Interaction Of Projectile Research Articles

Interaction of Soil and Penetration Projectile

The motion of a terradynamic penetrator is formulated, and some interaction characteristics as the added mass and the interaction pressure distribution are calculated. The magnitude of the added mass is found to be small compared to the penetrator's mass. The expression for the interaction pressure is shown to be composed of a static and a dynamic term. The calculated stresses and masses can be used for the dynamic analysis of the penetrator's structure.

Fusion and direct reactions for strongly and weakly bound projectiles

The interaction of 6Li, 9Be and 12C projectiles with a 28Si target was investigated by measuring the angular distributions of the elastically scattered projectiles and of the emitted protons, deuterons and α-particles. The experiment was performed in order to deduce direct and compound nucleus process contributions to the total reaction cross section and to study the influence of the projectile structure on the relative importance of these two mechanisms. Optical model parameters and therefore the total reaction cross section are strongly influenced by the binding energy of the projectile. The parameters of the Glas-Mosel model describing the fusion reaction vary smoothly with the atomic number. In the system 9Be + 28Si around 50% of all reactions are direct processes even at energies near the Coulomb barrier, whereas in the other systems the direct part amounts to 15 % ( 12C) and 30 % ( 6Li) only.

Single- and multiple-electron-loss-cross-section measurements from 20-MeVFe4+on thin gaseous targets

Single- and multiple-electron-loss cross sections have been measured with 20-MeV ${\mathrm{Fe}}^{4+}$ on thin He, Ne, Ar, Kr, Xe, ${\mathrm{H}}_{2}$, ${\mathrm{N}}_{2}$, ${\mathrm{O}}_{2}$, C${\mathrm{H}}_{4}$, C${\mathrm{O}}_{2}$, CH${\mathrm{F}}_{3}$, C${\mathrm{F}}_{4}$, and S${\mathrm{F}}_{6}$ gaseous targets; cross-section-per-atom data for each system are presented. Cross-section-per-atom data from targets with approximately the same average atomic number indicate that both nonadditivity and density effects, depending on the final charge state of the ion, play roles in electronloss processes during projectile interactions with molecular targets. A modified Bohr formula is developed which reproduces single-electron-loss-per-atom data for atomic targets.

An examination of the origin of molecular orbital X-rays from atomic and molecular impact on a series of solid targets

A number of targets of varying elemental composition, viz., aluminium; silicon; stainless steel; and alumina-coated stainless steel, have been bombarded with a series of molecular ions (100 keV N 2 +; CO + and CO 2 +) and atomic ions (50 keV N +; O +; C + and 120 keV A +). The resultant X-ray spectra, composed of a mixture of characteristic and molecular orbital (MO) X-rays, were measured with a gas flow proportional counter. In all cases the high energy end-point of the MO distribution could be examined, and used to deduce whether it arose predominantly from projectile/target or projectile/implanted projectile interactions. It was found that for practical purposes the MO distributions arose from projectile/implanted projectile interactions.

An exciton model analysis of (p, α) reactions induced in odd light nuclei

Three years ago it has been suggested that the exciton model could satisfactorily reproduce the energy dependence of the excitation functions of (p, a) reactions induced in odd light nuclei (L~). However the ignorance of the decay rates of the composite nucleus for cxeiton-exeiton interaction, forbade the evaluation of the absolute values of the cross-sections. Since that time several attempts have been reported to evaluate the decay rates, starting from free nucleon-nucleon cross-sections and the Fermi-gas model of the nucleus (3.7). In this letter we report the evaluation of the excitation functions of (p, ~) reactions on 11B, ~SN, I~F, for transitions to definite levels of the residual nucleus. The calculations make use of the decay rates for exeiton-exciton interaction evaluated with the semi-phenomenological approach of ref. (~,~), which proved to be successfull in reproducing the cross-sections of nucleon and a-particle induced reactions (~-s). The energy dependence of the excitation functions of these reactions suggests tha~ the most usual configuration of the composite system, just after the interaction of the projectile with the target nucleus, is of the 2p-Oh type Q). Without attempting in this letter to explain this finding, the initial configuration of the composite system does not appear to be of the 2p-lh type, as in the case of proton interactions with heavier nuclei, presumably as a consequence of the large amplitude, in the wave functions of the light nuclei here considered, of configurations in which several nucleons are closely correlated. The interaction of the incident proton with single nucleons of the Fermi sea could be hindered so that only interactions with a loosely bound nucleon with no excitation of hole states could be enhanced.

Elastic interaction of atomic projectiles in an amorphous target

Abstract The elastic interaction of 46 and 100 keV sodium ions and 300 keV argon ions penetrating thin carbon layers has been simulated within a binary collision model. The Thomas-Fermi and Lenz-Jensen scattering potentials have been used. The halfwidths of the angular distributions, the mean and most probable elastic stopping cross sections and the fluctuations in energy loss are reported. For each of these quantities the results of the simulations are summarized through an analytical expression.

Fuel tank wall response to hydraulic ram during the shock phase.

THIS Note outlines some preliminary work accomplished in a research program at the Naval Postgraduate School to study the effects of hydraulic ram in fuel tanks upon aircraft survivability and vulnerability. The problem of predicting the interaction of a high speed projectile with a liquid filled tank (hydraulic ram) is a complex but necessary study if kill probabilities are to be predicted for this type of event. Furthermore, to design survivable fuel tanks, it is necessary to understand hydraulic ram in detail. The hydraulic ram phenomenon may be divided into two phases: 1) the shock phase where the projectile exchanges some of its energy with the fluid by the production of a strong, nearly hemispherical shock wave originating from the entry wall, and 2) the cavity phase where further energy is imparted to the fluid by the production and collapse of a vapor filled cavity formed by separation of the fluid from the surface of the projectile as it moves through the tank. This Note considers the shock phase and examines the structural response of the entry wall during this phase.