The use of nuclear reactions and ion channeling to study trapping of Cu self-interstitial atoms by Be solute atoms in a Cu – 0.25 at.% Be crystal

1977 ◽  
Vol 55 (21) ◽  
pp. 1871-1883 ◽  
Author(s):  
M. L. Swanson ◽  
L. M. Howe ◽  
A. F. Quenneville
Keyword(s):  
Nuclear Reaction ◽  
Nuclear Reactions ◽  
Stage Iii ◽  
Ion Channeling ◽  
Interstitial Atoms ◽  
Solute Atoms

In a Cu – 0.25 at.% Be crystal, the 9Be(d,α)7Li and 9Be(d,p)10Be nuclear reaction yields were compared with backscattering yields of 0.6 MeV deuterons from Cu atoms at 30 K to study the irradiation-induced displacement of Be atoms from lattice sites. From an analysis of yields for [Formula: see text], [Formula: see text], and [Formula: see text] channels it was concluded that Be atoms were displaced approximately 0.13 nm in [Formula: see text] directions by the trapping of Cu self-interstitial atoms. Thus the trapping configuration was the [Formula: see text] mixed dumbbell. The Be atoms had returned to lattice sites by the end of stage III recovery (at 250 K).

scholarly journals The feasibility of measuring the nuclear reaction cross sections at energies of several KeV in a target under laser compression

1987 ◽  
Vol 5 (2) ◽  
pp. 399-404 ◽  
Author(s):  
V. I. Kukulin ◽  
V. M. Krasnopol'sky ◽  
V. T. Voronchev
Keyword(s):  
Nuclear Reaction ◽  
Cross Sections ◽  
Nuclear Reactions ◽  
Velocity Distribution Function ◽  
Reaction Cross ◽  
Straightforward Method ◽  
Energy Behaviour ◽  
Low Energies ◽  
Ion Velocity Distribution Function ◽  
Reaction Cross Sections

The work proposes a straightforward method for determining the nuclear reaction cross sections at extremely low energies (E ≃ 1–100 keV) on the basis of the measurements of the relative yield of fast particles which are products of the nuclear reactions in a target under laser compression. On the other hand, the proposed method makes it possible to find the averaged form of the ion velocity distribution function if the low-energy behaviour of the respective cross sections is known.

ABUNDANCE ANOMALIES PRODUCED BY NUCLEAR REACTIONS IN STELLAR SURFACE LAYERS: I. NUCLEAR-REACTION RATES

1967 ◽  
Vol 45 (10) ◽  
pp. 3275-3296 ◽  
Author(s):  
P. J. Brancazio ◽  
A. Gilbert ◽  
A. G. W. Cameron
Keyword(s):  
Statistical Theory ◽  
Nuclear Reaction ◽  
Cross Sections ◽  
Nuclear Reactions ◽  
Level Density ◽  
Preliminary Investigation ◽  
Computer Time ◽  
Reaction Rates ◽  
Reaction Cross ◽  
Surface Layers

A preliminary investigation of the effects on abundances in stellar surfaces of extensive nuclear bombardment required the calculation of more than 105 nuclear-reaction cross sections. It was necessary to develop simplified methods for using the statistical theory of nuclear reactions to make these calculations in order that the computer time should not be prohibitive. These methods are described here and the results are compared with experiment. The accuracy of the calculations is, in general, about as good as, or somewhat better than, that obtained in previous applications of the statistical theory, probably because the use of an accurate level density formula outweighed the crudity of other approximations.

scholarly journals Global predictions for astrophysics applications

2020 ◽  
Vol 13 ◽  
pp. 18
Author(s):  
P. Demetriou
Keyword(s):  
Nuclear Reaction ◽  
Cross Sections ◽  
Nuclear Reactions ◽  
Nuclear Astrophysics ◽  
Reaction Network ◽  
Reaction Rates ◽  
Reaction Cross ◽  
Hartree Fock ◽  
Microscopic Models ◽  
The Stability

Nuclear reaction rates play a crucial role in nuclear astrophysics. In the last decades there has been an enormous effort to measure reaction cross sections and extensive experimental databases have been compiled as a result. In spite of these efforts, most nuclear reaction network calculations still have to rely on theoretical predic- tions of experimentally unknown rates. In particular, in astrophysics applications such as the s-, r- and p-process nucleosynthesis involving a large number of nuclei and nuclear reactions (thousands). Moreover, most of the ingredients of the cal- culations of reaction rates have to be extrapolated to energy and/or mass regions that cannot be explored experimentally. For this reason it is important to develop global microscopic or semi-microscopic models of nuclear properties that give an accurate description of existing data and are reliable for predictions far away from the stability line. The need for more microscopic input parameters has led to new devel- opments within the Hartree-Fock-Bogoliubov method, some of which are presented in this paper.

STUDY OF LIGHT UNSTABLE NUCLEI VIA DIRECT NUCLEAR REACTIONS

2006 ◽  
Vol 15 (07) ◽  
pp. 1465-1470
Author(s):  
YANLIN YE ◽  
DANYANG PANG ◽  
CENG ZHANG ◽  
DONGXING JIANG ◽  
TAO ZHENG ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Nuclear Reaction ◽  
Transfer Reaction ◽  
Nuclear Reactions ◽  
S Wave ◽  
Preliminary Calculation ◽  
Unstable Nuclei ◽  
Neutron Configuration ◽  
D Wave ◽  
Direct Nuclear Reactions

Sensitivity of the direct nuclear reaction to the exotic structure of the unstable nuclei is outlined. The transfer reaction induced by 6 He on a 9 Be target at 25 MeV/u is described. The theoretical analysis using CRC model supports the di-neutron configuration of the two valence neutrons in 6 He . Preliminary calculation for 17 Ne were introduced which indicates the advantage of using transfer reaction to clarify the s-wave or d-wave configuration of the valence protons.

AB INITIO NUCLEAR STRUCTURE AND NUCLEAR REACTIONS IN LIGHT NUCLEI

2005 ◽  
Vol 14 (01) ◽  
pp. 85-93 ◽  
Author(s):  
PETR NAVRÁTIL
Keyword(s):  
Ab Initio ◽  
Shell Model ◽  
Nuclear Reaction ◽  
Nuclear Structure ◽  
Nuclear Reactions ◽  
Light Nuclei ◽  
Core Shell ◽  
Ab Initio Methods ◽  
Significant Progress ◽  
Nucleon Interactions

There has been significant progress in the ab initio approaches to the structure of light nuclei. One such method is the ab initio no-core shell model (NCSM). Starting from the realistic two- and three-nucleon interactions, this method can predict the low-lying levels in p-shell nuclei. It is a challenging task to extend the ab initio methods to describe nuclear reactions. In this contribution, we present a brief overview of the NCSM with examples of recent applications as well as the first steps taken toward nuclear reaction applications.

scholarly journals Interference Between Levels in Nuclear Reactions

1967 ◽  
Vol 20 (3) ◽  
pp. 341 ◽  
Author(s):  
FC Barker
Keyword(s):  
Nuclear Reaction ◽  
Cross Section ◽  
Nuclear Reactions ◽  
Matrix Theory ◽  
R Matrix ◽  
Single Level ◽  
The Cross

In this note we consider the cross section for a nuclear reaction in which one of the product nuclei is unstable, with two or more levels contributing to its decay. Previously a formula had been derived from R-matrix theory for the case where contributions come from only a single level of the nucleus with a given spin and parity.

scholarly journals Hydrogen and helium isotope inner radiation belts in the Earth's magnetosphere

1998 ◽  
Vol 16 (8) ◽  
pp. 931-939 ◽  
Author(s):  
G. I. Pugacheva ◽  
W. N. Spjeldvik ◽  
A. A. Gusev ◽  
I. M. Martin ◽  
N. M. Sobolevsky
Keyword(s):  
Nuclear Reaction ◽  
Transport Theory ◽  
Nuclear Reactions ◽  
High Energy ◽  
Reaction Model ◽  
Atmospheric Composition ◽  
Helium Isotope ◽  
Reaction Yield ◽  
Model Code ◽  
Radiation Zone

Abstract. Radial transport theory for inner radiation zone MeV ions has been extended by combining radial diffusive transport and losses due to Coulomb friction with local generation of D, T and 3He ions from nuclear reactions taking place on the inner edge of the inner radiation zone. Based on interactions between high energy trapped protons and upper atmospheric constituents we have included a nuclear reaction yield D, T and 3He flux source that was numerically derived from a nuclear reaction model code originally developed at the Institute of Nuclear Researches in Moscow, Russia. Magnetospheric transport computations have been made covering the L-shell range L=1.0–1.6. The resulting MeV energy D, T and 3He ion flux distributions show a strong influence of the local nuclear source mechanism on the inner zone energetic D, T and 3He ion content.Key words: Atmospheric composition and structure (Thermosphere-composition and chemistry) · Magnetospheric physics (Energetic particles · trapped).

The trapping configuration of Al interstitial atoms at Zn solute atoms in Al–0.1 at% Zn crystals

1975 ◽  
Vol 31 (2) ◽  
pp. 675-683 ◽  
Author(s):  
M. L. Swanson ◽  
L. M. Howe ◽  
A. F. Quenneville
Keyword(s):  
Interstitial Atoms ◽  
Solute Atoms
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