57 research outputs found
New direct measurement of the 10 B(p,α) 7 Be reaction with the activation technique
Boron plays an important role in astrophysics and, together with lithium and beryllium, is a probe of stellar structure during the pre-main sequence and main-sequence phases. In this context, the 10 B(p, α ) 7 Be reaction is of particular interest.The literature data show discrepancies in the energy range between 100 keV and 2 MeV. This also poses a normalization problem for indirect data obtained with the Trojan Horse Method.A new measurement of the 10 B(p, α ) 7 Be reaction cross section was performed at Legnaro National Laboratories (LNL). At LNL, the cross section was determined with the activation technique by measuring the activated samples at a low-background counting facility. The analysis of that experiment is now complete and the results are here presented
Trojan Horse Investigation for AGB Stellar Nucleosynthesis
Asymptotic Giant Branch (AGB) stars are among the most important astrophysical sites influencing the nucleosynthesis and the chemical abundances in the Universe. From a pure nuclear point of view, several processes take part during this peculiar stage of stellar evolution thus requiring detailed experimental cross section measurements. Here, we report on the most recent results achieved via the application of the Trojan Horse Method (THM) and Asymptotic Normalization Coefficient (ANC) indirect techniques, discussing the details of the experimental procedure and the deduced reaction rates. In addition, we report also on the on going studies of interest for AGB nucleosynthesis
The 10B(p,α)7Be S(E)-factor from 5 keV to 1.5 MeV using the Trojan Horse Method
The 10 B(p, α ) 7 Be reaction is the main responsible for the 10 B destruction in stellar interior [1]. In such environments this p-capture process occurs at a Gamow energy of 10 keV and takes places mainly through a resonant state (Ex = 8.701 MeV) of the compound 11 C nucleus. Thus a resonance right in the region of the Gamow peak is expected to significantly influence the behavior of the astrophysical S(E)-factor. The 10 B(p, α ) 7 Be reaction was studied via the Trojan Horse Method (THM) applied to the 2 H( 10 B, α 7 Be)n in order to extract the astrophysical S(E)-factor in a wide energy range from 5 keV to 1.5 MeV
New direct measurement of the 10
Boron plays an important role in astrophysics and, together with lithium and beryllium, is a probe of stellar structure during the pre-main sequence and main-sequence phases. In this context, the 10B(p,α)7 Be reaction is of particular interest.
The literature data show discrepancies in the energy range between 100 keV and 2 MeV. This also poses a normalization problem for indirect data obtained with the Trojan Horse Method.
A new measurement of the 10B(p,α)7 Be reaction cross section was performed at Legnaro National Laboratories (LNL). At LNL, the cross section was determined with the activation technique by measuring the activated samples at a low-background counting facility. The analysis of that experiment is now complete and the results are here presented
Trojan Horse Investigation for AGB Stellar Nucleosynthesis
Asymptotic Giant Branch (AGB) stars are among the most important astrophysical sites influencing the nucleosynthesis and the chemical abundances in the Universe. From a pure nuclear point of view, several processes take part during this peculiar stage of stellar evolution thus requiring detailed experimental cross section measurements. Here, we report on the most recent results achieved via the application of the Trojan Horse Method (THM) and Asymptotic Normalization Coefficient (ANC) indirect techniques, discussing the details of the experimental procedure and the deduced reaction rates. In addition, we report also on the on going studies of interest for AGB nucleosynthesis
Gellan gum-based nanocomposites films containing bio-reduced silver nanoparticles: Synthesis, characterisation and antifungal activity
The aim of this work was to develop and characterise nanocomposite thin films containing silver nanoparticles (AgNPs), as wound dressings and antifungal materials, using a green process for the nanoparticles’ synthesis and a single step procedure for the preparation of the nanocomposite films. To this end, polyphenol-rich extracts obtained from kiwi peels, an agri-food industrial by-product, were used as a reducing agent of silver nitrate salt. The AgNPs were let form within the film-forming solution, which was composed by low acyl gellan gum and a plasticising agent (glycerol or PEG 400 g/mol) and the corresponding nanocomposite films were deposited by the solvent casting technique. The plasticising agent affected the AgNPs distribution within the films, as observed by SEM and EDS analyses, and consequently their tensile behaviour. In specific, AgNPs act as stress intensifiers in the presence of glycerol, whereas they act as film reinforcement with PEG400. However, both glycerol-plasticised and PEG400-plasticised films exhibited similar antifungal efficacy against 16 clinical isolates of 5 different Candida spp (C. albicans, C. lusitaniae, C. haemulonii, C. krusei and C. glabrata). Globally, the present study provides a green and single-step procedure to develop nanocomposite films embedding AgNPs obtained by in situ reduction of silver ions with polyphenol-rich extracts
New direct measurement of the 10B(p,α)7Be reaction with the activation technique
Boron plays an important role in astrophysics and, together with lithium and beryllium, is a probe of stellar structure during the pre-main sequence and main-sequence phases. In this context, the 10B(p,α)7 Be reaction is of particular interest.
The literature data show discrepancies in the energy range between 100 keV and 2 MeV. This also poses a normalization problem for indirect data obtained with the Trojan Horse Method.
A new measurement of the 10B(p,α)7 Be reaction cross section was performed at Legnaro National Laboratories (LNL). At LNL, the cross section was determined with the activation technique by measuring the activated samples at a low-background counting facility. The analysis of that experiment is now complete and the results are here presented
Nuclear Physics in Stellar Lifestyles with the Trojan Horse Method
The Trojan Horse Method is an indirect technique to measure nuclear reactions of astrophysical relevance at the energies of interest, free of Coulomb suppression and electron screening effects. Its basic features in the framework of the theory of direct reactions will be discussed and the physics case of the 12C+12C fusion will be addressed
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