M. Laubenstein

Activation measurement of the He3(α,γ)Be7 cross section at low energy

The nuclear physics input from the 3He(alpha,gamma)7Be cross section is a major uncertainty in the fluxes of 7Be and 8B neutrinos from the Sun predicted by solar models and in the 7Li abundance obtained in big-bang nucleosynthesis calculations. The present work reports on a new precision experiment using the activation technique at energies directly relevant to big-bang nucleosynthesis. Previously such low energies had been reached experimentally only by the prompt-gamma technique and with inferior precision. Using a windowless gas target, high beam intensity, and low background gamma-counting facilities, the 3He(alpha,gamma)7Be cross section has been determined at 127, 148, and 169 keV center-of-mass energy with a total uncertainty of 4%. The sources of systematic uncertainty are discussed in detail. The present data can be used in big-bang nucleosynthesis calculations and to constrain the extrapolation of the 3He(alpha,gamma)7Be astrophysical S factor to solar energies.

Ultra-sensitive in-beam γ -ray spectroscopy for nuclear astrophysics at LUNA

Ultra-sensitive in-beam

First Direct Measurement of the 17O(p,γ)18F Reaction Cross Section at Gamow Energies for Classical Novae

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The He3(α,γ)Be7 S-factor at solar energies: The prompt γ experiment at LUNA

-ray spectroscopy studies for nuclear astrophysics are performed at the LUNA (Laboratory for Underground Nuclear Astrophysics) 400 kV accelerator, deep underground in Italy’s Gran Sasso laboratory. By virtue of a specially constructed passive shield, the laboratory

Underground nuclear astrophysics: Why and how

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Astrophysical S factor of the He3(α,γ)Be7 reaction measured at low energy via detection of prompt and delayed γ rays

-ray background for

The He-3(alpha,gamma)Be-7 S-factor at solar energies: The Prompt gamma experiment at LUNA

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3He(α,γ)7Be cross section at low energies

< 3 MeV at LUNA has been reduced to levels comparable to those experienced in dedicated offline underground

Astrophysical S-factor of the 3He(alpha,gamma)7Be reaction measured at low energy via prompt and delayed gamma detection

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Comparison of the LUNA 3He(α, γ)7Be activation results with earlier measurements and model calculations

-counting setups. The