scholarly journals Heavy ion nucleus scattering

1999 ◽  
Vol 112 (6) ◽  
pp. 587-596 ◽  
Author(s):  
A. Rahman ◽  
Sirajum Munir ◽  
H. M. Sen Gupta
Keyword(s):  
Heavy Ion ◽  
Nucleus Scattering

Quadronium and quantum electrodynamics

1996 ◽  
Vol 74 (7-8) ◽  
pp. 527-533 ◽  
Author(s):  
James J. Griffin
Keyword(s):  
Quantum Electrodynamics ◽  
Composite Particle ◽  
Bound State ◽  
Heavy Ion ◽  
Annihilation Rate ◽  
Small Correction ◽  
Order Matrix Element ◽  
Nucleus Scattering ◽  
Electron Magnetic Moment ◽  
Rule Out

The composite-particle scenario is a phenomenology that can organize the data of the "sharp lepton problem" posed by heavy-ion and (β+ + atom) studies. It hypothesizes a new composite particle (of mass ~3mc2) as the source of the observed sharp energy (e+e−) decay pairs. Available data rule out the possibilities that the source is a new elementary particle or that it is a quasi-bound state of (e+e−). Occam's razor therefore currently favors the quadronium structure, Q0 = (e+e+e−e−). Implications of quadronium for high-precision quantum electrodynamics (QED) are considered, and calculated and (or) measured deviations in QED that are sensitive to the existence of Q0 are identified. In particular, for the electron magnetic-moment anomaly, a(e) = (ge − 2)/2, a Q0–pole effects a small correction to the contributions of O(α4), which is therefore small compared to the largest current (theoretical) uncertainty. For photon–photon scattering, Q0 corrects the leading order matrix element, and allows resonant Q0 creation in photon–nucleus scattering. Finally, a Q0 bound state corrects the O(α) correction to the leading 3γ annihilation rate of triplet positronium. Therefore Q0 may contribute significantly to this decay rate, which is currently in a 10σ discrepancy with experiment. A current experimental gap is the lack of corroborative data on the sharp (Γ ≤ 2.1 keV) 330.1 keV electrons reported by Sakai from irradiations of U and Th with β+-decay positrons. A study of these (and (or) their expected partner positrons of the same energy) in collisions of (~3 MeV) beam positrons (or electrons) upon high-Z neutral atoms could fill this gap. Similar studies with positrons of 660–795 keV would test the expectation that recoilless resonance creation of the Q0 source of these pairs is also possible.

scholarly journals HIGH-ENERGY APPROXIMATION FOR NUCLEUS–NUCLEUS SCATTERING

2001 ◽  
Vol 10 (03) ◽  
pp. 169-183 ◽  
Author(s):  
V. K. LUKYANOV ◽  
E. V. ZEMLYANAYA
Keyword(s):  
Heavy Ion ◽  
High Energy ◽  
Ion Scattering ◽  
Heavy Ion Scattering ◽  
Energy Approximation ◽  
Nucleus Scattering ◽  
Type Potential ◽  
Comparison With Experimental Data ◽  
Straight Trajectory

The high-energy approximation is adapted for heavy ion scattering at energies of several dozen MeV/nucleon. It is shown that the closed form of the eikonal phase suggested for the realistic Woods–Saxon type potential is a hopeful one for further applications. The Glauber–Sitenko small angle approach is analyzed, and a role of the Coulomb deviation of the straight trajectory of motion is investigated. Methodical calculations and comparison with experimental data are made.

EVIDENCE AGAINST A HYPOTHETICAL LIGHT SCALAR PARTICLE PRODUCED IN HEAVY ION COLLISION SYSTEMS

1986 ◽  
Vol 01 (03) ◽  
pp. 157-160 ◽  
Author(s):  
U.E. SCHRÖDER
Keyword(s):  
Experimental Data ◽  
Scalar Particle ◽  
Heavy Ion ◽  
Low Energy ◽  
Heavy Ion Collision ◽  
Energy Neutron ◽  
Light Scalar ◽  
Nucleus Scattering ◽  
Ion Collision

The existence of a hypothetical light scalar particle with conventional coupling to hadrons that has been suggested in order to explain the positron lines observed in super-heavy collision systems is shown to be in violent contradiction with experimental data obtained in low energy neutron-nucleus scattering.

Axial Observation of X-Ray Spectra from a Beam-Foil Source

1988 ◽  
Vol 102 ◽  
pp. 339-342
Author(s):  
J.M. Laming ◽  
J.D. Silver ◽  
R. Barnsley ◽  
J. Dunn ◽  
K.D. Evans ◽  
...  
Keyword(s):  
Spectral Resolution ◽  
Heavy Ion ◽  
Ion Beams ◽  
Beam Axis ◽  
Doppler Broadening ◽  
X Ray ◽  
Beam Foil

AbstractNew observations of x-ray spectra from foil-excited heavy ion beams are reported. By observing the target in a direction along the beam axis, an improvement in spectral resolution, δλ/λ, by about a factor of two is achieved, due to the reduced Doppler broadening in this geometry.

Void-Lattice Formation in Natural Fluorite by Electron Irradiation

1976 ◽  
Vol 34 ◽  
pp. 614-615 ◽  
Author(s):  
L.E. Murr
Keyword(s):  
Electron Microscope ◽  
Electron Irradiation ◽  
Heavy Ion ◽  
High Energy ◽  
Stoichiometric Ratio ◽  
Direct Observations ◽  
Transmission Electron ◽  
Anion Vacancies ◽  
Cation And Anion Vacancies ◽  
Lattice Formation

The production of void lattices in metals as a result of displacement damage associated with high energy and heavy ion bombardment is now well documented. More recently, Murr has shown that a void lattice can be developed in natural (colored) fluorites observed in the transmission electron microscope. These were the first observations of a void lattice in an irradiated nonmetal, and the first, direct observations of color-center aggregates. Clinard, et al. have also recently observed a void lattice (described as a high density of aligned "pores") in neutron irradiated Al2O3 and Y2O3. In this latter work, itwas pointed out that in order that a cavity be formed,a near-stoichiometric ratio of cation and anion vacancies must aggregate. It was reasoned that two other alternatives to explain the pores were cation metal colloids and highpressure anion gas bubbles.Evans has proposed that void lattices result from the presence of a pre-existing impurity lattice, and predicted that the formation of a void lattice should restrict swelling in irradiated materials because it represents a state of saturation.

Electron and ion irradiation-induced dissolution of mechanical twins in the intermetalic U3Si: An in situ HVEM study

1989 ◽  
Vol 47 ◽  
pp. 652-653
Author(s):  
Charles W. Allen ◽  
Robert C. Birtcher
Keyword(s):  
Elevated Temperatures ◽  
Ion Irradiation ◽  
Ion Beam ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Heavy Ion ◽  
High Energy ◽  
Mechanical Twinning ◽  
In Situ Experiments

The uranium silicides, including U3Si, are under study as candidate low enrichment nuclear fuels. Ion beam simulations of the in-reactor behavior of such materials are performed because a similar damage structure can be produced in hours by energetic heavy ions which requires years in actual reactor tests. This contribution treats one aspect of the microstructural behavior of U3Si under high energy electron irradiation and low dose energetic heavy ion irradiation and is based on in situ experiments, performed at the HVEM-Tandem User Facility at Argonne National Laboratory. This Facility interfaces a 2 MV Tandem ion accelerator and a 0.6 MV ion implanter to a 1.2 MeV AEI high voltage electron microscope, which allows a wide variety of in situ ion beam experiments to be performed with simultaneous irradiation and electron microscopy or diffraction.At elevated temperatures, U3Si exhibits the ordered AuCu3 structure. On cooling below 1058 K, the intermetallic transforms, evidently martensitically, to a body-centered tetragonal structure (alternatively, the structure may be described as face-centered tetragonal, which would be fcc except for a 1 pet tetragonal distortion). Mechanical twinning accompanies the transformation; however, diferences between electron diffraction patterns from twinned and non-twinned martensite plates could not be distinguished.

Sound velocity of glassy Pd 80 Si 20 after heavy-ion irradiation at low temperatures

2002 ◽  
Vol 82 (11) ◽  
pp. 2333-2339
Author(s):  
G. Schumacher ◽  
R. C. Birtcher ◽  
D. P. Renusch ◽  
M. Grimsditch ◽  
L. E. Rehn
Keyword(s):  
Sound Velocity ◽  
Low Temperatures ◽  
Ion Irradiation ◽  
Heavy Ion ◽  
Heavy Ion Irradiation

On Kinetic Equations in Heavy-Ion Physics

1996 ◽  
Vol 21 (5) ◽  
pp. 461-502 ◽  
Author(s):  
E. Suraud
Keyword(s):  
Kinetic Equations ◽  
Heavy Ion ◽  
Heavy Ion Physics

The cross sections for different channels in heavy ion nuclear reactions

1971 ◽  
Vol 32 (1) ◽  
pp. 7-9 ◽  
Author(s):  
J. Galin ◽  
D. Guerreau ◽  
M. Lefort ◽  
X. Tarrago
Keyword(s):  
Cross Sections ◽  
Nuclear Reactions ◽  
Heavy Ion ◽  
The Cross
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