Nuclear astrophysics with radioactive beams (original) (raw)

Nuclear Astrophysics in Rare Isotope Facilities

Acta Physica Hungarica A) Heavy Ion Physics, 2004

Nuclear reactions in stars are difficult to measure directly in the laboratory at the small astrophysical energies. In recent years indirect methods with rare isotopes have been developed and applied to extract low-energy astrophysical cross sections .

Progress In Nuclear Astrophysics Using Secondary Radioactive Beams

Revista Mexicana de Fisica

We review progress in studying two central problems in Nuclear Astrophysics: The \be7pg reaction is one of the major source of uncertainties in estimating the \b8 solar neutrino flux and is critical for the Solar Neutrino Problem. We discuss a newly emerging method to extract this cross section from the Coulomb dissociation of the radioactive beam of \b8. The Coulomb dissociation appears to provide a viable alternative method for measuring the \be7pg reaction rate. Several attempts to constrain the p-wave S-factor of the \c12ag reaction at Helium burning temperatures (200 MK) using the beta-delayed alpha-particle emission of \n16 have been made, and it is claimed that this S-factor is known, as quoted by the TRIUMF collaboration. In contrast reanalyses (by G.M. hale) of all thus far available data (including the \n16 data) does not rule out a small S-factor solution. Furthermore, we improved our previous Yale-UConn study of the beta-delayed alpha-particle emission of \n16. Our newly...

Nuclear astrophysics with secondary (Radioactive) beams

Progress in Particle and Nuclear Physics, 1993

Some problems in nuclear astrophysics are discussed with emphasize on the ones central to the field which were not solved over the last two decades, including Helium Burning in massive stars (the 12 C(α, γ) 16 O reaction) and the 8 B Solar Neutrino Flux Problem (the 7 Be(p, γ) 8 B reaction). We demonstrate that a great deal of progress was achieved by measuring the time reverse process(es): the beta-delayed alpha-particle emission of 16 N and the Coulomb dissociation of 8 B, using Radioactive Beams (of 16 N and 8 B). In this way an amplification of the sought for cross section was achieved, allowing a measurement of the small cross section(s) of relevance for stellar (solar) processes.

Experimental Tools for Nuclear Astrophysics

Lecture Notes in Physics

This chapter concentrates on experimental techniques currently used to investigate nuclear reactions of astrophysical interest. After a brief introduction, I shall present the basic quantities and equations governing thermonuclear reaction rates in stellar plasma. The various astrophysical scenarios, from hydrostatic to advanced burning stages up to/and including explosive mechanisms, as well as some key reactions, are briefly presented. I will concentrate on the experimental approaches to study nuclear reactions involved in both quiescent and explosive stellar burning. Particular emphasis is given to the use of radioactive ion beams and their importance for characterizing explosive nucleosynthesis in novae and X-ray bursts. A few recent examples will be shown in more detail to illustrate these techniques. Some key open questions will be discussed in the context of future facilities.

Experimental Challenges in Nuclear Astrophysics

Nuclear Physics A, 2005

The experimental simulation of stellar processes requires a very broad range of experimental techniques. The field has been rapidly growing over the last decade and a large number of new experimental facilities have been developed. This includes underground accelerators to shield the Cosmic ray background for sub-Coulomb barrier measurements of stellar reaction rates, neutron spallation sources for exploring neutron capture reactions for the s-process during late stellar evolution, and radioactive beam facilities for studying far of stability processes in stellar explosions. In this paper I want to present a short overview about the experimental questions and challenges these new developments pose for the experimental nuclear astrophysicist.

Nuclear and High-Energy Astrophysics

Structure and Interaction of Hadronics Systems - Proceedings of the VIII International Workshop on Hadron Physics 2002, 2003

There has never been a more exciting time in the overlapping areas of nuclear physics, particle physics and relativistic astrophysics than today. Orbiting observatories such as the Hubble Space Telescope, Rossi X-ray Timing Explorer (RXTE), Chandra X-ray satellite, and the X-ray Multi Mirror Mission (XMM) have extended our vision tremendously, allowing us to see vistas with an unprecedented clarity and angular resolution that previously were only imagined, enabling astrophysicists for the first time ever to perform detailed studies of large samples of galactic and extragalactic objects. On the Earth, radio telescopes (e.g., Arecibo, Green Bank, Parkes, VLA) and instruments using adaptive optics and other revolutionary techniques have exceeded previous expectations of what can be accomplished from the ground. The gravitational wave detectors LIGO, LISA VIRGO, and Geo-600 are opening up a window for the detection of gravitational waves emitted from compact stellar objects such as neutron stars and black holes. Together with new experimental forefront facilities like ISAC, ORLaND and RIA, these detectors provide direct, quantitative physical insight into nucleosynthesis, supernova dynamics, accreting compact objects, cosmic-ray acceleration, and pairproduction in high energy sources which reinforce the urgent need for a strong and continuous feedback from nuclear and particle theory and theoretical astrophysics. In my lectures, I shall concentrate on three selected topics, which range from the behavior of superdense stellar matter, to general relativistic stellar models, to strange quark stars and possible signals of quark matter in neutron stars.

Nuclear astrophysics from direct reactions

Accurate nuclear reaction rates are needed for primordial nucleosynthesis and hydrostatic burning in stars. The relevant reactions are extremely difficult to measure directly in the laboratory at the small astrophysical energies. In recent years direct reactions have been developed and applied to extract low-energy astrophysical S-factors. These methods require a combination of new experimental techniques and theoretical efforts, which are the subject of this presentation.

Nuclear Astrophysicsand Nuclei Far from Stability

This lecture concentrates on nucleosynthesis processes in stellar evolution and stellar explosions, with an emphasis on the role of nuclei far from stability. A brief initial introduction is given to the physics in astrophysical plasmas which governs composition changes. We present the basic equations for thermonuclear reaction rates, nuclear reaction networks and burning processes. The required nuclear physics input is discussed for cross sections of nuclear reactions, photodisintegrations, electron and positron captures, neutrino captures, inelastic neutrino scattering, and for beta-decay half-lives. We examine the present state of uncertainties in predictions in general as well as the status of experiments far from stability. It follows a discussion of the fate of massive stars, core collapse supernova explosions (SNe II), and novae and X-ray bursts (explosive hydrogen and helium burning on accreting white dwarfs or neutron stars in binary stellar systems). We address also the production of heavy elements in the r-process up to Th, U and beyond and their possible origin from stellar explosion sites.