4 results match your criteria Canadian Journal Of Physics[Journal]

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A comparison of the multigroup and collocation methods for solving the low-energy neutron Boltzmann equation.

Can J Phys 2000 Jan;78(1):45-56

Department of Mathematics, Old Dominion University, Norfolk, VA 23529-0077, USA.

A low-energy neutron transport algorithm for use in space-radiation protection is developed. The algorithm is based upon a multiple energy group analysis of the straight ahead Boltzmann equation utilizing a mean value theorem for integrals. The algorithm developed is then verified by using a collocation method solution on the same straight ahead Boltzmann equation. Read More

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January 2000

A simplified optical model description of heavy ion fragmentation.

Can J Phys 1985 ;63:135-8

NASA Langley Research Center, Hampton, VA 23665, USA.

The fragmentation of 213 MeV/nucleon 40Ar ions by 12C targets is described within the context of a simple abrasion-ablation fragmentation model. The abrasion part of the theory utilizes a quantum-mechanical formalism based upon an optical model potential approximation to the exact nucleus-nucleus multiple-scattering series. The ablation stage of the fragmentation is treated as a compound nucleus evaporation. Read More

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October 1997

Total and differential cross sections for pion production via coherent isobar and giant resonance formation in heavy-ion collisions.

Can J Phys 1985 ;63:1242-8

Department of Physics, University of Idaho, Moscow 83843, USA.

A quantal many-body formalism is presented that investigates pion production through the coherent formation of a nucleonic isobar in the projectile and its subsequent decay to various pion charge states along with concomitant excitation of the target to a coherent spin-isospin giant resonance via a peripheral collision of relativistic heavy ions. Total cross sections as a function of the incident energy per nucleon and Lorentz-invariant differential cross sections as a function of pion energy and angle are calculated. It is shown that the pion angular distributions, in coincidence with the target giant resonance excitations, might provide a well-defined signature for these coherent processes. Read More

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August 1998
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Mean excitation energies for stopping powers in various materials composed of elements hydrogen through argon.

Can J Phys 1984 ;62(7):646-60

NASA Langley Research Center, Hampton, VA 23665, USA.

The basic model of Lindhard and Scharff, known as the local plasma model, is utilized to study the effects of the chemical and physical state of the medium on its stopping power. Unlike previous work with the local plasma model, in which individual electron shifts in the plasma frequency were estimated empirically, the Pines correction derived for a degenerate Fermi gas is shown herein to provide a reasonable estimate even on the atomic scale. Thus, the model is moved to a completely theoretical base requiring no empirical adjustments, adjustments characteristics of past applications. Read More

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October 1997
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