Catalogue Search | MBRL
Are you sure you want to remove the book from the shelf?
{{itemTitle}}
27,617
result(s) for
"Nuclear astrophysics"
Sort by:
High-energy astrophysics
This textbook covers all the essentials, weaving together the latest theory with the experimental techniques, instrumentation, and observational methods astronomers use to study high-energy radiation from space.
Book
Practicing aspects of gamma-ray spectroscopy for nuclear astrophysics
The experimental methodologies of
γ
-ray detection and spectroscopy are widely used in nuclear astrophysics research that typically centers on the measurement of cross sections of reactions constituting the network of stellar nucleosynthesis. This article identifies the key factors of such endeavors and analyzes their impact on the aspired objectives. Such perspectives are known to be taken into cognizance while planning a facility for nuclear astrophysics research as well as in defining a research programme therein.
Journal Article
FRENA: India’s first nuclear astrophysics accelerator center
To address several outstanding problems in nuclear astrophysics, an accelerator centre has been developed in India. The Facility for Research in Experimental Nuclear Astrophysics (FRENA) will serve as a laboratory dedicated to nuclear astrophysics measurements. The 3 MV high current, low energy two-stage accelerator housed at FRENA is capable of delivering different types of beams—protons, alphas, carbon, silicon, among others. The accelerator can provide direct, as well as, pulsed beams of protons and alphas. A set of dedicated high efficiency detector arrays composed of solid state detectors, scintillation detectors and other particle detectors will be used at different end-stations to perform different experiments in the coming years.
Journal Article
Nuclear astrophysics: recent progress in understanding element formation in the universe
The Gamow window lies below the Coulomb barrier in astrophysical and cosmological nuclear processes involving charged particles in the relevant energy region. In these stars, the fusion of progressively heavier elements occurs until it reaches Fe, where exothermic reactions stop. [...]red giants are used to probe the history of star formation and subsequent evolution of metallicity in the galaxies. Final abundances are also expected to depend on beta decay as extremely neutron-rich nuclei formed in r-process undergo beta decay to reach the valley of stability. [...]some of the tenets of nuclear structure physics, like the concept of magic numbers, are not sacrosanct anymore as one travels far from stability.
Journal Article
Constraining neutron-star matter with microscopic and macroscopic collisions
Interpreting high-energy, astrophysical phenomena, such as supernova explosions or neutron-star collisions, requires a robust understanding of matter at supranuclear densities. However, our knowledge about dense matter explored in the cores of neutron stars remains limited. Fortunately, dense matter is not probed only in astrophysical observations, but also in terrestrial heavy-ion collision experiments. Here we use Bayesian inference to combine data from astrophysical multi-messenger observations of neutron stars
1
–
9
and from heavy-ion collisions of gold nuclei at relativistic energies
10
,
11
with microscopic nuclear theory calculations
12
–
17
to improve our understanding of dense matter. We find that the inclusion of heavy-ion collision data indicates an increase in the pressure in dense matter relative to previous analyses, shifting neutron-star radii towards larger values, consistent with recent observations by the Neutron Star Interior Composition Explorer mission
5
–
8
,
18
. Our findings show that constraints from heavy-ion collision experiments show a remarkable consistency with multi-messenger observations and provide complementary information on nuclear matter at intermediate densities. This work combines nuclear theory, nuclear experiment and astrophysical observations, and shows how joint analyses can shed light on the properties of neutron-rich supranuclear matter over the density range probed in neutron stars.
The physics of dense matter extracted from neutron star collision data is demonstrated to be consistent with information obtained from heavy-ion collisions, and analyses incorporating both data sources as well as information from nuclear theory provide new constraints for neutron star matter.
Journal Article
The baryon density of the Universe from an improved rate of deuterium burning
Light elements were produced in the first few minutes of the Universe through a sequence of nuclear reactions known as Big Bang nucleosynthesis (BBN)
1
,
2
. Among the light elements produced during BBN
1
,
2
, deuterium is an excellent indicator of cosmological parameters because its abundance is highly sensitive to the primordial baryon density and also depends on the number of neutrino species permeating the early Universe. Although astronomical observations of primordial deuterium abundance have reached percent accuracy
3
, theoretical predictions
4
–
6
based on BBN are hampered by large uncertainties on the cross-section of the deuterium burning D(
p
,
γ
)
3
He reaction. Here we show that our improved cross-sections of this reaction lead to BBN estimates of the baryon density at the 1.6 percent level, in excellent agreement with a recent analysis of the cosmic microwave background
7
. Improved cross-section data were obtained by exploiting the negligible cosmic-ray background deep underground at the Laboratory for Underground Nuclear Astrophysics (LUNA) of the Laboratori Nazionali del Gran Sasso (Italy)
8
,
9
. We bombarded a high-purity deuterium gas target
10
with an intense proton beam from the LUNA 400-kilovolt accelerator
11
and detected the γ-rays from the nuclear reaction under study with a high-purity germanium detector. Our experimental results settle the most uncertain nuclear physics input to BBN calculations and substantially improve the reliability of using primordial abundances to probe the physics of the early Universe.
High-precision cross-sections of the nuclear reaction that burns deuterium to create helium-3 are used to produce theoretical estimates of the primordial baryon density that are in agreement with recent astronomical observations.
Journal Article
Forward-looking insights in laser-generated ultra-intense γ-ray and neutron sources for nuclear application and science
Ultra-intense MeV photon and neutron beams are indispensable tools in many research fields such as nuclear, atomic and material science as well as in medical and biophysical applications. For applications in laboratory nuclear astrophysics, neutron fluxes in excess of 10
21
n/(cm
2
s) are required. Such ultra-high fluxes are unattainable with existing conventional reactor- and accelerator-based facilities. Currently discussed concepts for generating high-flux neutron beams are based on ultra-high power multi-petawatt lasers operating around 10
23
W/cm
2
intensities. Here, we present an efficient concept for generating
γ
and neutron beams based on enhanced production of direct laser-accelerated electrons in relativistic laser interactions with a long-scale near critical density plasma at 10
19
W/cm
2
intensity. Experimental insights in the laser-driven generation of ultra-intense, well-directed multi-MeV beams of photons more than 10
12
ph/sr and an ultra-high intense neutron source with greater than 6 × 10
10
neutrons per shot are presented. More than 1.4% laser-to-gamma conversion efficiency above 10 MeV and 0.05% laser-to-neutron conversion efficiency were recorded, already at moderate relativistic laser intensities and ps pulse duration. This approach promises a strong boost of the diagnostic potential of existing kJ PW laser systems used for Inertial Confinement Fusion (ICF) research.
Laser-plasma interaction can provide alternative platform over conventional method for particle and photon beam generation. Here the authors demonstrate generation of gamma ray and neutron beams from intense laser interaction with near critical density plasma.
Journal Article
Find a hotter place
Find a hotter place! is the insightful story of the tortured path that led to our current understanding of how the elements in the Universe came to be. This is a story which began in Greek Antiquity, with the first musings on the nature of matter and the void, and continues today with ever more refined analyses involving virtually every aspect of 20th century physics, astronomy, cosmology and information technology. Identifying the source of stellar energy, probing the earliest instants of the Universe, and discovering of how and where each element was made are some of the outstanding success stories of the 20th century, but have received little attention beyond the specialized literature. The year 2007 marks the 50th anniversary of the publication of one of the key papers on stellar nucleosynthesis, universally referred to as the B2FH paper. This book is a timely survey of how a new discipline — nuclear astrophysics — was born, and how it has matured. Almost completely non-technical, the book remains scientifically rigorous, and thereby fills an important gap. Science is not a linear process, as the ill-named “scientific method” might suggest to the unwary. The author emphasizes the meanders, the dead ends and the obsessive dogmas which have guided researchers through the 20th century. He also makes it clear that our understanding of where the elements come from has come through discoveries in diverse, not necessarily related, disciplines.
eBook
Enhanced production of 60Fe in massive stars
Massive stars are a major source of chemical elements in the cosmos, ejecting freshly produced nuclei through winds and core-collapse supernova explosions into the interstellar medium. Among the material ejected, long-lived radioisotopes, such as 60Fe (iron) and 26Al (aluminum), offer unique signs of active nucleosynthesis in our galaxy. There is a long-standing discrepancy between the observed 60Fe/26Al ratio by γ-ray telescopes and predictions from supernova models. This discrepancy has been attributed to uncertainties in the nuclear reaction networks producing 60Fe, and one reaction in particular, the neutron-capture on 59Fe. Here we present experimental results that provide a strong constraint on this reaction. We use these results to show that the production of 60Fe in massive stars is higher than previously thought, further increasing the discrepancy between observed and predicted 60Fe/26Al ratios. The persisting discrepancy can therefore not be attributed to nuclear uncertainties, and points to issues in massive-star models.
Journal Article
FRENA, a facility for research in experimental nuclear astrophysics at SINP, Kolkata
FRENA is a new low energy high current accelerator facility commissioned at the Saha Institute of Nuclear Physics, Kolkata, India. The primary goal of the facility is to perform nuclear astrophysics experiments and address key issues in the field. It is a unique facility in India and is the first accelerator dedicated for astrophysical studies.
Journal Article