New experimental study of low-energy (p,gamma) resonances in magnesium isotopes

TL;DR

This study provides precise measurements of low-energy proton capture resonances in magnesium isotopes, crucial for astrophysical models of stellar nucleosynthesis, using advanced underground laboratory techniques to overcome experimental challenges.

Contribution

The paper reports new, more accurate resonance strength measurements for key magnesium isotopes, improving nuclear data for astrophysical applications.

Findings

Resonance strengths for 24Mg(p,gamma)25Al, 25Mg(p,gamma)26Al, and 26Mg(p,gamma)27Al were measured.

Higher accuracy results than previous studies were achieved.

The measurements were performed at the LUNA underground facility using multiple techniques.

Abstract

Proton captures on Mg isotopes play an important role in the Mg-Al cycle active in stellar H shell burning. In particular, the strengths of low-energy resonances with E < 200 keV in 25Mg(p,gamma)26Al determine the production of 26Al and a precise knowledge of these nuclear data is highly desirable. Absolute measurements at such low-energies are often very difficult and hampered by gamma-ray background as well as changing target stoichiometry during the measurements. The latter problem can be partly avoided using higher energy resonances of the same reaction as a normalization reference. Hence the parameters of suitable resonances have to be studied with adequate precision. In the present work we report on new measurements of the resonance strengths omega_gamma of the E = 214, 304, and 326 keV resonances in the reactions 24Mg(p,gamma)25Al, 25Mg(p,gamma)26Al, and 26Mg(p,gamma)27Al, respectively. These studies were performed at the LUNA facility in the Gran Sasso underground laboratory using multiple experimental techniques and provided results with a higher accuracy than previously achieved.