Indirect 2H(d,p)3H and 2H(d,n)3He fusion reactions measurement at energies relevant for Big Bang Nucleosynthesis
type: CreativeWork
description: The work presented in this thesis is focused on the experimental study of the two deuterium burning channels 2H(d,p)3H and 2H(d,n)3He in the Big Bang Nucleosynthesis (BBN) astrophysical scenario. In the beginning is presented this phase of the early universe and why the BBN model is still fine tuned with new results coming from observations and laboratory measurements. This model (if BBN is considered standard) can be adjusted such to have only a free parameter, the baryon to photon ratio of the universe eta at a certain time. Also the WMAP satellite results have been of great help to fix eta (and then all the others BBN numbers), but still persist some discrepancies, as for the lithium primordial abundances, between what is theoretically predicted and what is observed. The deuterium (and the reactions in which is involved) plays a key role in the evaluation of eta, thus for all BBN, so that is called the best baryometer. Then is explained that the need of new cross sections (and reaction rates) measurements for astrophysics can not be satisfied. This is because of the problems given by their measurements in the laboratory, as the presence of Coulomb barrier (that makes cross sections exponentially decrease in the energy range of interest) and the electron screening effect. For all these reasons the present measurements have been performed through the Trojan Horse Method (THM), an indirect method that allow to have a bare-nucleus cross section of the two-body reaction of astrophysical interest that is free of the Coulomb suppression. This is accomplished via the selection of the quasi-free mechanism in an appropriate three-body reaction, whose center-of-mass energy is greater than the Coulomb barrier. Two experimental runs have been carried out at the Nuclear Physics Institute of the Academy of Science of Czech Republic, in Rez (Prague). In the first one, with a 17 MeV 3He beam (in which only 2H(d,p)3H has been measured) the presence of quasi-free mechanism events h…
abstract: The work presented in this thesis is focused on the experimental study of the two deuterium burning channels 2H(d,p)3H and 2H(d,n)3He in the Big Bang Nucleosynthesis (BBN) astrophysical scenario. In the beginning is presented this phase of the early universe and why the BBN model is still fine tuned with new results coming from observations and laboratory measurements. This model (if BBN is considered standard) can be adjusted such to have only a free parameter, the baryon to photon ratio of the universe eta at a certain time. Also the WMAP satellite results have been of great help to fix eta (and then all the others BBN numbers), but still persist some discrepancies, as for the lithium primordial abundances, between what is theoretically predicted and what is observed. The deuterium (and the reactions in which is involved) plays a key role in the evaluation of eta, thus for all BBN, so that is called the best baryometer. Then is explained that the need of new cross sections (and reaction rates) measurements for astrophysics can not be satisfied. This is because of the problems given by their measurements in the laboratory, as the presence of Coulomb barrier (that makes cross sections exponentially decrease in the energy range of interest) and the electron screening effect. For all these reasons the present measurements have been performed through the Trojan Horse Method (THM), an indirect method that allow to have a bare-nucleus cross section of the two-body reaction of astrophysical interest that is free of the Coulomb suppression. This is accomplished via the selection of the quasi-free mechanism in an appropriate three-body reaction, whose center-of-mass energy is greater than the Coulomb barrier. Two experimental runs have been carried out at the Nuclear Physics Institute of the Academy of Science of Czech Republic, in Rez (Prague). In the first one, with a 17 MeV 3He beam (in which only 2H(d,p)3H has been measured) the presence of quasi-free mechanism events h…
author: SPARTA', ROBERTA
language: eng
keywords: nuclear astrophysics, d+d, d(d,p)t, d(d,n)3he, BBN, Big Bang Nucleosynthesis, reaction rate, eta, baryon-to-photon ratio, THM, Trojan Horse Method, 2H(d,p)3H, 2H(d,n)3He
date published: 2012-12-09
date modified: 2026-07-24T01:35:17Z
provider: Università degli Studi di Catania
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Università degli studi di Catania

PropertyValue
property ID: Handle
value: https://hdl.handle.net/20.500.11769/587305