Effects of nuclear cross sections on19F nucleosynthesis at low metallicities

Effects of nuclear cross sections on19F nucleosynthesis at low metallicities

Status of Direct 23Na(p, \(\gamma \))24Mg and 18O(p, \(\gamma \))19F Cross Section Measurements Underground at LUNA

Nuclear Astrophysics in underground laboratories: the LUNA experiment

Contact Info

Product

Resources

About

Effects of nuclear cross sections on¹⁹F nucleosynthesis at low metallicities

Effects of nuclear cross sections on¹⁹F nucleosynthesis at low metallicities

Status of Direct ²³Na(p, \(\gamma \))²⁴Mg and ¹⁸O(p, \(\gamma \))¹⁹F Cross Section Measurements Underground at LUNA