Penetration of fast projectiles into resistant media: From macroscopic to subatomic projectiles

Science.gov (United States)

Gaite, José

2017-09-01

The penetration of a fast projectile into a resistant medium is a complex process that is suitable for simple modeling, in which basic physical principles can be profitably employed. This study connects two different domains: the fast motion of macroscopic bodies in resistant media and the interaction of charged subatomic particles with matter at high energies, which furnish the two limit cases of the problem of penetrating projectiles of different sizes. These limit cases actually have overlapping applications; for example, in space physics and technology. The intermediate or mesoscopic domain finds application in atom cluster implantation technology. Here it is shown that the penetration of fast nano-projectiles is ruled by a slightly modified Newton's inertial quadratic force, namely, F ∼v 2 - β, where β vanishes as the inverse of projectile diameter. Factors essential to penetration depth are ratio of projectile to medium density and projectile shape.

The study of quasi-projectiles produced in Ni+Ni and Ni+Au collisions: excitation energy and spin

International Nuclear Information System (INIS)

Buta, A.

2003-02-01

During the collision between the projectile and the target nuclei in the intermediate energy regime (E < 100 MeV/nucleon) two excited nuclei are mainly observed in the exit channel, the quasi projectile (QP) and the quasi target. They disintegrate by particle emission. However, this binary picture is perturbed by the emission of particles and light fragments with velocities intermediate between the projectile velocity and the target one, all along the interaction (midrapidity component). This work aim to determine the excitation energy and the intrinsic angular momentum (or spin) of quasi-projectiles produced in the Ni+Ni and Ni+Au collisions at 52 and 90 MeV/nucleon. The excitation energy is deduced from the kinematical characteristics of particles emitted by the quasi-projectile. They have to be separated from midrapidity particles. Three different scenarios have been used for this purpose. The spin of the quasi-projectile has been extracted from the experimental data by mean of proton and alpha particles multiplicities emitted by the QP in the Ni+Au at 52 MeV/nucleon reaction. The results have been compared to the predictions of a theoretical model based on nucleon transfers. Their evolution is qualitatively reproduced as a function of the violence of the collision. (author)

Projectile excitation energy evolution in peripheral collisions for 16O + 197Au at 32.5, 50 and 70 MeV/N

International Nuclear Information System (INIS)

Pouliot, J.; Dore, D.; Houde, S.; Laforest, R.; Roy, R.; St-Pierre, C.; Chan, Y.; Horn, D.; Horn, D.

1991-01-01

A comparison of the multiple breakup of 16 O projectiles scattered by a Au target at three different energies (32.5, 50 and 70 MeV/N) is presented. The excitation energy spectra of the primary projectile-like nuclei decaying into specific output channels were reconstructed. The excitation energy of the target is found to increase faster with beam energy than the one for the quasi-projectile

Effect of projectile on incomplete fusion reactions at low energies

Directory of Open Access Journals (Sweden)

Sharma Vijay R.

2017-01-01

Full Text Available Present work deals with the experimental studies of incomplete fusion reaction dynamics at energies as low as ≈ 4 - 7 MeV/A. Excitation functions populated via complete fusion and/or incomplete fusion processes in 12C+175Lu, and 13C+169Tm systems have been measured within the framework of PACE4 code. Data of excitation function measurements on comparison with different projectile-target combinations suggest the existence of ICF even at slightly above barrier energies where complete fusion (CF is supposed to be the sole contributor, and further demonstrates strong projectile structure dependence of ICF. The incomplete fusion strength functions for 12C+175Lu, and 13C+169Tm systems are analyzed as a function of various physical parameters at a constant vrel ≈ 0.053c. It has been found that one neutron (1n excess projectile 13C (as compared to 12C results in less incomplete fusion contribution due to its relatively large negative α-Q-value, hence, α Q-value seems to be a reliable parameter to understand the ICF dynamics at low energies. In order to explore the reaction modes on the basis of their entry state spin population, the spin distribution of residues populated via CF and/or ICF in 16O+159Tb system has been done using particle-γ coincidence technique. CF-α and ICF-α channels have been identified from backward (B and forward (F α-gated γspectra, respectively. Reaction dependent decay patterns have been observed in different α emitting channels. The CF channels are found to be fed over a broad spin range, however, ICF-α channels was observed only for high-spin states. Further, the existence of incomplete fusion at low bombarding energies indicates the possibility to populate high spin states

Effect of projectile on incomplete fusion reactions at low energies

Science.gov (United States)

Sharma, Vijay R.; Shuaib, Mohd.; Yadav, Abhishek; Singh, Pushpendra P.; Sharma, Manoj K.; Kumar, R.; Singh, Devendra P.; Singh, B. P.; Muralithar, S.; Singh, R. P.; Bhowmik, R. K.; Prasad, R.

2017-11-01

Present work deals with the experimental studies of incomplete fusion reaction dynamics at energies as low as ≈ 4 - 7 MeV/A. Excitation functions populated via complete fusion and/or incomplete fusion processes in 12C+175Lu, and 13C+169Tm systems have been measured within the framework of PACE4 code. Data of excitation function measurements on comparison with different projectile-target combinations suggest the existence of ICF even at slightly above barrier energies where complete fusion (CF) is supposed to be the sole contributor, and further demonstrates strong projectile structure dependence of ICF. The incomplete fusion strength functions for 12C+175Lu, and 13C+169Tm systems are analyzed as a function of various physical parameters at a constant vrel ≈ 0.053c. It has been found that one neutron (1n) excess projectile 13C (as compared to 12C) results in less incomplete fusion contribution due to its relatively large negative α-Q-value, hence, α Q-value seems to be a reliable parameter to understand the ICF dynamics at low energies. In order to explore the reaction modes on the basis of their entry state spin population, the spin distribution of residues populated via CF and/or ICF in 16O+159Tb system has been done using particle-γ coincidence technique. CF-α and ICF-α channels have been identified from backward (B) and forward (F) α-gated γspectra, respectively. Reaction dependent decay patterns have been observed in different α emitting channels. The CF channels are found to be fed over a broad spin range, however, ICF-α channels was observed only for high-spin states. Further, the existence of incomplete fusion at low bombarding energies indicates the possibility to populate high spin states

Breakup of the projectile at 35 MeV/nucleon

International Nuclear Information System (INIS)

Gonthier, P.L.; Harper, P.; Bouma, B.; Ramaker, R.; Cebra, D.A.; Koenig, Z.M.; Fox, D.; Westfall, G.D.

1990-01-01

Projectile breakup processes are probed by studying the emission of α particles in coincidence with projectile-like fragments as a function of the dissipated energy in the collisions of 35 MeV/nucleon 16 O with 58 Ni. Energy correlations between α particles and projectile-like fragments at small-angle geometries allow the separation of the sources of α emission from projectile-like and target-like fragments. We find that the slope parameters of the decay energy distributions, the average excitation energies, and the α particle multiplicities of the projectile-like fragments increase with increasing dissipation of energy. If the linear dependence, exhibited by the data, of the slope parameter with the dissipated energy is included in model calculations, the majority of the coincidence yield in the forward hemisphere can be explained. However, an excess yield of the data on the opposite side of the beam from the observed projectile-like fragment still remains. Such analysis of the data suggests that the breakup of the projectile is the dominant source of light particles at forward angles. Processes resulting in the breakup of the projectile must be better understood in order to study other processes leading to similar phenomena

Atomic Nuclei Utter Disintegration into Nucleons by High Energy Nuclear Projectiles

International Nuclear Information System (INIS)

Strugalski, Z.

1994-01-01

The disintegration process of atomic nuclei by high energy nuclear projectiles is described. The physical basis for this process is the passage of hadrons through layers of intranuclear matter accompanied by the nucleon emission from the target nuclei observed in experiments; kinetic energies of the nucleons are from about 20 up to about 400 MeV - in the target nucleus reference system. 22 refs., 3 tabs

The collision of a hypervelocity massive projectile with free-standing graphene: Investigation of secondary ion emission and projectile fragmentation

Science.gov (United States)

Geng, Sheng; Verkhoturov, Stanislav V.; Eller, Michael J.; Della-Negra, Serge; Schweikert, Emile A.

2017-02-01

We present here the study of the individual hypervelocity massive projectiles (440-540 keV, 33-36 km/s Au4004+ cluster) impact on 1-layer free-standing graphene. The secondary ions were detected and recorded separately from each individual impact in the transmission direction using a time-of-flight mass spectrometer. We observed C1-10± ions emitted from graphene, the projectiles which penetrated the graphene, and the Au1-3± fragment ions in mass spectra. During the projectile-graphene interaction, the projectile loses ˜15% of its initial kinetic energy (˜0.18 keV/atom, 72 keV/projectile). The Au projectiles are neutralized when approaching the graphene and then partially ionized again via electron tunneling from the hot rims of the holes on graphene, obtaining positive and negative charges. The projectile reaches an internal energy of ˜450-500 eV (˜4400-4900 K) after the impact and then undergoes a ˜90-100 step fragmentation with the ejection of Au1 atoms in the experimental time range of ˜0.1 μs.

Projectile and target fragmentation at intermediate energies (20 MeV <= E/A <= 100 MeV)

International Nuclear Information System (INIS)

Dayras, R.A.

1985-04-01

In order to follow the evolution of the reaction mechanisms in the transition region of the intermediate energy range, detailed studies of projectile-like fragments from a 44 MeV/u 40 Ar projectile bombarding 27 Al and sup(NAT)T: targets have been made. Experimental results are given. Discussion of the data is presented: transfer reactions, isotopic distributions, the fragmentation model, and abrasion model are used in the discussion

Photon emission from massive projectile impacts on solids.

Science.gov (United States)

Fernandez-Lima, F A; Pinnick, V T; Della-Negra, S; Schweikert, E A

2011-01-01

First evidence of photon emission from individual impacts of massive gold projectiles on solids for a number of projectile-target combinations is reported. Photon emission from individual impacts of massive Au(n) (+q) (1 ≤ n ≤ 400; q = 1-4) projectiles with impact energies in the range of 28-136 keV occurs in less than 10 ns after the projectile impact. Experimental observations show an increase in the photon yield from individual impacts with the projectile size and velocity. Concurrently with the photon emission, electron emission from the impact area has been observed below the kinetic emission threshold and under unlikely conditions for potential electron emission. We interpret the puzzling electron emission and correlated luminescence observation as evidence of the electronic excitation resulting from the high-energy density deposited by massive cluster projectiles during the impact.

Fragmentation of Pb-Projectiles at SPS Energies

CERN Multimedia

2002-01-01

% EMU17 \\\\ \\\\ We have exposed stacks consisting of solid state nuclear track detectors (CR-39 plastic and BP-1 glass) and different target materials at the SPS to beams of Pb projectiles. Our detectors record tracks of relativistic nuclei with charge numbers of Z~$\\geq$~6 for CR-39 and Z~$\\geq$75 for BP-1. After development of the tracks by etching they are detected and measured using completely automated microscope systems. Thus experiments with high statistics are possible. \\\\ \\\\BP-1 detectors were exposed to measure total charge changing cross sections and elemental production cross sections for heavy projectile fragments. These experiments were performed for different targets CH$ _{2} $, C, Al, Cu, Ag and Pb. Comparison of the results for different targets allows to investigate contributions to charge changing reactions by electromagnetic dissociation. Multifragmentation events in which several intermediate mass fragments are emitted from the heavy Pb projectile are studied using stacks containing CR-39 d...

Energy distributions of H+ fragments ejected by fast proton and electron projectiles in collision with H2O molecules

International Nuclear Information System (INIS)

Barros, A. L. F. de; Lecointre, J.; Luna, H.; Montenegro, E. C.; Shah, M. B.

2009-01-01

Experimental measurements of the kinetic energy distribution spectra of H + fragment ions released during radiolysis of water molecules in collision with 20, 50, and 100 keV proton projectiles and 35, 200, 400, and 1000 eV electron projectiles are reported using a pulsed beam and drift tube time-of-flight based velocity measuring technique. The spectra show that H + fragments carrying a substantial amount of energy are released, some having energies well in excess of 20 eV. The majority of the ions lie within the 0-5 eV energy range with the proton spectra showing an almost constant profile between 1.5 and 5 eV and, below this, increasing gradually with decreasing ejection energy up to the near zero energy value while the electron spectra, in contrast, show a broad maximum between 1 and 3 eV and a pronounced dip around 0.25 eV. Beyond 5 eV, both projectile spectra show a decreasing profile with the electron spectra decreasing far more rapidly than the proton spectra. Our measured spectra thus indicate that major differences are present in the collision dynamics between the proton and the electron projectiles interacting with gas phase water molecules.

Finite element investigation of explosively formed projectiles (EFP)

International Nuclear Information System (INIS)

Ahmad, I.

1999-01-01

This thesis report represents the numerical simulation of explosively formed projectiles (EFP), a type of linear self-forging fragment device. The simulation is performed using a finite element code DYNA2D. It also explicates that how the shape, velocity and kinetic energy of an explosively formed projectile is effected by various parameters. Different parameters investigated are mesh density, material, thickness, contour and types of liner. Effect of shape of casing and material model is also analyzed. The shapes of projectiles at different times after detonation are shown. The maximum velocity and kinetic energy of the projectile have been used to ascertain the effect of above mentioned parameters. (author)

Projectile-power-compressed magnetic-field pulse generator

International Nuclear Information System (INIS)

Barlett, R.H.; Takemori, H.T.; Chase, J.B.

1983-01-01

Design considerations and experimental results are presented of a compressed magnetic field pulsed energy source. A 100-mm-diameter, gun-fired projectile of approx. 2MJ kinetic energy was the input energy source. An initial magnetic field was trapped and compressed by the projectile. With a shorted load, a magajoule in a nanohenry was the design goal, i.e., 50 percent energy transformation from kinetic to magnetic. Five percent conversion was the highest recorded before gauge failure

High energy nuclear collisions in the few GeV/nucleon region: projectile and target fragmentation

International Nuclear Information System (INIS)

Schroeder, L.S.

1980-06-01

A general review of nucleon-nucleus and nucleus-nucleus collisions for incident energies <10 GeV/nucleon is presented. The division of these interactions into peripheral and central collisions is briefly discussed. Subjects treated include the following: target and projectile fragmentation systematics, production of exotic nuclear fragments, studies of multiparticle final states, total cross section measurements, results from an experiment that indicate the production of projectile fragments with an anomalously short reaction mean free path, high-energy particle production at backward angles beyond simple N-N kinematic limits, and recent results on backward particle emission in studies with the Berkeley streamer chamber. Both the particle and nuclear physics aspects that are present are considered. A brief discussion of future trends in this energy range ends the presentation. 65 references, 37 figures

Development of odd-Z-projectile reactions for transactinide element synthesis

International Nuclear Information System (INIS)

Folden III, Charles Marvin

2004-01-01

The development of new odd-Z-projectile reactions leading to the production of transactinide elements is described. The cross section of the even-Z-projectile 208Pb(64Ni, n)271Ds reaction was measured at two new energies using the Berkeley Gas-filled Separator at the Lawrence Berkeley National Laboratory 88-Inch Cyclotron. In total, seven decay chains attributable to 271Ds were observed. These data, combined with previous results, establish an excitation function for the production of 271Ds. The maximum cross section was 20 +15 -11 pb at a center-of-target energy of 311.5 MeV in the laboratory frame.The data from the 271Ds experiments were used to estimate the optimum beam energy for the new odd-Z-projectile 208Pb(65Cu, n)272-111 reaction using the Fusion by Diffusion theory proposed by Swiatecki, Siwek-Wilczynska, and Wilczynski. A cross section for this reaction was measured for the first time, at a center-of-target energy of 321.1 MeV in the laboratory frame. The excitation energy f or compound nuclei formed at the target center was 13.2 MeV. One decay chain was observed, resulting in a measured cross section of 1.7 +3.9 -1.4 pb. This decay chain is in good agreement with previously published data on the decay of 272-111.The new odd-Z-projectile 208Pb(55Mn, n)262Bh reaction was studied at three different projectile energies, and 33 decay chains of 262Bh were observed. The existence of a previously reported alpha-decaying isomeric state in this nuclide was confirmed. Production of the ground state was preferred at all three beam energies. The maximum cross section was 540 +180 -150 pb at a projectile center-of-target energy of 264.0 MeV. This cross section is much larger than that previously reported for the even-Z-projectile 209Bi(54Cr, n)262Bh reaction, which may be because the 54Cr projectile energies in the latter reaction were too high for optimum production of the 1n product. At the highest projectile energy of 268.0 MeV in the target center, two decay

Secondary electron emission with molecular projectiles

International Nuclear Information System (INIS)

Kroneberger, K.; Rothard, H.; Koschar, P.; Lorenzen, P.; Kemmler, J.; Keller, N.; Maier, R.; Groeneveld, K.O.; Clouvas, A.; Veje, E.

1990-01-01

The authors present results for the secondary electron emission (SEE) from thin foil targets, induced by both molecular ions and their atomic constituents as projectiles. The Sternglass theory for kinetic SEE states a proportionality between γ and the electronic stopping power, S e , which has been verified in various experiments. With comparing secondary electron (SE) yields induced by molecular projectiles to those induced by monoatomic projectiles, it is therefore possible to test models for the energy loss of molecular or cluster projectiles. Since the atomic constituents of the molecule are repelled from each other due to Coulomb explosion (superimposed by multiple scattering) while traversing the solid, it is interesting to measure the residual mutual influence on SEE and S e with increasing internuclear separation. This can only be achieved with thin foils, where (as in the present case) the SE-yields from the exit surface can be measured separately. The authors measured the SE-yields from the entrance (γ B ) and exit (γ F ) surfaces of thin C- and Al-foils (150 to 1,000 angstrom) with CO + , C + and O + (15 to 85 keV/u) and H 2 + and H + (0.3 to 1.2 MeV/u). The molecular effect defined as the ratio R(γ) between the yields induced by molecular projectiles and the sum of those induced by their atomic constituents was calculated. The energy dependence of R(γ) can be well represented by the calculated energy loss ratio of di-proton-clusters by Brandt. This supports Brandt's model for the energy loss of clusters

Performance of primary repair on colon injuries sustained from low-versus high-energy projectiles.

Science.gov (United States)

Lazovic, Ranko; Radojevic, Nemanja; Curovic, Ivana

2016-04-01

Among various reasons, colon injuries may be caused by low- or high-energy firearm bullets, with the latter producing a temporary cavitation phenomenon. The available treatment options include primary repair and two-stage management, but recent studies have shown that primary repair can be widely used with a high success rate. This paper investigates the differences in performance of primary repair on these two types of colon injuries. Two groups of patients who sustained colon injuries due to single gunshot wounds, were retrospectively categorized based on the type of bullet. Primary colon repair was performed in all patients selected based on the inclusion and exclusion criteria (Stone and Fabian's criteria). An almost absolute homogeneity was attained among the groups in terms of age, latent time before surgery, and four trauma indexes. Only one patient from the low-energy firearm projectile group (4%) developed a postsurgical complication versus nine patients (25.8%) from the high-energy group, showing statistically significant difference (p = 0.03). These nine patients experienced the following postsurgical complications: pneumonia, abscess, fistula, suture leakage, and one multiorgan failure with sepsis. Previous studies concluded that one-stage primary repair is the best treatment option for colon injuries. However, terminal ballistics testing determined the projectile's path through the body and revealed that low-energy projectiles caused considerably lesser damage than their high-energy counterparts. Primary colon repair must be performed definitely for low-energy short firearm injuries but very carefully for high-energy injuries. Given these findings, we suggest that the treatment option should be determined based not only on the bullet type alone but also on other clinical findings. Copyright © 2016 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

Neutron-rich rare isotope production from projectile fission of heavy beams in the energy range of 20 MeV/nucleon

OpenAIRE

Vonta, N.; Souliotis, G. A.; Loveland, W. D.; Kwon, Y. K.; Tshoo, K.; Jeong, S. C.; Veselsky, M.; Bonasera, A.; Botvina, A.

2016-01-01

We investigate the possibilities of producing neutron-rich nuclides in projectile fission of heavy beams in the energy range of 20 MeV/nucleon expected from low-energy facilities. We report our efforts to theoretically describe the reaction mechanism of projectile fission following a multinucleon transfer collision at this energy range. Our calculations are mainly based on a two-step approach: the dynamical stage of the collision is described with either the phenomenological Deep-Inelastic Tr...

Energy, target, projectile and multiplicity dependences of intermittency behaviour in high energy O(Si,S) induced interactions

International Nuclear Information System (INIS)

Adamovich, M.I.; Alexandrov, Y.A.; Chernyavski, M.M.; Gerassimov, S.G.; Kharlamov, S.P.; Larionova, V.G.; Maslennikova, N.V.; Orlova, G.I.; Peresadko, N.G.; Salmanova, N.A.; Tretyakova, M.I.; Ameeva, Z.U.; Andreeva, N.P.; Anzon, Z.V.; Bubnov, V.I.; Chasnikov, I.Y.; Eligbaeva, G.Z.; Eremenko, G.Z.; Gaitinov, A.S.; Kalyachkina, G.S.; Kanygina, E.K.; Skakhova, C.I.; Bhalla, K.B.; Kumar, V.; Lal, P.; Lokanathan, S.; Mookerjee, S.; Raniwala, R.; Raniwala, S.; Burnett, T.H.; Grote, J.; Koss, T.; Lord, J.; Skelding, D.; Strausz, S.C.; Wilkes, R.J.; Cai, X.; Huang, H.; Liu, L.S.; Qian, W.Y.; Wang, H.Q.; Zhou, D.C.; Zhou, J.C.; Chernova, L.P.; Gadzhieva, S.I.; Gulamov, K.G.; Kadyrov, F.G.; Lukicheva, N.S.; Navotny, V.S.; Svechnikova, L.N.; Friedlander, E.M.; Heckman, H.H.; Lindstrom, P.J.; Garpman, S.; Jakobsson, B.; Otterlund, I.; Persson, S.; Soederstroem, K.; Stenlund, E.; Judek, B.; Nasyrov, S.H.; Petrov, N.V.; Xu, G.F.; Zheng, P.Y.

1991-01-01

Fluctuations of charged particles in high energy oxygen, silicon and sulphur induced interactions are investigated with the method of scaled factorial moments. It is found that for decreasing bin size down to δη∝0.1 the EMU01 data exhibits intermittent behaviour. The intermittency indexes are found to decrease with increasing incident energy and multiplicity and to increase with increasing target mass. It seems also to increase as the projectile mass increases. (orig.)

The dynamics of target ionization by fast higly charged projectiles

International Nuclear Information System (INIS)

Moshammer, R.; Ullrich, J.; Unverzagt, M.; Olsen, R.E.; Doerner, R.; Mergel, V.; Schmidt-Boecking, H.

1995-12-01

We report on the first kinematically complete investigation of single target ionization by fast heavy ions, on the measurement of all low energy electrons down to zero emission velocities and on the determination of the projectile energy loss on the level of ΔE p /E p ∼10 -7 . This has been achieved by combining a high-resolution recoil-ion momentum spectrometer with a novel 4π electron analyzer. The complete momentum balance between electron, recoil-ion and projectile for single ionization of helium by 3.6 MeV/u Ni 24+ was explored. Low energy electrons are found to be ejected mainly into the forward direction with a most likely longitudinal energy of only 2 eV. The electron momentum is not balanced, as might be expected, by the projectile momentum but is nearly completely compensated by the recoil ion. Surprisingly, the momenta of the helium-atom ''fragments'', the electron and the He 1+ recoil ion, are considerably larger than the total momentum loss of the projectile: the target atom seems to dissociate in the strong, longranging projectile potential. The collision has to be considered as a real three body interaction. (orig.)

Influence of the power supply parameters on the projectile energy in the permanent magnet electrodynamic accelerator

Science.gov (United States)

Waindok, Andrzej; Piekielny, Paweł

2017-10-01

The main objective of the research is to investigate, how the power supply parameters influence the kinetic energy of the movable element, called commonly a projectile or bullet. A calculation and measurement results of transient characteristics for an electrodynamic accelerator with permanent magnet support were presented in the paper. The calculations were made with using field-circuit model, which includes the parameters of the power supply, mass of the bullet and friction phenomenon. Characteristics of energy and muzzle velocity verso supply voltage (50 V to 350 V) and capacitance value (60 mF to 340.5 mF) were determined, as well. A measurement verification of selected points of calculation characteristics were carried out for investigated values of muzzle velocity. A good conformity between calculation and measurement results was obtained. Concluding, presented characteristics of the muzzle velocity and energy of the projectile vs. power supply parameters indicate, that accelerators could be used for fatigue testing of materials.

Influence of the power supply parameters on the projectile energy in the permanent magnet electrodynamic accelerator

Directory of Open Access Journals (Sweden)

Waindok Andrzej

2017-01-01

Full Text Available The main objective of the research is to investigate, how the power supply parameters influence the kinetic energy of the movable element, called commonly a projectile or bullet. A calculation and measurement results of transient characteristics for an electrodynamic accelerator with permanent magnet support were presented in the paper. The calculations were made with using field-circuit model, which includes the parameters of the power supply, mass of the bullet and friction phenomenon. Characteristics of energy and muzzle velocity verso supply voltage (50 V to 350 V and capacitance value (60 mF to 340.5 mF were determined, as well. A measurement verification of selected points of calculation characteristics were carried out for investigated values of muzzle velocity. A good conformity between calculation and measurement results was obtained. Concluding, presented characteristics of the muzzle velocity and energy of the projectile vs. power supply parameters indicate, that accelerators could be used for fatigue testing of materials.

Ionization of one-electron oxygen and fluorine projectiles by molecular hydrogen

International Nuclear Information System (INIS)

Tipping, T.N.; Sanders, J.M.; Hall, J.; Shinpaugh, J.L.; Lee, D.H.; McGuire, J.H.; Richard, P.

1988-01-01

Cross sections for projectile ionization have been measured for hydrogenlike oxygen and fluorine ions incident on a molecular-hydrogen target over a projectile energy range of 0.5--2.5 MeV/amu. The experimental cross sections are compared to the plane-wave Born approximation (PWBA) and to the Glauber-approximation cross sections all of which were calculated for atomic hydrogen and multiplied by 2. The PWBA calculations have a projectile energy dependence similar to the measured cross sections but slightly underestimate them. The Glauber approximation also underestimates the measured projectile-ionization cross sections when the hydrogen target electrons are neglected, while it overestimates the measured cross sections when the effects of the hydrogen target electrons are included. The measured projectile-ionization cross sections for hydrogenlike ions incident on molecular hydrogen are approximately a factor of 2 smaller than previously reported projectile-ionization cross sections for hydrogenlike ions incident on helium. No cross sections are available for atomic hydrogen in this velocity and ion-charge regime

Study of uranium dioxyde sputtering induced by multicharged heavy ions at low and very low kinetic energy: projectile charge effect

International Nuclear Information System (INIS)

Haranger, F.

2003-12-01

Ion beam irradiation of a solid can lead to the emission of neutral or ionized atoms, molecules or clusters from the surface. This comes as a result of the atomic motion in the vicinity of the surface, induced by the transfer of the projectile energy. Then, the study of the sputtering process appears as a means to get a better understanding of the excited matter state around the projectile trajectory. In the case of slow multicharged ions, a strong electronic excitation can be achieved by the projectile neutralization above the solid surface and / or its deexcitation below the surface. Parallel to this, the slowing down of such ions is essentially related to elastic collision with the target atoms. The study of the effect of the initial charge state of slow multicharged ions, in the sputtering process, has been carried out by measuring the absolute angular distributions of emission of uranium atoms from a uranium dioxide surface. The experiments have been performed in two steps. First, the emitted particles are collected onto a substrate during irradiation. Secondly, the surface of the collectors is analyzed by Rutherford Backscattering Spectrometry (RBS). This method allows the characterization of the emission of neutrals, which are the vast majority of the sputtered particles. The results obtained provide an access to the evolution of the sputtering process as a function of xenon projectile ions charge state. The measurements have been performed over a wide kinetic energy range, from 81 down to 1.5 keV. This allowed a clear separation of the contribution of the kinetic energy and initial projectile charge state to the sputtering phenomenon. (author)

Physics of projectile fragments

International Nuclear Information System (INIS)

Minamisono, Tadanori

1982-01-01

This is a study report on the polarization phenomena of the projectile fragments produced by heavy ion reactions, and the beta decay of fragments. The experimental project by using heavy ions with the energy from 50 MeV/amu to 250 MeV/amu was designed. Construction of an angle-dispersion spectrograph for projectile fragments was proposed. This is a two-stage spectrograph. The first stage is a QQDQQ type separator, and the second stage is QDQD type. Estimation shows that Co-66 may be separated from the nuclei with mass of 65 and 67. The orientation of fragments can be measured by detecting beta-ray. The apparatus consists of a uniform field magnet, an energy absorber, a stopper, a RF coil and a beta-ray hodoscope. This system can be used for not only this purpose but also for the measurement of hyperfine structure. (Kato, T.)

Transient processes induced by heavy projectiles in silicon

International Nuclear Information System (INIS)

Lazanu, Ionel; Lazanu, Sorina

2010-01-01

The thermal spike model developed for the electronic stopping power regime is extended to consider both ionization and nuclear energy loss processes of the projectile as electronic and atomic heat distinct sources. The time and space dependencies of the lattice and electron temperatures near the projectile trajectory are calculated and discussed for different ions in silicon, at room and cryogenic temperatures, taking into account the peculiarities of electron-phonon interaction in both domains. The model developed contributes to the understanding of transient microscopic processes immediately after the projectile interaction in the target.

Projectile ionization in fast heavy-ion--atom collisions

International Nuclear Information System (INIS)

Schneider, D.; Prost, M.; Stolterfoht, N.; Nolte, G.; Du Bois, R.

1983-01-01

Electron emission following the ionization of projectile ions has been investigated systematically in collisions with Ne/sup q/+ and Ar/sup q/+ ions at several hundred MeV incident on different target gases. The projectile electrons are concentrated within one maximum, the electron-loss peak (ELP). The variation of the shape and intensity of the ELP with the projectile energy, its charge state, the observation angle, and the target gas has been measured. Theoretical predictions which are based on the binary-encounter approximation show, in general, good agreement with the experimental data. The contributions of the different subshells to the ELP are deduced. It is shown that electronic screening of the target nucleus plays an important role in the ionization process of the projectile ions

A model for projectile fragmentation

International Nuclear Information System (INIS)

Chaudhuri, G; Mallik, S; Gupta, S Das

2013-01-01

A model for projectile fragmentation is developed whose origin can be traced back to the Bevalac era. The model positions itself between the phenomenological EPAX parametrization and transport models like 'Heavy Ion Phase Space Exploration' (HIPSE) model and antisymmetrised molecular dynamics (AMD) model. A very simple impact parameter dependence of input temperature is incorporated in the model which helps to analyze the more peripheral collisions. The model is applied to calculate the charge, isotopic distributions, average number of intermediate mass fragments and the average size of largest cluster at different Z bound of different projectile fragmentation reactions at different energies.

On ballistic parameters of less lethal projectiles influencing the severity of thoracic blunt impacts.

Science.gov (United States)

Pavier, Julien; Langlet, André; Eches, Nicolas; Jacquet, Jean-François

2015-01-01

The development and safety certification of less lethal projectiles require an understanding of the influence of projectile parameters on projectile-chest interaction and on the resulting terminal effect. Several energy-based criteria have been developed for chest injury assessment. Many studies consider kinetic energy (KE) or energy density as the only projectile parameter influencing terminal effect. In a common KE range (100-160 J), analysis of the firing tests of two 40 mm projectiles of different masses on animal surrogates has been made in order to investigate the severity of the injuries in the thoracic region. Experimental results have shown that KE and calibre are not sufficient to discriminate between the two projectiles as regards their injury potential. Parameters, such as momentum, shape and impedance, influence the projectile-chest interaction and terminal effect. A simplified finite element model of projectile-structure interaction confirms the experimental tendencies. Within the range of ballistic parameters used, it has been demonstrated that maximum thoracic deflection is a useful parameter to predict the skeletal level of injury, and it largely depends on the projectile pre-impact momentum. However, numerical simulations show that these results are merely valid for the experimental conditions used and cannot be generalised. Nevertheless, the transmitted impulse seems to be a more general factor governing the thorax deflection.

Fusion and direct reactions for strongly and weakly bound projectiles

International Nuclear Information System (INIS)

Hugi, M.; Lang, J.; Mueller, R.; Ungricht, E.; Bodek, K.; Jarczyk, L.; Kamys, B.; Magiera, A.; Strzalkowski, A.; Willim, G.

1981-01-01

The interaction of 6 Li, 9 Be and 12 C projectiles with a 28 Si target was investigated by measuring the angular distributions of the elasitcally scattered projectiles and of the emitted protons, deuterons and α-particles. The experiment was perfomred 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 describing the fusion reaction vary smoothly with the atomic number. In the system 9 B + 28 Si around 50% of all reactions are direct processes even at energies near the Coulomb barrier, whereas in the other systeme the direct part amounts to 15% ( 12 C) and 30% ( 6 Li) only. (orig.)

Analysis of the dependence parametrization of the allocations of heavy ions on light nuclei elastic scattering diffraction maxima from the projectile energy

International Nuclear Information System (INIS)

Ponkratenko, O.A.; Pyirnak, Val. M.; Rudchik, A.A.; Stepanenko, Yu.M.; Uleshchenko, V.V.; Shirma, Yu.O.

2015-01-01

Diffraction range of available experimental differential cross sections of heavy ions on light nuclei elastic scattering for the interactive nuclei 17 pairs with 4 ≤ A ≤ 20 have been analyzed in the projectile energy wide interval from 1 to 100 MeV/nucleon. Diffraction maxima and minima positions in the transferred momentum coordinates depending on projectile energy demonstrate smooth behavior at energies higher 2 - 4 MeV/nucleon and at energies to 30 - 40 MeV/nucleon - practically does not depend on energy. These energy dependences of maxima (minima) position. can be parameterized by simple functions. It was found the suitable approximations that describe reasonable the energy dependence of the maxima (minima) positions of the experimental elastic scattering differential cross sections. These approximations were evaluated with the same parameters for all colliding nuclei groups

Towards an unambiguous determination of the excitation energy of the projectile in heavy-ion reactions?

Energy Technology Data Exchange (ETDEWEB)

Buta, A.M.; Steckmeyer, J.C. [Caen Univ., 14 (France). Lab. de Physique Corpusculaire; Auger, G. [Grand Accelerateur National d' Ions Lourds (GANIL), 14 - Caen (France)] [and others

2002-03-01

The excitation energy of the quasi-projectiles produced in heavy-ion collisions is determined for the {sup 58}Ni+{sup 197}Au reactions at 52 and 90 AMeV. A new method is proposed for isolating unambiguously the particles evaporated by the source. It consists in observing them at small angles along the flight direction of the source. (authors)

Study of uranium dioxyde sputtering induced by multicharged heavy ions at low and very low kinetic energy: projectile charge effect; Etude de la pulverisation du dioxyde d'uranium induite par des ions lourds multicharges de basse et tres basse energie cinetique; effet de la charge du projectile

Energy Technology Data Exchange (ETDEWEB)

Haranger, F

2003-12-01

Ion beam irradiation of a solid can lead to the emission of neutral or ionized atoms, molecules or clusters from the surface. This comes as a result of the atomic motion in the vicinity of the surface, induced by the transfer of the projectile energy. Then, the study of the sputtering process appears as a means to get a better understanding of the excited matter state around the projectile trajectory. In the case of slow multicharged ions, a strong electronic excitation can be achieved by the projectile neutralization above the solid surface and / or its deexcitation below the surface. Parallel to this, the slowing down of such ions is essentially related to elastic collision with the target atoms. The study of the effect of the initial charge state of slow multicharged ions, in the sputtering process, has been carried out by measuring the absolute angular distributions of emission of uranium atoms from a uranium dioxide surface. The experiments have been performed in two steps. First, the emitted particles are collected onto a substrate during irradiation. Secondly, the surface of the collectors is analyzed by Rutherford Backscattering Spectrometry (RBS). This method allows the characterization of the emission of neutrals, which are the vast majority of the sputtered particles. The results obtained provide an access to the evolution of the sputtering process as a function of xenon projectile ions charge state. The measurements have been performed over a wide kinetic energy range, from 81 down to 1.5 keV. This allowed a clear separation of the contribution of the kinetic energy and initial projectile charge state to the sputtering phenomenon. (author)

Analysis of the dependence parametrization of the allocations of heavy ions on light nuclei elastic scattering diffraction maxima from the projectile energy

Directory of Open Access Journals (Sweden)

O. A. Ponkratenko

2015-10-01

Full Text Available Diffraction range of available experimental differential cross sections of heavy ions on light nuclei elastic scattering for 17 pairs of the interacting nuclei with 4 ≤ А ≤ 20 have been analyzed in the projectile energy wide interval from 1 to 100 МеV/nucleon. Diffraction maxima and minima positions in the transferred momentum coordinates depending on projectile energy demonstrate smooth behavior at energies higher 2 - 4 МeV/nucleon, and practically do not depend on energy at energies up to 30 - 40 МеV/nucleon. These energy dependences of maxima (minima positions can be parameterized by simple functions. It was found the suitable approximations that describe reasonably the energy dependence of the maxima (minima positions of the experimental elastic scattering differential cross sections. These approximations were evaluated with the same parameters for all colliding nuclei groups.

Systematics of new isotopic production cross sections from neon projectiles

International Nuclear Information System (INIS)

Chen, C.X.; Guzik, T.G.; McMahon, M.; Wefel, J.P.; Flores, I.; Lindstrom, P.J.; Tull, C.E.; Mitchell, J.W.; Cronqvist, M.; Crawford, H.J.

1996-02-01

New isotopic production cross sections from 22 Ne projectiles at 377,581 and 891 MeV/nucleon in a liquid hydrogen target have been measured. These data allow to investigate the projectile energy and nuclear composition dependence of the cross sections. The comparisons between data and predictions can have important consequences in source abundance investigations. (K.A.)

Prevention of breakdown behind railgun projectiles

International Nuclear Information System (INIS)

Hawke, R.S.

1992-01-01

An electromagnetic railgun accelerator system, for accelerating projectiles by a plasma arc, introduces a breakdown inhibiting gas into the railgun chamber behind the accelerating projectile. The breakdown inhibiting gas, which absorbs electrons, is a halide or a halide compound such as fluorine or SF 6 . The gas is introduced between the railgun rails after the projectile has passed through inlets in the rails or the projectile; by coating the rails or the projectile with a material which releases the gas after the projectile passes over it; by fabricating the rails or the projectile or insulators out of a material which releases the gas into the portions of the chamber through which the projectile has travelled. The projectile may have a cavity at its rear to control the release of ablation products. 12 figs

Binary projectile fragmentation of 12C at an incident energy of 33.3 MeV/nucleon

CERN Document Server

Förtsch, S V; Gadioli, E; Bassini, R; Buthelezi, E Z; Cerutti, F; Connell, S H; Cowley, A A; Fujita, H; Mabiala, J; Mairani, A; Mira, J; Papka, P; Neveling, R; Smit, F D

2010-01-01

Direct binary projectile fragmentation is being investigated for the case where a 400 MeV 12C projectile breaks up into an particle and a 8Be fragment in the interaction with a thin 93Nb and 197Au target. While the 8Be fragments were measured at 9 , the correlated particles were detected in an angular range between 16 and 30 on the opposite side of the beam. From the preliminary results presented here one may obtain information on the amount of quasi-elastic fragmentation (both fragments do not suffer any further interactions after they are produced). These experimental results indicate that the quasi-elastic break-up process is the dominant contribution to the measured correlation spectra. As was also observed in earlier work, the most forward quasi-elastically emitted particles have energies exceeding the beam velocity.

Systematics of new isotopic production cross sections from neon projectiles

Energy Technology Data Exchange (ETDEWEB)

Chen, C X; Guzik, T G; McMahon, M; Wefel, J P [Louisiana State Univ., Baton Rouge, LA (United States); Flores, I; Lindstrom, P J; Tull, C E [Lawrence Berkeley Lab., CA (United States); Mitchell, J W [National Aeronautics and Space Administration, Greenbelt, MD (United States). Goddard Space Flight Center; Cronqvist, M; Crawford, H J [California Univ., Berkeley, CA (United States). Space Sciences Lab.; and others

1996-02-01

New isotopic production cross sections from {sup 22}Ne projectiles at 377,581 and 891 MeV/nucleon in a liquid hydrogen target have been measured. These data allow to investigate the projectile energy and nuclear composition dependence of the cross sections. The comparisons between data and predictions can have important consequences in source abundance investigations. (K.A.). 9 refs.

Study of incomplete fusion sensitivity to projectile structure from forward recoil range distribution measurement

International Nuclear Information System (INIS)

Kumar, Harish; Tali, Suhail A.; Afzal Ansari, M.

2017-01-01

Recently, the projectile structure is found to affect the incomplete fusion (ICF) process by using α- and non-α-cluster structured projectiles which is explored in terms of projectile α-Q-value and is still limited only for a very few systems. Keeping in view the recent aspects especially the projectile structure effect on ICF, the present work is carried out in the series of experiment by using α- and non-α-cluster structured projectiles. Presently, the FRRDs of evaporation residues (ERs) produced in 13 C + 175 Lu system have been measured at ≈ 88 MeV energy. In this work, an attempt has been made to have a better knowledge of projectile α-Q-value effect on ICF

EMGWS, D1 projectile tests

International Nuclear Information System (INIS)

Creighton, W.J.

1991-01-01

This paper reports on the 90 mm EMGWS D1 Projectile which is an unguided projectile that is designed for launch from an Electromagnetic gun to achieve significant armor penetration. It is being developed under the broader program called Electromagnetic Gun Weapon System (EMGWS) which is sponsored by DARPA, DNA, and the U.S. Army. The 90 mm D1 Type II 'workhorse' Projectile is used to prove out material strength, fabrication techniques, and projectile structural integrity. The type II flight projectile is designed to allow maximum stress levels of 100-ksi when launched at 100-kilogees peak acceleration. The total weight of the projectile is 2.0 kg to attain a muzzle velocity of 3.0 km/s from a 9-Megajoule EM Gun. The Type II projectile configuration employs a tungsten nosetip plus 12 segmented tungsten penetrators, a two-piece aluminum discarding sabot, an aluminum pusher plate, and a nylon obturator. The pusher plate can incorporate either a solid or plasma armature

Water Ice Radiolytic O2, H2, and H2O2 Yields for Any Projectile Species, Energy, or Temperature: A Model for Icy Astrophysical Bodies

Science.gov (United States)

Teolis, B. D.; Plainaki, C.; Cassidy, T. A.; Raut, U.

2017-10-01

O2, H2, and H2O2 radiolysis from water ice is pervasive on icy astrophysical bodies, but the lack of a self-consistent, quantitative model of the yields of these water products versus irradiation projectile species and energy has been an obstacle to estimating the radiolytic oxidant sources to the surfaces and exospheres of these objects. A major challenge is the wide variation of O2 radiolysis yields between laboratory experiments, ranging over 4 orders of magnitude from 5 × 10-7 to 5 × 10-3 molecules/eV for different particles and energies. We revisit decades of laboratory data to solve this long-standing puzzle, finding an inverse projectile range dependence in the O2 yields, due to preferential O2 formation from an 30 Å thick oxygenated surface layer. Highly penetrating projectile ions and electrons with ranges ≳30 Å are therefore less efficient at producing O2 than slow/heavy ions and low-energy electrons (≲ 400 eV) which deposit most energy near the surface. Unlike O2, the H2O2 yields from penetrating projectiles fall within a comparatively narrow range of (0.1-6) × 10-3 molecules/eV and do not depend on range, suggesting that H2O2 forms deep in the ice uniformly along the projectile track, e.g., by reactions of OH radicals. We develop an analytical model for O2, H2, and H2O2 yields from pure water ice for electrons and singly charged ions of any mass and energy and apply the model to estimate possible O2 source rates on several icy satellites. The yields are upper limits for icy bodies on which surface impurities may be present.

On the Inertia Term of Projectile's Penetration Resistance

Directory of Open Access Journals (Sweden)

Yu Shan

2013-01-01

Full Text Available The effect of the target inertia term of rigid kinetic energy projectiles (KEP’s penetration resistance is investigated using nonlinear dynamic code LS-DYNA and four constitutive models. It is found that the damage number of target can be used to measure the influence of the inertia term. The smaller the damage number is, the less influence the inertia term has. The less dependent the resistance has on projectile velocity, the more accurate it is to treat the resistance as a constant. For the ogive-nose projectile with CRH of 3, when the target is aluminum, steel, or other metals, the threshold velocity for the constant resistance is at least 1258 m/s; when the target is concrete, rock, or other brittle materials, if the velocity of the projectile is greater than 400 m/s or so, the damage number would be very large, and the penetration resistance would clearly depend on the projectile’s velocity. The higher the elastic wave velocity is, the more penetration process is affected by the impact face.

Mechanisms of Li-projectile breakup-up

International Nuclear Information System (INIS)

Rebel, H.; Srivastava, D.K.

1990-08-01

Various experimental and theoretical features observed in recent studies of break-up of 6 Li and 7 Li projectiles in the field of atomic nuclei are discussed, in particular for the transitional energy regime of 10-30 MeV/amu. The discussion is organized as three independent lectures presented at the International School on Nuclear Physics, Kiev (UkSSR), 28 May - 8 June, 1990. After a survey on the main experimental facts and on the basic reaction mechanisms, current theoretical approaches are illustrated by an application to the analysis of elastic break-up of 156 MeV 6 Li projectiles. Finally Coulomb break-up is discussed as a novel tool of laboratory nuclear astrophysics. (orig.) [de

Backscattering of projectile-bound electrons from solid surfaces

International Nuclear Information System (INIS)

Tobisch, M.; Schosnig, M.; Kroneberger, K.; Kuzel, M.; Maier, R.; Jung, M.; Fiedler, C.; Rothard, H.; Clouvas, A.; Suarez, S.; Groeneveld, K.O.

1994-01-01

The contribution of projectile ionization (PI) to secondary electron emission is studied by collision of H 2 + and H 3 + ions (400 keV/u and 700 keV/u) with carbon, copper and gold targets (600 A). The measured doubly differential intensity distribution shows a peak of lost projectile electrons near - v p . We describe the subtraction of the contribution of target ionization (TI), and compare the remaining electron intensities with a BEA calculation. For solids we observe a strong energy shift of the electron loss peak, which is compared with the influence of electron transport and binding energy. Furthermore, the low energy tail of the electron loss peak indicates the simultaneous occurrence of PI and TI. Finally we discuss the influence of surface conditions and the dependence of the observation angles on the measured electron intensities. (orig.)

Measurement of the stopping power of water for carbon ions in the energy range of 1 MeV-6 MeV using the inverted Doppler-shift attenuation method

Energy Technology Data Exchange (ETDEWEB)

Rahm, Johannes Martin

2016-10-31

Cancer therapy using carbon ions has gained increasing interest in the last decade due to its advantageous dose distributions. For the dosimetry and treatment planning, the accurate knowledge of the stopping power of water for carbon ions is of crucial importance. In the high energy region, the stopping power can be calculated rather accurately by means of the Bethe-Bloch formula. In the case of projectile velocities comparable to those of the valence electrons of the target, these calculations are subject to large uncertainties. There exist no experimental data for the stopping power of water for projectile energies prevailing in the so-called Bragg peak region. The currently available stopping power data for water are derived from measurements in water vapour or D{sub 2}O ice and, hence, neglect the dependence on the state of aggregation. The stopping power of water for charged particles is of high interest not only for practical applications but also to consider how physical and chemical state of the target influence the collisional energy transfer. For the measurement of the stopping power of water, the inverted Doppler-shift attenuation method was used in this work. This method has the advantage that the projectile itself is not needed to be detected and can be slowed down entirely in the target. In this method, the stopping power is determined from the Doppler-shift of the gamma-quanta emitted by projectiles during their slow down. This experiment can be performed at atmospheric pressure and consequently, the stopping power of water can be measured in its real physiological condition. In this work, the stopping power of water for carbon ions was measured for the first time in the energy range between 1 MeV and 6 MeV covering the kinetic energies of carbon ions in the Bragg peak region. The experimental method is presented in detail along with the design of the apparatus and of the data acquisition system. A comprehensive analysis of instrumental effects

Double ionization of H2 caused by two sequential projectile-electron collisions

International Nuclear Information System (INIS)

Edwards, A.K.; Wood, R.M.; Ezell, R.L.

1985-01-01

The impact-parameter calculations of Hansteen et al. [J. Phys. B 17, 3545 (1984)] for K-shell ionization are used to predict the cross sections for the double ionization of H 2 and He by H + and D + projectiles as a function of projectile velocity. The calculated values in the case of the H 2 target are typically a factor of 12 lower than the measured values, but the calculations and measurements show similar velocity dependencies. The results indicate that for projectile energies less than 1 MeV/amu, the double-ionization process of H 2 occurs mainly by two independent interactions between the electrons and projectile. For the He target, the calculated and measured values for the double-ionization cross section are much closer in magnitude, but the calculations predict a more rapid falloff with projectile velocity than is observed

In-flight dynamics of volcanic ballistic projectiles

Science.gov (United States)

Taddeucci, J.; Alatorre-Ibargüengoitia, M. A.; Cruz-Vázquez, O.; Del Bello, E.; Scarlato, P.; Ricci, T.

2017-09-01

Centimeter to meter-sized volcanic ballistic projectiles from explosive eruptions jeopardize people and properties kilometers from the volcano, but they also provide information about the past eruptions. Traditionally, projectile trajectory is modeled using simplified ballistic theory, accounting for gravity and drag forces only and assuming simply shaped projectiles free moving through air. Recently, collisions between projectiles and interactions with plumes are starting to be considered. Besides theory, experimental studies and field mapping have so far dominated volcanic projectile research, with only limited observations. High-speed, high-definition imaging now offers a new spatial and temporal scale of observation that we use to illuminate projectile dynamics. In-flight collisions commonly affect the size, shape, trajectory, and rotation of projectiles according to both projectile nature (ductile bomb versus brittle block) and the location and timing of collisions. These, in turn, are controlled by ejection pulses occurring at the vent. In-flight tearing and fragmentation characterize large bombs, which often break on landing, both factors concurring to decrease the average grain size of the resulting deposits. Complex rotation and spinning are ubiquitous features of projectiles, and the related Magnus effect may deviate projectile trajectory by tens of degrees. A new relationship is derived, linking projectile velocity and size with the size of the resulting impact crater. Finally, apparent drag coefficient values, obtained for selected projectiles, mostly range from 1 to 7, higher than expected, reflecting complex projectile dynamics. These new perspectives will impact projectile hazard mitigation and the interpretation of projectile deposits from past eruptions, both on Earth and on other planets.

Excitation and multiple dissociation of 12C, 14N, and 16O projectiles in peripheral collisions at 32.5 MeV/nucleon

International Nuclear Information System (INIS)

Pouliot, J.; Chan, Y.; DiGregorio, D.E.; Harmon, B.A.; Knop, R.; Moisan, C.; Roy, R.; Stokstad, R.G.; Laboratoire de physique nucleaire, Universite Laval, Quebec, P.Q., Canada G1K7P4)

1991-01-01

Cross sections for the multiple breakup of 16 O, 14 N, and 12 C projectiles scattered by an Au target were measured with an array of 34 phoswich detectors. The dissociation of the projectiles into as many as five charged particles has been observed. The yields of different exit channels correlate approximately with the threshold energy for separation of the projectile into the observed fragments. The excitation spectrum of the primary projectile-like nucleus was reconstructed from the measured positions and kinetic energies of the individual fragments. The energy sharing between projectile and target is consistent with a fast excitation mechanism in which differential increases in projectile excitation energy appear to be accompanied by comparable increases in target excitation. Calculations of the yields based on a sequence of binary decays are presented

Fired missile projectiles

International Nuclear Information System (INIS)

Williams, K.D.; Gieszl, R.; Keller, P.J.; Drayer, B.P.

1989-01-01

This paper reports ferromagnetic properties of fired missile projectiles (bullets, BBs, etc) investigated. Projectile samples were obtained from manufactures, police, and commercial sources. Deflection measurements at the portal of a 1.5-T magnetic field were performed for 47 projectiles. Sixteen bullets were examined in gelatin phantoms for rotation-translation movements as well. Ferromagnetic bullets displayed considerable deflection forces in the presence of the magnetic field and could be rotated to 80 degrees from their previous alignments when introduced perpendicular to the magnetic field in our gelatin phantom experiments. Military bullet calibers appear to pose the greatest ferromagnetic risk. Commercial sporting ammunition is generally nonferromagnetic

Attenuation correction strategies for multi-energy photon emitters using SPECT

International Nuclear Information System (INIS)

Pretorius, P.H.; King, M.A.; Pan, T.S.

1996-01-01

The aim of this study was to investigate whether the photopeak window projections from different energy photons can be combined into a single window for reconstruction or if it is better to not combine the projections due to differences in the attenuation maps required for each photon energy. The mathematical cardiac torso (MCAT) phantom was modified to simulate the uptake of Ga-67 in the human body. Four spherical hot tumors were placed in locations which challenged attenuation correction. An analytical 3D projector with attenuation and detector response included was used to generate projection sets. Data were reconstructed using filtered backprojection (FBP) reconstruction with Butterworth filtering in conjunction with one iteration of Chang attenuation correction, and with 5 and 10 iterations of ordered-subset maximum-likelihood expectation-maximization reconstruction. To serve as a standard for comparison, the projection sets obtained from the two energies were first reconstructed separately using their own attenuation maps. The emission data obtained from both energies were added and reconstructed using the following attenuation strategies: (1) the 93 keV attenuation map for attenuation correction, (2) the 185 keV attenuation map for attenuation correction, (3) using a weighted mean obtained from combining the 93 keV and 185 keV maps, and (4) an ordered subset approach which combines both energies. The central count ratio (CCR) and total count ratio (TCR) were used to compare the performance of the different strategies. Compared to the standard method, results indicate an over-estimation with strategy 1, an under-estimation with strategy 2 and comparable results with strategies 3 and 4. In all strategies, the CCR's of sphere 4 were under-estimated, although TCR's were comparable to that of the other locations. The weighted mean and ordered subset strategies for attenuation correction were of comparable accuracy to reconstruction of the windows separately

The role of the spectator assumption in models for projectile fragmentation

International Nuclear Information System (INIS)

Mc Voy, K.W.

1984-01-01

This review is restricted to direct-reaction models for the production of projectile fragments in nuclear collisions, at beam energies of 10 or more MeV/nucleon. Projectile fragments are normally identified as those which have near-beam velocities, and there seem to be two principal mechanisms for the production of these fast particles: 1. Direct breakup, 2. Sequential breakup. Of the two, the authors exclude from their discussion the ''sequential breakup'' process, in which the projectile is excited by the initial collision (either via inelastic scattering or transfer to unbound states) and then subsequently decays, outside the range of interaction

Projectile Motion Hoop Challenge

Science.gov (United States)

Jordan, Connor; Dunn, Amy; Armstrong, Zachary; Adams, Wendy K.

2018-04-01

Projectile motion is a common phenomenon that is used in introductory physics courses to help students understand motion in two dimensions. Authors have shared a range of ideas for teaching this concept and the associated kinematics in The Physics Teacher; however, the "Hoop Challenge" is a new setup not before described in TPT. In this article an experiment is illustrated to explore projectile motion in a fun and challenging manner that has been used with both high school and university students. With a few simple materials, students have a vested interest in being able to calculate the height of the projectile at a given distance from its launch site. They also have an exciting visual demonstration of projectile motion when the lab is over.

Coincidence measurements of slow recoil ions with projectile ions in 42-MeV Arq+-Ar collisions

International Nuclear Information System (INIS)

Tonuma, T.; Kumagai, H.; Matsuo, T.; Tawara, H.

1989-01-01

Slow Ar recoil-ion production cross sections by projectiles of 1.05-MeV/amu Ar q+ (q=4,6,8,10,12,14) were measured using a projectile-ion--recoil-ion coincidence technique. The present results indicate that the average recoil ion charges left-angle i right-angle increase with increasing the incident projectile charge q and the number of the lost and captured electrons from and/or into projectiles, whereas the projectile charge-changing cross sections for loss ionization decrease steeply with increasing q for low-charge-state projectiles, and those for transfer ionization increase rapidly with increasing q for high-charge-state projectiles. For Ar projectiles with q=10, which corresponds to the equilibrium charge state of Ar projectiles at the present collision energy, the average recoil-ion charges are nearly the same in both loss and transfer ionization, and a pure ionization process plays a much more important role in producing highly charged recoil ions, in contrast to projectile electron loss or transfer processes, which play a role in other projectile charge states

Experimental investigation of magnetoplasma acceleration of dielectric projectiles in a rail gun

International Nuclear Information System (INIS)

Kondratenko, M.M.; Lebedev, E.F.; Ostashev, V.E.; Safonov, V.I.; Fortov, V.E.; Ul'yanov, A.V.

1988-01-01

The authors present results of experimental investigations of the process of a nondestructive electrodynamic acceleration of dielectric projectiles in a magnetoplasma accelerator of rail gun type upon discharge of the electrical energy of the capacitor bank. They describe the phenomenon of decay of the plasma driving piston. They describe the causes of this phenomenon and the practical steps to avoid it. In a specific facility regimes have been achieved with electrodynamic acceleration of projectiles without plasma piston decay at working currents of up to 0.7 MA. In acceleration of projectiles of mass ∼ 1 g a speed of 6 km/sec has been attained and reproduced. The facility constructed can be used efficiently in experiments to investigate the thermophysical properties of substances using dynamic methods as a means of creating intense kinetic energy pulses

Batch Computed Tomography Analysis of Projectiles

Science.gov (United States)

2016-05-01

ARL-TR-7681 ● MAY 2016 US Army Research Laboratory Batch Computed Tomography Analysis of Projectiles by Michael C Golt, Chris M...Laboratory Batch Computed Tomography Analysis of Projectiles by Michael C Golt and Matthew S Bratcher Weapons and Materials Research...values to account for projectile variability in the ballistic evaluation of armor. 15. SUBJECT TERMS computed tomography , CT, BS41, projectiles

Concrete structures under projectile impact

CERN Document Server

Fang, Qin

2017-01-01

In this book, the authors present their theoretical, experimental and numerical investigations into concrete structures subjected to projectile and aircraft impacts in recent years. Innovative approaches to analyze the rigid, mass abrasive and eroding projectile penetration and perforation are proposed. Damage and failure analyses of nuclear power plant containments impacted by large commercial aircrafts are numerically and experimentally analyzed. Ultra-high performance concrete materials and structures against the projectile impact are developed and their capacities of resisting projectile impact are evaluated. This book is written for the researchers, engineers and graduate students in the fields of protective structures and terminal ballistics.

Noble-gas ion sputtering yield of gold and copper: Dependence on the energy and angle of incidence of the projectiles

Energy Technology Data Exchange (ETDEWEB)

Oliva-Florio, A.; Baragiola, R.A.; Jakas, M.M.; Alonso, E.V.; Ferron, J.

1987-02-15

We have measured the sputtering yield of Au and Cu targets as a function of energy and the angle of incidence of noble-gas projectiles in the energy range 2--50 keV. The experimental results were compared with the analytical theory of sputtering and with computer simulations. Our study indicates that the linear-cascade model is applicable only asymptotically for low nuclear stopping powers.

Small caliber guided projectile

Science.gov (United States)

Jones, James F [Albuquerque, NM; Kast, Brian A [Albuquerque, NM; Kniskern, Marc W [Albuquerque, NM; Rose, Scott E [Albuquerque, NM; Rohrer, Brandon R [Albuquerque, NM; Woods, James W [Albuquerque, NM; Greene, Ronald W [Albuquerque, NM

2010-08-24

A non-spinning projectile that is self-guided to a laser designated target and is configured to be fired from a small caliber smooth bore gun barrel has an optical sensor mounted in the nose of the projectile, a counterbalancing mass portion near the fore end of the projectile and a hollow tapered body mounted aft of the counterbalancing mass. Stabilizing strakes are mounted to and extend outward from the tapered body with control fins located at the aft end of the strakes. Guidance and control electronics and electromagnetic actuators for operating the control fins are located within the tapered body section. Output from the optical sensor is processed by the guidance and control electronics to produce command signals for the electromagnetic actuators. A guidance control algorithm incorporating non-proportional, "bang-bang" control is used to steer the projectile to the target.

Systematics of the breakup probability function for {sup 6}Li and {sup 7}Li projectiles

Energy Technology Data Exchange (ETDEWEB)

Capurro, O.A., E-mail: capurro@tandar.cnea.gov.ar [Laboratorio TANDAR, Comisión Nacional de Energía Atómica, Av. General Paz 1499, B1650KNA San Martín, Buenos Aires (Argentina); Pacheco, A.J.; Arazi, A. [Laboratorio TANDAR, Comisión Nacional de Energía Atómica, Av. General Paz 1499, B1650KNA San Martín, Buenos Aires (Argentina); CONICET, Av. Rivadavia 1917, C1033AAJ Buenos Aires (Argentina); Carnelli, P.F.F. [CONICET, Av. Rivadavia 1917, C1033AAJ Buenos Aires (Argentina); Instituto de Investigación e Ingeniería Ambiental, Universidad Nacional de San Martín, 25 de Mayo y Francia, B1650BWA San Martín, Buenos Aires (Argentina); Fernández Niello, J.O. [Laboratorio TANDAR, Comisión Nacional de Energía Atómica, Av. General Paz 1499, B1650KNA San Martín, Buenos Aires (Argentina); CONICET, Av. Rivadavia 1917, C1033AAJ Buenos Aires (Argentina); Instituto de Investigación e Ingeniería Ambiental, Universidad Nacional de San Martín, 25 de Mayo y Francia, B1650BWA San Martín, Buenos Aires (Argentina); and others

2016-01-15

Experimental non-capture breakup cross sections can be used to determine the probability of projectile and ejectile fragmentation in nuclear reactions involving weakly bound nuclei. Recently, the probability of both type of dissociations has been analyzed in nuclear reactions involving {sup 9}Be projectiles onto various heavy targets at sub-barrier energies. In the present work we extend this kind of systematic analysis to the case of {sup 6}Li and {sup 7}Li projectiles with the purpose of investigating general features of projectile-like breakup probabilities for reactions induced by stable weakly bound nuclei. For that purpose we have obtained the probabilities of projectile and ejectile breakup for a large number of systems, starting from a compilation of the corresponding reported non-capture breakup cross sections. We parametrize the results in accordance with the previous studies for the case of beryllium projectiles, and we discuss their systematic behavior as a function of the projectile, the target mass and the reaction Q-value.

Ionization of atoms by bare ion projectiles

International Nuclear Information System (INIS)

Tribedi, L.C.

1997-01-01

The double differential cross sections (DDCS) for low energy electron emission can provide stringent tests to the theoretical models for ionization in ion-atom collision. The two-center effects and the post collision interactions play a major role in ionization by highly charged, high Z projectiles. We close-quote ll review the recent developments in this field and describe our efforts to study the energy and angular distributions of the low energy electrons emitted in ion-atom ionization. copyright 1997 American Institute of Physics

The Locus of the apices of projectile trajectories under constant drag

OpenAIRE

Hernández-Saldaña, H.

2017-01-01

We present an analytical solution for the projectile coplanar motion under constant drag parametrised by the velocity angle. We found the locus formed by the apices of the projectile trajectories. The range and time of flight are obtained numerically and we find that the optimal launching angle is smaller than in the free drag case. This is a good example of problems with constant dissipation of energy that includes curvature, and it is proper for intermediate courses of mechanics.

Heavy-ion stopping powers and the low-velocity-projectile z3 effect

International Nuclear Information System (INIS)

Porter, L.E.

1977-01-01

Recent heavy-ion stopping-power measurements with elemental solid targets have been analyzed in order to ascertain the influence on effective ion charge of incorporating the low-velocity-projectile z 3 effect in Bethe-Bloch calculations. Shell corrections and the mean excitation energy of a given target were held fixed while searching for the best-fit value of a single charge-state parameter. In general, excellent fits to the stopping powers at projectile energies above 0.3 MeV/amu were achieved. Results of the present study compare very favorably with those from other extant methods of analysis

Projectile penetration into ballistic gelatin.

Science.gov (United States)

Swain, M V; Kieser, D C; Shah, S; Kieser, J A

2014-01-01

Ballistic gelatin is frequently used as a model for soft biological tissues that experience projectile impact. In this paper we investigate the response of a number of gelatin materials to the penetration of spherical steel projectiles (7 to 11mm diameter) with a range of lower impacting velocities (projectile velocity are found to be linear for all systems above a certain threshold velocity required for initiating penetration. The data for a specific material impacted with different diameter spheres were able to be condensed to a single curve when the penetration depth was normalised by the projectile diameter. When the results are compared with a number of predictive relationships available in the literature, it is found that over the range of projectiles and compositions used, the results fit a simple relationship that takes into account the projectile diameter, the threshold velocity for penetration into the gelatin and a value of the shear modulus of the gelatin estimated from the threshold velocity for penetration. The normalised depth is found to fit the elastic Froude number when this is modified to allow for a threshold impact velocity. The normalised penetration data are found to best fit this modified elastic Froude number with a slope of 1/2 instead of 1/3 as suggested by Akers and Belmonte (2006). Possible explanations for this difference are discussed. © 2013 Published by Elsevier Ltd.

Initiation of Gaseous Detonation by Conical Projectiles

Science.gov (United States)

Verreault, Jimmy

qualitatively well with the experimental results for relatively blunt projectiles (cone half-angle larger than 35°) and low mixture pressures (lower than 100 kPa). The trend of the critical Damköhler number calculated along the projectile cone surface was similar to that of the experimental results for slender cones (cone half-angles lower 35°) and high mixture pressures (higher than 100 kPa). Steady 2D simulations of reacting flows over finite wedges using the method of characteristics with a one-step Arrhenius chemical reaction model reproduced the three regimes observed for direct initiation of a detonation: the subcritical, critical and supercritical regimes. It is shown that in order for a 2D wedge to be equivalent to the problem of blast initiation of a detonation (which is the essence of the Lee-Vasiljev model), the Mach number normal to the oblique shock needs to be greater than 50 and the wedge angle has to be smaller than 30°. Simulations of reacting flows over semi-infinite wedges and cones were validated with CFD results. Excellent agreement was reached between the angle of overdriven oblique detonations obtained from the simulations and those from a polar analysis. For wedge or cone angles equal or lower than the minimum angle for which an oblique detonation is attached (according to the polar analysis), a Chapman-Jouguet oblique detonation was initiated. In the conical configuration, the curvature around the cone axis allowed an oblique detonation to be self-sustained at an angle less than without the curvature effect. At larger activation energies, the initiation process of an oblique detonation wave at the tip of a semi-infinite wedge or cone was identified. Unsteady 2D computational simulations were also conducted and showed the cellular structure of an oblique detonation wave. Instabilities in the form of transverse shock waves along the oblique detonation front arise for large activation energies.

Backward ejected electrons from collisions of 1 MeV/u Oq+ projectiles with argon gas

International Nuclear Information System (INIS)

Berryman, J.W.; Breinig, M.; Segner, F.; Desai, D.

1993-01-01

We will be presenting results from a series of experiments measuring the yields and energy distributions of electrons emitted at 1800 with respect to the 1 MeV/u O q+ [q=3-8] ion beam. We have systematically studied the yield per incident ion and the energy distribution of electrons as a function of the incident projectile charge state. The energy distributions show two prominent structures: a narrow peak due to target LMM Auger electrons and a broad hump due to projectile binary-encounter electrons. The shapes and yields of the Auger electron peaks are nearly independent of the incident charge state. The shapes and yields of the binary-encounter electron peaks are sensitive functions of the number of projectile electrons carried into the collision. A well defined binary-encounter electron peak appears only for charge states q=3, 4, and 5

Projectile Balloting Attributable to Gun Tube Curvature

Directory of Open Access Journals (Sweden)

Michael M. Chen

2010-01-01

Full Text Available Transverse motion of a projectile during launch is detrimental to firing accuracy, structural integrity, and/or on-board electronics performance of the projectile. One manifest contributing factor to the undesired motion is imperfect bore centerline straightness. This paper starts with the presentation of a deterministic barrel model that possesses both vertical and lateral deviations from centerline in accordance with measurement data, followed by a novel approach to simulating comprehensive barrel centerline variations for the investigation of projectile balloting^1 motions. A modern projectile was adopted for this study. In-bore projectile responses at various locations of the projectile while traveling through the simulated gun tubes were obtained. The balloting was evaluated in both time and frequency domains. Some statistical quantities and the significance were outlined.

Molecular projectile effects for kinetic electron emission from carbon- and metal-surfaces bombarded by slow hydrogen ions

Science.gov (United States)

Cernusca, S.; Winter, HP.; Aumayr, F.; Díez Muiño, R.; Juaristi, J. I.

2003-04-01

Total yields for kinetic electron emission (KE) have been determined for impact of hydrogen monomer-, dimer- and trimer-ions (impact energy armour in magnetic fusion devices. The data are compared with KE yields for impact of same projectile ions on atomically clean highly oriented pyrolytic graphite and polycrystalline gold. We discuss KE yields for the different targets if bombarded by equally fast molecular and atomic ions in view to "projectile molecular effects" (different yields per proton for equally fast atomic and molecular ions), which are expected from calculated electronic projectile energy losses in these target materials.

Prediction of projectile ricochet behavior after water impact.

Science.gov (United States)

Baillargeon, Yves; Bergeron, Guy

2012-11-01

Although not very common, forensic investigation related to projectile ricochet on water can be required when undesirable collateral damage occurs. Predicting the ricochet behavior of a projectile is challenging owing to numerous parameters involved: impact velocity, incident angle, projectile stability, angular velocity, etc. Ricochet characteristics of different projectiles (K50 BMG, 0.5-cal Ball M2, 0.5-cal AP-T C44, 7.62-mm Ball C21, and 5.56-mm Ball C77) were studied in a pool. The results are presented to assess projectile velocity after ricochet, ricochet angle, and projectile azimuth angle based on impact velocity or incident angle for each projectile type. The azimuth ranges show the highest variability at low postricochet velocity. The critical ricochet angles were ranging from 15 to 30°. The average ricochet angles for all projectiles were pretty close for all projectiles at 2.5 and 10° incident angles for the range of velocities studied. © 2012 Her Majesty the Queen in Right of Canada 2012. Reproduced with the permission of the Minister of the Department of National Defence.

Reaction dynamics of {sup 34-38}Mg projectile with carbon target using Glauber model

Energy Technology Data Exchange (ETDEWEB)

Shama, Mahesh K., E-mail: maheshphy82@gmail.com [School of Physics and Material Sciences, Thapar University Patiala-147004 (India); Department of Applied Sciences, Chandigarh Engineering College, Landran Mohali-140307 (India); Panda, R. N. [Department of Physics, ITER, Shiksha O Anusandhan University, Bhubaneswar-751030 (India); Sharma, Manoj K. [School of Physics and Material Sciences, Thapar University Patiala-147004 (India); Patra, S. K. [Institute of Physics, Sachivalaya marg Bhubneswar-751005 (India)

2015-08-28

We have studied nuclear reaction cross-sections for {sup 34-38}Mg isotopes as projectile with {sup 12}C target at projectile energy 240AMeV using Glauber model with the conjunction of densities from relativistic mean filed formalism. We found good agreement with the available experimental data. The halo status of {sup 37}Mg is also investigated.

Ionization of hydrogen by a relativistic heavy projectile

International Nuclear Information System (INIS)

Hofstetter, S.; Hofmann, C.; Soff, G.

1991-10-01

Using a relativistic analogue of the classical trajectory Monte-Carlo method we investigate the influence of the magnetic field of a relativistic heavy projectile on the ionization cross section of hydrogen. In particular we focus our attention on the angular and energy distribution of the emitted delta electrons. (orig.)

Reaction 40Ca+natCu at 35 MeV/nucleon measured with the AMPHORA multidetector. Study of the excitation energy and angular momentum of the reconstructed projectile-like fragment

International Nuclear Information System (INIS)

Elhage, H.

1992-10-01

We have studied the reaction of 40 Ca with nat Cu at 35 MeV/nucleon with the AMPHORA multidetector. Three different reaction models were developed and we have shown that a simulation of the AMPHORA response is necessary to interpret the experimental results. Only two-body events were analyzed. Kinematic selection criterions, based on relative velocity, were used in order to isolate particles and residues coming from the de-excitation of the projectile-like fragment. The reconstitution of such a nucleus allowed to define the reaction plane and to calculate the energy balance event-by-event. We have proposed a method to determine the angular momentum based on the emission asymmetry of the light particles with respect to the normal to the reaction plane. The estimated angular momenta are in good agreement with the theoretical predictions. The projectile-like fragment temperature was estimated from the energy spectra of the light particles. The independent determination of the excitation energy, temperature and angular momentum allowed to calculate the level density parameter. This quantity does not evolve with the excitation energy and is equal to A/8. The projectile-like fragment de-excitation mode is mainly evaporation

Some physical magnitudes of interest for nuclear reactions and their dependence on the projectile-target system

International Nuclear Information System (INIS)

Fernandez Niello, J.O.; Pacheco, A.J.

1984-01-01

The design and analysis of experiences with heavy ions requires the knwoledge of several characteristic parameters of the collision and their dependence on the reactant system. In the case of an electrostatic accelerator as the TANDAR, the bombarding energy (function of the projectile) is a direct consequence of the evolution of the charged state distribution for the projectile at the exit of the last stripper, as a function of the atomic number. The complexity resulting from this dependence originated the confection of a series of diagrams. The diagrams correpond to the different physical magnitudes of interest in the analysis of nuclear reactions as a function of the projectile-target combination for terminal tensions similar to those expected to reach at the TANDAR. In each case, the curves are refered to the following physical magnitudes: Ecm/Bc Kinetic energy in the center of the mass system and Coulomb barrier for the projectile-target system, Lgr = angular momentum corresponding to the grazing collisions. Diagrams of the average projectile energy per nucleon for the different values of the terminal tensions with one or two solid strippers are included. The use of the diagrams in some practical applications is illustrated through four examples. The diagrams may be extended, if necesary, to other physical magnitudes, at different accelerator's operating conditions. (M.E.L.) [es

Ionization of heavy targets by impact of relativistic projectiles

International Nuclear Information System (INIS)

Deco, G.R.; Fainstein, P.D.; Comision Nacional de Energia Atomica, San Carlos de Bariloche; Rivarola, R.D.

1988-01-01

Electron ejection from atomic targets by impact of bare heavy projectiles at relativistic collision energies is studied theoretically. First-order Born calculations are presented by using initial Darwin and final Sommerfeld-Maue wavefunctions. Comparisons with other calculations and experimental data are given. (orig.)

Locus of the apices of projectile trajectories under constant drag

Science.gov (United States)

Hernández-Saldaña, H.

2017-11-01

Using the hodograph method, we present an analytical solution for projectile coplanar motion under constant drag, parametrised by the velocity angle. We find the locus formed by the apices of the projectile trajectories, and discuss its implementation for the motion of a particle on an inclined plane in presence of Coulomb friction. The range and time of flight are obtained numerically, and we find that the optimal launching angle is smaller than in the drag-free case. This is a good example of a problem with constant dissipation of energy that includes curvature; it is appropriate for intermediate courses of mechanics.

Ablation and deceleration of mass-driver launched projectiles for space disposal of nuclear wastes

International Nuclear Information System (INIS)

Park, C.; Bowen, S.W.

1981-01-01

The energy cost of launching a projectile containing nuclear waste is two orders of magnitude lower with a mass driver than with a typical rocket system. A mass driver scheme will be feasible, however, only if ablation and deceleration are within certain tolerable limits. It is shown that if a hemisphere-cylinder-shaped projectile protected thermally with a graphite nose is launched vertically to attain a velocity of 17 km/sec at an altitude of 40 km, the mass loss from ablation during atmospheric flight will be less than 0.1 ton, provided the radius of the projectile is under 20 cm and the projectile's mass is of the order of 1 ton. The velocity loss from drag will vary from 0.4 to 30 km/sec, depending on the mass and radius of the projectile, the smaller velocity loss corresponding to large mass and small radius. Ablation is always within a tolerable range for schemes using a mass driver launcher to dispose of nuclear wastes outside the solar system. Deceleration can also be held in the tolerable range if the mass and diameter of the projectile are properly chosen

Continuous measurements of in-bore projectile velocity

International Nuclear Information System (INIS)

Asay, J.R.; Konrad, C.H.; Hall, C.A.; Shahinpoor, M.

1989-01-01

The application of velocity interferometry to the continuous measurement of in-bore projectile velocity in a small-bore three-stage railgun is described. These measurements are useful for determining projectile acceleration and for evaluating gun performance. The launcher employed in these studies consists of a two-stage light gas gun used to inject projectiles into a railgun for additional acceleration. Results obtained for projectile velocities to 7.4 km/s with the two-stage injector are reported and potential improvements for railgun applications are discussed

New projectiles: multicharged metal clusters and biopolymers

International Nuclear Information System (INIS)

Della-Negra, S.; Gardes, D.; Le Beyec, Y.; Waast, B.

1991-01-01

Metal clusters and molecules are the one mean to realize simultaneous impacts of several atoms on a reduced surface(∼100A). The interaction characteristics is the non-linearity of energy deposition; the perturbation that the cluster produces, is above than the sum of the perturbation induced by its components, taken separately. The purpose of ORION project is to accelerate these new projectiles at ORSAY Tandem. The considered mass range is from 100 Daltons to 100 000 Daltons and energy range from MeV to GeV

Multiple electromagnetic excitations of relativistic projectiles

International Nuclear Information System (INIS)

Llope, W.J.; Braun-Munzinger, P.

1992-01-01

Conditions optimum for the first experimental verification of the multiplication electromagnetic excitations of nuclei in relativistic nucleus-nucleus collisions are described. The relative magnitudes of three important physical processes that might interfere with such a measurement are compared to the predicted strengths for the single and multiple electromagnetic excitations for various choices of the projectile mass and beam energy. Strategies are presented for making inferences concerning the presence of multiple excitation strength in experimental data

First spatial isotopic separation of relativistic uranium projectile fragments

International Nuclear Information System (INIS)

Magel, A.; Voss, B.; Armbruster, P.; Aumann, T.; Clerc, H.G.; Czajkowski, S.; Folger, H.; Grewe, A.; Hanelt, E.; Heinz, A.; Irnich, H.; Jong, M. de; Junghans, A.; Nickel, F.; Pfuetzner, M.; Roehl, C.; Scheidenberger, C.; Schmidt, K.H.; Schwab, W.; Steinhaeuser, S.; Suemmerer, K.; Trinder, W.; Wollnik, H.

1994-07-01

Spatial isotopic separation of relativistic uranium projectile fragments has been achieved for the first time. The fragments were produced in peripheral nuclear collisions and spatially separated in-flight with the fragment separator FRS at GSI. A two-fold magnetic-rigidity analysis was applied exploiting the atomic energy loss in specially shaped matter placed in the dispersive central focal plane. Systematic investigations with relativistic projectiles ranging from oxygen up to uranium demonstrate that the FRS is a universal and powerful facility for the production and in-flight separation of monoisotopic, exotic secondary beams of all elements up to Z=92. This achievement has opened a new area in heavy-ion research and applications. (orig.)

Derivation of linear attenuation coefficients from CT numbers for low-energy photons

International Nuclear Information System (INIS)

Watanabe, Y.

1999-01-01

One can estimate photon attenuation properties from the CT number. In a standard method one assumes that the linear attenuation coefficient is proportional to electron density and ignores its nonlinear dependence on atomic number. When the photon energy is lower than about 50 keV, such as for brachytherapy applications, however, photoelectric absorption and Rayleigh scattering become important. Hence the atomic number must be explicitly considered in estimating the linear attenuation coefficient. In this study we propose a method to more accurately estimate the linear attenuation coefficient of low-energy photons from CT numbers. We formulate an equation that relates the CT number to the electron density and the effective atomic number. We use a CT calibration phantom to determine unknown coefficients in the equation. The equation with a given CT number is then solved for the effective atomic number, which in turn is used to calculate the linear attenuation coefficient for low-energy photons. We use the CT phantom to test the new method. The method significantly improves the standard method in estimating the attenuation coefficient at low photon energies (20keV≤E≤40keV) for materials with high atomic numbers. (author)

Multifragmentation induced by light relativistic projectiles and heavy ions: similarities and differences

International Nuclear Information System (INIS)

Karnaukhov, V.A.; Avdeev, S.P.; Kuznetsov, V.D.

1998-01-01

The experimental data on fragment multiplicities, their energy and charge distributions, the emission times are considered for the nuclear multifragmentation process induced by relativistic light projectiles (protons, helium) and heavy ions. With light projectiles, the multifragmentation is a pure 'thermal' process, well described by the statistical models. Heavy-ion-induced multifragmentation is influenced by dynamic effects related first of all to the compression of the system in the collision. But statistical models can also be applied to rendering the partition of the system if the excitation energy is less than 10 MeV/nucleon and compression is modest. For the central collision of heavy ions the statistical approach fails to describe the data

Molecular projectile effects for kinetic electron emission from carbon- and metal-surfaces bombarded by slow hydrogen ions

International Nuclear Information System (INIS)

Cernusca, S.; Winter, H.P.; Aumayr, F.; Diez Muino, R.; Juaristi, J.I.

2003-01-01

Total yields for kinetic electron emission (KE) have been determined for impact of hydrogen monomer-, dimer- and trimer-ions (impact energy <10 keV) on atomically clean surfaces of carbon-fiber inforced graphite used as first-wall armour in magnetic fusion devices. The data are compared with KE yields for impact of same projectile ions on atomically clean highly oriented pyrolytic graphite and polycrystalline gold. We discuss KE yields for the different targets if bombarded by equally fast molecular and atomic ions in view to 'projectile molecular effects' (different yields per proton for equally fast atomic and molecular ions), which are expected from calculated electronic projectile energy losses in these target materials

Molecular projectile effects for kinetic electron emission from carbon- and metal-surfaces bombarded by slow hydrogen ions

CERN Document Server

Cernusca, S; Aumayr, F; Diez-Muino, R; Juaristi, J I

2003-01-01

Total yields for kinetic electron emission (KE) have been determined for impact of hydrogen monomer-, dimer- and trimer-ions (impact energy <10 keV) on atomically clean surfaces of carbon-fiber inforced graphite used as first-wall armour in magnetic fusion devices. The data are compared with KE yields for impact of same projectile ions on atomically clean highly oriented pyrolytic graphite and polycrystalline gold. We discuss KE yields for the different targets if bombarded by equally fast molecular and atomic ions in view to 'projectile molecular effects' (different yields per proton for equally fast atomic and molecular ions), which are expected from calculated electronic projectile energy losses in these target materials.

Intercomparison of medium-energy neutron attenuation in iron and concrete

International Nuclear Information System (INIS)

Hirayama, H.

1999-01-01

Neutron attenuation of medium energy below 1 GeV has not been well understood until now. It is desired to obtain common agreements concerning the behaviours of neutrons inside various materials. This is necessary in order to agree on definitions of the attenuation length, which is very important for shielding calculations involving high energy accelerators. As one attempt, it was proposed by Japanese attendants of SATIF-2 to compare the attenuation of medium-energy neutrons inside iron and concrete shields between various computer codes and data, and was cited as a suitable action for SATIF. The first results from three groups were presented at SATIF-3. It has become clear that neutrons above 20 MeV are important for understanding the attenuation inside materials and that the geometry, planar or spherical, does not affect the results very much. Considering the CPU times required for Monte Carlo calculations and this result, revised problems to be calculated were prepared by the Japanese Working Group and sent to the participants of this action. The geometry is only plane, and calculations are required only for neutrons above 20 MeV. The secondary neutrons from high energy protons, which were calculated by H. Nakashima, are also included in the problem. The results from four groups were sent to the organizer at the end of August. This paper presents a comparison between groups concerning the attenuation length together with the neutron spectrum and the future themes which come from this intercomparison. (author)

Dynamic effects of interaction of composite projectiles with targets

Energy Technology Data Exchange (ETDEWEB)

Zakharov, V. M. [Scientific Research Institute of Applied Mathematics and Mechanics of Tomsk State University, 36, Lenin Avenue, Tomsk, 634050 (Russian Federation)

2016-01-15

The process of high-speed impact of projectiles against targets of finite thickness is experimentally investigated. Medium-hard steel plates are used as targets. The objective of this research is to carry out a comparative analysis of dynamic effects of interaction of various types of projectiles with targets, such as characteristics of destruction of the target, the state of the projectile behind the target, and particularities of the after-penetration stream of fragments after the target has been pierced. The projectiles are made of composites on the basis of tungsten carbide obtained by caking and the SHS-technology. To compare effectiveness of composite projectiles steel projectiles are used. Their effectiveness was estimated in terms of the ballistic limit. High density projectiles obtained by means of the SHS-technology are shown to produce results comparable in terms of the ballistic limit with high-strength projectiles that contain tungsten received by caking.

Function behavior of a gas-operated accelerator for kinetic energy projectiles

International Nuclear Information System (INIS)

Heine, H.

1979-01-01

The test facility - presented here - was designed and constructed in order to make investigations on the load case 'airplane crash'. The facility consists mainly of the accelerator on a rail track, an abutment, a control centre, and a measuring-bunker.To perform a test the two parts of the accelerator - a compression chamber and an expansion tube (diameter 613 mm) - are strongly connected after the projectile has been inserted into the tube. The chamber - closed by a steel membrane - is filled with a mixture of methane and compressed air. The mixture is ignited and expands. The membrane opens and the projectile is accelerated. The velocity range can be varied between 80 and 300 m/s.The reinforced concrete slabs that are impacted during the main test series have the dimensions of 6.00 m by 6.50 m and a maximum thickness of 90 cm. During the test the slab hangs at a cross beam so that there is no friction between the specimen and the abutment. (orig.)

Effect of Nonsmooth Nose Surface of the Projectile on Penetration Using DEM Simulation

Directory of Open Access Journals (Sweden)

Jing Han

2017-01-01

Full Text Available The nonsmooth body surface of the reptile in nature plays an important role in reduction of resistance and friction when it lives in a soil environment. To consider whether it was feasible for improving the performance of penetrating projectile we investigated the influence of the convex as one of nonsmooth surfaces for the nose of projectile. A numerical simulation study of the projectile against the concrete target was developed based on the discrete element method (DEM. The results show that the convex nose surface of the projectile is beneficial for reducing the penetration resistance greatly, which is also validated by the experiments. Compared to the traditional smooth nose structure, the main reason of difference is due to the local contact normal pressure, which increases dramatically due to the abrupt change of curvature caused by the convex at the same condition. Accordingly, the broken particles of the concrete target obtain more kinetic energy and their average radial flow velocities will drastically increase simultaneously, which is in favor of decreasing the interface friction and the compaction density of concrete target around the nose of projectile.

Isotopic distribution of the projectile-like products in the reaction 36Ar + 124Sn at 35 MeV/u

International Nuclear Information System (INIS)

Xiao Zhigang; Jin Genming; Wu Heyu; Hu Rongjiang; Wang Hongwei; Li Zuyu; Duan Limin; Wang Sufang; Wei Zhiyong; Zhang Baoguo; Liu Jianye; Zhu Yongtai

2003-01-01

The projectile-like products at 5.3 degree in the reaction 35 MeV/u 36 Ar + 124 Sn were inclusively measured with good isotopic identification. With increasing kinetic energy, the average N/Z ratio of the products gradually decreases, approaching to that of the projectile. It is shown from the isospin dependent quantum mechanics (IQMD) that with the increasing of reaction time, the average kinetic energy of the projectile-like products decreases, while the N/Z ratio increases gradually. Moreover, the isotropic composition is obviously dependent on the impact parameter, and the N/Z radio is becoming smaller with increasing collision centrality

Improvements to a model of projectile fragmentation

International Nuclear Information System (INIS)

Mallik, S.; Chaudhuri, G.; Das Gupta, S.

2011-01-01

In a recent paper [Phys. Rev. C 83, 044612 (2011)] we proposed a model for calculating cross sections of various reaction products which arise from disintegration of projectile-like fragments resulting from heavy-ion collisions at intermediate or higher energy. The model has three parts: (1) abrasion, (2) disintegration of the hot abraded projectile-like fragment (PLF) into nucleons and primary composites using a model of equilibrium statistical mechanics, and (3) possible evaporation of hot primary composites. It was assumed that the PLF resulting from abrasion has one temperature T. Data suggested that, while just one value of T seemed adequate for most cross-section calculations, a single value failed when dealing with very peripheral collisions. We have now introduced a variable T=T(b) where b is the impact parameter of the collision. We argue that there are data which not only show that T must be a function of b but, in addition, also point to an approximate value of T for a given b. We propose a very simple formula: T(b)=D 0 +D 1 [A s (b)/A 0 ] where A s (b) is the mass of the abraded PLF and A 0 is the mass of the projectile; D 0 and D 1 are constants. Using this model we compute cross sections for several collisions and compare with data.

Projectile break-up of 14N at 62,7 MeV

International Nuclear Information System (INIS)

Bozek, E.; Cassagnou, Y.; Dayras, R.; Legrain, R.; Pagano, A.; Rodriguez, L.; Lanzano, G.; Palmeri, A.; Pappalardo, G.

1983-01-01

In plane and out of plane angular correlations between light particles and heavy ions have been measured in the reaction 14 N + 12 C at 62.7 MeV bombarding energy. Special attention has been given to the break-up of 14 N into 13 C + p, 12 C + d and 10 B + α. The observed correlations are consistent with sequential break-up of the 14 N projectile. A Monte-Carlo calculation assuming isotropic emission of particles in the rest frame of the projectile from well defined states in 14 N is in good agreement with the experimental angular correlations. From a comparison between calculated and experimental boron and carbon single energy spectra, it appears that after transfer reactions, sequential break-up of 14 N is the dominant process to produce these nuclei

Dynamic analysis of a guided projectile during engraving process

Directory of Open Access Journals (Sweden)

Tao Xue

2014-06-01

Full Text Available The reliability of the electronic components inside a guided projectile is highly affected by the launch dynamics of guided projectile. The engraving process plays a crucial role on determining the ballistic performance and projectile stability. This paper analyzes the dynamic response of a guided projectile during the engraving process. By considering the projectile center of gravity moving during the engraving process, a dynamics model is established with the coupling of interior ballistic equations. The results detail the stress situation of a guided projectile band during its engraving process. Meanwhile, the axial dynamic response of projectile in the several milliseconds following the engraving process is also researched. To further explore how the different performance of the engraving band can affect the dynamics of guided projectile, this paper focuses on these two aspects: (a the effects caused by the different band geometry; and (b the effects caused by different band materials. The time domain and frequency domain responses show that the dynamics of the projectile are quite sensitive to the engraving band width. A material with a small modulus of elasticity is more stable than one with a high modulus of elasticity.

Investigation of multilayered nanocomposites as low energy X-Rays attenuators

Energy Technology Data Exchange (ETDEWEB)

Silva, Liliane; Batista, Adriana S.M.; Nascimento, Jefferson P.; Furtado, Clascídia A.; Faria, Luiz O., E-mail: asfisica@gmail.com, E-mail: adriananuclear@yahoo.com.br, E-mail: farialo@cdtn.br, E-mail: nascimentopatricio@yahoo.com.br, E-mail: clas@cdtn.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil); Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2017-11-01

The development of radiation attenuating materials has application in radioprotection and conditioning of short-lived waste. Polymeric materials can serve as a matrix for the dispersion of nanomaterials with good attenuation features, resulting in lightweight, conformable, flexible and easy-to-process materials. Thus, some well-known shielding materials could be used in low proportion for the formation of new materials. On the other hand, nanostructured carbon materials, such as graphene oxide (GO) and carbon nanotubes (NTCs), have been reported recently to show enhanced attenuation properties. In this sense, polymeric matrixes provide the necessary flexibility for use in various applications that require molding. For the present work, poly(vinylidene fluoride) [PVDF] homopolymers and its fluorinated copolymers were filled with nanosized metallic and graphene oxides in order to produce nanocomposites with increased low energy X-ray attenuation efficiency. Film samples of PVDF/reduced Graphene Oxide [PVDF/rGO] and Poly(vinylidene fluoride – tryfluorethylene)/Barium Oxide [P(VDF-TrFE)/BaO] were synthesized. In a second step, the samples were then sandwiched between Kapton® layers and exposed to X-rays source (8.5 keV). The samples were characterized with Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). The attenuation coefficient was evaluated and compared with the attenuation of the individual constituents. It was observed an increase in the linear attenuation coefficient of the layered materials, justifying further investigation of these nanostructured composites as X-ray or gamma radiation attenuators. (author)

Investigation of multilayered nanocomposites as low energy X-Rays attenuators

International Nuclear Information System (INIS)

Silva, Liliane; Batista, Adriana S.M.; Nascimento, Jefferson P.; Furtado, Clascídia A.; Faria, Luiz O.

2017-01-01

The development of radiation attenuating materials has application in radioprotection and conditioning of short-lived waste. Polymeric materials can serve as a matrix for the dispersion of nanomaterials with good attenuation features, resulting in lightweight, conformable, flexible and easy-to-process materials. Thus, some well-known shielding materials could be used in low proportion for the formation of new materials. On the other hand, nanostructured carbon materials, such as graphene oxide (GO) and carbon nanotubes (NTCs), have been reported recently to show enhanced attenuation properties. In this sense, polymeric matrixes provide the necessary flexibility for use in various applications that require molding. For the present work, poly(vinylidene fluoride) [PVDF] homopolymers and its fluorinated copolymers were filled with nanosized metallic and graphene oxides in order to produce nanocomposites with increased low energy X-ray attenuation efficiency. Film samples of PVDF/reduced Graphene Oxide [PVDF/rGO] and Poly(vinylidene fluoride – tryfluorethylene)/Barium Oxide [P(VDF-TrFE)/BaO] were synthesized. In a second step, the samples were then sandwiched between Kapton® layers and exposed to X-rays source (8.5 keV). The samples were characterized with Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). The attenuation coefficient was evaluated and compared with the attenuation of the individual constituents. It was observed an increase in the linear attenuation coefficient of the layered materials, justifying further investigation of these nanostructured composites as X-ray or gamma radiation attenuators. (author)

Charge-exchange products of BEVALAC projectiles

International Nuclear Information System (INIS)

Rasmussen, J.

1982-11-01

There is a substantial production of fragments of all masses lighter than the projectile, such fragments being centered in a narrow region of velocity space around the beam velocity. The exciting studies about anomalons deal with the curious enhanced reactivity of some of these secondary fragments. I direct attention here to the rather rare fragments of the same mass number as the projectile but differing in charge by one unit. We also keep track, as a frame of reference, of the products that have lost one neutron from the projectile

Electrostatic potentials and energy loss due to a projectile propagating through a non-Maxwellian dusty plasma

International Nuclear Information System (INIS)

Deeba, F.; Ahmad, Zahoor; Murtaza, G.

2006-01-01

The electrostatic potentials (Debye and wake) and energy loss due to a charged projectile propagating through an unmagnetized collisionless dusty plasma are derived employing kappa and generalized (r,q) velocity distributions for the dust acoustic wave. It is found that these quantities in general differ from their Maxwellian counterparts and are sensitive to the values of spectral index, κ in the case of kappa distribution and to r, q in the case of generalized (r,q) distribution. The amplitudes of these quantities are less for small values of the spectral index (κ, r=0, q) but approach the Maxwellian in the limit κ→∞ (for kappa distribution) and for r=0, q→∞ [for generalized (r,q) distribution]. For any nonzero value of r, the potential and the energy loss grow beyond the Maxwellian results. The effect of kappa and generalized (r,q) distributions on potential and energy loss is also studied numerically and the results are compared with those of the Maxwellian distribution

Angry Birds realized: water balloon launcher for teaching projectile motion with drag

International Nuclear Information System (INIS)

Edwards, Boyd F; Sam, David D; Christiansen, Michael A; Booth, William A; Jessup, Leslie O

2014-01-01

A simple, collapsible design for a large water balloon slingshot launcher features a fully adjustable initial velocity vector and a balanced launch platform. The design facilitates quantitative explorations of the dependence of the balloon range and time of flight on the initial speed, launch angle, and projectile mass, in an environment where quadratic air drag is important. Presented are theory and experiments that characterize this drag, and theory and experiments that characterize the nonlinear elastic energy and hysteresis of the latex tubing used in the slingshot. The experiments can be carried out with inexpensive and readily available tools and materials. The launcher provides an engaging way to teach projectile motion and elastic energy to students of a wide variety of ages. (paper)

The influence of projectile ion induced chemistry on surface pattern formation

Energy Technology Data Exchange (ETDEWEB)

Karmakar, Prasanta, E-mail: prasantak@vecc.gov.in [Variable Energy Cyclotron Centre, 1/AF, Bidhannagar, Kolkata 700064 (India); Satpati, Biswarup [Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064 (India)

2016-07-14

We report the critical role of projectile induced chemical inhomogeneity on surface nanostructure formation. Experimental inconsistency is common for low energy ion beam induced nanostructure formation in the presence of uncontrolled and complex contamination. To explore the precise role of contamination on such structure formation during low energy ion bombardment, a simple and clean experimental study is performed by selecting mono-element semiconductors as the target and chemically inert or reactive ion beams as the projectile as well as the source of controlled contamination. It is shown by Atomic Force Microscopy, Cross-sectional Transmission Electron Microscopy, and Electron Energy Loss Spectroscopy measurements that bombardment of nitrogen-like reactive ions on Silicon and Germanium surfaces forms a chemical compound at impact zones. Continuous bombardment of the same ions generates surface instability due to unequal sputtering and non-uniform re-arrangement of the elemental atom and compound. This instability leads to ripple formation during ion bombardment. For Argon-like chemically inert ion bombardment, the chemical inhomogeneity induced boost is absent; as a result, no ripples are observed in the same ion energy and fluence.

Considerations about projectile and target X-rays induced during heavy ion bombardment

Science.gov (United States)

Fernandes, F.; Bauer, D. V.; Duarte, A.; Ferrari, T. M.; Niekraszewicz, L. A. B.; Amaral, L.; Dias, J. F.

2018-02-01

In this work we present some results concerning the X-rays emitted by heavy ions during target bombardment. In this case, Cl4+ and Cl5+ ions with energies from 4 MeV to 10 MeV were employed to irradiate vitreous carbon planchets. Moreover, total X-ray production cross sections of titanium X-rays induced by chlorine ions were obtained as well for the same energy range. Only inner shell transitions were considered in the present work. The titanium target consisted of a thin film deposited over vitreous carbon planchets. The results indicate that the projectile X-ray yields increase as a function of the bombarding energy for the present energy range. Effects due to projectile charge state appears to be of minor importance at these low ion velocities. It is shown that a simple exponential function can represent the continuum background of such complex spectra. The chlorine transition rates Kβ/Kα obtained from chlorine acting as a projectile interacting with a carbon target are about half the value when compared to the chlorine Kβ/Kα ratios obtained when a LiCl target is bombarded with C+ and C3+ ions with energies from 2 MeV to 6 MeV. As far as the total X-ray production cross sections of Ti induced by chlorine ions are concerned, the ECPSSR theory underestimates the Ti total X-rays production cross sections by several orders of magnitude. The role of electron capture and possible mechanisms responsible for these effects are discussed.

Energy and target dependence of projectile breakup effect in the elastic scattering of 6Li

International Nuclear Information System (INIS)

Sakuragi, Y.

1986-03-01

Over the wide range of incident energy (E lab = 40 ∼ 170 MeV) and target mass number (A = 12 ∼ 208), projectile breakup effects in the elastic scattering of 6 Li have been investigated with a microscopic coupled-channel method. The coupling to the 6 Li → α + d breakup process is treated with the method of coupled discretized continuum channels (CDCC). 6 Li-target interactions are provided by the folding of the M3Y effective nucleon-nucleon potential with nucleon densities of colliding nuclei. The calculation well reproduces the observed elastic scattering for all the targets and incident energies without any renormalization in the real folding potentials. The breakup effect is found to depend little on the energy and target, which is confirmed by calculating the dynamical polarization potentials induced by the coupling to the breakup process. Almost irrespectively of energy and target, the potential has a repulsive real part with strength of about 40 % of the folding potential in addition to a negligible imaginary part, which explains well the empirical reduction factor of the double-folding model. Discussions are made on the origin of repulsive nature of the breakup effect. (author)

Fusion, reaction and break-up cross sections of weakly bound projectiles on 64Zn

International Nuclear Information System (INIS)

Gomes, P.R.S.; Padron, I.; Rodriguez, M.D.; Marti, G.V.; Anjos, R.M.; Lubian, J.; Veiga, R.; Liguori Neto, R.; Crema, E.; Added, N.; Chamon, L.C.; Fernandez Niello, J.O.; Capurro, O.A.; Pacheco, A.J.; Testoni, J.E.; Abriola, D.; Arazi, A.; Ramirez, M.; Hussein, M.S.

2004-01-01

We present new measurements and a general discussion of the behavior of the fusion, break-up and reaction cross sections of different projectiles on the same target 64 Zn, at near and above barrier energies. The projectiles are the tightly bound 16 O, the stable weakly bound 6 Li, 7 Li and 9 Be and the radioactive very weakly bound 6 He nuclei. We also compare the results with the ones for heavier targets

Fragmentation of small molecules induced by 46 keV/amu N+ and N2+ projectiles

International Nuclear Information System (INIS)

Kovacs, S.T.S.; Juhasz, Z.; Herczku, P.; Sulik, B.

2012-01-01

Complete text of publication follows. Collisional molecule fragmentation experiments has gain increasing attention in several research and applied fields. In order to understand the fundamental processes of molecule fragmentation one has to start with collisions of small few-atomic molecules. Moreover, fragments of small molecules such as water can cause damages of large molecules (DNA) very effectively in living tissues. In the last few years a new experimental setup was developed at Atomki. It was designed especially for molecule fragmentation experiments. Now the measurements using this system are running routinely. In 2012 the studied targets were water vapor, methane and nitrogen gases, injected into the collision area by an effusive molecular gas jet system. 650 keV N + and 1,3 MeV N 2 + ions were used as projectiles produced by the VdG-5 electrostatic accelerator. The velocity of the two types of projectiles was the same. Energy and angular distribution of the produced fragments was measured by an energy dispersive electrostatic spectrometer. For atomic ionization a symmetric, diatomic molecular projectile (e.g. N 2 + ) yields about twice more electrons compared to those of singly charged ion projectiles of the same atom (N + ) at the same velocity. In such cases the two atomic centers in the molecular ion can be considered as two individual atomic centers. For the fragmentation of molecular targets the picture is not so simple because in this case close collision of two extended systems is investigated. As figure 1 and 2 show, the measured yields for molecular projectile is not simply twice of the ones for atomic projectile. The shape of the energy spectra are different. The measured data are under evaluation. Acknowledgements. This work was supported by the Hungarian National Science Foundation OTKA (Grant: K73703) and by the TAMOP-4.2.2/B-10/1-2010-0024 project. The project is cofinanced by the European Union and the European Social Fund.

Penetrating chest trauma caused by a blank cartridge actuated rubber ball projectile: case presentation and ballistic investigation of an uncommon weapon type.

Science.gov (United States)

Frank, Matthias; Peters, Dieter; Klemm, Wolfram; Grossjohann, Rico; Ekkernkamp, Axel; Bockholdt, Britta; Seifert, Julia

2017-09-01

Recently, an increasing number of an uncommon weapon type based on a caliber 6-mm Flobert blank cartridge actuated revolver which discharges 10-mm-diameter rubber ball projectiles has been confiscated by police authorities following criminal offenses. A recent trauma case presenting with a penetrating chest injury occasioned an investigation into the basic ballistic parameters of this type of weapon. Kinetic energy E of the test projectiles was calculated between 5.8 and 12.5 J. Energy density ED of the test projectiles was close to or higher than the threshold energy density of human skin. It can be concluded that penetrating skin injuries due to free-flying rubber ball projectiles discharged at close range cannot be ruled out. However, in case of a contact shot, the main injury potential of this weapon type must be attributed to the high energy density of the muzzle gas jet which may, similar to well-known gas or alarm weapons, cause life-threatening or even lethal injuries.

Predicting the Accuracy of Unguided Artillery Projectiles

Science.gov (United States)

2016-09-01

ability to penetrate a target. If the impact angle is small, the projectile may more likely ricochet, and any penetration will not be as deep as a...projectile experiences less drag and thus increased impact velocity and penetration . However, a blunt nose projectile has more strength at the tip and...fire 15. NUMBER OF PAGES 139 16. PRICE CODE 17. SECURITY CLASSIFICATION OF REPORT Unclassified 18. SECURITY CLASSIFICATION OF THIS PAGE

Electron-hydrogen collisions with dressed target and Volkov projectile states in a laser field

International Nuclear Information System (INIS)

Smith, P.H.G.; Flannery, M.R.

1992-01-01

Cross sections for the 1S-2S and 1S-2P O transitions in laser-assisted e - -H(1S) collisions are calculated in both the multi-channel eikonal treatment and the Born wave approximation, as a function of impact energy and laser field intensity. The laser considered is a monotonic, plane-polarized CO 2 laser (photon energy = 0.117 eV) with the polarization direction parallel to the initial projectile velocity. The first part of this paper confines the laser perturbation to the bound electrons of the atom. The second part extends the laser perturbation to the projectile electron, and the familiar Volkov dressed states are used. (author)

Singly and Doubly Charged Projectile Fragments in Nucleus-Emulsion Collisions at Dubna Energy in the Framework of the Multi-Source Model

International Nuclear Information System (INIS)

Er-Qin, Wang; Fu-Hu, Liu; Jian-Xin, Sun; Rahim, Magda A.; Fakhraddin, S.

2011-01-01

The multiplicity distributions of projectile fragments emitted in interactions of different nuclei with emulsion are studied by using a multi-source model. Our calculated results show that the projectile fragments can be described by the model and each source contributes an exponential distribution. As the weighted sum of the folding result of many exponential distributions, a multi-component Erlang distribution is used to describe the experimental data. The relationship between the height (or width) of the distribution and the mass of the incident projectile, as well as the dependence of projectile fragments on target groups, are investigated too. (nuclear physics)

Stopping power. Projectile and target modeled as oscillators

International Nuclear Information System (INIS)

Stevanovic, N.; Nikezic, D.

2005-01-01

In this Letter the collision of two quantum harmonic oscillators was considered. The oscillators interact through the Coulomb interaction. Stopping power of projectile was calculated assuming that both, target and projectile may be excited. It has been shown that the frequency of the projectile oscillation, ω p influences on stopping power, particularly in the region of Bragg peak. If, ω p ->0 is substitute in the expression for stopping power derived in this Letter, then it comes to the form when the projectile has been treated as point like charged particle

Graphical Method for Determining Projectile Trajectory

Science.gov (United States)

Moore, J. C.; Baker, J. C.; Franzel, L.; McMahon, D.; Songer, D.

2010-01-01

We present a nontrigonometric graphical method for predicting the trajectory of a projectile when the angle and initial velocity are known. Students enrolled in a general education conceptual physics course typically have weak backgrounds in trigonometry, making inaccessible the standard analytical calculation of projectile range. Furthermore,…

Orientation estimation algorithm applied to high-spin projectiles

International Nuclear Information System (INIS)

Long, D F; Lin, J; Zhang, X M; Li, J

2014-01-01

High-spin projectiles are low cost military weapons. Accurate orientation information is critical to the performance of the high-spin projectiles control system. However, orientation estimators have not been well translated from flight vehicles since they are too expensive, lack launch robustness, do not fit within the allotted space, or are too application specific. This paper presents an orientation estimation algorithm specific for these projectiles. The orientation estimator uses an integrated filter to combine feedback from a three-axis magnetometer, two single-axis gyros and a GPS receiver. As a new feature of this algorithm, the magnetometer feedback estimates roll angular rate of projectile. The algorithm also incorporates online sensor error parameter estimation performed simultaneously with the projectile attitude estimation. The second part of the paper deals with the verification of the proposed orientation algorithm through numerical simulation and experimental tests. Simulations and experiments demonstrate that the orientation estimator can effectively estimate the attitude of high-spin projectiles. Moreover, online sensor calibration significantly enhances the estimation performance of the algorithm. (paper)

Orientation estimation algorithm applied to high-spin projectiles

Science.gov (United States)

Long, D. F.; Lin, J.; Zhang, X. M.; Li, J.

2014-06-01

High-spin projectiles are low cost military weapons. Accurate orientation information is critical to the performance of the high-spin projectiles control system. However, orientation estimators have not been well translated from flight vehicles since they are too expensive, lack launch robustness, do not fit within the allotted space, or are too application specific. This paper presents an orientation estimation algorithm specific for these projectiles. The orientation estimator uses an integrated filter to combine feedback from a three-axis magnetometer, two single-axis gyros and a GPS receiver. As a new feature of this algorithm, the magnetometer feedback estimates roll angular rate of projectile. The algorithm also incorporates online sensor error parameter estimation performed simultaneously with the projectile attitude estimation. The second part of the paper deals with the verification of the proposed orientation algorithm through numerical simulation and experimental tests. Simulations and experiments demonstrate that the orientation estimator can effectively estimate the attitude of high-spin projectiles. Moreover, online sensor calibration significantly enhances the estimation performance of the algorithm.

Defining the essential anatomical coverage provided by military body armour against high energy projectiles.

Science.gov (United States)

Breeze, John; Lewis, E A; Fryer, R; Hepper, A E; Mahoney, Peter F; Clasper, Jon C

2016-08-01

Body armour is a type of equipment worn by military personnel that aims to prevent or reduce the damage caused by ballistic projectiles to structures within the thorax and abdomen. Such injuries remain the leading cause of potentially survivable deaths on the modern battlefield. Recent developments in computer modelling in conjunction with a programme to procure the next generation of UK military body armour has provided the impetus to re-evaluate the optimal anatomical coverage provided by military body armour against high energy projectiles. A systematic review of the literature was undertaken to identify those anatomical structures within the thorax and abdomen that if damaged were highly likely to result in death or significant long-term morbidity. These structures were superimposed upon two designs of ceramic plate used within representative body armour systems using a computerised representation of human anatomy. Those structures requiring essential medical coverage by a plate were demonstrated to be the heart, great vessels, liver and spleen. For the 50th centile male anthropometric model used in this study, the front and rear plates from the Enhanced Combat Body Armour system only provide limited coverage, but do fulfil their original requirement. The plates from the current Mark 4a OSPREY system cover all of the structures identified in this study as requiring coverage except for the abdominal sections of the aorta and inferior vena cava. Further work on sizing of plates is recommended due to its potential to optimise essential medical coverage. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Stability Criterion for a Finned Spinning Projectile

OpenAIRE

S. D. Naik

2000-01-01

The state-of-the-art in gun projectile technology has been used for the aerodynamic stabilisation.This approach is acceptable for guided and controlled rockets but the free-flight rockets suffer fromunacceptable dispersion. Sabot projectiles with both spin and fms developed during the last decadeneed careful analysis. In this study, the second method of Liapunov has been used to develop stability criterion for a projectile to be designed with small fins and is made to spin in the flight. This...

Elastic scattering of 7Li projectiles in the energy range of 20 to 34 MeV

International Nuclear Information System (INIS)

Khallaf, S.A.E.

1983-01-01

As far as it is known, the Watanabe folding model has not been used to analyse the elastic scattering of 7 Li projectiles. The main purpose of the present work is to calculate the differential cross sections for 7 Li elastic scattering von 90 Zr, 48 , 40 Ca, 16 O and 12 C at incident energies of 20 to 34 MeV using the Watanabe folding model and to study the applicability of this model for 7 Li elastic scattering. The potentials of 7 Li ions are revealed by Taylor expansions of alpha and triton cluster potentials. The resulting differential cross sections are compared with the predicted cross sections using phenomenological potentials of 7 Li ions. (orig./WL)

Projectile Demilitarization Facilities

Data.gov (United States)

Federal Laboratory Consortium — The Projectile Wash Out Facility is US Army Ammunition Peculiar Equipment (APE 1300). It is a pilot scale wash out facility that uses high pressure water and steam...

Energy loss, range and fluence distributions, total reaction and projectile fragment production cross sections for proton-nucleus and nucleus-nucleus interactions

International Nuclear Information System (INIS)

Sihver, L.; Kanai, T.

1992-07-01

We have developed a computer code for calculations of energy loss (dE/dx) and range distributions for heavy ions in any media. The results from our calculations are in very good agreement with previous calculations. We have developed semiempirical total reaction cross section formulae for proton-nucleus (with Z p ≤26) and nucleus-nucleus (with Z p and Z t ≤26) reactions. These formulae apply for incident energies above 15 MeV and 100 MeV/nucleon respectively. From the total reaction cross sections, we can calculate the mean free paths and the fluence distributions of protons and heavy ions in any media. We have compared all the calculated reaction cross sections and the mean free paths with experimental data, and the agreement is good. We have also constructed a procedure for calculating projectile fragment production cross sections, by scaling semiempirical proton-nucleus partial cross section systematics. The scaling is performed using a scaling parameter deduced from our reaction cross sections formulae, and additional enhancements factors. All products with atomic number ranging from that of the projectile (Z p ) down to Z=2 can be calculated. The agreement between the calculated cross sections and the experimental data is better than earlier published results. (author)

Hydrodynamic Drag on Streamlined Projectiles and Cavities

KAUST Repository

Jetly, Aditya

2016-04-19

The air cavity formation resulting from the water-entry of solid objects has been the subject of extensive research due to its application in various fields such as biology, marine vehicles, sports and oil and gas industries. Recently we demonstrated that at certain conditions following the closing of the air cavity formed by the initial impact of a superhydrophobic sphere on a free water surface a stable streamlined shape air cavity can remain attached to the sphere. The formation of superhydrophobic sphere and attached air cavity reaches a steady state during the free fall. In this thesis we further explore this novel phenomenon to quantify the drag on streamlined shape cavities. The drag on the sphere-cavity formation is then compared with the drag on solid projectile which were designed to have self-similar shape to that of the cavity. The solid projectiles of adjustable weight were produced using 3D printing technique. In a set of experiments on the free fall of projectile we determined the variation of projectiles drag coefficient as a function of the projectiles length to diameter ratio and the projectiles specific weight, covering a range of intermediate Reynolds number, Re ~ 104 – 105 which are characteristic for our streamlined cavity experiments. Parallel free fall experiment with sphere attached streamlined air cavity and projectile of the same shape and effective weight clearly demonstrated the drag reduction effect due to the stress-free boundary condition at cavity liquid interface. The streamlined cavity experiments can be used as the upper bound estimate of the drag reduction by air layers naturally sustained on superhydrophobic surfaces in contact with water. In the final part of the thesis we design an experiment to test the drag reduction capacity of robust superhydrophobic coatings deposited on the surface of various model vessels.

Visualization of Projectile Flying at High Speed in Dusty Atmosphere

Science.gov (United States)

Masaki, Chihiro; Watanabe, Yasumasa; Suzuki, Kojiro

2017-10-01

Considering a spacecraft that encounters particle-laden environment, such as dust particles flying up over the regolith by the jet of the landing thruster, high-speed flight of a projectile in such environment was experimentally simulated by using the ballistic range. At high-speed collision of particles on the projectile surface, they may be reflected with cracking into smaller pieces. On the other hand, the projectile surface will be damaged by the collision. To obtain the fundamental characteristics of such complicated phenomena, a projectile was launched at the velocity up to 400 m/s and the collective behaviour of particles around projectile was observed by the high-speed camera. To eliminate the effect of the gas-particle interaction and to focus on only the effect of the interaction between the particles and the projectile's surface, the test chamber pressure was evacuated down to 30 Pa. The particles about 400μm diameter were scattered and formed a sheet of particles in the test chamber by using two-dimensional funnel with a narrow slit. The projectile was launched into the particle sheet in the tangential direction, and the high-speed camera captured both projectile and particle motions. From the movie, the interaction between the projectile and particle sheet was clarified.

Projectile rapidity dependence in target fragmentation

International Nuclear Information System (INIS)

Haustein, P.E.; Cumming, J.B.; Hseuh, H.C.

1979-01-01

The thick-target, thick-catcher technique was used to determine mean kinetic properties of selected products of the fragmentation of Cu by 1 H, 4 He, and 12 C ions (180 to 28,000 MeV/amu). Momentum transfer, as inferred from F/B ratios, is ovserved to occur most efficiently for the lower velocity projectiles. Recoil properties of target fragments vary strongly with product mass, but show only a weak dependence on projectile type. The projectile's rapidity is shown to be a useful variable for quantitative intercomparison of different reactions. These results indicate that E/sub proj//A/sub proj/ is the dominant parameter which governs the mean recoil behavior of target fragments. 20 references

Electromagnetic dissociation of target nuclei by $^{16}$O and $^{32}$S projectiles

CERN Multimedia

2002-01-01

We have measured the inclusive cross sections for electromagnetic dissociation (ED) of $^{197}$Au targets by 60 and 200 GeV/nucleon $^{16}$O and $^{32}$S projectiles. This is an extension of similar measurements carried out earlier at 2 GeV/nucleon. ED is a purely electromagnetic process occuring when a virtual photon is exchanged between projectile and target. The experiment emphasized precise measurement of total one-neutron-out cross sections. A secondary goal was to test the applicability of the concepts of factorization and limiting fragmentation at ultrarelativistic energies.\\\\ \\\\ Each individual target will be irradiated upstream and parasitic to experiment NA38 on the dimuon spectrometer. Cross sections for reactions of interest will be determined by off-line counting of the appropriate residual $\\gamma$ ray activities in Ames, Iowa, USA. Preliminary results indicate an ED one-neutron removal cross section for 200 GeV/nucleon $^{16}$O projectiles on $^{197}$Au of approximately 0.45~barns. The result i...

Transfer of 6Li break-up fragments at 6Li projectile energies far above the coulomb barrier

International Nuclear Information System (INIS)

Neumann, B.; Buschmann, J.; Rebel, H.; Gils, H.J.; Klewe-Nebenius, H.

1979-05-01

Transfer of beam-velocity fragments has been experimentally investigated in 6 Li induced reactions on 208 Pb and 209 Bi in the energy range Esub(Li) = 60-156 MeV. The experimental techniques involve the observation of the target residues and measurements of the recoil ranges of heavy residual nuclei produced by charged particle bombardment. The determination of the recoil energy enables the discrimination of different reaction paths leading to the same residual nuclei. ( 6 Li, xn+p) excitation functions prove to be very similar to (α,(x-1)n) reactions at Esub(α) approximately 2/3 x Esub(Li). The results present experimental evidence for a particular reaction type indicated in previous experiments: Dissociation of the 6 Li projectile with capture of the beam-velocity alpha particle indicating an (α,xn) reaction ('internal break-up'). (orig.) [de

Tandem-method for measurement of destruction cross-sections of neutral projectiles at intermediate and high velocities

International Nuclear Information System (INIS)

Sant'Anna, M.M.; Magnani, B.F.; Correa, R.S.; Coelho, L.F.S.

2007-01-01

We have recently presented destruction cross-section data for negative ions obtained with a technique that uses the gas stripper of a tandem accelerator as the collision target. In this work, we develop an extension of that technique to measure destruction cross-sections for neutral projectiles, important parameters to estimate neutral beam attenuation in Heavy Ion Fusion applications. Measurements for the H+N 2 collision system are used to exemplify and discuss the capabilities and limitations of the proposed experimental method

Computed tomography of projectile injuries

International Nuclear Information System (INIS)

Jeffery, A.J.; Rutty, G.N.; Robinson, C.; Morgan, B.

2008-01-01

Computed tomography (CT) is a gold standard in clinical imaging but forensic professions have been slow to embrace radiological advances. Forensic applications of CT are now exponentially expanding, replacing other imaging methods. As post-mortem cross-sectional imaging increases, radiologists will fall under increasing pressure to interpret complex forensic cases involving both living and deceased patients. This review presents a wide variety of weapon and projectile types aiding interpretation of projectile injuries both in forensic and clinical practice

A design of inverse Taylor projectiles using material simulation

International Nuclear Information System (INIS)

Tonks, Michael; Harstad, Eric; Maudlin, Paul; Trujillo, Carl

2008-01-01

The classic Taylor cylinder test, in which a right circular cylinder is projected at a rigid anvil, exploits the inertia of the projectile to access strain rates that are difficult to achieve with more traditional uniaxial testing methods. In this work we present our efforts to design inverse Taylor projectiles, in which a tapered projectile becomes a right circular cylinder after impact, from annealed copper and show that the self-correcting geometry leads to a uniform compressive strain in the radial direction. We design projectiles using finite element simulation and optimization that deform as desired in tests with minor deviations in the deformed geometry due to manufacturing error and uncertainty in the initial velocity. The inverse Taylor projectiles designed in this manner provide a simple means of validating constitutive models. This work is a step towards developing a general method of designing Taylor projectiles that provide stress–strain behavior relevant to particular engineering problems

The WRAIR projectile concussive impact model of mild traumatic brain injury: re-design, testing and preclinical validation.

Science.gov (United States)

Leung, Lai Yee; Larimore, Zachary; Holmes, Larry; Cartagena, Casandra; Mountney, Andrea; Deng-Bryant, Ying; Schmid, Kara; Shear, Deborah; Tortella, Frank

2014-08-01

The WRAIR projectile concussive impact (PCI) model was developed for preclinical study of concussion. It represents a truly non-invasive closed-head injury caused by a blunt impact. The original design, however, has several drawbacks that limit the manipulation of injury parameters. The present study describes engineering advancements made to the PCI injury model including helmet material testing, projectile impact energy/head kinematics and impact location. Material testing indicated that among the tested materials, 'fiber-glass/carbon' had the lowest elastic modulus and yield stress for providing an relative high percentage of load transfer from the projectile impact, resulting in significant hippocampal astrocyte activation. Impact energy testing of small projectiles, ranging in shape and size, showed the steel sphere produced the highest impact energy and the most consistent impact characteristics. Additional tests confirmed the steel sphere produced linear and rotational motions on the rat's head while remaining within a range that meets the criteria for mTBI. Finally, impact location testing results showed that PCI targeted at the temporoparietal surface of the rat head produced the most prominent gait abnormalities. Using the parameters defined above, pilot studies were conducted to provide initial validation of the PCI model demonstrating quantifiable and significant increases in righting reflex recovery time, axonal damage and astrocyte activation following single and multiple concussions.

Eikonal calculation of electron-capture cross sections in collisions of H atoms with fast projectiles

International Nuclear Information System (INIS)

Ho, T.S.; Lieber, M.; Chan, F.T.

1981-01-01

We have employed the eikonal method to calculate the cross section for the capture of an electron into an arbitrary nl subshell in collisions between hydrogen atoms and fast projectiles. the projectiles were protons, C 6+ , O 8+ , and Fe 24+ . The energy ranges considered were 20--100 keV in the proton case, and 40--200 keV per nucleon in the other cases. These projectiles were selected because of their importance in fusion plasmas. For the highly charged case of Fe 24+ we found that our formulas, while exact, involved a high degree of cancellation and produced unreliable numerical results, so that a numerical integration of the penultimate formula was substituted. In the proton case agreement with recent experimental data is excellent

Femoral vessel injury by a nonlethal weapon projectile

Directory of Open Access Journals (Sweden)

Rodrigo Bruno Biagioni, MD

2018-06-01

Full Text Available Rubber projectiles are used as an alternative to metal bullets owing to their lower morbidity and mortality rate. There are few reports of vascular lesions of extremities caused by rubber projectiles in the literature. The authors report the case of a 37-year-old man who was the victim of a penetrating injury to the left thigh with a rubber projectile. He reported only pain at the site of the injury; pulses were decreased in the affected limb. After arteriography confirmed an injury to the superficial femoral artery, he underwent an arterial and venous femorofemoral bypass using a reversed contralateral saphenous vein. Keywords: Vascular trauma, Nonlethal projectile, Penetrating trauma

Backward ejected electrons produced by 1-MeV/u Oq+ (q=3--8) projectile ions colliding with argon gas

International Nuclear Information System (INIS)

Breinig, M.; Berryman, J.W.; Segner, F.; Desai, D.D.

1994-01-01

The cross sections for ejecting electrons into a cone of half-angle ∼2 degree centered on the backward direction have been measured as a function of electron energy for 1-MeV/u O q+ (q=3--8) projectiles colliding with Ar. For O 3+ and O 4+ projectiles, the cross sections have also been measured in coincidence with exit charge states (q+1) and (q+2) of the projectile. A prominent feature in all spectra is a target LMM Auger peak. The cross sections for producing Ar LMM Auger electrons are nearly independent of projectile incident charge states. A projectile electron-loss peak is produced when the projectile brings loosely bound L-shell electrons into the collision. The shape of this peak is independent of the projectile exit charge state within experimental error. The measured electron-loss production cross sections at 180 degree are compared with the predictions of various on-shell approximations to the impulse approximation. Peak height and position are sensitive functions of the on-shell approximation used. The predictions of the elastic scattering model agree well with the data

Empirical formulae for mass attenuation and energy absorption coefficients from 1 keV to 20 MeV

International Nuclear Information System (INIS)

Manjunatha, H.C.; Sowmya, N.; Seenappa, L.; Sridhar, K.N.; Hanumantharayappa, C.

2017-01-01

Mass attenuation and energy absorption coefficients represents attenuation and absorption of X-rays and gamma rays in the material medium. A new empirical formula is proposed for mass attenuation and energy absorption coefficients in the region 1 < Z < 92 and from 1 keV to 20 MeV. The mass attenuation and energy absorption coefficients do not varies linearly with energy. We have performed the nonlinear regressions/nonlinear least square fittings and proposed the simple empirical relations between mass attenuation coefficients (μ/ρ) and mass energy absorption coefficients (μ en /ρ) and energy. We have compared the values produced by this formula with that of experiments. A good agreement of present formula with the experiments/previous models suggests that the present formulae could be used to evaluate mass attenuation and energy absorption coefficients in the region 1 < Z < 92. This formula is a model-independent formula and is the first of its kind that produces a mass attenuation and energy absorption coefficient values with the only simple input of energy for wide energy range 1 keV - 20 MeV in the atomic number region 1 < Z < 92. This formula is very much useful in the fields of radiation physics and dosimetry

Peripheral collisions of heavy ions induced by 40Ar at intermediate energies: giant resonance high energy structures and projectile fragmentation

International Nuclear Information System (INIS)

Blumenfeld, Y.

1987-09-01

The results obtained in similar studies at low incident energies are first of all reviewed. The time of flight spectrometer built for the experiments is then described. A study of the properties of the projectile-like fragments shows numerous deviations from the relativistic energy fragmentation model. Evidence for a strong surface transfer reaction component is given and the persistence of mean field effects at intermediate energies is stressed. A calculation of the contribution of the transfer evaporation mechanism to the inelastic spectra shows that this mechanism is responible for the major part of the background measured at high excitation energy and can in some cases induce narrow structures in the spectra. The inelastic spectra shows a strong excitation of the giant quadrupole resonance. In the region between 20 and 80 MeV excitation energy narrow structures are present for all the studied systems. Statistical and Fourier analysises allow to quantify the probabilities of existence, the widths and the excitation energies of these structures. A transfer evaporation hypothesis cannot consistently reproduce all the observed structures. The excitation energies of the structures can be well described by phenomenological laws where the energies are proportional to the -1/3 power of the target mass. Complete calculations of the excitation probabilities of giant resonances and multiphonon states are performed within a model where the nuclear excitation are calculated microscopically in the Random Phase Approximation. It is shown that a possible interpretation of the structures is the excitation of multiphonon states built with 2 + giant resonances [fr

Measurements of the Coulomb dissociation cross section of 156 MeV 6Li projectiles at extremely low relative fragment energies of astrophysical interest

International Nuclear Information System (INIS)

Kiener, J.; Gils, H.J.; Rebel, H.; Zagromski, S.; Gsottschneider, G.; Heide, N.; Jelitto, H.; Wentz, J.; Baur, G.

1991-04-01

Coulomb dissociation of light nuclear projectiles in the electric field of heavy target nuclei has been experimentally investigated as an alternative access to radiative capture cross sections at low relative energies of the fragments, which are of astrophysical interest. As a pilot experiment the breakup of 156 MeV 6 Li-projectiles at 208 Pb with small emission angles of the a particle and deuteron fragments has been studied. Both fragments were coincidentally detected in the focal plane of a magnetic spectrograph at several reaction angles well below the grazing angle and with relative angles between the fragments of 0deg-2deg. The experimental cross sections have been analyzed on the basis of the Coulomb breakup theory. The results for the resonant breakup give evidence for the strong dominance of the Coulomb dissociation mechanism and the absence of nuclear distortions, while the cross section for the nonresonant breakup follow theoretical predictions of the astrophysical S-factor and extrapolations of corresponding radiative capture reaction cross section to very low c. m. energies of the a particle and deuterons. Various implications of the approach are discussed. (orig.) [de

Effectiveness of projectile screening in single and multiple ionization of Ne by B{sup 2+}

Energy Technology Data Exchange (ETDEWEB)

Wolff, W.; Luna, H.; Santos, A. C. F.; Montenegro, E. C. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, Rio de Janeiro, 21945-970 RJ (Brazil); DuBois, R. D. [Department of Physics, Missouri University of Science and Technology, Rolla, Missouri 65409 (United States); Montanari, C. C.; Miraglia, J. E. [Instituto de Astronomia y Fisica del Espacio, Casilla de Correo 67, Sucursal 28, C1428EGA, Buenos Aires (Argentina)

2011-10-15

Pure multiple ionization cross sections of Ne by B{sup 2+} projectiles have been measured in the energy range of 0.75 to 4.0 MeV and calculated using the continuum distorted wave-eikonal initial state approximation. The experiment and calculations show that the ionization cross sections by B{sup 2+}, principally for the production of highly charged recoils, is strongly enhanced when compared to the bare projectile with the same charge state, He{sup 2+}, at the same velocities.

Dependence of ion-electron emission from clean metals on the incidence angle of the projectile

International Nuclear Information System (INIS)

Ferron, J.; Alonso, E.V.; Baragiola, R.A.; Oliva-Florio, A.

1981-01-01

We have studied the dependence of electron yields γ from clean Cu and Au surfaces on the incidence angle theta of 5--50-keV He + , Ar + , and Xe + projectiles, in the angular range 0--80 0 , and under ultrahigh-vacuum conditions. We have found that, at small angles, γproportionalsec/sup f/theta, with f generally different from unity. For Xe + on Cu, γ(theta) presents an energy-dependence maximum, similar to that obtained for sputtering. The results are explained in terms of the anisotropy of the electron cascade in the solid, the depth distribution of the inelastic energy deposited by the projectile and by rapidly recoiling target atoms in the near-surface region of the solid

Projectile Nose Mass Abrasion of High-Speed Penetration into Concrete

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Haijun Wu

2012-01-01

Full Text Available Based on the dynamic spherical cavity expansion theory of concrete and the analysis of experimental data, a mass abrasion model of projectile considering the hardness of aggregates, the relative strength of target and projectile, and the initial impact velocity is constructed in this paper. Furthermore, the effect of mass abrasion on the penetration depth of projectile and the influence of hardness of aggregates and strength of projectile on penetration depth and mass loss are also analyzed. The results show that, for the ogive-nose projectile with the CRH of 3 and aspect ratio of 7 penetrating the concrete of 35 MPa, the “rigid-body penetration” model is available when the initial impact velocity is lower than 800 m/s. However, when the initial impact velocity is higher than 800 m/s, the “deforming/eroding body penetration” model should be adopted. Through theoretical analysis and numerical calculation, the results indicate that the initial impact velocity is the most important factor of mass abrasion. The hardness of aggregates and the strength of projectile are also significant factors. But relatively speaking, the sensitivity of strength of projectile to mass abrasion is higher, which indicates that the effect of projectile material on mass abrasion is more dramatic than the hardness of aggregates.

Optimization of $^{178m2}$/Hf isomer production in spallation reactions at projectile energies up to 100 MeV using STAPRE and ALICE code simulations

CERN Document Server

Kirischuk, V I; Khomenkov, V P; Strilchuk, N V; Zheltonozhskij, V A

2004-01-01

/sup 178m2/Hf isomer production in different spallation reactions with protons, alpha particles and neutrons at projectile energies up to 100 MeV has been analyzed using both STAPRE and ALICE code simulations. The STAPRE code was used to calculate the isomeric ratios, while the ALICE code was used to simulate the excitation functions of the respective ground states. A number of spallation reactions have been compared taking into account not only /sup 178m2 /Hf isomer productivity but also, first, the isomeric ratios calculated by the STAPRE code; second, the accumulation of the most undesirable Hf isotopes and isomers, such as /sup 172/Hf, /sup 175 /Hf, and /sup 179m/Hf; and, third, the production of other admixtures and by-products that could degrade the quality of the produced /sup 178m2/Hf isomer sources, including all stable Hf isotopes as well. Possibilities and ways of optimizing /sup 178m2/Hf isomer production in spallation reactions at projectile energies up to 100 MeV are discussed. This can be consi...

Impact of Thin-Walled Projectiles with Concrete Targets

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Rayment E. Moxley

1995-01-01

Full Text Available An experimental program to determine the response of thin-walled steel projectiles to the impact with concrete targets was recently conducted. The projectiles were fired against 41-MPa concrete targets at an impact velocity of 290 m/s. This article contains an outline of the experimental program, an examination of the results of a typical test, and predictions of projectile deformation by classical shell theory and computational simulation. Classical shell analysis of the projectile indicated that the predicted impact loads would result in circumferential buckling. A computational simulation of a test was conducted with an impact/penetration model created by linking a rigid-body penetration trajectory code with a general-purpose finite element code. Scientific visualization of the resulting data revealed that circumferential buckling was induced by the impact conditions considered.

Penetration analysis of projectile with inclined concrete target

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Kim S.B.

2015-01-01

Full Text Available This paper presents numerical analysis result of projectile penetration with concrete target. We applied dynamic material properties of 4340 steels, aluminium and explosive for projectile body. Dynamic material properties were measured with static tensile testing machine and Hopkinson pressure bar tests. Moreover, we used three concrete damage models included in LS-DYNA 3D, such as SOIL_CONCRETE, CSCM (cap model with smooth interaction and CONCRETE_DAMAGE (K&C concrete models. Strain rate effect for concrete material is important to predict the fracture deformation and shape of concrete, and penetration depth for projectiles. CONCRETE_DAMAGE model with strain rate effect also applied to penetration analysis. Analysis result with CSCM model shows good agreement with penetration experimental data. The projectile trace and fracture shapes of concrete target were compared with experimental data.

Penetration analysis of projectile with inclined concrete target

Science.gov (United States)

Kim, S. B.; Kim, H. W.; Yoo, Y. H.

2015-09-01

This paper presents numerical analysis result of projectile penetration with concrete target. We applied dynamic material properties of 4340 steels, aluminium and explosive for projectile body. Dynamic material properties were measured with static tensile testing machine and Hopkinson pressure bar tests. Moreover, we used three concrete damage models included in LS-DYNA 3D, such as SOIL_CONCRETE, CSCM (cap model with smooth interaction) and CONCRETE_DAMAGE (K&C concrete) models. Strain rate effect for concrete material is important to predict the fracture deformation and shape of concrete, and penetration depth for projectiles. CONCRETE_DAMAGE model with strain rate effect also applied to penetration analysis. Analysis result with CSCM model shows good agreement with penetration experimental data. The projectile trace and fracture shapes of concrete target were compared with experimental data.

Investigations in atomic physics by heavy ion projectiles

International Nuclear Information System (INIS)

Berenyi, D.

1983-01-01

The utilization of heavy ion reactions in atomic physics is surveyed. The basic collision mechanisms and their consequences in atomic physics are summarized. The atomic and electronic processes during and after heavy ion collisions are reviewed as functions of the projectile energy. The main detection and measuring methods are described. Reviews of new information about the structure of electronic cloud and about fundamental processes based on the analysis of heavy ion reaction data are given. (D.Gy.)

Multiplicity of secondary electrons emitted by carbon thin targets by impact of H0, H2+ and H3+ projectiles at MeV energies

International Nuclear Information System (INIS)

Vidovic, Zvonimir

1997-01-01

This work focuses on the study of the emission statistics of secondary electrons from thin carbon foils bombarded with H 0 , H 2 + and H 3 + projectiles in the 0.25 - 2.2 MeV energy range. The phenomenon of secondary electron emission from solids under the impact of swift ions is mainly due to inelastic interactions with target electrons. Phenomenological and theoretical descriptions as well as a summary of the main theoretical models are the subjects of the first chapter. The experimental set-up used to measure event by event the electron emission of the two faces of the thin carbon foils crossed by an energetic projectile is described in the chapter two. In this chapter there are also presented the method and the algorithms used to process experimental spectra in order to obtain the statistical distribution of the emitted electrons. Chapter three presents the measurements of secondary electron emission induced by H 0 atoms passing through thin carbon foils. The secondary electron yields are studied in correlation with emergent projectile charge state. We show the peculiar role of the projectile electron, whether it remains or not bound to the incident proton. The fourth chapter is dedicated to the secondary electron emission induced by H 2 + and H 3 + polyatomic ions. The results are interpreted in terms of collective effects in the interactions of the ions with solids. The role of the proximity of the protons, molecular ions fragments, upon the amplitude of these collected effects is evidenced from the study of the statistics of forward emission. The experiments allowed us to shed light on various aspects of atom and polyatomic ion interactions with solid surfaces. (author)

Classical molecular dynamics simulation of weakly-bound projectile heavy-ion reactions

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Morker Mitul R.

2015-01-01

Full Text Available A 3-body classical molecular dynamics approach for heavy-ion reactions involving weakly bound projectiles is developed. In this approach a weakly bound projectile is constructed as a two-body cluster of the constituent tightly bound nuclei in a configuration corresponding to the observed breakup energy. This 3-body system with their individual nucleon configuration in their ground state is dynamically evolved for given initial conditions using the three-stage classical molecular dynamics approach (3S-CMD. Various levels of rigidbody constraints on the projectile constituents and the target are considered at appropriate stages. This 3-dimensional approach explicitly takes into account not only the long range Coulomb reorientation of the deformed collision partner but internal excitations and breakup probabilities at distances close to the barrier also. Dynamical simulations of 6Li+209Bi show all the possible reaction mechanism like complete fusion, incomplete fusion, scattering and breakup scattering. Complete fusion cross sections of 6Li+209Bi and 7Li+209Bi reactions are calculated in this approach with systematic relaxations of the rigid-body constraints on one or more constituent nuclei.

Dependence of ion-electron emission from clean metals on the incidence angle of the projectile

Energy Technology Data Exchange (ETDEWEB)

Ferron, J.; Alonso, E.V.; Baragiola, R.A.; Oliva-Florio, A.

1981-10-15

We have studied the dependence of electron yields ..gamma.. from clean Cu and Au surfaces on the incidence angle theta of 5--50-keV He/sup +/, Ar/sup +/, and Xe/sup +/ projectiles, in the angular range 0--80 /sup 0/, and under ultrahigh-vacuum conditions. We have found that, at small angles, ..gamma..proportionalsec/sup f/theta, with f generally different from unity. For Xe/sup +/ on Cu, ..gamma..(theta) presents an energy-dependence maximum, similar to that obtained for sputtering. The results are explained in terms of the anisotropy of the electron cascade in the solid, the depth distribution of the inelastic energy deposited by the projectile and by rapidly recoiling target atoms in the near-surface region of the solid.

Charged-particle spectroscopy in the microsecond range following projectile fragmentation

CERN Document Server

Pfützner, M; Grzywacz, R; Janas, Z; Momayezi, M; Bingham, C; Blank, B; Chartier, M; Geissel, H; Giovinazzo, J; Hellström, M; Kurcewicz, J; Lalleman, A S; Mazzocchi, C; Mukha, I; Plettner, C; Roeckl, E; Rykaczewski, K; Schmidt, K; Simon, R S; Stanoiu, M; Thomas, J C

2002-01-01

We present a new approach to charged-particle spectroscopy of short-lived nuclei produced by relativistic projectile fragmentation. The system based on digital DGF-4C CAMAC modules and newly developed fast-reset preamplifiers was tested at the Fragment Separator of GSI. We were able to detect low-energy (approx 1 MeV) decay signals occurring a few microseconds after a heavy-ion implantation accompanied by a release of approx 1 GeV energy. Applications for the study of one- and two-proton radioactivity are discussed.

Signatures of projectile-nucleus scattering in three-dimensional (e,2e) cross sections for argon

Energy Technology Data Exchange (ETDEWEB)

Ren Xueguang; Senftleben, Arne; Pflueger, Thomas; Dorn, Alexander; Ullrich, Joachim [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Bartschat, Klaus, E-mail: Xueguang.Ren@mpi-hd.mpg.d, E-mail: Alexander.Dorn@mpi-hd.mpg.d [Department of Physics and Astronomy, Drake University, Des Moines, Iowa 50311 (United States)

2010-02-14

Electron impact ionization (E{sub 0} = 195 eV) of the 3p-orbital in argon is investigated experimentally and theoretically. The triple-differential cross sections (TDCS) obtained using a multi-particle momentum spectrometer (reaction microscope) cover more than 80% of the full solid angle for the slow emitted electron up to an energy of 25 eV and a range of projectile scattering angles from -5 deg. to -15 deg. Inside the projectile scattering plane the TDCS shape is in rather good agreement with a hybrid distorted-wave plus R-matrix (DWBA-RM) calculation. Outside the scattering plane relatively strong electron emission is observed which is reproduced by theory in magnitude but not in shape. A systematic study of the TDCS behaviour and structure in this region indicates that its origin lies in high-order projectile-target interaction.

Electromagnetic launcher for heavy projectiles

Science.gov (United States)

Kozlov, A. V.; Kotov, A. V.; Polistchook, V. P.; Shurupov, A. V.; Shurupov, M. A.

2017-11-01

In this paper, we present the electromagnetic launcher with capacitive power source of 4.8 MJ. Our installation allows studying of the projectile acceleration in railgun in two regimes: with a solid armature and with a plasma piston. The experiments with plasma piston were performed in the railgun with the length of barrel of 0.7-1.0 m and its inner diameter of 17-24 mm. The velocities of lexan projectiles with weight of 5-15 g were in a range of 2.5-3.5 km/s. The physical mechanisms that limit speed of throwing in railgun are discussed.

The Response of Clamped Shallow Sandwich Arches with Metallic Foam Cores to Projectile Impact Loading

Directory of Open Access Journals (Sweden)

Yanping Fan

Full Text Available Abstract The dynamic response and energy absorption capabilities of clamped shallow sandwich arches with aluminum foam core were numerically investigated by impacting the arches at mid-span with metallic foam projectiles. The typical deformation modes, deflection response, and core compression of sandwich arches obtained from the tests were used to validate the computation model. The resistance to impact loading was quantified by the permanent transverse deflection at mid-span of the arches as a function of projectile momentum. The sandwich arches have a higher shock resistance than the monolithic arches of equal mass, and shock resistance could be significantly enhanced by optimizing geometrical configurations. Meanwhile, decreasing the face-sheet thickness and curvature radius could enhance the energy absorption capability of the sandwich arches. Finite element calculations indicated that the ratio of loading time to structural response time ranged from 0.1 to 0.4. The projectile momentum, which was solely used to quantify the structural response of sandwich arches, was insufficient. These findings could provide guidance in conducting further theoretical studies and producing the optimal design of metallic sandwich structures subjected to impact loading.

Local behavior of reinforced concrete slabs to aircraft engine projectile impact

International Nuclear Information System (INIS)

Yoo, Hyeon Kyeong; Choi, Hyun; Chung, Chul Hun; Lee, Jung Whee; Kim, Sang Yun

2011-01-01

Structural safety evaluation of nuclear power plant considers two distinct types of structural failure, local failure and global failure. In the local failure evaluation, considered projectiles can be divided as internal and external projectile according to the impact location, and they also can be divided as rigid and soft projectile according to the deformation level after impact. Frequently considered projectiles are aircraft engine, tornado, and turbine projectile. When the speed and weight of the projectiles are considered, the most influential projectile is aircraft engine, which is one of the soft projectiles. Sugano et al. performed impact test using an engine model projectile, which is derived from GE-J79 engine and concentrated mass-spring model idealization. Kojima and Sugano et al. demonstrated from their experiments that steel liner on the rear side of the concrete wall reduces impact induced damage and suppresses debris scattering. Chung et al. performed comparison study of various formulae suggested for local damage evaluation using previously performed numerous local impact test results. Also, they validated a methodology of numerical analysis for impact simulation using LS-DYNA. Previously suggested formulae and research results do not consider the effect of liner plate or curved shape of the containment building walls on the local damage. In this research, flat wall and curved wall are individually modeled using the same curvature of nuclear power plants, and the effects of curvature and liner plates on the local damage are analytically investigated

Femoral vessel injury by a nonlethal weapon projectile.

Science.gov (United States)

Biagioni, Rodrigo Bruno; Miranda, Gustavo Cunha; Mota de Moraes, Leonardo; Nasser, Felipe; Burihan, Marcelo Calil; Ingrund, José Carlos

2018-06-01

Rubber projectiles are used as an alternative to metal bullets owing to their lower morbidity and mortality rate. There are few reports of vascular lesions of extremities caused by rubber projectiles in the literature. The authors report the case of a 37-year-old man who was the victim of a penetrating injury to the left thigh with a rubber projectile. He reported only pain at the site of the injury; pulses were decreased in the affected limb. After arteriography confirmed an injury to the superficial femoral artery, he underwent an arterial and venous femorofemoral bypass using a reversed contralateral saphenous vein.

Analytical continuous slowing down model for nuclear reaction cross-section measurements by exploitation of stopping for projectile energy scanning and results for {sup 13}C({sup 3}He,α){sup 12}C and {sup 13}C({sup 3}He,p){sup 15}N

Energy Technology Data Exchange (ETDEWEB)

Möller, S., E-mail: s.moeller@fz-juelich.de

2017-03-01

Ion beam analysis is a set of precise, calibration free and non-destructive methods for determining surface-near concentrations of potentially all elements and isotopes in a single measurement. For determination of concentrations the reaction cross-section of the projectile with the targets has to be known, in general at the primary beam energy and all energies below. To reduce the experimental effort of cross-section measurements a new method is presented here. The method is based on the projectile energy reduction when passing matter of thick targets. The continuous slowing down approximation is used to determine cross-sections from a thick target at projectile energies below the primary energy by backward calculation of the measured product spectra. Results for {sup 12}C({sup 3}He,p){sup 14}N below 4.5 MeV are in rough agreement with literature data and reproduce the measured spectra. New data for reactions of {sup 3}He with {sup 13}C are acquired using the new technique. The applied approximations and further applications are discussed.

Design and testing of high-pressure railguns and projectiles

International Nuclear Information System (INIS)

Peterson, D.R.; Fowler, C.M.

1984-01-01

The results of high-pressure tests of four railgun designs and four projectile types are presented. All tests were conducted at the Los Alamos explosive magnetic-flux compression facility in Ancho Canyon. The data suggest that the high-strength projectiles have lower resistance to acceleration than the low strength projectiles, which expand against the bore during acceleration. The railguns were powered by explosive magneticflux compression generators. Calculations to predict railgun and power supply performance were performed by Kerrisk

Investigations of nuclear projectile break-up reactions

International Nuclear Information System (INIS)

Rebel, H.

1986-10-01

The cross sections for radiative capture of α-particles, deuterons and protons by light nuclei at very low relative energies are of particular importance for the understanding of the nucleosynthesis of chemical elements and for determining the relative elemental abundances in stellar burning processes at various astrophysical sites. As example we quote the reactions α+d → 6 Li+γ, α+ 3 He → 7 Be+γ, or α+ 12 C → 16 O+γ. As an alternative to the direct experimental study of these processes we consider the inverse process, the photodisintegration, by means of the virtual photons provided by a nuclear Coulomb field: Z+a → Z+b+c. The radiative capture process b+c → a+γ is related to the inverse process, the photodisintegration γ+a → b+c by the detailed balance theorem. Except for the extreme case very close to the threshold the phase space favours the photodisintegration cross section as compared to the radiative capture. The Coulomb dissociation cross section proves to be enhanced due to the large virtual photon number, seen by the passing projectile, and the kinematics of the process leads to particular advantages for studies of the interaction of the two break-up fragments at small relative energies E bc . The conditions of dedicated experimental investigations are discussed and demonstrated by recent experimental and theoretical studies of the break-up of 156 MeV 6 Li projectiles. In addition, a brief review about general features of break-up processes of light ions in the field of atomic nuclei is given. (orig.) [de

Cambodian students’ prior knowledge of projectile motion

Science.gov (United States)

Piten, S.; Rakkapao, S.; Prasitpong, S.

2017-09-01

Students always bring intuitive ideas about physics into classes, which can impact what they learn and how successful they are. To examine what Cambodian students think about projectile motion, we have developed seven open-ended questions and applied into grade 11 students before (N=124) and after (N=131) conventional classes. Results revealed several consistent misconceptions, for instance, many students believed that the direction of a velocity vector of a projectile follows the curved path at every position. They also thought the direction of an acceleration (or a force) follows the direction of motion. Observed by a pilot sitting on the plane, the falling object, dropped from a plane moving at a constant initial horizontal speed, would travel backward and land after the point of its release. The greater angle of the launched projectile creates the greater horizontal range. The hand force imparted with the ball leads the ball goes straight to hit the target. The acceleration direction points from the higher position to lower position. The misconceptions will be used as primary resources to develop instructional instruments to promote Cambodian students’ understanding of projectile motion in the following work.

Determination of diffuseness parameter to estimate the survival probability of projectile using Woods-Saxon formula at intermediate beam energies

International Nuclear Information System (INIS)

Kumar, Rajiv; Goyal, Monika; Roshni; Singh, Pradeep; Kharab, Rajesh

2017-01-01

In present work, the S-matrix has been evaluated by using simple Woods-Saxon formula as well as the realistic expression for a number of projectiles varying from 26N e to 76 Ge at intermediate incident beam energies ranging from 30 MeV/A to 300 MeV/A. The target is 197 Au in each and every case. The realistic S-matrix is compared with that of obtained by using the simple Woods-Saxon formula. The motive of this comparison is to fix the value of otherwise free Δ so that the much involved evaluation of realistic S-matrix can be replaced by the simple Woods-Saxon formula

Projectile fragmentation in reactions induced by 19F at low energy

International Nuclear Information System (INIS)

Pop, A.; Cenja, M.; Duma, M.; Dumitrescu, R.; Isbasescu, A.; Magda, M.T.

1984-09-01

Light-particle emission was studied in 19 F + 12 C and 19 F + 27 Al reactions at 72 MeV. The spectral shape shows an important breakup component in the case of 2 H, 3 H and 3 He while in the case of 1 H and 4 He the statistical contribution is predominant. The emission of 6 He, 6 Li, 7 Li and 9 Be was also observed and explained by the projectile breakup mechanism within the Serber model. The experimental isotope yields are in good agreement with the theoretical predictions of the Friedman model. (authors)

Evidence for anomalous nuclei among relativistic projectile fragments at Bevalac energies

International Nuclear Information System (INIS)

Heckman, H.H.

1981-01-01

Two independent emulsion experiments using beams of 16 O and 56 Fe at approximately 2 GeV/nucleon find that the reaction mean free paths of projectile fragments (PF) with Z between 3 and 26 are shorter for a few centimeters after their emission than at larger distances, or than predicted from experiments on beam nuclei. Under the assumption that there are two populations of PF, a best fit to the data is obtained when approximately 6% of the PF have an anomalously short mean free path. The anomalous property of PF persists in subsequent fragmentation reactions. 6 figures

Multiple-energy tissue-cancellation applications of a digital beam attenuator to chest radiography

International Nuclear Information System (INIS)

Dobbins, J.T. III.

1985-01-01

The digitally-formed primary beam attenuator (DBA) spatially modulates the x-ray fluence incident upon the patient to selectively attenuate regions of interest. The DBA attenuating mask is constructed from CeO 2 powder by a modified printing technique and uses image information from an initial low-dose exposure. Two tissue-cancellation imaging techniques are investigated with the DBA: (1) energy-dependent information is used to form a beam attenuator that attenuates specific tissues in the primary x-ray beam for tissue-cancelled film radiography; (2) the beam attenuator is used to improve image signal-to-noise and scattered radiation properties in traditional energy-subtraction tissue-cancellation imaging with digital detectors. The tissue-cancellation techniques in the primary x-ray beam were capable of adequately removing either soft-tissue or bone from the final compensated film radiograph when using a phantom with well defined soft-tissue and bone sections. However, when tried on an anthropomorphic chest phantom the results were adequate for cancellation of large soft tissue structures, but unsatisfactory for cancellation of bony structures such as the ribs, because of the limited spatial frequency content of the attenuating mask. The second technique (with digital detectors) showed improved uniformity of image signal-to-noise and a two-fold increase in soft-tissue nodule contrast due to improved scattered radiation properties. The tissue-cancelled images contained residual image contributions from the presence of the attenuating mask, but this residual may be correctable by future algorithms

The influence of aerodynamic coefficients on the elements of classic projectile paths

Directory of Open Access Journals (Sweden)

Damir D. Jerković

2011-04-01

Full Text Available The article deals with the results of the research on the influence of aerodynamic coefficient values on the trajectory elements and the stability parameters of classic axisymmetric projectiles. It presents the characteristic functions of aerodynamic coefficients with regard to aerodynamic parameters and the projectile body shape. The trajectory elements of the model of classic axisymmetric projectiles and the analyses of their changes were presented with respect to the aerodynamic coefficient values. Introduction Classic axisymmetric projectiles fly through atmosphere using muzzle velocity as initial energy resource, so the aerodynamic force and moment have the most significant influence on the motion of projectiles. The aerodynamic force and moment components represented as aerodynamic coefficients depend on motion velocity i. e. flow velocity, the flow features produced by projectile shape and position in the flow, and angular velocity (rate of the body. The functional dependence of aerodynamic coefficients on certain influential parameters, such as angle of attack and angular velocity components is expressed by the derivative of aerodynamic coefficients. The determination of aerodynamic coefficients and derivatives enables complete definition of the aerodynamic force and moment acting on the classic projectile. The projectile motion problem is considered in relation to defining the projectile stability parameters and the conditions under which the stability occurs. The comparative analyses of aerodynamic coefficient values obtained by numerical methods, semi empirical calculations and experimental research give preliminary evaluation of the quality of the determined values. The flight simulation of the motion of a classic axisymetric projectile, which has the shape defined by the aerodynamic coefficient values, enables the comparative analyses of the trajectory elements and stability characteristics. The model of the classic projectile

Design and Analysis of A Spin-Stabilized Projectile Experimental Apparatus

Science.gov (United States)

Siegel, Noah; Rodebaugh, Gregory; Elkins, Christopher; van Poppel, Bret; Benson, Michael; Cremins, Michael; Lachance, Austin; Ortega, Raymond; Vanderyacht, Douglas

2017-11-01

Spinning objects experience an effect termed `The Magnus Moment' due to an uneven pressure distribution based on rotation within a crossflow. Unlike the Magnus force, which is often small for spin-stabilized projectiles, the Magnus moment can have a strong detrimental effect on aerodynamic flight stability. Simulations often fail to accurately predict the Magnus moment in the subsonic flight regime. In an effort to characterize the conditions that cause the Magnus moment, researchers in this work employed Magnetic Resonance Velocimetry (MRV) techniques to measure three dimensional, three component, sub-millimeter resolution fluid velocity fields around a scaled model of a spinning projectile in flight. The team designed, built, and tested using a novel water channel apparatus that was fully MRI-compliant - water-tight and non-ferrous - and capable of spinning a projectile at a constant rotational speed. A supporting numerical simulation effort informed the design process of the scaled projectile to thicken the hydrodynamic boundary layer near the outer surface of the projectile. Preliminary testing produced two-dimensional and three-dimensional velocity data and revealed an asymmetric boundary layer around the projectile, which is indicative of the Magnus effect.

Energy-Specific Optimization of Attenuation Thresholds for Low-Energy Virtual Monoenergetic Images in Renal Lesion Evaluation.

Science.gov (United States)

Patel, Bhavik N; Farjat, Alfredo; Schabel, Christoph; Duvnjak, Petar; Mileto, Achille; Ramirez-Giraldo, Juan Carlos; Marin, Daniele

2018-05-01

The purpose of this study was to determine in vitro and in vivo the optimal threshold for renal lesion vascularity at low-energy (40-60 keV) virtual monoenergetic imaging. A rod simulating unenhanced renal parenchymal attenuation (35 HU) was fitted with a syringe containing water. Three iodinated solutions (0.38, 0.57, and 0.76 mg I/mL) were inserted into another rod that simulated enhanced renal parenchyma (180 HU). Rods were inserted into cylindric phantoms of three different body sizes and scanned with single- and dual-energy MDCT. In addition, 102 patients (32 men, 70 women; mean age, 66.8 ± 12.9 [SD] years) with 112 renal lesions (67 nonvascular, 45 vascular) measuring 1.1-8.9 cm underwent single-energy unenhanced and contrast-enhanced dual-energy CT. Optimal threshold attenuation values that differentiated vascular from nonvascular lesions at 40-60 keV were determined. Mean optimal threshold values were 30.2 ± 3.6 (standard error), 20.9 ± 1.3, and 16.1 ± 1.0 HU in the phantom, and 35.9 ± 3.6, 25.4 ± 1.8, and 17.8 ± 1.8 HU in the patients at 40, 50, and 60 keV. Sensitivity and specificity for the thresholds did not change significantly between low-energy and 70-keV virtual monoenergetic imaging (sensitivity, 87-98%; specificity, 90-91%). The AUC from 40 to 70 keV was 0.96 (95% CI, 0.93-0.99) to 0.98 (95% CI, 0.95-1.00). Low-energy virtual monoenergetic imaging at energy-specific optimized attenuation thresholds can be used for reliable characterization of renal lesions.

Influence of projectile α-breakup threshold on complete fusion

International Nuclear Information System (INIS)

Mukherjee, A.; Subinit Roy; Pradhan, M.K.; Saha Sarkar, M.; Basu, P.; Dasmahapatra, B.; Bhattacharya, T.; Bhattacharya, S.; Basu, S.K.; Chatterjee, A.; Tripathi, V.; Kailas, S.

2006-01-01

Complete fusion excitation functions for B11,10+Tb159 have been measured at energies around the respective Coulomb barriers, and the existing complete fusion measurements for Li7+Tb159 have been extended to higher energies. The measurements show significant reduction of complete fusion cross sections at above-barrier energies for both the reactions, B10+Tb159 and Li7+Tb159, when compared to those for B11+Tb159. The comparison shows that the extent of suppression of complete fusion cross sections is correlated with the α-separation energies of the projectiles. Also, the two reactions, B10+Tb159 and Li7+Tb159 were found to produce incomplete fusion products at energies near the respective Coulomb barriers, with the α-particle emitting channel being the favoured incomplete fusion process in both the cases

Analysis on the resistive force in penetration of a rigid projectile

Directory of Open Access Journals (Sweden)

Xiao-wei Chen

2014-09-01

Full Text Available According to the dimensionless formulae of DOP (depth of penetration of a rigid projectile into different targets, the resistive force which a target exerts on the projectile during the penetration of rigid projectile is theoretically analyzed. In particular, the threshold Vc of impact velocity applicable for the assumption of constant resistive force is formulated through impulse analysis. The various values of Vc corresponding to different pairs of projectile-target are calculated, and the consistency of the relative test data and numerical results is observed.

Steady-state and transient hydrocarbon production in graphite by low energy impact of atomic and molecular deuterium projectiles

International Nuclear Information System (INIS)

Zhang, H.; Meyer, F.W.

2009-01-01

We report measurements of steady-state yields of methyl, methane and heavier hydrocarbons for deuterium atomic and molecular ions incident on ATJ graphite, HOPG, and a-C:D thin films in the energy range 10-200 eV/D. The yields were determined using a QMS technique in conjunction with calibrated hydrocarbon leaks. We have also studied transient hydrocarbon production and hydrogen (deuterium) re-emission for 80 and 150 eV/D D + , D 2 + , and D 3 + projectiles incident on ATJ graphite surfaces pre-loaded to steady state by 20 eV/D beams of the corresponding species. Immediately after starting the higher-energy beams, transient hydrocarbon and D 2 re-emission yields significantly larger than steady-state values were observed, which exponentially decayed as a function of beam fluence. The initial yield values were related to the starting hydrocarbon and deuterium densities in the prepared sample, while the exponential decay constants provided information on the hydrocarbon kinetic release and hydrogen (deuterium) detrapping cross-sections.

Resonance effects in projectile-electron loss in relativistic collisions with excited atoms

International Nuclear Information System (INIS)

Voitkiv, A B

2005-01-01

The theory of electron loss from projectile-ions in relativistic ion-atom collisions is extended to the case of collisions with excited atoms. The main feature of such collisions is a resonance which can emerge between electron transitions in the ion and atom. The resonance becomes possible due to the Doppler effect and has a well-defined impact energy threshold. In the resonance case, the ion-atom interaction is transmitted by the radiation field and the range of this interaction becomes extremely long. Because of this the presence of other atoms in the target medium and the size of the space occupied by the medium have to be taken into account and it turns out that microscopic loss cross sections may be strongly dependent on such macroscopic parameters as the target density, temperature and size. We consider both the total and differential loss cross sections and show that the resonance can have a strong impact on the angular and energy distributions of electrons emitted from the projectiles and the total number of electron loss events

Fragmentation cross section measurements of iron projectiles using CR-39 plastic nuclear track detectors

CERN Document Server

Flesch, F; Huentrup, G; Roecher, H; Streibel, T; Winkel, E; Heinrich, W

1999-01-01

For long term space missions in which larger radiation doses are accumulated it is necessary to improve the precision of models predicting the space radiation environment. Different models are available to determine the flux of cosmic ray heavy ions behind shielding material. The accuracy of these predictions depends on the knowledge of the fragmentation cross sections, especially at energies of several hundred MeV/nucleon, where the particle flux is at a maximum and especially for those particles with high LET, i.e. iron nuclei. We have measured fragmentation cross sections of sup 5 sup 6 Fe projectiles at beam energies of 700 and 1700 A MeV using experimental set-ups with plastic nuclear track detectors. In this paper we describe the experimental technique to study the fragmentation reactions of sup 5 sup 6 Fe projectiles using CR-39 plastic nuclear track detectors. Results for different targets are presented.

Decay patterns of target-like and projectile-like nuclei in 84Kr+197Au, natU reactions at E/A=150 MeV

International Nuclear Information System (INIS)

Quednau, B.M.; Galin, J.; Ledoux, X.; Crema, E.; Gebauer, B.; Hilscher, D.; Jahnke, U.; Jacquet, D.; Leray, S.; and others.

1996-01-01

The reactions 84 Kr+ 197 Au and 84 Kr+ nat U were studied at E/A=150 MeV employing the large-volume neutron multiplicity filter ORION at SATURNE. The observed correlations between the atomic number of projectile-like nuclei and neutron multiplicity indicate large excitation energies in the primary projectile- and target-like fragments. Angular correlations between the fission fragments of the U-like nucleus and the projectile-like fragments show a memory of the reaction plane, however no indications of spin effects are found. (author)

Research on critical behaviour during fragmentation of the projectile in the Xe+Sn (at 50 MeV/A) reaction; Recherche d`un comportement critique dans la fragmentation du projectile dans la reaction Xe+Sn a 50 MeV/A

Energy Technology Data Exchange (ETDEWEB)

Benlliure, J

1995-03-01

The study of moments of fragments charge distributions produced in heavy ions collisions can give us evidence of a critical behavior of nuclear matter which could explain the multifragmentation pattern. From an experimental point of view, in order to perform this capabilities of the INDRA detector has made it possible to identify all these particles and to reconstruct the initial projectile-like fragment coming from binary collisions in the reaction Xe+Sn at 50 MeV/A. We have selected events where the initial projectile-like fragments keep their entire charge in a large range of excitation energy. The study of these fragment`s characteristics show clearly a change in the deexcitation pattern. The evolution of moments of the fragment charge distributions has been reproduced within a percolation model, in this sense we can interpreter this change in the deexcitation pattern as a function of the initial projectile-like fragment`s size shows the existence of finite-size effects. However, the signature of a phase transition remains independent on the projectile-like fragment`s size. (author). 74 refs., 58 figs., 9 tabs.

Corrected Launch Speed for a Projectile Motion Laboratory

Science.gov (United States)

Sanders, Justin M.; Boleman, Michael W.

2013-01-01

At our university, students in introductory physics classes perform a laboratory exercise to measure the range of a projectile fired at an assigned angle. A set of photogates is used to determine the initial velocity of the projectile (the launch velocity). We noticed a systematic deviation between the experimentally measured range and the range…

Atom and molecule projectile and fast aggregate excitation, ionization and dissociation in thin targets in the out-of-charge equilibrium field

International Nuclear Information System (INIS)

Clouvas, A.

1985-12-01

The aim of this experimental study is to confirm the possible existence of bound states for light atomic and molecular projectiles inside solid targets, in the MeV energy range. For this purpose we have used, various experimental methods such as charge state distribution measurements, energy loss measurements, beam foil spectroscopy and electron spectroscopy. It was confirmed that bound states of light atomic and molecular projectiles can exist in a solid medium. The various cross sections (charge exchange, excitation, ionisation, dissociation) relative to these bound states have been measured [fr

Projectile-z3 and -z4 corrections to basic Bethe-Bloch stopping power theory and mean excitation energies of Al, Si, Ni, Ge, Se, Y, Ag and Au

International Nuclear Information System (INIS)

Porter, L.E.; Bryan, S.R.

1980-01-01

Three independent sets of measurements of the stopping power of solid elemental targets for alpha particles were previously analyzed in terms of basic Bethe-Bloch theory with the low velocity projectile-z 3 correction term included. These data for Al, Si, Ni, Ge, Se, Y, Ag and Au have now been analyzed with the Bloch projectile-z 4 term and a revised projectile-z 3 term incorporated in the Bethe-Bloch formula, the projectile-z 3 revision having been effected by variation of the single free parameter of the projectile-z 3 effect formalism. The value of this parameter, fixed at 1.8 in previous studies, which counteracts inclusion of the projectile-z 4 term is 1.3 +- 0.1 for all target elements except Si. (orig.)

Study of the peripheral projectile-like fragments from the reaction 129Xe on 27Al, natCu, 139La and 165Ho, at E/A = 50 MeV

International Nuclear Information System (INIS)

Garcia-Solis, E.J.; Russ, D.E.; Madani, H.

1996-01-01

There are several reaction mechanisms identified for peripheral heavy-ion collisions. For low bombarding energies (E/A ∼ 10 MeV) the predominant reaction channel is the deep-inelastic reaction mechanism. In this process, the projectile and target form a rotating binary system, interchanging nucleons and angular momentum until they separate. At higher bombarding energies (E/A ∼ 50 to 100 MeV) incomplete fusion is thought to be the prevailing reaction channel. In this type of interaction part of the projectile merges with the target during the collision. Finally, for energies greater than 100 MeV/A, the main reaction channel is characterized by the formation of a highly-excited separate fragment (fireball) produced during the overlap between the projectile and the target. The data set studied was from an experiment designed to characterize the projectile-like products of the 27 Al, nat Cu, 139 La, and 165 Ho reactions at E/A = 50 MeV, which was performed at the Michigan State University Super Cyclotron Laboratory (MSU-NSCL). The Maryland Forward Array (MFA), was used to measure projectile-like fragments in coincidence with target-like fragments and light-charge particles in the MSU 4π detector

Fatal lawn mower related projectile injury.

Science.gov (United States)

Colville-Ebeling, Bonnie; Lynnerup, Niels; Banner, Jytte

2014-06-01

Fatal lawn mower related injuries are a relatively rare occurrence. In a forensic setting, the primary aim is to reconstruct the injury mechanism and establish the cause of death. A relatively rare, but characteristic type of injury is a so-called projectile or missile injury. This occurs when the operator or a bystander is impacted by an object mobilized from the grass by the rotating mower blades. This type of injury often leaves only modest external trauma, which increases the risk of overlooking an entry wound. In this paper we present a case of a fatal lawn mower related projectile injury which was initially overlooked, later interpreted as a possible gunshot homicide, and finally identified as a lawn mower related projectile injury when autopsy revealed a piece of metal thread in the main bronchus to the right middle lobe, hemopericardium, and right-sided hemothorax. To our knowledge, this injury mechanism has not previously been reported as a cause of death. This case illustrates the importance of postmortem radiological imaging and interdisciplinary cooperation when establishing manner and cause of death in unusual cases.

Virtual non-contrast in second-generation, dual-energy computed tomography: Reliability of attenuation values

International Nuclear Information System (INIS)

Toepker, Michael; Moritz, Thomas; Krauss, Bernhard; Weber, Michael; Euller, Gordon; Mang, Thomas; Wolf, Florian; Herold, Christian J.; Ringl, Helmut

2012-01-01

Purpose: To evaluate the reliability of attenuation values in virtual non-contrast images (VNC) reconstructed from contrast-enhanced, dual-energy scans performed on a second-generation dual-energy CT scanner, compared to single-energy, non-contrast images (TNC). Materials and methods: Sixteen phantoms containing a mixture of contrast agent and water at different attenuations (0–1400 HU) were investigated on a Definition Flash-CT scanner using a single-energy scan at 120 kV and a DE-CT protocol (100 kV/SN140 kV). For clinical assessment, 86 patients who received a dual-phase CT, containing an unenhanced single-energy scan at 120 kV and a contrast enhanced (110 ml Iomeron 400 mg/ml; 4 ml/s) DE-CT (100 kV/SN140 kV) in an arterial (n = 43) or a venous phase, were retrospectively analyzed. Mean attenuation was measured within regions of interest of the phantoms and in different tissue types of the patients within the corresponding VNC and TNC images. Paired t-tests and Pearson correlation were used for statistical analysis. Results: For all phantoms, mean attenuation in VNC was 5.3 ± 18.4 HU, with respect to water. In 86 patients overall, 2637 regions were measured in TNC and VNC images, with a mean difference between TNC and VNC of −3.6 ± 8.3 HU. In 91.5% (n = 2412) of all cases, absolute differences between TNC and VNC were under 15 HU, and, in 75.3% (n = 1986), differences were under 10 HU. Conclusions: Second-generation dual-energy CT based VNC images provide attenuation values close to those of TNC. To avoid possible outliers multiple measurements are recommended especially for measurements in the spleen, the mesenteric fat, and the aorta.

Virtual non-contrast in second-generation, dual-energy computed tomography: reliability of attenuation values.

Science.gov (United States)

Toepker, Michael; Moritz, Thomas; Krauss, Bernhard; Weber, Michael; Euller, Gordon; Mang, Thomas; Wolf, Florian; Herold, Christian J; Ringl, Helmut

2012-03-01

To evaluate the reliability of attenuation values in virtual non-contrast images (VNC) reconstructed from contrast-enhanced, dual-energy scans performed on a second-generation dual-energy CT scanner, compared to single-energy, non-contrast images (TNC). Sixteen phantoms containing a mixture of contrast agent and water at different attenuations (0-1400 HU) were investigated on a Definition Flash-CT scanner using a single-energy scan at 120 kV and a DE-CT protocol (100 kV/SN140 kV). For clinical assessment, 86 patients who received a dual-phase CT, containing an unenhanced single-energy scan at 120 kV and a contrast enhanced (110 ml Iomeron 400 mg/ml; 4 ml/s) DE-CT (100 kV/SN140 kV) in an arterial (n=43) or a venous phase, were retrospectively analyzed. Mean attenuation was measured within regions of interest of the phantoms and in different tissue types of the patients within the corresponding VNC and TNC images. Paired t-tests and Pearson correlation were used for statistical analysis. For all phantoms, mean attenuation in VNC was 5.3±18.4 HU, with respect to water. In 86 patients overall, 2637 regions were measured in TNC and VNC images, with a mean difference between TNC and VNC of -3.6±8.3 HU. In 91.5% (n=2412) of all cases, absolute differences between TNC and VNC were under 15HU, and, in 75.3% (n=1986), differences were under 10 HU. Second-generation dual-energy CT based VNC images provide attenuation values close to those of TNC. To avoid possible outliers multiple measurements are recommended especially for measurements in the spleen, the mesenteric fat, and the aorta. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Study of the multiple ionization in the ion-atom collisions with highly charged sulfur as well as with neutral and lowly charged fluorine projectiles

International Nuclear Information System (INIS)

Konrad, J.

1986-01-01

With the collisional systems 115 MeV S +Q (Q=+13, +15, +16) on He, Ne, Ar, and Kr as well as 4 MeV F +Q (Q=-1, 0, +1) on Ne the multiple ionization in the ion-atom collision was studied. With the collisional system 4 MeV F +Q on Ne the multiple ionization of target and projectile was studied by coincidence measurement between the recoil ions and projectiles with the charge state Q' after the collision (Q'=-1 to +3). In the pure ionization (no change of the projectile charge) the measured ionization cross sections for the single positive and negative charged projectile are equally large, those of the neutral F projectiles are lower. The comparison with the point particles protons and electrons resulted that the ionization cross sections of the F projectiles are larger and more strongly higher charged recoil ions are produced. The measured ionization cross sections of the F projectile are larger than those of the Ne target atom which is to be reduced to the lower ionization energies of the F projectile. With the highly charged S projectiles the multiple ionization with capture into the projectile was studied. By the measurement of triple coincidcences between recoil ions, projectiles, and SKX-radiation the cases with and without capture into the K shell can be discriminated. The charge distribution with is shifted against that without capture into the K shell to higher charges. This shift is to be reduced to the decay of autoionization states which arise by the capture into the K shell. (orig./HSI) [de

Breakup conditions of projectile spectators from dynamical observables

Energy Technology Data Exchange (ETDEWEB)

Begemann-Blaich, M.; Lindenstruth, V.; Pochodzalla, J. [and others

1998-03-01

Momenta and masses of heavy projectile fragments (Z {>=} 8), produced in collisions of {sup 197}Au with C, Al, Cu and Pb targets at E/A=600 MeV, were determined with the ALADIN magnetic spectrometer at SIS. Using these informations, an analysis of kinematic correlations between the two and three heaviest projectile fragments in their rest frame was performed. The sensitivity of these correlations to the conditions at breakup was verified within the schematic SOS-model. For a quantitative investigation, the data were compared to calculations with statistical multifragmentation models and to classical three-body calculations. With classical trajectory calculations, where the charges and masses of the fragments are taken from a Monte Carlo sampling of the experimental events, the dynamical observables can be reproduced. The deduced breakup parameters, however, differ considerably from those assumed in the statistical multifragmentation models which describe the charge correlations. If, on the other hand, the analysis of kinematic and charge correlations is performed for events with two and three heavy fragments produced by statistical multifragmentation codes, a good agreement with the data is found with the exception that the fluctuation widths of the intrinsic fragment energies are significantly underestimated. A new version of the multifragmentation code MCFRAG was therefore used to investigate the potential role of angular momentum at the breakup stage. If a mean angular momentum of 0.75 {Dirac_h}/nucleon is added to the system, the energy fluctuations can be reproduced, but at the same time the charge partitions are modified and deviate from the data. (orig.)

Breakup conditions of projectile spectators from dynamical observables

International Nuclear Information System (INIS)

Begemann-Blaich, M.; Lindenstruth, V.; Pochodzalla, J.

1998-03-01

Momenta and masses of heavy projectile fragments (Z ≥ 8), produced in collisions of 197 Au with C, Al, Cu and Pb targets at E/A=600 MeV, were determined with the ALADIN magnetic spectrometer at SIS. Using these informations, an analysis of kinematic correlations between the two and three heaviest projectile fragments in their rest frame was performed. The sensitivity of these correlations to the conditions at breakup was verified within the schematic SOS-model. For a quantitative investigation, the data were compared to calculations with statistical multifragmentation models and to classical three-body calculations. With classical trajectory calculations, where the charges and masses of the fragments are taken from a Monte Carlo sampling of the experimental events, the dynamical observables can be reproduced. The deduced breakup parameters, however, differ considerably from those assumed in the statistical multifragmentation models which describe the charge correlations. If, on the other hand, the analysis of kinematic and charge correlations is performed for events with two and three heavy fragments produced by statistical multifragmentation codes, a good agreement with the data is found with the exception that the fluctuation widths of the intrinsic fragment energies are significantly underestimated. A new version of the multifragmentation code MCFRAG was therefore used to investigate the potential role of angular momentum at the breakup stage. If a mean angular momentum of 0.75 ℎ/nucleon is added to the system, the energy fluctuations can be reproduced, but at the same time the charge partitions are modified and deviate from the data. (orig.)

CDW-EIS theoretical calculations of projectile deflection for single ionization in highly charged ion-atom collisions

International Nuclear Information System (INIS)

Rodriguez, V.D.

2003-01-01

We present continuum distorted wave-eikonal initial state (CDW-EIS) theoretical calculations for the projectile deflection in single ionization of helium by heavy-ion impact as a function of ionized electron energies. These calculations account for the helium passive electron shielding in the internuclear interaction improving standard CDW-EIS theory. The results are compared with recent experimental results by impact of 100 MeV/amu C 6+ and 3.6 MeV/amu Au 53+ . For highly charged projectiles there is a poor quantitative agreement between theory and experiment. However, this refined calculation does share some qualitative features with the data. In particular the variation of the effective charge of the residual He + ion from Z eff =1 to Z eff =2 when going from small to large projectile scattering angles is able to represent a shoulder observed in the double differential cross sections. Important qualitative differences are observed at the level of triple differential cross sections

Attenuation of 10 MeV electron beam energy to achieve low doses does not affect Salmonella spp. inactivation kinetics

International Nuclear Information System (INIS)

Hieke, Anne-Sophie Charlotte; Pillai, Suresh D.

2015-01-01

The effect of attenuating the energy of a 10 MeV electron beam on Salmonella inactivation kinetics was investigated. No statistically significant differences were observed between the D 10 values of either Salmonella 4,[5],12:i:- or a Salmonella cocktail (S. 4,[5],12:i:-, Salmonella Heidelberg, Salmonella Newport, Salmonella Typhimurium, Salmonella) when irradiated with either a non-attenuated 10 MeV eBeam or an attenuated 10 MeV eBeam (~2.9±0.22 MeV). The results show that attenuating the energy of a 10 MeV eBeam to achieve low doses does not affect the inactivation kinetics of Salmonella spp. when compared to direct 10 MeV eBeam irradiation. - Highlights: • 10 MeV eBeam energy was attenuated to 2.9±0.22 MeV using HDPE sheets. • Attenuation of eBeam energy does not affect the inactivation kinetics of Salmonella. • Microbial inactivation is independent of eBeam energy in the range of 3–10 MeV

Assessing the Blunt Trauma Potential of Free Flying Projectiles for Development and Safety Certification of Non-Lethal Kinetic Impactors

National Research Council Canada - National Science Library

Widder, Jeffrey

1997-01-01

The primary performance objective for non-lethal, antipersonnel kinetic energy impact projectiles is to reliably deter or incapacitate without causing injuries that require medical treatment beyond...

Hidrodinamički model podvodnog projektila / Hidrodinamical model of an underwater projectile

Directory of Open Access Journals (Sweden)

Miroslav Radosavljević

2008-07-01

Full Text Available Radi dobijanja kvalitetnog matematičkog modela podvodnog projektila u radu su definisane ulazne i izlazne veličine, brzine i ubrzanje projektila. Uz zadate uslove mogućeg kretanja projektila definisan je model podvodnog projektila sa šest jednačina. / The paper analyzes an underwater projectile. The input and output values, the projectile speed and acceleration are defined for a quality definition of the projectile mathematical model. With the conditions of the projectile potential movement previously set out, the torpedo model is defined by six equations.

High-velocity Penetration of Concrete Targets with Three Types of Projectiles: Experiments and Analysis

Directory of Open Access Journals (Sweden)

Shuang Zhang

Full Text Available Abstract This study conducted high-velocity penetration experiments using conventional ogive-nose, double-ogive-nose, and grooved-tapered projectiles of approximately 2.5 kg and initial velocities between 1000 and 1360 m/s to penetrate or perforate concrete targets with unconfined compressive strengths of nominally 40MPa. The penetration performance data of these three types of projectiles with two different types of materials (i.e., AerMet100 and DT300 were obtained. The crater depth model considering both the projectile mass and the initial velocity was proposed based on the test results and a theoretical analysis. The penetration ability and the trajectory stability of these three projectile types were compared and analyzed accordingly. The results showed that, under these experimental conditions, the effects of these two different kinds of projectile materials on the penetration depth and mass erosion rate of projectile were not obvious. The existing models could not reflect the crater depths for projectiles of greater weights or higher velocities, whereas the new model established in this study was reliable. The double-ogive-nose has a certain effect of drag reduction. Thus, the double-ogive-nose projectile has a higher penetration ability than the conventional ogive-nose projectile. Meanwhile, the grooved-tapered projectile has a better trajectory stability, because the convex parts of tapered shank generated the restoring moment to stabilize the trajectory.

X-ray yields from high-energy heavy ions channeled through a crystal: their crystal thickness and projectile dependences

International Nuclear Information System (INIS)

Kondo, C.; Takabayashi, Y.; Muranaka, T.; Masugi, S.; Azuma, T.; Komaki, K.; Hatakeyama, A.; Yamazaki, Y.; Takada, E.; Murakami, T.

2005-01-01

X-rays emitted from Ar 17+ , Fe 24+ and Kr 35+ ions of about 400 MeV/u transmitting through a thin Si crystal of about 20 μm thickness have been measured in a planar channeling condition and compared with those in a random incident condition. We have found that the X-ray yield from Ar 17+ ions is larger for the channeling condition than for the random incidence, while those from Fe 24+ and Kr 35+ ions are rather smaller. Such tendencies are explained by considering the projectile dependences of excitation and ionization probabilities together with X-ray emission rates. A crude simulation has qualitatively reproduced these experimental results. When the crystal thickness is small, the X-ray yield is smaller in the channeling condition than in the random incident condition, because excitation is depressed. However, for thicker crystals, the X-ray yield is larger, since the survived population of projectile-bound electrons is larger due to small ionization probabilities under the channeling condition. This inversion occurs at a specific crystal thickness depending on projectile species. Whether the thickness of the used crystal is smaller or larger than the inversion thickness determines enhancement or depression of the X-ray yield in the channeling condition

A Flexible Online Apparatus for Projectile Launch Experiments

Directory of Open Access Journals (Sweden)

Carlos Manuel Paiva

2013-01-01

Full Text Available In order to provide a more flexible learning environment in physics, the developed projectile launch apparatus enables students to determine the acceleration of gravity and the dependence of a set of parameters in the projectile movement. This apparatus is remotely operated and accessed via web, by first scheduling an access time slot. This machine has a number of configuration parameters that support different learning scenarios with different complexities.

Projectile Motion Hoop Challenge

Science.gov (United States)

Jordan, Connor; Dunn, Amy; Armstrong, Zachary; Adams, Wendy K.

2018-01-01

Projectile motion is a common phenomenon that is used in introductory physics courses to help students understand motion in two dimensions. Authors have shared a range of ideas for teaching this concept and the associated kinematics in "The Physics Teacher" ("TPT"); however, the "Hoop Challenge" is a new setup not…

Spinning projectile's attitude measurement with LW infrared radiation under sea-sky background

Science.gov (United States)

Xu, Miaomiao; Bu, Xiongzhu; Yu, Jing; He, Zilu

2018-05-01

With the further development of infrared radiation research in sea-sky background and the requirement of spinning projectile's attitude measurement, the sea-sky infrared radiation field is used to carry out spinning projectile's attitude angle instead of inertial sensors. Firstly, the generation mechanism of sea-sky infrared radiation is analysed. The mathematical model of sea-sky infrared radiation is deduced in LW (long wave) infrared 8 ∼ 14 μm band by calculating the sea surface and sky infrared radiation. Secondly, according to the movement characteristics of spinning projectile, the attitude measurement model of infrared sensors on projectile's three axis is established. And the feasibility of the model is analysed by simulation. Finally, the projectile's attitude calculation algorithm is designed to improve the attitude angle estimation accuracy. The results of semi-physical experiments show that the segmented interactive algorithm estimation error of pitch and roll angle is within ±1.5°. The attitude measurement method is effective and feasible, and provides accurate measurement basis for the guidance of spinning projectile.

Simultaneous K plus L shell ionized atoms during heavy-ion ...

Indian Academy of Sciences (India)

Co and Cu elements using carbon ions at different projectile energies. The present ... considered the critical absorption of energy shifted Kβ X-rays while passing through an external ... The attenuation coefficients corresponding to the energies.

Electron loss and capture from low-charge-state oxygen projectiles in methane

International Nuclear Information System (INIS)

Santos, A C F; Wolff, W; Sant’Anna, M M; Sigaud, G M; DuBois, R D

2013-01-01

Absolute cross sections for single- and double-electron loss and single- and multiple-electron capture of 15–1000 keV oxygen projectiles (q = −1, 0, 1, 2) colliding with the methane molecule are presented. The experimental data are used to examine cross-section scaling characteristics for the electron loss of various projectiles. In addition, a modified version of the free-collision model was employed for the calculation of the single- and total-electron-loss cross sections of oxygen projectiles presented in this work. The comparison of the calculated cross sections with the present experimental data shows very good agreement for projectile velocities above 1.0 au. The comparison of the present single-electron-capture cross sections with other projectiles having the same charge shows good agreement, and a common curve can be drawn through the different data sets. (paper)

A Simple General Solution for Maximal Horizontal Range of Projectile Motion

OpenAIRE

Busic, Boris

2005-01-01

A convenient change of variables in the problem of maximizing the horizontal range of the projectile motion, with an arbitrary initial vertical position of the projectile, provides a simple, straightforward solution.

Effects of Re-heating Tissue Samples to Core Body Temperature on High-Velocity Ballistic Projectile-tissue Interactions.

Science.gov (United States)

Humphrey, Caitlin; Henneberg, Maciej; Wachsberger, Christian; Maiden, Nicholas; Kumaratilake, Jaliya

2017-11-01

Damage produced by high-speed projectiles on organic tissue will depend on the physical properties of the tissues. Conditioning organic tissue samples to human core body temperature (37°C) prior to conducting ballistic experiments enables their behavior to closely mimic that of living tissues. To minimize autolytic changes after death, the tissues are refrigerated soon after their removal from the body and re-heated to 37°C prior to testing. This research investigates whether heating 50-mm-cube samples of porcine liver, kidney, and heart to 37°C for varying durations (maximum 7 h) can affect the penetration response of a high-speed, steel sphere projectile. Longer conditioning times for heart and liver resulted in a slight loss of velocity/energy of the projectile, but the reverse effect occurred for the kidney. Possible reasons for these trends include autolytic changes causing softening (heart and liver) and dehydration causing an increase in density (kidney). © 2017 American Academy of Forensic Sciences.

Materials analysis using x-ray linear attenuation coefficient measurements at four photon energies

International Nuclear Information System (INIS)

Midgley, S M

2005-01-01

The analytical properties of an accurate parameterization scheme for the x-ray linear attenuation coefficient are examined. The parameterization utilizes an additive combination of N compositional- and energy-dependent coefficients. The former were derived from a parameterization of elemental cross-sections using a polynomial in atomic number. The compositional-dependent coefficients are referred to as the mixture parameters, representing the electron density and higher order statistical moments describing elemental distribution. Additivity is an important property of the parameterization, allowing measured x-ray linear attenuation coefficients to be written as linear simultaneous equations, and then solved for the unknown coefficients. The energy-dependent coefficients can be determined by calibration from measurements with materials of known composition. The inverse problem may be utilized for materials analysis, whereby the simultaneous equations represent multi-energy linear attenuation coefficient measurements, and are solved for the mixture parameters. For in vivo studies, the choice of measurement energies is restricted to the diagnostic region (approximately 20 keV to 150 keV), where the parameterization requires N ≥ 4 energies. We identify a mathematical pathology that must be overcome in order to solve the inverse problem in this energy regime. An iterative inversion strategy is presented for materials analysis using four or more measurements, and then tested against real data obtained at energies 32 keV to 66 keV. The results demonstrate that it is possible to recover the electron density to within ±4% and fourth mixture parameter. It is also a key finding that the second and third mixture parameters cannot be recovered, as they are of minor importance in the parameterization at diagnostic x-ray energies

Strain Behavior of Concrete Panels Subjected to Different Nose Shapes of Projectile Impact.

Science.gov (United States)

Lee, Sangkyu; Kim, Gyuyong; Kim, Hongseop; Son, Minjae; Choe, Gyeongcheol; Nam, Jeongsoo

2018-03-09

This study evaluates the fracture properties and rear-face strain distribution of nonreinforced and hooked steel fiber-reinforced concrete panels penetrated by projectiles of three different nose shapes: sharp, hemispherical, and flat. The sharp projectile nose resulted in a deeper penetration because of the concentration of the impact force. Conversely, the flat projectile nose resulted in shallower penetrations. The penetration based on different projectile nose shapes is directly related to the impact force transmitted to the rear face. Scabbing can be more accurately predicted by the tensile strain on the rear face of concrete due to the projectile nose shape. The tensile strain on the rear face of the concrete was reduced by the hooked steel fiber reinforcement because the hooked steel fiber absorbed some of the impact stress transmitted to the rear face of the concrete. Consequently, the strain behavior on the rear face of concrete according to the projectile nose shape was confirmed.

Strain Behavior of Concrete Panels Subjected to Different Nose Shapes of Projectile Impact

Directory of Open Access Journals (Sweden)

Sangkyu Lee

2018-03-01

Full Text Available This study evaluates the fracture properties and rear-face strain distribution of nonreinforced and hooked steel fiber-reinforced concrete panels penetrated by projectiles of three different nose shapes: sharp, hemispherical, and flat. The sharp projectile nose resulted in a deeper penetration because of the concentration of the impact force. Conversely, the flat projectile nose resulted in shallower penetrations. The penetration based on different projectile nose shapes is directly related to the impact force transmitted to the rear face. Scabbing can be more accurately predicted by the tensile strain on the rear face of concrete due to the projectile nose shape. The tensile strain on the rear face of the concrete was reduced by the hooked steel fiber reinforcement because the hooked steel fiber absorbed some of the impact stress transmitted to the rear face of the concrete. Consequently, the strain behavior on the rear face of concrete according to the projectile nose shape was confirmed.

Fairly direct hit. Advances in imaging of shotgun projectiles in MRI

Energy Technology Data Exchange (ETDEWEB)

Eggert, Sebastian [Kantonsspital Baden AG, Department of Radiology, Baden (Switzerland); University of Zurich, Institute of Forensic Medicine, Zurich (Switzerland); Kubik-Huch, Rahel A.; Peters, Alexander [Kantonsspital Baden AG, Department of Radiology, Baden (Switzerland); Klarhoefer, Markus [Siemens Healthcare, Zurich (Switzerland); Bolliger, Stephan A.; Thali, Michael J. [University of Zurich, Institute of Forensic Medicine, Zurich (Switzerland); Anderson, Suzanne [Kantonsspital Baden AG, Department of Radiology, Baden (Switzerland); University of Notre Dame Australia, Radiology, Sydney School of Medicine, Sydney, NSW (Australia); Froehlich, Johannes M. [Federal Institute of Technology, Pharmaceutical Sciences, Zurich (Switzerland)

2015-09-15

To investigate the magnetic properties of different types of projectiles and qualify the metal artefact reduction technique for diagnostic and/or forensic MRI. Ten different projectiles embedded in ordnance gelatine blocks underwent an in vitro 1.5-T MR study with seven sequences including a recently developed metal artefact reduction sequence (Advanced WARP) combining VAT (view-angle-tilting) and SEMAC (slice-encoding metal-artefact-correction). Resulting image quality (five-point scale: 1=best; 5=worst) was scored. Quantifiable magnetic characteristics were correlated with qualitative rating of the MR sequences and torque dislodgment. Metal artefact reduction sequence (median: 2.5) significantly (p < 0.001) improves depiction of projectiles in comparison to all other MR pulse sequences (median: 4.75). Images from diamagnetic composed bullets (median: 2) are much less disturbed compared to magnetic attracted ones (median: 5). Correlation (0.623) between deflection angle measurement (ferromagnetic mean 84.2 ; paramagnetic 62 ; diamagnetic mean 0 ) and median qualitative image quality was highly significant (p = 0.027). Torque dislodgement was distinct for elongated magnetic attracted projectiles. Significant improvement of MR imaging of projectiles using metal artefact reduction techniques has important implications for diagnostic/forensic work-up. The correlations between magnetic attraction force, deflection-angle results and image properties demonstrate that the MR safety of projectiles can be estimated with one of these methods. (orig.)

Fairly direct hit. Advances in imaging of shotgun projectiles in MRI

International Nuclear Information System (INIS)

Eggert, Sebastian; Kubik-Huch, Rahel A.; Peters, Alexander; Klarhoefer, Markus; Bolliger, Stephan A.; Thali, Michael J.; Anderson, Suzanne; Froehlich, Johannes M.

2015-01-01

To investigate the magnetic properties of different types of projectiles and qualify the metal artefact reduction technique for diagnostic and/or forensic MRI. Ten different projectiles embedded in ordnance gelatine blocks underwent an in vitro 1.5-T MR study with seven sequences including a recently developed metal artefact reduction sequence (Advanced WARP) combining VAT (view-angle-tilting) and SEMAC (slice-encoding metal-artefact-correction). Resulting image quality (five-point scale: 1=best; 5=worst) was scored. Quantifiable magnetic characteristics were correlated with qualitative rating of the MR sequences and torque dislodgment. Metal artefact reduction sequence (median: 2.5) significantly (p < 0.001) improves depiction of projectiles in comparison to all other MR pulse sequences (median: 4.75). Images from diamagnetic composed bullets (median: 2) are much less disturbed compared to magnetic attracted ones (median: 5). Correlation (0.623) between deflection angle measurement (ferromagnetic mean 84.2 ; paramagnetic 62 ; diamagnetic mean 0 ) and median qualitative image quality was highly significant (p = 0.027). Torque dislodgement was distinct for elongated magnetic attracted projectiles. Significant improvement of MR imaging of projectiles using metal artefact reduction techniques has important implications for diagnostic/forensic work-up. The correlations between magnetic attraction force, deflection-angle results and image properties demonstrate that the MR safety of projectiles can be estimated with one of these methods. (orig.)

Shakeoff Ionization near the Coulomb Barrier Energy

Science.gov (United States)

Sharma, Prashant; Nandi, T.

2017-11-01

We measure the projectile K x-ray spectra as a function of the beam energies around the Coulomb barrier in different collision systems. The energy is scanned in small steps around the barrier aiming to explore the nuclear effects on the elastically scattered projectile ions. The variation of the projectile x-ray energy with the ion-beam energies exhibits an unusual increase in between the interaction barrier and fusion barrier energies. This additional contribution to the projectile ionization can be attributed to the shakeoff of outer-shell electrons of the projectile ions due to the sudden nuclear recoil (˜10-21 sec ) caused by the attractive nuclear potential, which gets switched on near the interaction barrier energy. In the sudden approximation limit, the theoretical shakeoff probability calculation due to the nuclear recoil explains the observed data well. In addition to its fundamental interest, such processes can play a significant role in dark matter detection through the possible mechanism of x-ray emissions, where the weakly interacting massive particle-nucleus elastic scattering can lead to the nuclear-recoil-induced inner-shell vacancy creations. Furthermore, the present work may provide new prospects for atomic physics research at barrier energies as well as provide a novel technique to perform barrier distribution studies for two-body systems.

An experimental study on the deformation and fracture modes of steel projectiles during impact

International Nuclear Information System (INIS)

Rakvåg, K.G.; Børvik, T.; Westermann, I.; Hopperstad, O.S.

2013-01-01

Highlights: • The fracture process is ductile for the unhardened projectiles. • A combined ductile–brittle fracture process is obtained for the HRC 40 projectiles. • The fragmentation of HRC 52 projectiles has cleavage as the main mechanism. • The fracture modes were confirmed in a metallurgical study. • The hardened materials have a stochastic variation of the mechanical properties. - Abstract: Previous investigations of the penetration and perforation of high-strength steel plates struck by hardened steel projectiles have shown that under certain test conditions the projectile may fracture or even fragment upon impact. Simulations without an accurate failure description for the projectile material will then predict perforation of the target instead of fragmentation of the projectile, and thus underestimate the ballistic limit velocity of the target plate. This paper presents an experimental investigation of the various deformation and fracture modes that may occur in steel projectiles during impact. This is studied by conducting Taylor bar impact tests using 20 mm diameter, 80 mm long, tool steel projectiles with three different hardness values (HRC 19, 40 and 52). A gas gun was used to fire the projectiles into a rigid wall at impact velocities ranging from 100 to 350 m/s, and the deformation and fracture processes were captured by a high-speed video camera. From the tests, several different deformation and fracture modes were registered for each hardness value. To investigate the influence of material on the deformation and fracture modes, several series of tensile tests on smooth axisymmetric specimens were carried out to characterise the mechanical properties of the three materials. To gain a deeper understanding of the various processes causing fracture and fragmentation during impact, a metallurgical investigation was conducted. The fracture surfaces of the failed projectiles of different hardness were investigated, and the microstructure was

Identification of very low energy projectile autoionizing transitions in high velocity collisions using zero-degree Auger electron spectroscopy

International Nuclear Information System (INIS)

Zouros, T.J.M.; Liao, C.; Montenegro, E.C.; Hagmann, S.; Richard, P.; Grabbe, S.; Bhalla, C.P.; Wong, K.L.

1995-01-01

The unusual looking ''mesa''-shaped cusp observed in O 3+ collisions with He [N. Stolterfoht et al., Proc. 2nd US-Mexico Symp. on Atomic and Molecular Phy. eds. A. Cisneros and T. Morgan (Instituto de Fysica, Cuernavaca, Mexico, 1986) p. 51.], has been investigated using zero-degree electron spectroscopy, in both high resolution singles measurements and lower resolution electron-projectile coincidence measurements at 10, 15 and 23 MeV. The high resolution studies indicate the ''mesa'' peak to be actually composed of primarily two (other than the cusp) very strong autoionizing peaks corresponding to energies of 60 and 100 meV in the emitter frame. The coincidence studies, indicate these lines to originate from excitation of the O 3+ ion followed by autoionization. Ongoing Hartree-Fock-Slater calculations, severely tested at these extremely small transition energies, indicate that these lines can indeed result from the autoionization of t he O 3+ (1s 2 2s2p5l) Rydberg states produced during the collision. Furthermore, the unusually sharp edges of these lines giving rise to the characteristic ''mesa''-shape look, can be explained in terms of the kinematic constraints imposed by the energy and angular acceptance range of the spectrometer. (orig.)

Role of projectile charge state in convoy electron emission by fast protons colliding with LiF(0 0 1)

Energy Technology Data Exchange (ETDEWEB)

Aldazabal, I. [Departamento de Fisica de Materiales, Facultad de Quimicas UPV/EHU, Apartado 1072, 20080 San Sebastian (Spain)]. E-mail: ialdazabal@sq.ehu.es; Gravielle, M.S. [Instituto de Astronomia y Fisica del Espacio, Consejo Nacional de Investigaciones Cientificas y Tecnicas and Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, C.C. 67, Suc. 28, 1428 Buenos Aires (Argentina); Miraglia, J.E. [Instituto de Astronomia y Fisica del Espacio, Consejo Nacional de Investigaciones Cientificas y Tecnicas and Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, C.C. 67, Suc. 28, 1428 Buenos Aires (Argentina); Arnau, A. [Centro Mixto CSIC-UPV/EHU, Apartado 1072, 20080 San Sebastian (Spain); Ponce, V.H. [Donostia International Physics Center DIPC, San Sebastian (Spain); Centro Atomico Bariloche, Bariloche (Argentina)

2005-05-01

Target ionization and projectile ionization differential cross sections are used to calculate the electron emission spectra by fast proton impact on ionic crystal surfaces under grazing incidence conditions. Both bare protons and neutral hydrogen species are considered. We use a planar potential approach to determine the projectile trajectory that later on allows us to calculate the charge state fractions. We show that, although the fraction of protons is significantly higher, the contribution from neutral hydrogen ionization has to be considered. The energy and angular dependence of the spectra is analyzed.

Role of projectile charge state in convoy electron emission by fast protons colliding with LiF(0 0 1)

International Nuclear Information System (INIS)

Aldazabal, I.; Gravielle, M.S.; Miraglia, J.E.; Arnau, A.; Ponce, V.H.

2005-01-01

Target ionization and projectile ionization differential cross sections are used to calculate the electron emission spectra by fast proton impact on ionic crystal surfaces under grazing incidence conditions. Both bare protons and neutral hydrogen species are considered. We use a planar potential approach to determine the projectile trajectory that later on allows us to calculate the charge state fractions. We show that, although the fraction of protons is significantly higher, the contribution from neutral hydrogen ionization has to be considered. The energy and angular dependence of the spectra is analyzed

Effect of projectile structure on evaporation residue yields in incomplete fusion reactions

CERN Document Server

Babu, K S; Sudarshan, K; Shrivastava, B D; Goswami, A; Tomar, B S

2003-01-01

The excitation functions of heavy residues, representing complete and incomplete fusion products, produced in the reaction of sup 1 sup 2 C and sup 1 sup 3 C on sup 1 sup 8 sup 1 Ta have been measured over the projectile energy range of 5 to 6.5 MeV/nucleon by the recoil catcher method and off-line gamma-ray spectrometry. Comparison of the measured excitation functions with those calculated using the PACE2 code based on the statistical model revealed the occurrence of incomplete fusion reactions in the formation of alpha emission products. The fraction of incomplete fusion cross sections in the sup 1 sup 2 C + sup 1 sup 8 sup 1 Ta reaction was found to be higher, by a factor of approx 2, than that in the sup 1 sup 3 C + sup 1 sup 8 sup 1 Ta reaction. The results have been discussed in terms of the effect of alpha cluster structure of the projectile on incomplete fusion reactions.

Electron loss from heavy heliumlike projectiles in ultrarelativistic collisions with many-electron atomic targets

International Nuclear Information System (INIS)

Mueller, C.; Gruen, N.; Voitkiv, A.B.

2002-01-01

We study single- and double-electron loss from heavy heliumlike projectiles in ultrarelativistic collisions with neutral many-electron target atoms. The simultaneous interaction of the target with two projectile electrons is found to be the dominant process in the double-electron loss provided the atomic number of the projectile, Z p , that of the target, Z t , and the collision velocity, v, satisfy the condition Z p Z t /v>0.4. It is shown that for a wide range of projectile and target atomic numbers the asymptotic double-to-single loss ratio strongly depends on the target atomic number but is nearly independent of the nuclear charge of the projectile. It is also demonstrated that many-photon exchange between the target and each of the projectile electrons considerably influences the double loss in collisions with very heavy targets

Features of projectile motion in the special theory of relativity

International Nuclear Information System (INIS)

Shahin, Ghassan Y

2006-01-01

A relativistic projectile motion in a vacuum is examined by means of elementary consequences of special relativity. Exact analytical expressions were found for the kinematics variables using basic mathematical tools. The trajectory equation was established and the area under the trajectory traversed by the relativistic projectile was determined. It was found that, unlike non-relativistic projectile motion, the launching angles that maximize both the horizontal range as well as the area under the trajectory are functions of the initial speed. It is anticipated that this paper will be consistent with the intuition of students and serve as a resource for further problems usually encountered in the special theory of relativity

The FRS Ion Catcher : A facility for high-precision experiments with stopped projectile and fission fragments

NARCIS (Netherlands)

Plass, W. R.; Dickel, T.; Purushothaman, S.; Dendooven, P.; Geissel, H.; Ebert, J.; Haettner, E.; Jesch, C.; Ranjan, M.; Reiter, M. P.; Weick, H.; Amjad, F.; Ayet, S.; Diwisch, M.; Estrade, A.; Farinon, F.; Greiner, F.; Kalantar-Nayestanaki, N.; Knoebel, R.; Kurcewicz, J.; Lang, J.; Moore, I.; Mukha, I.; Nociforo, C.; Petrick, M.; Pfuetzner, M.; Pietri, S.; Prochazka, A.; Rink, A. -K.; Rinta-Antila, S.; Schaefer, D.; Scheidenberger, C.; Takechi, M.; Tanaka, Y. K.; Winfield, J. S.; Yavor, M. I.

2013-01-01

At the FRS Ion Catcher at GSI, projectile and fission fragments are produced at relativistic energies, separated in-flight, range-focused, slowed down and thermalized in a cryogenic stopping cell. A multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) is used to perform direct mass

Production of pions and anomalous projectile fragments in heavy ion collisions

International Nuclear Information System (INIS)

Noren, B.

1988-05-01

Results are presented from investigations of the mean free path (mfp) of multiply charged fragments, produced by 1.8 A GeV argon nuclei. The mfp's have been studied experimentally, and no dependence of the mfp on the distance from the preceeding collision is observed. In a Monte Carlo simulation, the mfp estimators are investigated for different statistics, with or without an enhanced reaction probability. Intermediate energy heavy ion collisions have been studied using the carbon beam produced at the CERN SC-accelerator. Cross-sections for pion + and pion - have been measured over a wide range of angles and targets. Also, coincidence measurements with projectile-like fragments have been performed. The pion - /pion + ratio has been studied for C+Li, C+C, C+Pb, C+ 116 Sn and C+ 124 Sn. Inconsistencies in the target mass dependence of the pion yield disappear if a correction for reabsorption in the target nucleus is included. The projectile breakup is significantly stronger for pion producing collisions than for the average collision, thus indicating a much stronger abundance of central collisions. (With 32 refs.) (author)

Ultrahigh-speed X-ray imaging of hypervelocity projectiles

Science.gov (United States)

Miller, Stuart; Singh, Bipin; Cool, Steven; Entine, Gerald; Campbell, Larry; Bishel, Ron; Rushing, Rick; Nagarkar, Vivek V.

2011-08-01

High-speed X-ray imaging is an extremely important modality for healthcare, industrial, military and research applications such as medical computed tomography, non-destructive testing, imaging in-flight projectiles, characterizing exploding ordnance, and analyzing ballistic impacts. We report on the development of a modular, ultrahigh-speed, high-resolution digital X-ray imaging system with large active imaging area and microsecond time resolution, capable of acquiring at a rate of up to 150,000 frames per second. The system is based on a high-resolution, high-efficiency, and fast-decay scintillator screen optically coupled to an ultra-fast image-intensified CCD camera designed for ballistic impact studies and hypervelocity projectile imaging. A specially designed multi-anode, high-fluence X-ray source with 50 ns pulse duration provides a sequence of blur-free images of hypervelocity projectiles traveling at speeds exceeding 8 km/s (18,000 miles/h). This paper will discuss the design, performance, and high frame rate imaging capability of the system.

Detailed determination of the fusion nuclear radius in reactions involving weakly bound projectiles

International Nuclear Information System (INIS)

Gomez Camacho, A.; Aguilera, E. F.; Quiroz, E. M.

2007-01-01

A detailed determination of the fusion radius parameter is performed within the Distorted Wave Born Approximation for reactions involving weakly bound projectiles. Specifically, a simultaneous X 2- analysis of elastic and fusion cross section data is done using a Woods-Saxon potential with volume and surface parts. The volume part is assumed to be responsible for fusion reactions while the surface part for all other direct reactions. It is proved that in order to fit fusion data, particularly for energies below the Coulomb barrier where fusion is enhanced, it is necessary to have a value of around 1.4 fm for the fusion radial parameter of the fusion potential (W F ). This value is much higher than that frequently used in Barrier Penetration models (1.0 fm). The calculations are performed for reactions involving the weakly bound projectile 9 Be with several medium mass targets. (Author)

Characteristics and measurement of supersonic projectile shock waves by a 32-microphone ring array

Science.gov (United States)

Chang, Ho; Wu, Yan-Chyuan; Tsung, Tsing-Tshih

2011-08-01

This paper discusses about the characteristics of supersonic projectile shock wave in muzzle region during firing of high explosive anti-tank (HEAT) and high explosive (HE) projectiles. HEAT projectiles are fired horizontally at a muzzle velocity of Mach 3.5 from a medium caliber tank gun equipped with a newly designed multi-perforated muzzle brake, whereas HE projectiles are fired at elevation angles at a muzzle velocity of Mach 2 from a large caliber howitzer equipped with a newly designed double-baffle muzzle brake. In the near field, pressure signatures of the N-wave generated from projectiles are measured by 32-microphone ring array wrapped by cotton sheath. Records measured by the microphone array are used to demonstrate several key characteristics of the shock wave of supersonic projectile. All measurements made in this study can be a significant reference for developing guns, tanks, or the chassis of fighting vehicles.

Experimental Determination of Ballistic Performance of Composite Material Kevlar 29 and Alumina Powder/ Epoxy by Spherical Projectile

Directory of Open Access Journals (Sweden)

Luay Hashem Abbud

2016-12-01

Full Text Available In this study, a response of hybrid composite laminate woven fiber Kevlar29 – Al2O3 Powder/ Epoxy subjected to high velocity impact loading is presented. The energy absorbed due to impact of small rigid projectile on composite materials targets is determined experimentally. The energy absorbed due to impact of hemispherical projectiles on the developed composite laminates is investigated. The results revealed the maximum ballistic limit at impact velocity is found to be 390.87 ± 6 m/s for an the 18 mm target thickness. The ballistic limit velocity predictions are based on the theoretical method presented from another article. The initial velocity and residual velocity results showed good is agreement compared with the predicted results of Ipson and Recht equations. With 5.4 % of accuracy based on the experimental value for the theoretical model for ballistic limit velocity.

Non-contact and contact measurement system for detecting projectile position in electromagnetic launch bore

Science.gov (United States)

Xu, Weidong; Yuan, Weiqun; Xu, Rong; Zhao, Hui; Cheng, Wenping; Zhang, Dongdong; Zhao, Ying; Yan, Ping

2017-12-01

This paper introduces a new measurement system for measuring the position of a projectile within a rapid fire electromagnetic launching system. The measurement system contains both non-contact laser shading and metal fiber contact measurement devices. Two projectiles are placed in the rapid fire electromagnetic launch bore, one in the main accelerating segment and the other in the pre-loading segment. The projectile placed in the main accelerating segment should be shot first, and then the other is loaded into the main segment from the pre-loading segment. The main driving current (I-main) can only be discharged again when the second projectile has arrived at the key position (the projectile position corresponds to the discharging time) in the main accelerating segment. So, it is important to be able to detect when the second projectile arrives at the key position in the main accelerating segment. The B-dot probe is the most widely used system for detecting the position of the projectile in the electromagnetic launch bore. However, the B-dot signal is affected by the driving current amplitude and the projectile velocity. There is no current in the main accelerating segment when the second projectile moves into this segment in rapid fire mode, so the B-dot signal for detecting the key position is invalid. Due to the presence of a high-intensity magnetic field, a high current, a high-temperature aluminum attachment, smoke and strong vibrations, it is very difficult to detect the projectile position in the bore accurately. So, other measurements need to be researched and developed in order to achieve high reliability. A measurement system based on a laser (non-contact) and metal fibers (contact) has been designed, and the integrated output signal based on this detector is described in the following paper.

Determination of the excitation energy and angular momentum of the quasi-projectiles produced in the heavy ion collisions Xe + Sn; Determination de l'energie d'excitation et du moment angulaire des quasi-projectiles produits dans les collisions d'ions lourds Xe + Sn

Energy Technology Data Exchange (ETDEWEB)

Genouin-Duhamel, Emmanuel [Lab. de Physique Corpusculaire, Caen Univ., 14 Caen (France)

1999-04-08

This work is a contribution to the study of properties of hot nuclei formed in heavy ion collisions at intermediate energies. The experiment has been performed with the INDRA multidetector. It is shown that most of the reaction cross section is associated with binary dissipative collisions, accompanied by the production of particles from a region between the two reaction partners. This study is focussed on excitation energy and angular momentum of projectile-like fragment (PLF) in {sup 129}Xe + {sup nat}Sn reactions from 25 to 50 MeV per nucleon. Several methods are used to characterize hot nuclei (velocity, charge, mass and excitation energy). All these methods are compared between them and indicate that high energies are deposited in the nuclei during collision (it may exceed the nucleus binding energy). The angular momentum transferred into intrinsic spin to PLF in the peripheral collisions has been deduced from angular distributions and kinetic energies of the emitted light charged particles (atomic number smaller ar equal to 2). Both methods agree qualitatively. The spin values decrease with the violence of the collision. These values correspond to values averaged over the whole deexcitation chain of nuclei. The predictions of transport models reproduce qualitatively the most peripheral collisions and suggest that high spins are transferred to PLF (from 30 to 50 {Dirac_h}). Larger angular momentum values are observed at the lowest incident energy. The time hierarchy in the evaporation process and the role of mid-rapidity emission are also discussed.

Optimisation of design parameters for modular range enhanced projectile

OpenAIRE

Jelic, Z

2016-01-01

There is an underpinning requirement for artillery systems to achieve longer range, better precision, and an adequate lethal effect. The main objective of this research is to investigate various methods of range increase and propose optimal solution for range extension of existing artillery systems. The proposed solution is novel, modular projectile design. Several methodologies for projectile range increment (such as improved aerodynamics and ballistic profile) were combined to achieve the "...

Multiplicity distributions of projectile fragments in interactions of nuclei with emulsion at 4.1-4.5 A GeV/c

International Nuclear Information System (INIS)

Fakhraddin, S; Rahim, Magda A

2008-01-01

The results of our systematic studies of projectile fragments (PFs) multiplicity distributions in interactions of 4 He, 12 C, 16 O, 22 Ne and 28 Si with emulsion at 4.1-4.5 A GeV/c are presented in this paper. The mean values for the three different multiplicities of PFs at nearly the same energy are given. The dependence of these mean values on the projectile mass number A p , as well as the dependence of the PFs on target groups (H, CNO and AgBr), has been investigated

Roll Attitude Determination of Spin Projectile Based on GPS and Magnetoresistive Sensor

Directory of Open Access Journals (Sweden)

Dandan Yuan

2017-01-01

Full Text Available Improvement in attack accuracy of the spin projectiles is a very significant objective, which increases the overall combat efficiency of projectiles. The accurate determination of the projectile roll attitude is the recent objective of the efficient guidance and control. The roll measurement system for the spin projectile is commonly based on the magnetoresistive sensor. It is well known that the magnetoresistive sensor produces a sinusoidally oscillating signal whose frequency slowly decays with time, besides the possibility of blind spot. On the other hand, absolute sensors such as GPS have fixed errors even though the update rates are generally low. To earn the benefit while eliminating weaknesses from both types of sensors, a mathematical model using filtering technique can be designed to integrate the magnetoresistive sensor and GPS measurements. In this paper, a mathematical model is developed to integrate the magnetoresistive sensor and GPS measurements in order to get an accurate prediction of projectile roll attitude in a real flight time. The proposed model is verified using numerical simulations, which illustrated that the accuracy of the roll attitude measurement is improved.

Comparing 511 keV Attenuation Maps Obtained from Different Energy Mapping Methods for CT Based Attenuation Correction of PET Data

Directory of Open Access Journals (Sweden)

Maryam Shirmohammad

2008-06-01

Full Text Available Introduction:  The  advent  of  dual-modality  PET/CT  scanners  has  revolutionized  clinical  oncology  by  improving lesion localization and facilitating treatment planning for radiotherapy. In addition, the use of  CT images for CT-based attenuation correction (CTAC decreases the overall scanning time and creates  a noise-free  attenuation  map  (6map.  CTAC  methods  include  scaling,  segmentation,  hybrid  scaling/segmentation, bilinear and dual energy methods. All CTAC methods require the transformation  of CT Hounsfield units (HU to linear attenuation coefficients (LAC at 511 keV. The aim of this study is  to compare the results of implementing different methods of energy mapping in PET/CT scanners.   Materials and Methods: This study was conducted in 2 phases, the first phase in a phantom and the  second  one  on  patient  data.  To  perform  the  first  phase,  a  cylindrical  phantom  with  different  concentrations of K2HPO4 inserts was CT scanned and energy mapping methods were implemented on  it. For performing the second phase, different energy  mapping  methods  were implemented on several  clinical studies and compared to the transmission (TX image derived using Ga-68 radionuclide source  acquired on the GE Discovery LS PET/CT scanner.   Results: An ROI analysis was performed on different positions of the resultant 6maps and the average  6value of each ROI was compared to the reference value. The results of the 6maps obtained for 511 keV  compared to the theoretical  values showed that in the phantom for low  concentrations  of K 2 HPO 4 all  these  methods  produce  511  keV  attenuation  maps  with  small  relative  difference  compared  to  gold  standard. The relative difference for scaling, segmentation, hybrid, bilinear and dual energy methods was  4.92,  3.21,  4.43,  2.24  and  2.29%,  respectively.  Although  for  high  concentration �

Determination of the excitation energy and angular momentum of the quasi-projectiles produced in the heavy ion collisions Xe + Sn

International Nuclear Information System (INIS)

Genouin-Duhamel, Emmanuel

1999-01-01

This work is a contribution to the study of properties of hot nuclei formed in heavy ion collisions at intermediate energies. The experiment has been performed with the INDRA multidetector. It is shown that most of the reaction cross section is associated with binary dissipative collisions, accompanied by the production of particles from a region between the two reaction partners. This study is focussed on excitation energy and angular momentum of projectile-like fragment (PLF) in 129 Xe + nat Sn reactions from 25 to 50 MeV per nucleon. Several methods are used to characterize hot nuclei (velocity, charge, mass and excitation energy). All these methods are compared between them and indicate that high energies are deposited in the nuclei during collision (it may exceed the nucleus binding energy). The angular momentum transferred into intrinsic spin to PLF in the peripheral collisions has been deduced from angular distributions and kinetic energies of the emitted light charged particles (atomic number smaller ar equal to 2). Both methods agree qualitatively. The spin values decrease with the violence of the collision. These values correspond to values averaged over the whole deexcitation chain of nuclei. The predictions of transport models reproduce qualitatively the most peripheral collisions and suggest that high spins are transferred to PLF (from 30 to 50 ℎ). Larger angular momentum values are observed at the lowest incident energy. The time hierarchy in the evaporation process and the role of mid-rapidity emission are also discussed. (author)

Determination of extra trajectory parameters of projectile layout motion

Science.gov (United States)

Ishchenko, A.; Burkin, V.; Faraponov, V.; Korolkov, L.; Maslov, E.; Diachkovskiy, A.; Chupashev, A.; Zykova, A.

2017-11-01

The paper presents a brief description of the experimental track developed and implemented on the base of the RIAMM TSU for external trajectory investigations on determining the main aeroballistic parameters of various shapes projectiles, in the wide velocity range. There is comparison between the experimentally obtained dependence of the fin-stabilized projectile mock-up aerodynamic drag coefficient on the Mach number with the 1958 aerodynamic drag law and aerodynamic tests of the same mock-up

Single electron capture by state-prepared Ar2+ projectiles in Ar

International Nuclear Information System (INIS)

Puerta, J.; Huber, B.A.

1985-03-01

Electron capture by state-selected Ar 2+ projectiles in Ar has been studied at low collision energies ( 2+ ions are measured explaining existing discrepancies of partial and total cross sections in the Ar 2+ /Ar collision system. Although highly excited metastable ions ( 5 D 4 0 , 3 F 4 0 ) represent a minor contamination of a non-prepared Ar 2+ beam (proportional1%), their contributions are found to dominate the capture process due to cross section values larger than 10 -15 cm 2 . (orig.)

Multiplicity of secondary electrons emitted by carbon thin targets by impact of H{sup 0}, H{sub 2}{sup +} and H{sub 3}{sup +} projectiles at MeV energies; Multiplicite des electrons secondaires emis par des cibles minces de carbone sous l`impact de projectiles H{sup 0}, H{sub 2}{sup +} et H{sub 3}{sup +} d`energie de l`ordre du MeV

Energy Technology Data Exchange (ETDEWEB)

Vidovic, Zvonimir [Inst. de Physique Nucleaire, Lyon-1 Univ., 69 - Villeurbanne (France)

1997-06-24

This work focuses on the study of the emission statistics of secondary electrons from thin carbon foils bombarded with H{sup 0}, H{sub 2}{sup +} and H{sub 3}{sup +} projectiles in the 0.25 - 2.2 MeV energy range. The phenomenon of secondary electron emission from solids under the impact of swift ions is mainly due to inelastic interactions with target electrons. Phenomenological and theoretical descriptions as well as a summary of the main theoretical models are the subjects of the first chapter. The experimental set-up used to measure event by event the electron emission of the two faces of the thin carbon foils crossed by an energetic projectile is described in the chapter two. In this chapter there are also presented the method and the algorithms used to process experimental spectra in order to obtain the statistical distribution of the emitted electrons. Chapter three presents the measurements of secondary electron emission induced by H{sup 0} atoms passing through thin carbon foils. The secondary electron yields are studied in correlation with emergent projectile charge state. We show the peculiar role of the projectile electron, whether it remains or not bound to the incident proton. The fourth chapter is dedicated to the secondary electron emission induced by H{sub 2}{sup +} and H{sub 3}{sup +} polyatomic ions. The results are interpreted in terms of collective effects in the interactions of the ions with solids. The role of the proximity of the protons, molecular ions fragments, upon the amplitude of these collected effects is evidenced from the study of the statistics of forward emission. The experiments allowed us to shed light on various aspects of atom and polyatomic ion interactions with solid surfaces. (author) 136 refs., 41 figs., 3 tabs.

Projectile-like fragments from 129Xe+natCu reactions at E/A = 40 MeV

International Nuclear Information System (INIS)

Russ, D.E.; Mignerey, A.C.; Garcia-Solis, E.J.

1996-01-01

The bombarding of heavy nuclei with energetic heavy projectiles has been one of the most important experimental tools for nuclear science. At low beam energies, (E/A) beam 100 MeV, these mean field effects are less important and nucleon-nucleon interactions dominate. Within the intermediate energy region, the situation is less clear because of both the mean field and nucleon-nucleon effects contribute. There is no consensus on the theoretical treatment of nuclear reaction in the intermediate energy regime and statistical, dynamical, and hybrid models have been used with limited success. Previous studies of 136 Xe + 209 Bi at E/A = 28 MeV carried out at Michigan State University (MSU) have been well described by a damped reaction mechanism. On the other hand, 129 Xe + nat Cu at E/A = 50 MeV also at MSU has been compared with a hybrid model with reasonable success. In order to see a transition from a damped reaction mechanism to more fragmentation-like processes, an experiment was carried out at MSU using 129 Xe beams at E/A = 30, 40, 50, and 60 MeV. The targets were Cu, Sc, and Au. The current study only looks at the projectile-like fragments (PLF) detected in the Maryland Forward Array (MFA)

Calculation of forces arising from impacting projectiles upon yielding structures

International Nuclear Information System (INIS)

Drittler, K.; Gruner, P.; Krivy, J.

1977-01-01

Calculations concerning the impact of airplanes upon nuclear power plant buildings usually imply that the building [QUOTE]acts' as a rigid target. This assumption is justified for considerations concerning the structural integrity of the building being hit. However, for investigating induced vibrations of components within the structure, this approach might-in general-be too conservative. It is expected, that yielding of the structure during impact reduces the peak values of the loads and changes the temporal behaviour of the load function which is obtained for a rigid target. To calculate the changes of the load function which are due to deformations of the structure, Riera's method is extended for the case of a yielding target. The calculations are performed with a one-dimensional model for the projectile. The presented model calculations seem to verify that the motion of the target does not have much influence on the impact force for projectiles similar to the model projectile, provided the displacement of the yielding target is small in comparison with the path covered by the free-flying projectile during a time which is equivalent to the total time of impact. (Auth.)

Study on low-energy sputtering near the threshold energy by molecular dynamics simulations

Directory of Open Access Journals (Sweden)

C. Yan

2012-09-01

Full Text Available Using molecular dynamics simulation, we have studied the low-energy sputtering at the energies near the sputtering threshold. Different projectile-target combinations of noble metal atoms (Cu, Ag, Au, Ni, Pd, and Pt are simulated in the range of incident energy from 0.1 to 200 eV. It is found that the threshold energies for sputtering are different for the cases of M1 < M2 and M1 ≥ M2, where M1 and M2 are atomic mass of projectile and target atoms, respectively. The sputtering yields are found to have a linear dependence on the reduced incident energy, but the dependence behaviors are different for the both cases. The two new formulas are suggested to describe the energy dependences of the both cases by fitting the simulation results with the determined threshold energies. With the study on the energy dependences of sticking probabilities and traces of the projectiles and recoils, we propose two different mechanisms to describe the sputtering behavior of low-energy atoms near the threshold energy for the cases of M1 < M2 and M1 ≥ M2, respectively.

Optimization of Construction of the rocket-assisted projectile

Directory of Open Access Journals (Sweden)

Arkhipov Vladimir

2017-01-01

Full Text Available New scheme of the rocket motor of rocket-assisted projectile providing the increase in distance of flight due to controlled and optimal delay time of ignition of the solid-propellant charge of the SRM and increase in reliability of initiation of the SRM by means of the autonomous system of ignition excluding the influence of high pressure gases of the propellant charge in the gun barrel has been considered. Results of the analysis of effectiveness of using of the ignition delay device on motion characteristics of the rocket-assisted projectile has been presented.

Multiplicity distributions of projectile fragments in interactions of nuclei with emulsion at 4.1-4.5 A GeV/c

Energy Technology Data Exchange (ETDEWEB)

Fakhraddin, S; Rahim, Magda A [Physics Department, Faculty of Science, Sana' a University, Republic of Yemen (Yemen)], E-mail: sakinafa1@hotmail.com, E-mail: dr.magda2006@hotmail.com

2008-07-15

The results of our systematic studies of projectile fragments (PFs) multiplicity distributions in interactions of {sup 4}He, {sup 12}C, {sup 16}O, {sup 22}Ne and {sup 28}Si with emulsion at 4.1-4.5 A GeV/c are presented in this paper. The mean values for the three different multiplicities of PFs at nearly the same energy are given. The dependence of these mean values on the projectile mass number A{sub p}, as well as the dependence of the PFs on target groups (H, CNO and AgBr), has been investigated.

Calculation of high-dimensional fission-fusion potential-energy surfaces in the SHE region

International Nuclear Information System (INIS)

Moeller, Peter; Sierk, Arnold J.; Ichikawa, Takatoshi; Iwamoto, Akira

2004-01-01

We calculate in a macroscopic-microscopic model fission-fusion potential-energy surfaces relevant to the analysis of heavy-ion reactions employed to form heavy-element evaporation residues. We study these multidimensional potential-energy surfaces both inside and outside the touching point.Inside the point of contact we define the potential on a multi-million-point grid in 5D deformation space where elongation, merging projectile and target spheroidal shapes, neck radius and projectile/target mass asymmetry are independent shape variables. The same deformation space and the corresponding potential-energy surface also describe the shape evolution from the nuclear ground-state to separating fragments in fission, and the fast-fission trajectories in incomplete fusion.For separated nuclei we study the macroscopic-microscopic potential energy, that is the ''collision surface'' between a spheroidally deformed target and a spheroidally deformed projectile as a function of three coordinates which are: the relative location of the projectile center-of-mass with respect to the target center-of-mass and the spheroidal deformations of the target and the projectile. We limit our study to the most favorable relative positions of target and projectile, namely that the symmetry axes of the target and projectile are collinear

Projectile Aerodynamic Jump Due to Lateral Impulsives

National Research Council Canada - National Science Library

Cooper, Gene

2003-01-01

.... The formulation shows for sufficiently long-range target interception; lateral impulse trajectory response for a guided projectile is independent of when the impulse is activated during the yaw cycle...

Earliest stone-tipped projectiles from the Ethiopian rift date to >279,000 years ago.

Science.gov (United States)

Sahle, Yonatan; Hutchings, W Karl; Braun, David R; Sealy, Judith C; Morgan, Leah E; Negash, Agazi; Atnafu, Balemwal

2013-01-01

Projectile weapons (i.e. those delivered from a distance) enhanced prehistoric hunting efficiency by enabling higher impact delivery and hunting of a broader range of animals while reducing confrontations with dangerous prey species. Projectiles therefore provided a significant advantage over thrusting spears. Composite projectile technologies are considered indicative of complex behavior and pivotal to the successful spread of Homo sapiens. Direct evidence for such projectiles is thus far unknown from >80,000 years ago. Data from velocity-dependent microfracture features, diagnostic damage patterns, and artifact shape reported here indicate that pointed stone artifacts from Ethiopia were used as projectile weapons (in the form of hafted javelin tips) as early as >279,000 years ago. In combination with the existing archaeological, fossil and genetic evidence, these data isolate eastern Africa as a source of modern cultures and biology.

Earliest stone-tipped projectiles from the Ethiopian rift date to >279,000 years ago.

Directory of Open Access Journals (Sweden)

Yonatan Sahle

Full Text Available Projectile weapons (i.e. those delivered from a distance enhanced prehistoric hunting efficiency by enabling higher impact delivery and hunting of a broader range of animals while reducing confrontations with dangerous prey species. Projectiles therefore provided a significant advantage over thrusting spears. Composite projectile technologies are considered indicative of complex behavior and pivotal to the successful spread of Homo sapiens. Direct evidence for such projectiles is thus far unknown from >80,000 years ago. Data from velocity-dependent microfracture features, diagnostic damage patterns, and artifact shape reported here indicate that pointed stone artifacts from Ethiopia were used as projectile weapons (in the form of hafted javelin tips as early as >279,000 years ago. In combination with the existing archaeological, fossil and genetic evidence, these data isolate eastern Africa as a source of modern cultures and biology.

Multifragmentation of gold nuclei interacting with photoemulsion nuclei at an energy of 10.7 GeV per projectile nucleon

International Nuclear Information System (INIS)

Gulamov, K.G.; Navotny, V.Sh.; Uzhinskii, V.V.

1999-01-01

Experimental data on the distributions of fragments with respect to the bound charge (Z bound , Z b3 ) and with respect to the multiplicities and on their correlations are presented. These data are compared with analogous data at 600 MeV per projectile nucleon that were obtained at the ALADIN facility. It has been shown that the processes of gold-nucleus multifragmentation at intermediate and high energies have some common features. At the same time, the multiplicity of medium-mass fragments becomes somewhat less at high energies. Data presented in this study are analyzed within the framework combining the statistical model of nuclear multifragmentation with the Regge model of the breakup of nuclei. This combined model has been shown to reproduce qualitatively the experimental results under discussion. The most pronounced discrepancies have been observed for the yields of doubly charged fragments. The transverse momenta of fragments have been analyzed as functions of the bound charge Z bound . It has been demonstrated that the model underestimates considerably the transverse momenta of fragments. This is interpreted as evidence for a strong radial flow of spectator fragments

A Mass Loss Penetration Model to Investigate the Dynamic Response of a Projectile Penetrating Concrete considering Mass Abrasion

Directory of Open Access Journals (Sweden)

NianSong Zhang

2015-01-01

Full Text Available A study on the dynamic response of a projectile penetrating concrete is conducted. The evolutional process of projectile mass loss and the effect of mass loss on penetration resistance are investigated using theoretical methods. A projectile penetration model considering projectile mass loss is established in three stages, namely, cratering phase, mass loss penetration phase, and remainder rigid projectile penetration phase.

Antiscreening mode of projectile-electron loss

International Nuclear Information System (INIS)

Montanari, C.C.; Miraglia, J.E.; Arista, N.R.

2003-01-01

The inelastic contribution of target electrons to different electronic processes in the projectile is obtained by employing the local-density approximation as usually applied in the dielectric formalism. Projectile-electron-loss cross sections due to the electron-electron interaction are calculated and compared with those obtained by using atomic antiscreening theories. We also calculate ionization cross sections and stopping power for bare ions impinging on different gases. The good agreement with the experimental data and the simplicity of the local-density approximation make it an efficient method for describing inelastic processes of gaseous target electrons. It is expected to be useful for targets with large atomic number. In this case, the number of possible final states to be considered by the traditional atomic methods makes it a tough task to be tackled. On the contrary, the more electrons the target has, the better the local plasma approximation is expected to be

Evaluating the risk of eye injuries: intraocular pressure during high speed projectile impacts.

Science.gov (United States)

Duma, Stefan M; Bisplinghoff, Jill A; Senge, Danielle M; McNally, Craig; Alphonse, Vanessa D

2012-01-01

To evaluate the risk of eye injuries by determining intraocular pressure during high speed projectile impacts. A pneumatic cannon was used to impact eyes with a variety of projectiles at multiple velocities. Intraocular pressure was measured with a small pressure sensor inserted through the optic nerve. A total of 36 tests were performed on 12 porcine eyes with a range of velocities between 6.2 m/s and 66.5 m/s. Projectiles selected for the test series included a 6.35  mm diameter metal ball, a 9.25  mm diameter aluminum rod, and an 11.16  mm diameter aluminum rod. Experiments were designed with velocities in the range of projectile consumer products such as toy guns. A range of intraocular pressures ranged between 2017 mmHg to 26,426 mmHg (39 psi-511 psi). Four of the 36 impacts resulted in globe rupture. Intraocular pressures dramatically above normal physiological pressure were observed for high speed projectile impacts. These pressure data provide critical insight to chronic ocular injuries and long-term complications such as glaucoma and cataracts.

On the nuclear fragmentation mechanisms in nuclear collisions at intermediate and high energies

International Nuclear Information System (INIS)

Jipa, Al; Besliu, C.; Felea, D.

2004-01-01

The nuclear fragmentation mechanisms can be discussed by taking into account different scales related to the fragment sizes. Considering two fragmentation mechanisms of the nuclei at the same incident energy an analysis of the experimental results obtained was done. Goldhaber formula was improved by analyzing the discrepancies between data and theories concerning the projectile fragmentation. We implied that the projectile fragmentation process would be governed by the distribution of nucleon momenta in the projectile after the collision occurred. We used in our analysis protons from the 4 He + 7 Li at 4.5 GeV/c per nucleon incident momentum, as well as from 40 Ar + 12 C at 213 AMeV bombarding energy. We proved that in order to proceed in analyzing the projectile fragmentation process at intermediate and high energies one has to consider the dependence σ 0 on the apparent temperature of projectile nucleus after the collision took place. The generalized Bertsch correction for light projectile nuclei and fragments was used and the number of spatial correlations between identical nucleons having anticorrelated momenta was found. Thus we found apparent temperature values close to the separation energies of the considered fragments per number of fragments. The temperatures associated to kinetic energy spectra of the projectile fragments were calculated following two methods. The results from Bauer's method were compared with those obtained by fitting the kinetic energy distributions of the projectile fragments in the rest frame of the projectile with a Maxwellian curve. We also accomplished the comparison of the experimental results with similar events simulated with RQMD 2.4. All the results obtained suggested two nuclear fragmentation mechanisms: a sudden fragmentation by explosive mechanisms, like shock waves and a slow fragmentation by the 'fission' of the spectator regions, mainly because of the interactions with the particles or fragments emitted from the

Classical gluon production amplitude for nucleus-nucleus collisions:First saturation correction in the projectile

International Nuclear Information System (INIS)

Chirilli, Giovanni A.; Kovchegov, Yuri V.; Wertepny, Douglas E.

2015-01-01

We calculate the classical single-gluon production amplitude in nucleus-nucleus collisions including the first saturation correction in one of the nuclei (the projectile) while keeping multiple-rescattering (saturation) corrections to all orders in the other nucleus (the target). In our approximation only two nucleons interact in the projectile nucleus: the single-gluon production amplitude we calculate is order-g"3 and is leading-order in the atomic number of the projectile, while resumming all order-one saturation corrections in the target nucleus. Our result is the first step towards obtaining an analytic expression for the first projectile saturation correction to the gluon production cross section in nucleus-nucleus collisions.

Projectile X-ray emission in relativistic ion-atom collisions

Energy Technology Data Exchange (ETDEWEB)

Salem, Shadi Mohammad Ibrahim

2010-03-16

This work reports on the study of the projectile X-ray emission in relativistic ion-atom collisions. Excitation of K-shell in He-like uranium ions, electron capture into H-like uranium ions and Simultaneous ionization and excitation of initially He-like uranium ions have been studied using the experimental storage ring at GSI. For the K{sub {alpha}}{sub 1} and K{sub {alpha}}{sub 2} transitions originating from the excitation of the He-like uranium ions, no alignment was observed. In contrast, the Ly{sub {alpha}}{sub 1} radiation from the simultaneous ionization-excitation process of the He-like uranium ions shows a clear alignment. The experimental value leads to the inclusion of a magnetic term in the interaction potential. The capture process of target electrons into the highly-charged heavy ions was studied using H-like uranium ions at an incident energy of 220 MeV/u, impinging on N{sub 2} gas-target. It was shown that, the strongly aligned electrons captured in 2p{sub 3/2} level couple with the available 1s{sub 1/2} electron which shows no initial directional preference. The magnetic sub-state population of the 2p{sub 3/2} electron is redistributed according to the coupling rules to the magnetic sub-states of the relevant two-electron states. This leads to the large anisotropy in the corresponding individual ground state transitions contributing to the K{sub {alpha}}{sub 1} emission. From the K{sub {alpha}}{sub 1}/K{sub {alpha}}{sub 2} ratio, the current results show that the incoherent addition of the E1 and M2 transition components yield to an almost isotropic emission of the total K{sub {alpha}}{sub 1}. In contrast to the radiative electron capture, the experimental results for the K-shell single excitation of He-like uranium ions indicate that only the {sup 1}P{sub 1} level contributes to the K{sub {alpha}}{sub 1} transition. For this case, the anisotropy parameter {beta}{sub 20} was found to be -0.20{+-}0.03. This work also reports on the study of a two

Scattering of mass-3 projectiles from heavy nuclei

International Nuclear Information System (INIS)

Mukhopadyay, S.; Srivastava, D.K.; Ganguly, N.K.

1976-01-01

The interaction between heavy ions is a subject of great interest. It is well known that α-particle scattering shows most of the features which are observed in heavy ion scattering. In as much as mass-3 system is intermediate between heavy and light particles it will be interesting to investigate the scattering of mass-3 projectiles to see if it is possible to extend it to study the heavy ion scattering. Indeed; it has been seen that the 'molecular type' potentials, with a soft repulsive core and a shallow attractive well used for heavy ion collisions can be used to fit the elastic scattering data of mass-3 projectiles also. In the first part of this paper, a description is given of how this potential is generated with a special emphasis on saturation and second order effect through a density dependent interaction between nucleon and mass-3 projectiles. In the second part it is shown that the asymmetry dependence observed in the potential describing the scattering of mass-3 particles from heavier nuclei actually originates from the isospin interaction, when triton and helion are treated as two members of an isospin doublet. (Auth.)

Attenuation coefficients of soils and some building materials of Bangladesh in the energy range 276-1332 keV

International Nuclear Information System (INIS)

Alam, M.N.; Miah, M.M.H.; Chowdhury, M.I.; Kamal, M.; Ghose, S.; Rahman, Runi

2001-01-01

The linear and mass attenuation coefficients of different types of soil, sand, building materials and heavy beach mineral samples from the Chittagong and Cox's Bazar area of Bangladesh were measured using a high-resolution HPGe detector and the γ-ray energies 276.1, 302.8, 356.0, 383.8, 661.6 and 1173.2 and 1332.5 keV emitted from point sources of 133 Ba, 137 Cs and 60 Co, respectively. The linear attenuation coefficients show a linear relationship with the corresponding densities of the samples studied. The variations of the mass attenuation coefficient with γ-ray energy were exponential in nature. The measured mass attenuation coefficient values were compared with measurements made in other countries for similar kinds of materials. The values are in good agreement with each other in most cases

Dispersion Analysis of the XM881APFSDS Projectile

Directory of Open Access Journals (Sweden)

Thomas F. Erline

2001-01-01

Full Text Available This study compares the results of a dispersion test with mathematical modeling. A 10-round group of modified 25-mm XM881 Armor Piercing Fin Stabilized Discarding Sabot projectiles was fired from the M242 chain gun into a designated target. The mathematical modeling results come from BALANS, a product of Arrow Tech Associates. BALANS is a finite-element lumped parameter code that has the capability to model a flexible projectile being fired from a flexible gun. It also has the unique feature of an automated statistical evaluation of dispersion. This study represents an effort to evaluate a simulation approach with experiment.

Decay analysis of compound nuclei formed in reactions with exotic neutron-rich 9Li projectile and the synthesis of 217At* within the dynamical cluster-decay model

Science.gov (United States)

Kaur, Arshdeep; Kaushal, Pooja; Hemdeep; Gupta, Raj K.

2018-01-01

The decay of various compound nuclei formed via exotic neutron-rich 9Li projectile is studied within the dynamical cluster-decay model (DCM). Following the earlier work of one of us (RKG) and collaborators (M. Kaur et al. (2015) [1]), for an empirically fixed neck-length parameter ΔRemp, the only parameter in the DCM, at a given incident laboratory energy ELab, we are able to fit almost exactly the (total) fusion cross section σfus =∑x=16σxn for 9Li projectile on 208Pb and other targets, with σfus depending strongly on the target mass of the most abundant isotope and its (magic) shell structure. This result shows the predictable nature of the DCM. The neck-length parameter ΔRemp is fixed empirically for the decay of 217At* formed in 9Li + 208Pb reaction at a fixed laboratory energy ELab, and then the total fusion cross section σfus calculated for all other reactions using 9Li as a projectile on different targets. Apparently, this procedure could be used to predict σfus for 9Li-induced reactions where experimental data are not available. Furthermore, optimum choice of "cold" target-projectile combinations, forming "hot" compact configurations, are predicted for the synthesis of compound nucleus 217At* with 8Li + 209Pb as one of the target-projectile combination, or another (t , p) combination 48Ca + 169Tb, with a doubly magic 48Ca, as the best possibility.

Maximizing the Range of a Projectile.

Science.gov (United States)

Brown, Ronald A.

1992-01-01

Discusses solutions to the problem of maximizing the range of a projectile. Presents three references that solve the problem with and without the use of calculus. Offers a fourth solution suitable for introductory physics courses that relies more on trigonometry and the geometry of the problem. (MDH)

Fatal lawn mower related projectile injury

DEFF Research Database (Denmark)

Colville-Ebeling, Bonnie; Lynnerup, Niels; Banner, Jytte

2014-01-01

was initially overlooked, later interpreted as a possible gunshot homicide, and finally identified as a lawn mower related projectile injury when autopsy revealed a piece of metal thread in the main bronchus to the right middle lobe, hemopericardium, and right-sided hemothorax. To our knowledge, this injury...

Effect of Projectile Materials on Foreign Object Damage of a Gas-Turbine Grade Silicon Nitride

Science.gov (United States)

Choi, Sung R.; Racz, Zsolt; Bhatt, Ramakrishna T.; Brewer, David N.; Gyekenyesi, John P.

2005-01-01

Foreign object damage (FOD) behavior of AS800 silicon nitride was determined using four different projectile materials at ambient temperature. The target test specimens rigidly supported were impacted at their centers by spherical projectiles with a diameter of 1.59 mm. Four different types of projectiles were used including hardened steel balls, annealed steel balls, silicon nitride balls, and brass balls. Post-impact strength of each target specimen impacted was determined as a function of impact velocity to better understand the severity of local impact damage. The critical impact velocity where target specimens fail upon impact was highest with brass balls, lowest with ceramic ball, and intermediate with annealed and hardened steel balls. Degree of strength degradation upon impact followed the same order as in the critical impact velocity with respect to projectile materials. For steel balls, hardened projectiles yielded more significant impact damage than annealed counterparts. The most important material parameter affecting FOD was identified as hardness of projectiles and was correlated in terms of critical impact velocity, impact deformation, and impact load.

Evolution of the nucleus-nucleus interaction in the transition energy region

International Nuclear Information System (INIS)

Harar, S.

1984-05-01

How the reaction mechanisms behave with projectile mass and energy. What are the limits of the complete fusion. Can we heat the nuclear matter up to the boiling point. At what energy the projectile fragmentation require occurs

Subthreshold pion production of 20-100 MeV energy with various projectiles (p, 3He, 12C, 16O)

International Nuclear Information System (INIS)

Sanouillet, G.; Bolore, M.; Charlot, X.

1986-05-01

The described experiments refer to pion production below and near the threshold with different projectiles (p, 3 He, 12 C, 16 O). The pion detection device was a range telescope. Experimental methods are presented and discussed. Data are compared to predictions of some models [fr

Investigation of Energy Absorption in Aluminum Foam Sandwich Panels By Drop Hammer Test: Experimental Results

Directory of Open Access Journals (Sweden)

Mohammad Nouri Damghani

2016-05-01

Full Text Available The sandwich panel structures with aluminum foam core and metal surfaces have light weight with high performance in dispersing energy. This has led to their widespread use in the absorption of energy. The cell structure of foam core is subjected to plastic deformation in the constant tension level that absorbs a lot of kinetic energy before destruction of the structure. In this research, by making samples of aluminum foam core sandwich panels with aluminum surfaces, experimental tests of low velocity impact by a drop machine are performed for different velocities and weights of projectile on samples of sandwich panels with aluminum foam core with relative density of 18%, 23%, and 27%. The output of device is acceleration‐time diagram which is shown by an accelerometer located on the projectile. From the experimental tests, the effect of weight, velocity and energy of the projectile and density of the foam on the global deformation, and energy decrease rate of projectile have been studied. The results of the experimental testes show that by increasing the density of aluminum foam, the overall impression is reduced and the slop of energy loss of projectile increases. Also by increasing the velocity of the projectile, the energy loss increases.

Charge dependence of one and two electron processes in collisions between hydrogen molecules and fast projectiles

International Nuclear Information System (INIS)

Wells, E.; Ben-Itzhak, I.; Carnes, K.D.; Krishnamurthi, V.

1996-01-01

The ratio of double- to single-ionization (DI/SI) as well as the ratio of ionization-excitation to single-ionization (IE/SI) in hydrogen molecules was studied by examining the effect of the projectile charge on these processes. The DI/SI and IE/SI ratios were measured using the coincidence time of flight technique at a fixed velocity (1 MeV/amu) over a range of projectile charge states (q = 1-9,14,20). Preliminary results indicate that for a highly charged F 9+ projectile the DI/SI and IE/SI ratios are 6.8% and 24.7%, respectively, a large increase from the ratios of 0.13% and 1.95%, respectively, for H + projectiles. For low charge states, the DI/SI is negligible relative to the IE/SI ratio, while for more highly charged projectiles the DI/SI ratio becomes comparable to the IE/SI ratio. This indicates that double-ionization increases much more rapidly with projectile charge than ionization-excitation

Accuracy Improvement Capability of Advanced Projectile Based on Course Correction Fuze Concept

Directory of Open Access Journals (Sweden)

Ahmed Elsaadany

2014-01-01

Full Text Available Improvement in terminal accuracy is an important objective for future artillery projectiles. Generally it is often associated with range extension. Various concepts and modifications are proposed to correct the range and drift of artillery projectile like course correction fuze. The course correction fuze concepts could provide an attractive and cost-effective solution for munitions accuracy improvement. In this paper, the trajectory correction has been obtained using two kinds of course correction modules, one is devoted to range correction (drag ring brake and the second is devoted to drift correction (canard based-correction fuze. The course correction modules have been characterized by aerodynamic computations and flight dynamic investigations in order to analyze the effects on deflection of the projectile aerodynamic parameters. The simulation results show that the impact accuracy of a conventional projectile using these course correction modules can be improved. The drag ring brake is found to be highly capable for range correction. The deploying of the drag brake in early stage of trajectory results in large range correction. The correction occasion time can be predefined depending on required correction of range. On the other hand, the canard based-correction fuze is found to have a higher effect on the projectile drift by modifying its roll rate. In addition, the canard extension induces a high-frequency incidence angle as canards reciprocate at the roll motion.

Accuracy improvement capability of advanced projectile based on course correction fuze concept.

Science.gov (United States)

Elsaadany, Ahmed; Wen-jun, Yi

2014-01-01

Improvement in terminal accuracy is an important objective for future artillery projectiles. Generally it is often associated with range extension. Various concepts and modifications are proposed to correct the range and drift of artillery projectile like course correction fuze. The course correction fuze concepts could provide an attractive and cost-effective solution for munitions accuracy improvement. In this paper, the trajectory correction has been obtained using two kinds of course correction modules, one is devoted to range correction (drag ring brake) and the second is devoted to drift correction (canard based-correction fuze). The course correction modules have been characterized by aerodynamic computations and flight dynamic investigations in order to analyze the effects on deflection of the projectile aerodynamic parameters. The simulation results show that the impact accuracy of a conventional projectile using these course correction modules can be improved. The drag ring brake is found to be highly capable for range correction. The deploying of the drag brake in early stage of trajectory results in large range correction. The correction occasion time can be predefined depending on required correction of range. On the other hand, the canard based-correction fuze is found to have a higher effect on the projectile drift by modifying its roll rate. In addition, the canard extension induces a high-frequency incidence angle as canards reciprocate at the roll motion.

Fragmentation of armor piercing steel projectiles upon oblique perforation of steel plates

Directory of Open Access Journals (Sweden)

Aizik F.

2012-08-01

Full Text Available In this study, a constitutive strength and failure model for a steel core of a14.5 mm API projectile was developed. Dynamic response of a projectile steel core was described by the Johnson-Cook constitutive model combined with principal tensile stress spall model. In order to obtain the parameters required for numerical description of projectile core material behavior, a series of planar impact experiments was done. The parameters of the Johnson-Cook constitutive model were extracted by matching simulated and experimental velocity profiles of planar impact. A series of oblique ballistic experiments with x-ray monitoring was carried out to study the effect of obliquity angle and armor steel plate thickness on shattering behavior of the 14.5 mm API projectile. According to analysis of x-ray images the fragmentation level increases with both steel plate thickness and angle of inclination. The numerical modeling of the ballistic experiments was done using commercial finite element code, LS-DYNA. Dynamic response of high hardness (HH armor steel was described using a modified Johnson-Cook strength and failure model. A series of simulations with various values of maximal principal tensile stress was run in order to capture the overall fracture behavior of the projectile’s core. Reasonable agreement between simulated and x-ray failure pattern of projectile core has been observed.

Computational Simulation of High-Speed Projectiles in Air, Water, and Sand

Science.gov (United States)

2007-12-03

Supercavitating projectiles can be used for underwater mine neutralization, beach and surf zone mine clearance, littoral ASW, and neutralizing combat...swimmer systems. The water entry phase of flight is interesting and challenging due to projectile transitioning from flight in air to supercavitating ...is formed. Neaves and Edwards [1] simulated this case using a supercavitation code developed at NSWC-PC. The results presented are in good agreement

Simulation of the flow past a long-range artillery projectile

OpenAIRE

Kaurinkoski, Petri

2000-01-01

In this work, an eddy breakup model for chemical reactions is implemented to an existing multi-block Navier-Stokes solver, which is then used to solve the flow past a supersonic long-range base-bleed projectile. The new scheme is validated by simulating an axisymmetric bluff-body stabilized flame, which has been measured in a wind tunnel and simulated numerically by other work groups. Comparison of the numerical results for the projectile shows the importance of the chemistry modelling fo...

Measurements of recoil and projectile momentum distributions for 19-MeV F9+ + Ne collisions

International Nuclear Information System (INIS)

Frohne, V.; Cheng, S.; Ali, R.M.; Raphaelian, M.L.; Cocke, C.L.; Olson, R.

1996-01-01

The collision system of 19-MeV F 9+ on Ne has been studied using recoil and projectile momentum spectroscopy. For each event, identified by final recoil and projectile charge state, the three-dimensional momentum vector of the recoil ion and the transverse momentum vector of the projectile ion were measured. The transverse momenta of the recoil and projectile ions were found to be equal in magnitude and opposite in direction, indicating that the transverse momentum exchange is dominated by interactions between the two ion cores. The transverse momentum distributions are well described by nCTMC calculations. The longitudinal momentum distributions of the recoil ions show that a large fraction of the momentum transferred to the projectile is carried off by continuum electrons. The recoil ions are scattered slightly backward, in partial agreement with predictions of nCTMC calculations. copyright 1996 The American Physical Society

Dual-energy attenuation coefficient decomposition with differential filtration and application to a microCT scanner

International Nuclear Information System (INIS)

Taschereau, R; Silverman, R W; Chatziioannou, A F

2010-01-01

Dual-energy x-ray computed tomography (DECT) has the capability to decompose attenuation coefficients using two basis functions and has proved its potential in reducing beam-hardening artifacts from reconstructed images. The method typically involves two successive scans with different x-ray tube voltage settings. This work proposes an approach to dual-energy imaging through x-ray beam filtration that requires only one scan and a single tube voltage setting. It has been implemented in a preclinical microCT tomograph with minor modifications. Retrofitting of the microCT scanner involved the addition of an automated filter wheel and modifications to the acquisition and reconstruction software. Results show that beam-hardening artifacts are reduced to noise level. Acquisition of a μ-Compton image is well suited for attenuation-correction of PET images while dynamic energy selection (4D viewing) offers flexibility in image viewing by adjusting contrast and noise levels to suit the task at hand. All dual-energy and single energy reference scans were acquired at the same soft tissue dose level of 50 mGy.

Dual-energy attenuation coefficient decomposition with differential filtration and application to a microCT scanner

Energy Technology Data Exchange (ETDEWEB)

Taschereau, R; Silverman, R W; Chatziioannou, A F [Crump Institute for Molecular Imaging, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095 (United States)], E-mail: rtaschereau@mednet.ucla.edu

2010-02-21

Dual-energy x-ray computed tomography (DECT) has the capability to decompose attenuation coefficients using two basis functions and has proved its potential in reducing beam-hardening artifacts from reconstructed images. The method typically involves two successive scans with different x-ray tube voltage settings. This work proposes an approach to dual-energy imaging through x-ray beam filtration that requires only one scan and a single tube voltage setting. It has been implemented in a preclinical microCT tomograph with minor modifications. Retrofitting of the microCT scanner involved the addition of an automated filter wheel and modifications to the acquisition and reconstruction software. Results show that beam-hardening artifacts are reduced to noise level. Acquisition of a {mu}-Compton image is well suited for attenuation-correction of PET images while dynamic energy selection (4D viewing) offers flexibility in image viewing by adjusting contrast and noise levels to suit the task at hand. All dual-energy and single energy reference scans were acquired at the same soft tissue dose level of 50 mGy.

Collisions of polyatomic ions with surfaces: incident energy partitioning and chemical reactions

International Nuclear Information System (INIS)

Zabka, J.; Roithova, J.; Dolejsek, Z.; Herman, Z.

2002-01-01

Collision of polyatomic ions with surfaces were investigated in ion-surface scattering experiments to obtain more information on energy partitioning in ion-surface collision and on chemical reactions at surfaces. Mass spectra, translation energy and angular distributions of product ions were measured in dependence on the incident energy and the incident angle of polyatomic projectiles. From these data distributions of energy fractions resulting in internal excitation of the projectile, translation energy of the product ions, and energy absorbed by the surface were determined. The surface investigated were a standard stainless steel surface, covered by hydrocarbons, carbon surfaces at room and elevated temperatures, and several surfaces covered by a self-assembled monolayers (C 12 -hydrocarbon SAM, C 11 -perfluorohydrocarbon SAM, and C 11 hydrocarbon with terminal -COOH group SAM). The main processes observed at collision energies of 10 - 50 eV were: neutralization of the ions at surfaces, inelastic scattering and dissociations of the projectile ions, quasi elastic scattering of the projectile ions, and chemical reactions with the surface material (usually hydrogen-atom transfer reactions). The ion survival factor was estimated to be a few percent for even-electron ions (like protonated ethanol ion, C 2 H 5 O + , CD 5 + ) and about 10 - 10 2 times lower for radical ions (like ethanol and benzene molecular ions, CD 4 + ). In the polyatomic ion -surface energy transfer experiments, the ethanol molecular ion was used as a well-characterized projectile ion. The results with most of the surfaces studied showed in the collision energy range of 13 - 32 eV that most collisions were strongly inelastic with about 6 - 8 % of the incident projectile energy transformed into internal excitation of the projectile (independent of the incident angle) and led partially to its further dissociation in a unimolecular way after the interaction with the surface. The incident energy

High energy collisions of nuclei: experiments

International Nuclear Information System (INIS)

Heckman, H.H.

1977-09-01

Heavy-ion nuclear reactions with projectile energies up to 2.1 GeV/A are reviewed. The concept of ''rapidity'' is elucidated, and the reactions discussed are divided into sections dealing with target fragmentation, projectile fragmentation, and the intermediate region, with emphasis on the production of light nuclei in high-energy heavy-ion collisions. Target fragmentation experiments using nuclear emulsion and AgCl visual track detectors are also summarized. 18 figures

Projectile fragmentation processes in 35-MeV/amu (α,xy) reactions

International Nuclear Information System (INIS)

Koontz, R.W.; Chang, C.C.; Holmgren, H.D.; Wu, J.R.

1979-01-01

Coincidence measurements with 35-MeV/amu α particles show that at least three projectile-fragmentation processes occur. The dominant process is ''absorptive'' breakup, where one component of the projectile interacts strongly with the target resulting in the emission of evaporation or nonstatistical particles while the other component behaves as a spectator. The other fragmentation processes which are observed account for only a few percent of the breakup cross section

Experimental study of the penetrating of plates by projectile at low initial speeds

Science.gov (United States)

Orlov, M. Yu; Orlova, Yu N.; Smakotin, Ig L.; Glazyrin, V. P.; Orlov, Yu N.

2017-11-01

The research of the penetration process of lightweight plates by a projectile in the range of initial velocities up to 325 m/s was attempted. The projectile was a shell bullet and the barriers were of ice, MDF-panels and plexiglas barriers. The response of barriers to impact loading is studied. High-speed shooting of each experiment is obtained, including photos of the front and rear sides of the barriers. An attempt was made to reproduce the scenario of the destruction of barriers. The results of experiments can be interpreted only as qualitative tests. Projectile was not destroyed.

Charge correlations in the breakup of gold projectiles in reactions at E/A=600 MeV

International Nuclear Information System (INIS)

Kreutz, P.

1992-09-01

In the present thesis the charge correlations in the breakup of gold projectiles in heavy ion collisions at an incident energy of E/A=600 MeV were studied. Thereby it has been proved that the sum of the charges from the projectile source under exclusion of the protons (Z bound ) is saliently suited for the classification of the nuclear reactions. At large values of Z bound we fins fission and spallation reactions. For smaller values of Z bound we observe events with an increasing number of medium-heavy fragments. Thereby the multifragment events appear in the Dalitz diagrams as a continuation of more symmetric becoming spallation events. In reactions with Z bound ≅ 35 the conditions for the formation of medium-heavy fragments are optimal and the multifragment events represent the dominating exit channel. A mean multiplicity of the medium-heavy fragments of ≅ 4 is reached. (orig./HSI) [de

Ballistics considerations for small-caliber, low-density projectiles

International Nuclear Information System (INIS)

Gouge, M.J.; Baylor, L.R.; Combs, S.K.; Fisher, P.W.; Foster, C.A.; Foust, C.R.; Milora, S.L.; Qualls, A.L.

1993-01-01

One major application for single- and two-stage light gas guns is for fueling magnetic fusion confinement devices. Powder guns are not a feasible alternative due to possible plasma contamination by residual powder gases and the eventual requirement of steady-state operation at ∼ 1 Hz, which will dictate a closed gas handling system where propellant gases are recovered, processed and recompressed. Interior ballistic calculations for single-stage light gas guns, both analytical and numerical, are compared to an extensive data base for low density hydrogenic projectiles (pellets). Some innovative range diagnostics are described for determining the size and velocity of these small (several mm) size projectiles. A conceptual design of a closed cycle propellant gas system is presented including tradeoffs between different light propellant gases

Extended Range of a Gun Launched Smart Projectile Using Controllable Canards

Directory of Open Access Journals (Sweden)

Mark Costello

2001-01-01

Full Text Available This effort investigates the extent to which moveable canards can extend the range of indirect fire munitions using both projectile body and canard lift. Implications on terminal velocity and time of flight using this mechanism to extend range are examined for various canard configurations. Performance predictions are conducted using a six-degree-of-freedom simulation model that has previously been validated against range data. The projectile dynamic equations are formed in the body frame and aerodynamic loads from the body and canards are Mach number and angle of attack dependent. The projectile body aerodynamic moments include unsteady aerodynamic damping. The focus of the study is directed toward low cost competent munitions that extend range and as such a simple flight control system is considered which utilizes only timer, roll rate, and roll attitude inputs.

Experimental study of hydraulic ram effects on a liquid storage tank: Analysis of overpressure and cavitation induced by a high-speed projectile.

Science.gov (United States)

Lecysyn, Nicolas; Bony-Dandrieux, Aurélia; Aprin, Laurent; Heymes, Frédéric; Slangen, Pierre; Dusserre, Gilles; Munier, Laurent; Le Gallic, Christian

2010-06-15

This work is part of a project for evaluating catastrophic tank failures caused by impacts with a high-speed solid body. Previous studies on shock overpressure and drag events have provided analytical predictions, but they are not sufficient to explain ejection of liquid from the tank. This study focuses on the hydrodynamic behavior of the liquid after collision to explain subsequent ejection of liquid. The study is characterized by use of high-velocity projectiles and analysis of projectile dynamics in terms of energy loss to tank contents. New tests were performed at two projectile velocities (963 and 1255 m s(-1)) and over a range of viscosities (from 1 to 23.66 mPa s) of the target liquid. Based on data obtained from a high-speed video recorder, a phenomenological description is proposed for the evolution of intense pressure waves and cavitation in the target liquids. Copyright 2010 Elsevier B.V. All rights reserved.

Effects of breakup of weakly bound projectile and neutron transfer on fusion reactions around Coulomb barrier

International Nuclear Information System (INIS)

Lin, C.J.; Zhang, H.Q.; Yang, F.; Ruan, M.; Liu, Z.H.; Wu, Y.W.; Wu, X.K.; Zhou, P.; Zhang, C.L.; Zhang, G.L.; An, G.P.; Jia, H.M.; Xu, X.X.

2007-01-01

The excitation functions of quasielastic and elastic scattering at backward angles have been measured for the systems of 16 O+ 152 Sm, 6,7 Li+ 208 Pb and 32 S+ 90,96 Zr. The barrier distributions are extracted from these measured excitation functions and compared with the corresponding fusion barrier distributions. Except some details, the barrier distributions derived from the data of fusion and quasielastic/elastic scattering are almost the same for the tightly bound reaction systems. For the reaction systems with weakly bound projectile, the barrier distributions extracted from quasielastic scattering are obviously different from the fusion barrier distributions. However, the barrier distributions extracted from the excitation functions of the quasielastic scattering plus breakup are almost the same as the one extracted from the complete fusion data. This result means that barrier distribution not only bears the information of nuclear structures but also contains the knowledge of reaction mechanisms. Our results show that the complete fusion of the weakly bound projectile with heavy target is suppressed at the above barrier energies as compared with the model predictions. In addition, the measured barrier distribution of 32 S+ 96 Zr is broaden and extends to lower energy than in the case of 32 S+ 90 Zr due to the coupling of neutron transfer with positive Q-values, which result in a significant enhancement of fusion cross sections at the subbarrier energies

Extended Range of a Gun Launched Smart Projectile Using Controllable Canards

OpenAIRE

Mark Costello

2001-01-01

This effort investigates the extent to which moveable canards can extend the range of indirect fire munitions using both projectile body and canard lift. Implications on terminal velocity and time of flight using this mechanism to extend range are examined for various canard configurations. Performance predictions are conducted using a six-degree-of-freedom simulation model that has previously been validated against range data. The projectile dynamic equations are formed in the body frame and...

Attenuation coefficients for fibrous self-compacting concrete in the energy range of 50-3000 keV

Energy Technology Data Exchange (ETDEWEB)

Bento, W.V.; Magalhaes, L.A.M.; Conti, C.C., E-mail: ccconti@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

2017-04-01

The fibrous self-compacting concrete is a high performance concrete with uniformly distributed iron fibers. Transmission measurements, with {sup 137}Cs and {sup 60}Co sources were performed for the attenuation coefficients determination for both ordinary and fibrous self-compacting concretes. The results were compared to each other and to the values found in the literature for ordinary concrete. The mass attenuation coefficient for the fibrous self-compacting concrete showed to be higher than those for ordinary concrete of about 5%, depending on the gamma energy. However, it should be noted that the density of fibrous self-compacting concrete is higher than ordinary concrete, 2.4 g/cm{sup 3} and 1.9 g/cm{sup 3} respectively, increasing still further the difference in mass attenuation coefficient. In addition to that, by using Monte Carlo simulations, with MCNP5 Monte Carlo computer code, the data was extended to the 50-3000 keV gamma energy range. (author)

Attenuation coefficients for fibrous self-compacting concrete in the energy range of 50-3000 keV

International Nuclear Information System (INIS)

Bento, W.V.; Magalhaes, L.A.M.; Conti, C.C.

2017-01-01

The fibrous self-compacting concrete is a high performance concrete with uniformly distributed iron fibers. Transmission measurements, with "1"3"7Cs and "6"0Co sources were performed for the attenuation coefficients determination for both ordinary and fibrous self-compacting concretes. The results were compared to each other and to the values found in the literature for ordinary concrete. The mass attenuation coefficient for the fibrous self-compacting concrete showed to be higher than those for ordinary concrete of about 5%, depending on the gamma energy. However, it should be noted that the density of fibrous self-compacting concrete is higher than ordinary concrete, 2.4 g/cm"3 and 1.9 g/cm"3 respectively, increasing still further the difference in mass attenuation coefficient. In addition to that, by using Monte Carlo simulations, with MCNP5 Monte Carlo computer code, the data was extended to the 50-3000 keV gamma energy range. (author)

Microadaptive Flow Control Applied to a Spinning Projectile

National Research Council Canada - National Science Library

McMichael, J; Lovas, A; Plostins, P; Sahu, J; Brown, G; Glezer, A

2005-01-01

... technology developed, the flight control technology required to enable the MAFC on spinning projectiles, the design of the flight test and validation hardware, and the results of the open-loop flight test...

Ramifications of projectile velocity on the ballistic dart penetration of sand

Science.gov (United States)

Sable, Peter Anthony

With the advent of novel in-situ experimental measurement techniques, highly resolved quantitative observations of dynamic events within granular media can now be made. In particular, high speed imagery and digital analysis now allow for the ballistic behaviors of sand to be examined not only across a range of event velocities but across multiple length scales. In an attempt to further understand the dynamic behavior of granular media, these new experimental developments were implemented utilizing high speed photography coupled with piezo-electric stress gauges to observe visually accessible ballistic events of a dart penetrating Ottawa sand. Projectile velocities ranged from 100 to over 300 meters per second with two distinct chosen fields of view to capture bulk and grain-scale behaviors. Each event was analyzed using the digital image correlation technique, particle image velocimetry from which two dimensional, temporally resolved, velocity fields were extracted, from which bulk granular flow and compaction wave propagation were observed and quantified. By comparing bulk, in situ, velocity field behavior resultant from dart penetration, momentum transfer could be quantified measuring radius of influence or dilatant fluid approximations from which a positive correlation was found across the explored velocity regime, including self similar tendencies. This was, however, not absolute as persistent scatter was observed attributed to granular heterogeneous effects. These were tentatively measured in terms of an irreversible energy amount calculated via energy balance. Grain scale analysis reveals analogous behavior to the bulk response with more chaotic structure, though conclusions were limited by the image processing method to qualitative observations. Even so, critical granular behaviors could be seen, such as densification, pore collapse, and grain fracture from which basic heterogeneous phenomena could be examined. These particularly dominated near nose

Electromagnetic interference analysis of magnetic resistance sensors inside a projectile under complex electromagnetic environments

International Nuclear Information System (INIS)

Guo, Qingwei; Gao, Min; Lu, Zhicai; Yang, Peijie

2013-01-01

Accurate measurement of angular motion has long been recognized as a daunting task. In recent years the measurement of projectiles utilizing magnetic resistance sensors has become a hot research field. Electromagnetic interference on attitude measurement cannot be ignored in complex electromagnetic environments such as battlefield conditions. In this paper, the influence and function pattern of electromagnetic interference on the measuring performance are theoretically analyzed, and the shielding effectiveness (SE) simulation of projectile is conducted via software Computer Simulation Technology (CST). Considering the specific tests, the intensity of the influence is judged. The simulation indicates that the battlefield's complex electromagnetic environment influences the environment inside the projectile, especially its electronic components and capability. The research results can provide important theoretical support on the errors compensation and precision improvement of the projectile attitude measurement with Magnetic Resistance sensor.

The scaling and dynamics of a projectile obliquely impacting a granular medium.

Science.gov (United States)

Wang, Dengming; Ye, Xiaoyan; Zheng, Xiaojing

2012-01-01

In this paper, the dynamics of a spherical projectile obliquely impacting into a two-dimensional granular bed is numerically investigated using the discrete element method. The influences of projectile's initial velocities and impacting angles are mainly considered. Numerical results show that the relationship between the final penetration depth and the initial impact velocity is very similar to that in the vertical-impact case. However, the dependence of the stopping time on the impact velocity of the projectile exhibits critical characteristics at different impact angles: the stopping time approximately increases linearly with the impact velocity for small impact angles but decreases in an exponential form for larger impact angles, which demonstrates the existence of two different regimes at low and high impact angles. When the impact angle is regarded as a parametric variable, a phenomenological force model at large impact angles is eventually proposed based on the simulation results, which can accurately describe the nature of the resistance force exerted on the projectile by the granular medium at different impact angels during the whole oblique-impact process. The degenerate model agrees well with the existing experimental results in the vertical-impact cases.

Floating attenuator wave energy device: Wavegen HYDRA project

Energy Technology Data Exchange (ETDEWEB)

NONE

2004-07-01

This report describes research funded by the Department of Trade and Industry (DTI) into the feasibility of developing and constructing a floating attenuator wave energy device known as HYDRA following initial studies by Wavegen. HYDRA is a floating externally tensioned articulated raft wave energy generator based on work by Professor FJM Farley and colleagues during the 1980s. The project's first four work tasks confirmed the theoretical potential of the device but also highlighted significant practical problems in translating that potential into a viable design. It was therefore decided not to proceed further, i.e. not to construct and test a prototype device. The report provides a general description of the device and describes the results of the initial analysis and the first series of model tests. It then discusses device design and component testing and explains the methodology for determining device performance at a particular site and mathematical modelling of a one-third scale device. To help future research and development programmes, the report emphasises the generic problems associated with the development of wave devices.

Emission of projectile helium fragments in 14N interactions at 2.1 GeV/nucleon

International Nuclear Information System (INIS)

Bhanja, R.; Devi, N.A.L.; Joseph, R.R.; Ojha, I.D.; Shyam, M.; Tuli, S.K.

1983-01-01

An analysis of projectile helium fragments has been performed from the point of view of testing the factorization and limiting fragmentation hypothesis. An event-by-event examination of 923 interactions of 14 N in emulsion at 2.1 GeV per nucleon has been made for target identification. Events with projectile fragments have been divided into various reaction channels according to the multiplicity of He nuclei. The multiplicity distribution, angular structure and other properties of the projectile He fragments have been investigated to see the dependence on different targets and target excitation. The properties of He fragments emitted from the projectile have been found to remain independent of target in peripheral collision processes. The target and projectile breakup properties have been analysed in terms of the collision geometry. Gaussian distributions have been fitted to the projected angular distribution data for He fragments at various intervals of impact parameter and in different reaction channels. The properties of emitted He nuclei exhibit characteristic features of factorization and limiting fragmentation. (orig.)

Inclusive projectile fragmentation in the spectator model

International Nuclear Information System (INIS)

Hussein, M.S.; McVoy, K.W.

1985-01-01

Crazing-angle single spectra for projectile fragments from nuclear collisions exhibit a broad peak centered near the beam velocity, suggesting that these observed fragments play only a 'spectator' role in the reaction. Using only this spectator assumption (but not DWBA), it is found that a 'prior form' formulation of the reaction leads, via closure, to a -type estimate of the inclusive spectator spectrum, thus relating it to the reaction cross section for the 'participant' with the target. It is shown explicitly that this expression includes an improved multi-channel version of the Udagawa-Tamura formula for the 'breakup-fusion' or incomplete fusion cross section, and identifies it as the fluctuation part of the participant-target reaction cross section. A Glauber-type estimate of the distorted wave functions which enter clearly shows how the width of the peak in the spectator spectrum arises from the 'Fermi motion' within the projectile, as in the simple Serber model, but is modified by the 'overlap geometry' of the collision. (Author) [pt

Pulse height defect in ion implanted silicon detector for heavy ions with Z=6-28 in the energy range ∼ 0.25-2.5 MeV/u

International Nuclear Information System (INIS)

Diwan, P.K.; Sharma, V.; Shyam Kumar; Avasthi, D.K.

2005-01-01

The response of ion implanted silicon detector has been studied for heavy ions with Z= 6-28 in the energy range ∼ 0.25-2.5 MeV/u utilizing the 15UD Pelletron Accelerator facility at Nuclear Science Centre, New Delhi, India. The variation of pulse height in ion implanted silicon detector with projectile's atomic number and its energy have been investigated. It has been observed that pulse height-energy calibration for a given projectile is described well by a linear relationship indicating no pulse height defect with the variation in energy for specific Z projectile. Pulse height defect has been found to increase with increasing projectile atomic number. The mean slope of the collected charge signal versus projectile energy depends significantly on the atomic number of the projectile. (author)

The linear attenuation coefficients as features of multiple energy CT image classification

International Nuclear Information System (INIS)

Homem, M.R.P.; Mascarenhas, N.D.A.; Cruvinel, P.E.

2000-01-01

We present in this paper an analysis of the linear attenuation coefficients as useful features of single and multiple energy CT images with the use of statistical pattern classification tools. We analyzed four CT images through two pointwise classifiers (the first classifier is based on the maximum-likelihood criterion and the second classifier is based on the k-means clustering algorithm) and one contextual Bayesian classifier (ICM algorithm - Iterated Conditional Modes) using an a priori Potts-Strauss model. A feature extraction procedure using the Jeffries-Matusita (J-M) distance and the Karhunen-Loeve transformation was also performed. Both the classification and the feature selection procedures were found to be in agreement with the predicted discrimination given by the separation of the linear attenuation coefficient curves for different materials

Experimental study on the penetration effect of ceramics composite projectile on ceramic / A3 steel compound targets

Directory of Open Access Journals (Sweden)

Di-qi Hu

2017-08-01

Full Text Available In order to improve the penetration of projectiles into ceramic composite armors, the nose of 30 mm standard projectile was replaced by a toughened ceramic nose, and the performance of ceramic-nose projectiles penetrating into ceramic/A3 steel composite targets has been experimentally researched. According to impact dynamics theory,, the performances of 30 mm ceramic-nose projectile and 30 mm standard projectile penetrating into the ceramic/A3 steel composite targets were analyzed and compared using DOP method, especially focusing on the effects made by different nose structures and materials. The aperture and depth of perforation of projectile into the armor plates as well as the residual mass of bullet core under the same conditions were comparatively analyzed. A numerical simulation was built and computed by ANSYS/LS-DYNA. Based on the simulated results, the penetration performance was further analyzed in terms of the residual mass of bullet core. The results show that the ceramic nose has a great effect on the protection of bullet core.

In-pipe aerodynamic characteristics of a projectile in comparison with free flight for transonic Mach numbers

Science.gov (United States)

Hruschka, R.; Klatt, D.

2018-03-01

The transient shock dynamics and drag characteristics of a projectile flying through a pipe 3.55 times larger than its diameter at transonic speed are analyzed by means of time-of-flight and pipe wall pressure measurements as well as computational fluid dynamics (CFD). In addition, free-flight drag of the 4.5-mm-pellet-type projectile was also measured in a Mach number range between 0.5 and 1.5, providing a means for comparison against in-pipe data and CFD. The flow is categorized into five typical regimes the in-pipe projectile experiences. When projectile speed and hence compressibility effects are low, the presence of the pipe has little influence on the drag. Between Mach 0.5 and 0.8, there is a strong drag increase due to the presence of the pipe, however, up to a value of about two times the free-flight drag. This is exactly where the nose-to-base pressure ratio of the projectile becomes critical for locally sonic speed, allowing the drag to be estimated by equations describing choked flow through a converging-diverging nozzle. For even higher projectile Mach numbers, the drag coefficient decreases again, to a value slightly below the free-flight drag at Mach 1.5. This behavior is explained by a velocity-independent base pressure coefficient in the pipe, as opposed to base pressure decreasing with velocity in free flight. The drag calculated by CFD simulations agreed largely with the measurements within their experimental uncertainty, with some discrepancies remaining for free-flying projectiles at supersonic speed. Wall pressure measurements as well as measured speeds of both leading and trailing shocks caused by the projectile in the pipe also agreed well with CFD.

Studies of projectile-like fragments in the 16O + 238U reaction at 20 MeV/u

International Nuclear Information System (INIS)

Dyer, P.; Awes, T.C.; Gelbke, C.K.; Back, B.B.; Mignerey, A.C.; Wolf, K.L.; Breuer, H.; Viola, V.E.; Meyer, W.G.

1979-01-01

Projectile residues were studied in coincidence with angle-correlated fission fragments resulting from reactions of 20-MeV/u 16 O ions on 238 U. Distributions of the missing parallel momentum are shown for different projectile residues, and the dependence of the average parallel recoil momentum on the average parallel momentum of the projectile residue is plotted. 2 figures

Progress in the development of global medium-energy nucleon-nucleus optical model potentials

International Nuclear Information System (INIS)

Madland, D.G.

1997-01-01

Two existing global medium-energy nucleon-nucleus phenomenological optical model potentials are described and compared with experiment and with each other. The first of these employs a Dirac approach (second-order reduction) that is global in projectile energy and projectile isospin and applies to the target nucleus 208 Pb. The second of these employs a relativistic equivalent to the Schroedinger equation (including relativistic kinematics) that is global in projectile energy, projectile isospin, and target (Z,A). Finally, current work is described and the influence of the nuclear bound state problem (treated in relativistic mean field theory) on the Dirac scattering problem is mentioned. Spherical target nuclei are treated in the present work and strongly-collective target nuclei (rotational and vibrational) requiring coupled-channels approaches will be treated in a future paper. (author)

Inelastic scattering of quasifree electrons on O7+ projectiles

International Nuclear Information System (INIS)

Toth, G.; Grabbe, S.; Richard, P.; Bhalla, C.P.

1996-01-01

Absolute doubly differential cross sections (DDCS close-quote s) for the resonant inelastic scattering of quasifree target electrons on H-like projectiles have been measured. Electron spectra for 20.25-MeV O 7+ projectiles on an H 2 target were measured. The spectra contain a resonant contribution from the 3l3l ' doubly excited states of O 6+ , which decay predominantly to the 2l states of the O 7+ via autoionization, and a nonresonant contribution from the direct excitation of the projectiles to the O 7+ (2l) state by the quasifree target electrons. Close-coupling R-matrix calculations for the inelastic scattering of free electrons on O 7+ ions were performed. The relation between the electron-ion inelastic scattering calculation and the electron DDCS close-quote s for the ion-atom collision was established by using the inelastic scattering model (ISM). We found excellent agreement between the theoretical and measured resonant peak positions and relative peak heights. The calculated absolute double differential cross sections for the resonance processes are also in good agreement with the measured data. The implication is that collisions of highly charged ions on hydrogen can be used to obtain high-resolution, angle- resolved differential inelastic electron-scattering cross section. copyright 1996 The American Physical Society

Accuracy Improvement Capability of Advanced Projectile Based on Course Correction Fuze Concept

OpenAIRE

Elsaadany, Ahmed; Wen-jun, Yi

2014-01-01

Improvement in terminal accuracy is an important objective for future artillery projectiles. Generally it is often associated with range extension. Various concepts and modifications are proposed to correct the range and drift of artillery projectile like course correction fuze. The course correction fuze concepts could provide an attractive and cost-effective solution for munitions accuracy improvement. In this paper, the trajectory correction has been obtained using two kinds of course corr...

Evaluating simulant materials for understanding cranial backspatter from a ballistic projectile.

Science.gov (United States)

Das, Raj; Collins, Alistair; Verma, Anurag; Fernandez, Justin; Taylor, Michael

2015-05-01

In cranial wounds resulting from a gunshot, the study of backspatter patterns can provide information about the actual incidents by linking material to surrounding objects. This study investigates the physics of backspatter from a high-speed projectile impact and evaluates a range of simulant materials using impact tests. Next, we evaluate a mesh-free method called smoothed particle hydrodynamics (SPH) to model the splashing mechanism during backspatter. The study has shown that a projectile impact causes fragmentation at the impact site, while transferring momentum to fragmented particles. The particles travel along the path of least resistance, leading to partial material movement in the reverse direction of the projectile motion causing backspatter. Medium-density fiberboard is a better simulant for a human skull than polycarbonate, and lorica leather is a better simulant for a human skin than natural rubber. SPH is an effective numerical method for modeling the high-speed impact fracture and fragmentations. © 2015 American Academy of Forensic Sciences.

Fragmentation of Millimeter-Size Hypervelocity Projectiles on Combined Mesh-Plate Bumpers

Directory of Open Access Journals (Sweden)

Aleksandr Cherniaev

2017-01-01

Full Text Available This numerical study evaluates the concept of a combined mesh-plate bumper as a shielding system protecting unmanned spacecraft from small (1 mm orbital debris impacts. Two-component bumpers consisting of an external layer of woven mesh (aluminum or steel directly applied to a surface of the aluminum plate are considered. Results of numerical modeling with a projectile velocity of 7 km/s indicate that, in comparison to the steel mesh-combined bumper, the combination of aluminum mesh and aluminum plate provides better fragmentation of small hypervelocity projectiles. At the same time, none of the combined mesh/plate bumpers provide a significant increase of ballistic properties as compared to an aluminum plate bumper. This indicates that the positive results reported in the literature for bumpers with metallic meshes and large projectiles are not scalable down to millimeter-sized particles. Based on this investigation’s results, a possible modification of the combined mesh/plate bumper is proposed for the future study.

Near- and subbarrier elastic and quasielastic scattering of the weakly bound 6Li projectile on 144Sm

International Nuclear Information System (INIS)

Monteiro, D. S.; Otomar, D. R.; Lubian, J.; Gomes, P. R. S.; Capurro, O. A.; Marti, G. V.; Arazi, A.; Figueira, J. M.; Heimann, D. Martinez; Negri, A. E.; Pacheco, A. J.; Niello, J. O. Fernandez; Guimaraes, V.

2009-01-01

High-precision data of backward-angle elastic and quasielastic scattering for the weakly bound 6 Li projectile on 144 Sm target at deep-sub-barrier, near-, and above-barrier energies were measured. From the deep-sub-barrier data, the surface diffuseness of the nuclear interacting potential was studied. Barrier distributions were extracted from the first derivatives of the elastic and quasielastic excitation functions. It is shown that sequential breakup through the first resonant state of the 6 Li is an important channel to be included in coupled-channels calculations, even at deep-sub-barrier energies

Radioactive nuclear beam facilities based on projectile fragmentation

International Nuclear Information System (INIS)

Sherrill, B.M.

1992-01-01

The production of radioactive beams using direct separation techniques is discussed. The reaction mechanisms which can be used to produce radioactive beams with these techniques can be broadly divided into three groups, projectile fragmentation, nucleon transfer, and Coulomb disassociation. Radioactive nuclei produced in these ways have large forward momenta with relatively sharp angular distributions peaked near zero degrees which are suitable for collection with magnetic devices. Secondary beam intensities of up to a few percent of the primary beam intensity are possible, although depending on the production mechanism the beam emittance may be poor. Further beam purification can be achieved using atomic processes with profiled energy degraders. The features of the production reaction mechanism, separation techniques, and a review of world wide efforts are presented. The advantages and disadvantages of the method are presented, with discussion of techniques to overcome some of the disadvantages. (Author)

Detection of two electrons in low-lying continuum states of a single projectile ion resulting from the collision of a 10.7-MeV Ag4+ ion with an Ar gas atom

International Nuclear Information System (INIS)

Richards, J.D.; Breinig, M.; Gaither, C.C.; Berryman, J.W.; Hasson, B.F.

1993-01-01

Two electrons, excited just above the double-ionization threshold of an Ag q+ (q=5,6) core in a single collision of a 0.1-MeV/u Ag 4+ projectile ion with an Ar atom, are detected. The electron detector consists of electrically isolated anode segments located behind a microchannel-plate electron multiplier. A large electrostatic 30 degree parallel-plate analyzer is used to deflect the two free electrons, which move with approximately the projectile velocity, into the detector. The cross sections for producing final states consisting of a positively charged ionic core and two electrons just above the threshold for double ionization in ion-atom collisions have been measured. The cross sections for producing states with one electron moving with a kinetic energy less than 0.13 eV in the projectile frame and the other moving with somewhat higher kinetic energy are presented

Counterpulse railgun energy recovery circuit

International Nuclear Information System (INIS)

Honig, E.M.

1986-01-01

This patent describes a counterpulse railgun energy recovery circuit for propelling a projectile along a railgun the counterpulse railgun energy recovery circuit consists of: a railgun having an effective inductance; a source inductor initially charged to an initial current; current means for initially charging the source inductor to the initial current; first current-zero type switching means; second current-zero type switching; third current-zero type switching; muzzle current-zero type switching means; transfer capacitor, the transfer capacitor is for cooperating with the first, second, third, and muzzle current-zero type switching means for providing a resonant circuit for transferring current from the source inductor to the effective inductance of the railgun during the propelling of a projectile along the railgun and for returning current from the effective inductance of the railgun to the source inductance after the projectile has exited the railgun

Very forward studies of projectile-like fragments by using a telescopic mode of a double spectrometer

International Nuclear Information System (INIS)

Bacri, C.O.

1989-01-01

On the tenth anniversary of projectile fragmentation, the question of the real occurrence of this process at the GANIL energies seems to be still open. At first, we will see the importance of doing complete angular distribution including very forward measurements in the study of the fragmentation process. Then, a new type of use of a double spectrometer will be presented and the possibility to get precise angular measurements at and around O 0 , even at very small excitation energies, will be demonstrated. At last, some results obtained at O 0 will be compared to grazing angle measurements

Speed, Acceleration, Chameleons and Cherry Pit Projectiles

Science.gov (United States)

Planinsic, Gorazd; Likar, Andrej

2012-01-01

The paper describes the mechanics of cherry pit projectiles and ends with showing the similarity between cherry pit launching and chameleon tongue projecting mechanisms. The whole story is written as an investigation, following steps that resemble those typically taken by scientists and can therefore serve as an illustration of scientific…

Methods of quasi-projectile and quasi-target reconstruction in binary collisions

International Nuclear Information System (INIS)

Genouin-Duhamel, E.; Steckmeyer, J.C.; Vient, E.; Bocage, F.; Bougault, R.; Brou, R.; Colin, J; Cussol, D.; Durand, D.; Gulminelli, F.; Lecolley, J.F.; Lefort, T.; Le Neindre, N.; Lopez, O.; Louvel, M.; Nguyen, A.D.; Peter, J.; Tamain, B.

1997-01-01

In very dissipative collisions one or more nuclei of hot nuclear matter are formed. According to the stored energy these decay in times varying from several tens of fm/c to several tens of thousands of fm/c. Thus, we have to trace down in time and reconstruct the original nuclei starting from a mixture of decay products of these nuclei and all the particles dynamically emitted in the very first moments of the collision. In this paper different methods of reconstruction of hot nuclei formed after collision at Fermi energies are presented and compared. All the methods have in commune the same theoretical hypotheses and experimental limitations. The first method uses the largest detected fragment which is supposed to preserve the memory of the initial velocity of the quasi-projectile (QP). All the intermediate mass fragments (IMF) situated in the forward hemisphere are considered as statistically emitted by the QP. The initial velocity of the source is determined by summation of the fragment momenta, event by event. Once the decay products assigned to the QP its total charge can be calculated and its mass is obtained from the projectile A/Z ratio. Finally, the QP excitation energy is calculated from calorimetric data. In the second method ('Nautilus') the velocity space is separated by cutting the center-of-mass velocity perpendicular to the main axis of the momentum ellipsoid. We take into consideration all the IMFs situated in the forward part of the ellipsoid to determine the velocity of the rapid source. The charge is constructed by summing the largest detected fragment and doubling the charge of the particles emitted in the forward hemisphere of the rapid source. The mass and excitation energy of QP per nucleon are determined as above. The third method called of 'estoc' is a purely computational one. It is based on the hypothesis that the IMFs coming from a given source are all in the same region of the momentum space. A comparison of the three methods is

Quantitative functional analysis of Late Glacial projectile points from northern Europe

DEFF Research Database (Denmark)

Dev, Satya; Riede, Felix

2012-01-01

This paper discusses the function of Late Glacial arch-backed and tanged projectile points from northern Europe in general and southern Scandinavia in particular. Ballistic requirements place clear and fairly well understood constraints on the design of projectile points. We outline the argument...... surely fully serviceable, diverged considerably from the functional optimum predicated by ballistic theory. These observations relate directly to southern Scandinavian Late Glacial culture-history which is marked by a sequence of co-occurrence of arch-backed and large tanged points in the earlier part...

Modeling and Experiments on Ballistic Impact into UHMWPE Yarns Using Flat and Saddle-Nosed Projectiles

Directory of Open Access Journals (Sweden)

Stuart Leigh Phoenix

2017-03-01

Full Text Available Yarn shooting experiments were conducted to determine the ballistically-relevant, Young’s modulus and tensile strength of ultra-high molecular weight polyethylene (UHMWPE fiber. Target specimens were Dyneema® SK76 yarns (1760 dtex, twisted to 40 turns/m, and initially tensioned to stresses ranging from 29 to 2200 MPa. Yarns were impacted, transversely, by two types of cylindrical steel projectiles at velocities ranging from 150 to 555 m/s: (i a reverse-fired, fragment simulating projectile (FSP where the flat rear face impacted the yarn rather than the beveled nose; and (ii a ‘saddle-nosed projectile’ having a specially contoured nose imparting circular curvature in the region of impact, but opposite curvature transversely to prevent yarn slippage off the nose. Experimental data consisted of sequential photographic images of the progress of the triangular transverse wave, as well as tensile wave speed measured using spaced, piezo-electric sensors. Yarn Young’s modulus, calculated from the tensile wave-speed, varied from 133 GPa at minimal initial tension to 208 GPa at the highest initial tensions. However, varying projectile impact velocity, and thus, the strain jump on impact, had negligible effect on the modulus. Contrary to predictions from the classical Cole-Smith model for 1D yarn impact, the critical velocity for yarn failure differed significantly for the two projectile types, being 18% lower for the flat-faced, reversed FSP projectile compared to the saddle-nosed projectile, which converts to an apparent 25% difference in yarn strength. To explain this difference, a wave-propagation model was developed that incorporates tension wave collision under blunt impact by a flat-faced projectile, in contrast to outward wave propagation in the classical model. Agreement between experiment and model predictions was outstanding across a wide range of initial yarn tensions. However, plots of calculated failure stress versus yarn pre

Mass attenuation and mass energy absorption coefficients for 10 keV to 10 MeV photons; Coefficients d'attenuation massique et d'absorption massique en energie pour les photons de 10 keV a 10 MeV

Energy Technology Data Exchange (ETDEWEB)

Joffre, H; Pages, L [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1968-07-01

In this report are given the elements allowing the definition of the values of mass attenuation coefficients and mass energy absorption coefficients for some elements and mixtures, necessary for the study of tissue equivalent materials, for photons in the energy range 10 keV to 10 MeV. After a short reminding of the definitions of the two coefficients, follows, in table form, a compilation of these coefficients, as a function of energy, for simple elements, for certain mineral compounds, organic compounds, gases and particularly of soft tissues. (author) [French] Dans ce rapport, sont donnes les elements permettant de determiner les valeurs des coefficients d'attenuation massique et d'absorption massique en energie pour certains elements et melanges necessaires a l'etude des materiaux equivalents aux tissus pour les photons dans le domaine d'energie allant de 10 keV a 10 MeV. Apres un bref rappel des definitions des deux coefficients, suit, sous forme de tableaux, un recueil de ces coefficients, en fonction de l'energie, pour les elements simples, certains composes mineraux, composes organiques, gaz, et, particulierement, pour les tissus mous. (auteur)

Experimental impact-parameter--dependent probabilities for K-shell vacancy production by fast heavy-ion projectiles

International Nuclear Information System (INIS)

Randall, R.R.; Bednar, J.A.; Curnutte, B.; Cocke, C.L.

1976-01-01

The impact-parameter dependence of the probability for production of target K x rays has been measured for oxygen projectiles on copper and for carbon and fluorine projectiles on argon at scaled velocities near 0.5. The O-on-Cu data were taken for 1.56-, 1.88-, and 2.69-MeV/amu O beams incident upon thin Cu foils. A thin Ar-gas target was used for 1.56-MeV/amu C and F beams, permitting measurements to be made for charge-pure C +4 , C +6 , F +9 and F +5 projectiles. Ar and Cu K x rays were observed with a Si(Li) detector and scattered projectiles with a collimated surface-barrier detector. Comparison of the shapes of the measured K-vacancy--production probability curves with predictions of the semiclassical Coulomb approximation (SCA) shows adequate agreement for the O-on-Cu system. For the higher ratio of projectile-to-target nuclear charge (Z 1 /Z 2 ) characterizing the C-on-Ar and F-on-Ar systems, the SCA predictions are entirely inadequate in describing the observed impact-parameter dependence. In particular, they cannot account for large probabilities found at large impact parameters. Furthermore, the dependence of the shapes on the projectile charge state is found to become pronounced at larger Z 1 /Z 2 . Attempts to account for this behavior in terms of alternative vacancy-production processes are discussed

Supercavitating Projectile Tracking System and Method

Science.gov (United States)

2009-12-30

Distribution is unlimited 20100104106 Attorney Docket No. 96681 SUPERCAVITATING PROJECTILE TRACKING SYSTEM AND METHOD STATEMENT OF GOVERNMENT...underwater track or path 14 of a supercavitating vehicle under surface 16 of a body of water. In this embodiment, passive acoustic or pressure...transducers 12 are utilized to measure a pressure field produced by a moving supercavitating vehicle. The present invention provides a low-cost, reusable

Treatment of Ion-Atom Collisions Using a Partial-Wave Expansion of the Projectile Wavefunction

Science.gov (United States)

Wong, T. G.; Foster, M.; Colgan, J.; Madison, D. H.

2009-01-01

We present calculations of ion-atom collisions using a partial-wave expansion of the projectile wavefunction. Most calculations of ion-atom collisions have typically used classical or plane-wave approximations for the projectile wavefunction, since partial-wave expansions are expected to require prohibitively large numbers of terms to converge…

Unusual behavior of projectile fragments formed in the bombardment of copper with relativistic Ar ions

International Nuclear Information System (INIS)

Dersch, G.; Beckmann, R.; Feige, G.

1985-01-01

The interaction properties of projectile fragments from the fragmentation of 0.9 GeV/nucleon and 1.8 GeV/nucleon 40 Ar with Cu have been studied using radioactivation techniques. In this experiment, two identical copper blocks, 1 cm thick and 8 cm in diameter, are irradiated by relativistic projectiles in different configurations. In configuration 0, the blocks are touching while in configuration 10 or 20, the blocks are separated by 10 or 20 cm of air, respectively. It is assumed that when the relativistic projectiles interact with the first block of each pair, projectile fragments are created which interact with other nuclei in the first and second blocks. What is measured is the ratio of some target fragment activity, such as 24 Na or 28 Mg, produced in the second block relative to the first block, R

Deformations on Hole and Projectile Surfaces Caused By High Velocity Friction During Ballistic Impact

Science.gov (United States)

Karamış, M. B.

2018-01-01

In this study, the deformations caused by the ballistic impact on the MM composites and on projectile surfaces are examined. The hole section and grain deformation of unreinforced targets are also examined after impact. The relatively high complexity of impact problems is caused by the large number of intervening parameters like relative velocity of projectile and target, shape of colliding objects, relative stiffness and masses, time-dependent surface of contact, geometry and boundary conditions and material characteristics. The material used in this investigation are 2024 and 7075 aluminum alloys as matrix reinforced with SiC and Al2O3 particles. The matrix materials are extensively used in defense applications due to its favorable ballistic properties, moderate strength, high corrosion resistance and super plastic potential. Two different composites were produced; one by casting and the other by lamination. The ballistic tests of the composite targets were carried out according to NIJ Standard-0101.04, Temperature 21 °C, RH=65% with 7.62 mm projectiles. The bullet weight was 9.6 g and their muzzle velocities were in the range of 770-800 m/s. The projectiles consisted of a steel core, copper jacket and lead material. The composite targets were positioned 15 m from the rifle. The interaction between projectiles and the target hole created after impact were examined by light microscopy and photography. Different damage and failure mechanisms such as petalling, cracking, spalling, dishing, etc., were observed on the target body. On the other hand, dramatic wear and damages on the projectile surface were also observed. The targets were supported with Al-5083 backing blocks having 40 mm thickness.

COREL, Ion Implantation in Solids, Range, Straggling Using Thomas-Fermi Cross-Sections. RASE4, Ion Implantation in Solids, Range, Straggling, Energy Deposition, Recoils. DAMG2, Ion Implantation in Solids, Energy Deposition Distribution with Recoils

International Nuclear Information System (INIS)

Brice, D. K.

1979-01-01

1 - Description of problem or function: COREL calculates the final average projected range, standard deviation in projected range, standard deviation in locations transverse to projected range, and average range along path for energetic atomic projectiles incident on amorphous targets or crystalline targets oriented such that the projectiles are not incident along low index crystallographic axes or planes. RASE4 calculates the instantaneous average projected range, standard deviation in projected range, standard deviation in locations transverse to projected range, and average range along path for energetic atomic projectiles incident on amorphous targets or crystalline targets oriented such that the projectiles are not incident along low index crystallographic axes or planes. RASE4 also calculates the instantaneous rate at which the projectile is depositing energy into atomic processes (damage) and into electronic processes (electronic excitation), the average range of target atom recoils projected onto the direction of motion of the projectiles, and the standard deviation in the recoil projected range. DAMG2 calculates the distribution in depth of the energy deposited into atomic processes (damage), electronic processes (electronic excitation), or other energy-dependent quality produced by energetic atomic projectiles incident on amorphous targets or crystalline targets oriented such that the projectiles are not incident along low index crystallographic axes or planes. 2 - Method of solution: COREL: The truncated differential equation which governs the several variables being sought is solved through second-order by trapezoidal integration. The energy-dependent coefficients in the equation are obtained by rectangular integration over the Thomas-Fermi elastic scattering cross section. RASE4: The truncated differential equation which governs the range and straggling variables is solved through second-order by trapezoidal integration. The energy

Experimental characterisation of sprays resulting from impacts of liquid-containing projectiles

Energy Technology Data Exchange (ETDEWEB)

Hostikka, Simo, E-mail: simo.hostikka@aalto.fi [Aalto University, Espoo (Finland); Silde, Ari; Sikanen, Topi; Vepsä, Ari; Paajanen, Antti [VTT Technical Research Centre of Finland Ltd, Espoo (Finland); Honkanen, Markus [Pixact Oy, Tampere (Finland)

2015-12-15

Highlights: • Detailed characterisation of sprays resulting from the impacts of water-filled metal projectiles on a hard wall. • Experimental measurements of spray speed, direction and droplet size. • Detailed analysis of overall spray evolution. • The spray characterisation information can be used in CFD analyses of aircraft impact fires. - Abstract: Modelling and analysing fires following aircraft impacts requires information about the behaviour of liquid fuel. In this study, we investigated sprays resulting from the impacts of water-filled metal projectiles on a hard wall. The weights of the projectiles were in the range of 38–110 kg, with 8.6–68 kg water, and the impact speeds varied between 96 and 169 m/s. The overall spray behaviour was observed with high-speed video cameras. Ultra-high-speed cameras were used in backlight configuration for measuring the droplet size and velocity distributions. The results indicate that the liquid leaves the impact position as a thin sheet of spray in a direction perpendicular to the projectile velocity. The initial spray speeds were 1.5–2.5 times the impact speed, and the Sauter mean diameters were in the 147–344 μm range. This data can be used as boundary conditions in CFD fire analyses, considering the two-phase fuel flow. The overall spray observations, including the spray deceleration rate, can be used for validating the model.

Enhanced RAMAC performance in subdetonative propulsion mode with semi-combustible projectile

Energy Technology Data Exchange (ETDEWEB)

Legendre, J.F.; Giraud, M. [French-German Res. Inst., Saint-Louis (France)

2000-11-01

Investigations are carried out at ISL to determine the experimental conditions required to accelerate a projectile in the mass range from 1.5 to 2 kg up to a muzzle velocity of 3 km/s while keeping the maximum acceleration below 40,000 g. Therefore, two smooth-bore ram-accelerators denoted RAMAC 30-II and RAMAC 90, in caliber 30 and 90 mm respectively, are being operated in the thermally choked propulsion mode. Different material configurations for the projectile afterbody have been investigated, while keeping an aluminum nose cone. Besides afterbodies made of aluminum or magnesium alloy only, a third configuration is presented relying on a short magnesium part fitted to the base of an aluminum afterbody. This configuration denoted as ''semi-combustible'' is designed so that magnesium particles are steadily injected and burnt-out within the combustion zone at the base, therefore providing an additional heat release and consequently a significantly greater forward thrust. Experimental results achieved in both 30 and 90 mm along a 300-caliber-long ram-section and using up to three different gaseous mixtures are presented. To date, for a given semi-combustible projectile and an injection velocity into the ram-section of 1380 m/s, a maximum muzzle velocity of 2380 m/s has been achieved in RAMAC 30-II and 2180 m/s in RAMAC 90, the initial projectile mass being 69 g and 1608 g respectively. (orig.)

The conditions for total reflection of low-energy atoms from crystal surfaces

International Nuclear Information System (INIS)

Hou, M.; Robinson, M.T.

1978-01-01

The critical angles for the total reflection of low-energy particles from Cu rows and (001) planes have been investigated, using the binary collision approximation computer simulation code MARLOWE Breakthrough angles were evaluated for H, N, Ne, Ar, Cu, Xe, and Au in the energy range from 0.1 to 7.5 keV. In both the axial and the planar cases, recoiling of the target atoms lowers the energy barrier which the target surface presents to the heavy projectiles. Consequently, the breakthrough angles are reduced for heavy projectiles below the values expected either from observations on light projectiles or from analytical channeling theory. (orig.) [de

Geometrical aspects of reaction cross sections for 3He, 4He and 12C projectiles

International Nuclear Information System (INIS)

Ingemarsson, A.; Lantz, M.

2003-04-01

A black-disc model combined with accurate matter densities has been used for an investigation of reaction cross sections for 3 He, 4 He and 12 C projectiles. A simple relation is derived between the energy dependence of the reaction cross sections and the strength of the nucleon-nucleon interaction. A comparison is also made of the reaction cross sections for 3 He and 4 He for six different nuclei 12 C, 16 O, 40 Ca, 58,60 Ni and 208 Pb

Measurement of thick target neutron yield from the reaction (p+181 Ta) with projectiles in the range of 6-20 MeV

Science.gov (United States)

Paul, Sabyasachi; Sahoo, G. S.; Tripathy, S. P.; Sharma, S. C.; Joshi, D. S.; Bandyopadhyay, T.

2018-02-01

181Ta is a commonly used backing material for many targets in nuclear reaction studies. When the target thickness is less than the range of bombarded projectiles, the interaction via Ta(p,n) reactions in the backing can be a significant source of background. In this study, the neutron spectral yields from the reaction of protons of different energies (between 6 to 20 MeV) with a thick Ta target were determined using CR-39 detectors. The results from this study can be used as a correction factor in such situations. The parameters of registered tracks in CR-39 were analysed using an in-house image analysing program autoTRAK_n and then to derive the associated dose values. The spectral yields obtained experimentally were compared with those obtained from the theoretical calculations. The neutron yield was found to increase with increase in projectile energy mainly due to the opening of reaction channels from (p, n) to (p, 3n).

Projectile metallic foreign bodies in the orbit: a retrospective study of epidemiologic factors, management, and outcomes.

Science.gov (United States)

Finkelstein, M; Legmann, A; Rubin, P A

1997-01-01

Intraorbital projectile metallic foreign bodies are associated with significant ocular and orbital injuries. The authors sought to evaluate epidemiologic factors, the incidence of associated ocular and orbital injury, and the nature and necessity of surgical intervention in these cases. Charts of all patients with projectile intraorbital metallic foreign bodies seen at our institution (27) over the preceding 7 years were evaluated with respect to age, sex, type of injury, associated ocular and orbital injuries, location of the projectile (anterior, epibulbar, or posterior), postinjury visual acuity, and surgical intervention. The majority of patients were male, between the ages of 11 and 30, and had BB pellet injuries. Thirteen projectiles were lodged anteriorly, 4 were in an epibulbar position, and the remaining 10 were posterior to the equator. Twelve of 13 anterior, and 4 of 4 epibulbar foreign bodies were removed surgically, whereas only 2 of 10 posterior foreign bodies required surgery. No case of surgical intervention resulted in a decrease of visual acuity. Associated ocular injuries were both more common and severe in patients with posteriorly located foreign bodies. Final visual acuity was better at presentation and at discharge in patients with anteriorly located foreign bodies. Intraorbital projectile metallic foreign bodies can be a source of significant ocular morbidity. Management of these cases is dependent on the location of the projectile. Ancillary radiographic studies can be helpful. Surgery to remove the projectile should be considered in each case, but foreign bodies that are not readily accessible often may be left safely in place. Closer regulation of the pellet gun industry, with an emphasis on education and protective eyewear use, would be helpful in reducing these injuries.

Commissioning the A1900 projectile fragment separator

CERN Document Server

Morrissey, D J; Steiner, M; Stolz, A; Wiedenhöver, I

2003-01-01

An important part of the recent upgrade of the NSCL facility is the replacement of the A1200 fragment separator with a new high acceptance device called the A1900. The design of the A1900 device represents a third generation projectile fragment separator (relative to the early work at LBL) as it is situated immediately after the primary accelerator, has a very large acceptance, a bending power significantly larger than that of the cyclotron and is constructed from large superconducting magnets (quadrupoles with 20 and 40 cm diameter warm bores). The A1900 can accept over 90% of a large range of projectile fragmentation products produced at the NSCL, leading to large gains in the intensity of the secondary beams. The results of initial tests of the system with a restricted momentum acceptance (+-0.5%) indicate that the A1900 is performing up to specifications. Further large gains in the intensities of primary beams, typically two or three orders of magnitude, will be possible as the many facets of high current...

Time of flight and range of the motion of a projectile in a constant gravitational field

Directory of Open Access Journals (Sweden)

P. A. Karkantzakos

2009-01-01

Full Text Available In this paper we study the classical problem of the motion of a projectile in a constant gravitational field under the influenceof a retarding force proportional to the velocity. Specifically, we express the time of flight, the time of fall and the range ofthe motion as a function of the constant of resistance per unit mass of the projectile. We also prove that the time of fall isgreater than the time of rise with the exception of the case of zero constant of resistance where we have equality. Finally weprove a formula from which we can compute the constant of resistance per unit mass of the projectile from time of flight andrange of the motion when the acceleration due to gravity and the initial velocity of the projectile are known.

Study of soil aggregate breakdown dynamics under low dispersive ultrasonic energies with sedimentation and X-ray attenuation

Science.gov (United States)

Schomakers, Jasmin; Zehetner, Franz; Mentler, Axel; Ottner, Franz; Mayer, Herwig

2015-10-01

It has been increasingly recognized that soil organic matter stabilization is strongly controlled by physical binding within soil aggregates. It is therefore essential to measure soil aggregate stability reliably over a wide range of disruptive energies and different aggregate sizes. To this end, we tested highaccuracy ultrasonic dispersion in combination with subsequent sedimentation and X-ray attenuation. Three arable topsoils (notillage) from Central Europe were subjected to ultrasound at four different specific energy levels: 0.5, 6.7, 100 and 500 J cm-3, and the resulting suspensions were analyzed for aggregate size distribution by wet sieving (2 000-63 μm) and sedimentation/X-ray attenuation (63-2 μm). The combination of wet sieving and sedimentation technique allowed for a continuous analysis, at high resolution, of soil aggregate breakdown dynamics after defined energy inputs. Our results show that aggregate size distribution strongly varied with sonication energy input and soil type. The strongest effects were observed in the range of low specific energies (aggregate stability and release of soil organic matter upon aggregate breakdown.

Study of soil aggregate breakdown dynamics under low dispersive ultrasonic energies with sedimentation and X-ray attenuation**

Science.gov (United States)

Schomakers, Jasmin; Zehetner, Franz; Mentler, Axel; Ottner, Franz; Mayer, Herwig

2016-01-01

It has been increasingly recognized that soil organic matter stabilization is strongly controlled by physical binding within soil aggregates. It is therefore essential to measure soil aggregate stability reliably over a wide range of disruptive energies and different aggregate sizes. To this end, we tested high-accuracy ultrasonic dispersion in combination with subsequent sedimentation and X-ray attenuation. Three arable topsoils (notillage) from Central Europe were subjected to ultrasound at four different specific energy levels: 0.5, 6.7, 100 and 500 J cm−3, and the resulting suspensions were analyzed for aggregate size distribution by wet sieving (2 000-63 μm) and sedimentation/X-ray attenuation (63-2 μm). The combination of wet sieving and sedimentation technique allowed for a continuous analysis, at high resolution, of soil aggregate breakdown dynamics after defined energy inputs. Our results show that aggregate size distribution strongly varied with sonication energy input and soil type. The strongest effects were observed in the range of low specific energies (aggregate stability and release of soil organic matter upon aggregate breakdown. PMID:27099408

Survival probability in small angle scattering of low energy alkali ions from alkali covered metal surfaces

International Nuclear Information System (INIS)

Neskovic, N.; Ciric, D.; Perovic, B.

1982-01-01

The survival probability in small angle scattering of low energy alkali ions from alkali covered metal surfaces is considered. The model is based on the momentum approximation. The projectiles are K + ions and the target is the (001)Ni+K surface. The incident energy is 100 eV and the incident angle 5 0 . The interaction potential of the projectile and the target consists of the Born-Mayer, the dipole and the image charge potentials. The transition probability function corresponds to the resonant electron transition to the 4s projectile energy level. (orig.)

Numerical Study on the Projectile Impact Resistance of Multi-Layer Sandwich Panels with Cellular Cores

Directory of Open Access Journals (Sweden)

Liming Chen

Full Text Available Abstract The projectile impact resistance of sandwich panels with cellular cores with different layer numbers has been numerically investigated by perpendicular impact of rigid blunt projectile in ABAQUS/Explicit. These panels with corrugation, hexagonal honeycomb and pyramidal truss cores are impacted at velocities between 50 m/s and 202 m/s while the relative density ranges from 0.001 to 0.15 The effects of core configuration and layer number on projectile impact resistance of sandwich panels with cellular cores are studied. At low impact velocity, sandwich panels with cellular cores outperform the corresponding solid ones and non-montonicity between relative density and projectile resistance of sandwich panels is found and analyzed. Multiplying layer can reduce the maximum central deflection of back face sheet of the above three sandwich panels except pyramidal truss ones in high relative density. Hexagonal honeycomb sandwich panel is beneficial to increasing layer numbers in lowering the contact force and prolonging the interaction time. At high impact velocity, though corrugation and honeycomb sandwich panels are inferior to the equal-weighted solid panels, pyramidal truss ones with high relative density outperform the corresponding solid panels. Multiplying layer is not the desirable way to improve high-velocity projectile resistance.

A High-Spin Rate Measurement Method for Projectiles Using a Magnetoresistive Sensor Based on Time-Frequency Domain Analysis.

Science.gov (United States)

Shang, Jianyu; Deng, Zhihong; Fu, Mengyin; Wang, Shunting

2016-06-16

Traditional artillery guidance can significantly improve the attack accuracy and overall combat efficiency of projectiles, which makes it more adaptable to the information warfare of the future. Obviously, the accurate measurement of artillery spin rate, which has long been regarded as a daunting task, is the basis of precise guidance and control. Magnetoresistive (MR) sensors can be applied to spin rate measurement, especially in the high-spin and high-g projectile launch environment. In this paper, based on the theory of a MR sensor measuring spin rate, the mathematical relationship model between the frequency of MR sensor output and projectile spin rate was established through a fundamental derivation. By analyzing the characteristics of MR sensor output whose frequency varies with time, this paper proposed the Chirp z-Transform (CZT) time-frequency (TF) domain analysis method based on the rolling window of a Blackman window function (BCZT) which can accurately extract the projectile spin rate. To put it into practice, BCZT was applied to measure the spin rate of 155 mm artillery projectile. After extracting the spin rate, the impact that launch rotational angular velocity and aspect angle have on the extraction accuracy of the spin rate was analyzed. Simulation results show that the BCZT TF domain analysis method can effectively and accurately measure the projectile spin rate, especially in a high-spin and high-g projectile launch environment.

Photon attenuation by intensifying screens

International Nuclear Information System (INIS)

Holje, G.

1983-01-01

The photon attenuation by intensifying screens of different chemical composition has been determined. The attenuation of photons between 20 keV and 120 keV was measured by use of a multi-channel analyzer and a broad bremsstrahlung distribution. The attenuation by the intensifying screens was hereby determined simultaneously at many different monoenergetic photon energies. Experimentally determined attenuations were found to agree well with attenuation calculated from mass attenuation coefficients. The attenuation by the screens was also determined at various bremsstrahlung distributions, simulating those occurring behind the patient in various diagnostic X-ray examinations. The high attenuation in some of the intensifying screens form the basis for an analysis of the construction of asymmetric screen pairs. Single screen systems are suggested as a favourable alternative to thick screen pair systems. (Author)

Light particles emitted with very forward quasi-projectiles and the mechanism in the fragmentation of 44 MeV/a.m.u. 40Ar

International Nuclear Information System (INIS)

Roussel, P.; Bacri, Ch.O.; Borrel, V.; Stephan, C.; Tassan-Got, L.; Beaumel, D.; Bernas, M.; Clapier, F.; Mirea, M.

1998-01-01

The mechanism of projectile fragmentation in the Fermi-energy region has been investigated for fragments emitted in the incident beam direction by detecting fast protons and neutrons evaporated by the projectile-like fragments. The proton coincidence rate is shown to increase with fragment velocity loss. This increase is also correlated to the decrease of the fragment yield, with the coincident rate doubling when the yield decreases by a factor of 10. The coincidence rate is found to be also proportional to the fragment mass loss for fragments with the beam velocity. A two-step mechanism is sketched out to interpret these results. For fragments with the beam velocity, the projectile nucleon removal is equally shared between a first fast step and the second evaporative step, while for fragments at the tenth of the maximum yield, the nucleons are removed by evaporation. Finally, the experimental observation that the most probable velocity for forward fragments is very close to that of the beam may be the result of a strong forward/backward momentum asymmetry in a Goldhaber-type analysis. (author)

Attenuation properties of radiation shielding materials such as granite and marble against γ-ray energies between 80 and 1350 keV

Energy Technology Data Exchange (ETDEWEB)

Eke, Canel [Akdeniz Univ., Antalya (Turkey). Nuclear Sciences Application and Research Center; Akdeniz Univ., Antalya (Turkey). Div. of Physics Education; Agar, Osman [Akdeniz Univ., Antalya (Turkey). Nuclear Sciences Application and Research Center; Karamanoglu Mehmetbey Univ., Karaman (Turkey). Dept. of Physics; Segebade, Christian [Akdeniz Univ., Antalya (Turkey). Nuclear Sciences Application and Research Center; Boztosun, Ismail [Akdeniz Univ., Antalya (Turkey). Nuclear Sciences Application and Research Center; Akdeniz Univ., Antalya (Turkey). Dept. of Physics

2017-07-01

In this study, the γ-ray energy-dependent mass and linear attenuation coefficients of various granite and Turkish marble species have been experimentally obtained. Radionuclides ({sup 133}Ba, {sup 137}Cs, {sup 60}Co and {sup 22}Na) with point geometry were used as γ-ray sources. The absorption capacity of each sample at nine γ-ray energies was measured using a high resolution γ-ray spectrometer equipped with a high purity germanium (HPGe) detector. To obtain the precision of the results (1σ standard deviation of the single value), this procedure was repeated six times for each species of granite and marble, respectively. The energy-dependent mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), the half (HVL) and the tenth value layer (TVL) were calculated following that the MAC and LAC results were compared to the literature values.

Study of the effect of hard projectiles impacting reinforced concrete walls

International Nuclear Information System (INIS)

Berriaud, C.; Sokolovsky, A.

1977-01-01

Among the risks examined in the framework of nuclear safety in France, quite unlikely events are examined as constituting a safety cover. This type of event includes the possible impact of aircrafts, or rotor splinters. Research on the limit strength of a wall under the impact of a hard projectile presently gives incentive results. First, a good agreement appears between works performed in parallel directions by EDF and CEA. Secondly, the special field of aerial projectiles is much better known as it was with previous formulations. Third, such research highly contributes to the knowledge of the mechanical strength of reinforced concrete structures [fr

Annotated references on shielding experiment and calculation of high energy particles

International Nuclear Information System (INIS)

Hirayama, H.; Ban, S.; Nakamura, T.

1990-12-01

The literature on shielding experiment and calculation of high energy particles above 20 MeV has been surveyed. The survey covers thirteen journals, from 1965 up to 1989. For each paper, applicable information is listed on type and energy of the projectile, the accelerator used, composition and thickness of the target and shielding materials, shielding geometry, the experimental and calculational methods, and the quantities obtained. The references on shielding experiment and on shielding calculation are accessed through two indices which list the projectile-target and shielding material combination, shielding geometry and the projectile energy range. The literature on neutron, photon and hadron production from thick target bombarded by charged particles has been surveyed mainly from 1984 as a complement of the previous work. (author)

A model for high-energy heavy-ion collisions

International Nuclear Information System (INIS)

Myers, W.D.

1978-01-01

A model is developed for high-energy heavy-ion collisions that treats the variation across the overlap region of the target and projectile in the amount of energy and momentum that is deposited. The expression for calculating any observable takes the form of a sum over a series of terms, each one of which consists of a geometric, a kinematic, and a statistical factor. The geometrical factors for a number of target projectile systems are tabulated. (Auth.)

Penetration Experiments with 6061-T6511 Aluminum Targets and Spherical-Nose Steel Projectiles at Striking Velocities Between 0.5 and 3.0 km/s

Energy Technology Data Exchange (ETDEWEB)

Forrestal, M.J.; Piekutowski, A.J.

1999-02-04

We conducted depth of penetration experiments with 7.11-mm-diameter, 74.7-mm-long, spherical-nose, 4340 steel projectiles launched into 250-mm-diameter, 6061-T6511 aluminum targets. To show the effect of projectile strength, we used projectiles that had average Rockwell harnesses of R{sub c} = 36.6, 39.5, and 46.2. A powder gun and two-stage, light-gas guns launched the 0.023 kg projectiles at striking velocities between 0.5 and 3.0 km/s. Post-test radiographs of the targets showed three response regions as striking velocities increased: (1) the projectiles remained visibly undeformed, (2) the projectiles permanently deformed without erosion, and (3) the projectiles eroded and lost mass. To show the effect of projectile strength, we compared depth-of-penetration data as a function of striking velocity for spherical-nose rods with three Rockwell harnesses at striking velocities ranging from 0.5 to 3.0 km/s. To show the effect of nose shape, we compared penetration data for the spherical-nose projectiles with previously published data for ogive-nose projectiles.

Peripheral heavy-ion induced reactions at intermediate energies 20MeV

International Nuclear Information System (INIS)

Barrette, J.; Berthier, B.; Chavez, E.

1984-03-01

Inclusive energy spectra and angular distributions of projectile like fragments in reactions induced by a 44 MeV/nucleon 40 Ar beam bombarding 27 Al and sup(nat)Ti targets show many of the features of high energy fragmentation. However, several aspects such as energy dissipation and production of fragments heavier than the projectile are reminiscent of a low energy behaviour

Allotropic effects on the energy loss of swift H+ and He+ ion beams through thin foils

International Nuclear Information System (INIS)

Garcia-Molina, Rafael; Abril, Isabel; Denton, Cristian D.; Heredia-Avalos, Santiago

2006-01-01

We have developed a theoretical treatment and a simulation code to study the energy loss of swift H + and He + ion beams interacting with thin foils of different carbon allotropes. The former is based on the dielectric formalism, and the latter combines Monte Carlo with the numerical solution of the motion equation for each projectile to describe its trajectory and interactions through the target. The capabilities of both methods are assessed by the reasonably good agreement between their predictions and the experimental results, for a wide range of projectile energies and target characteristics. Firstly, we apply the theoretical procedure to calculate the stopping cross sections for H + and He + beams in foils of different allotropic forms of carbon (such as diamond, graphite, amorphous carbon, glassy carbon and C 60 -fullerite), as a function of the projectile energy. We take into account the electronic structure of the projectile, as well as the different charge states it can acquire, the energy loss associated to the electronic capture and loss processes, the polarization of the projectile, and a realistic description of the target. On the other hand, the simulation code is used to evaluate the energy distributions of swift H + and He + ion beams when traversing several foils of the above mentioned allotropic forms of carbon, in order to analyze the influence of the chemical and physical state of the target in the projectile energy loss. These allotropic effects are found to become more important around the maximum of the stopping cross-section

Identification of more than a 100 new isotopes from 238U projectile fission and beams of neutron-rich nuclei at BRENDA

International Nuclear Information System (INIS)

Bernas, M.; Donzaud, C.; Dessagne, Ph.

1996-01-01

Projectile fission of 238 U was investigated at a bombarding energy of 750 A MeV using Pb and Be targets. The fully stripped forward emitted fragments from Ti to Cs were analyzed with the Fragment Separator (FRS) and unambiguously identified by their energy-loss and time-of-flight. The magnetic selection of the largest momenta acted as a trigger of the low-energy fission component. More than a hundred new nuclear species were identified including the 78 Ni, for which a cross-section of 300 pb was measured. (author)

Velocity determination of neutron-rich projectile fragments with a ring-imaging Cherenkov detector

International Nuclear Information System (INIS)

Zeitelhack, K.

1992-11-01

For the velocity determination of relativistic heavy ions (A>100) in the energy range 300A.MeV ≤ E kin ≤ 2A.GeV a highly resolving, compact ring-imaging Cherenkov counter with large dynamical measurement range was developed. The Cherenkov light cone emitted in the flight of a relativistic heavy ion by a liquid layer (C 6 F 14 ) is focused on the entrance window of a one-dimensional position-resolving VUV-sensitive photon detector. This gas detector is operated at atmospheric pressure with a mixture of 90% methane and 10% isobutane with 0.04% TMAE as photosensitive admixture. For 725A.MeV 129 Xe ions a velocity resolution Δβ/β=1.8.10 -3 and a nuclear charge-number resolution ΔZ/Z=5.1.10 -2 was reached. The over the photon energy range 5.4 eV ≤ E γ ≤ 7.2 eV averaged detection efficiency of the detector system was determined to ε tot =2.8%>. At the 0deg magnet spectrometer Fragmentseparator of the GSI Darmstadt the RICH detector was for the first time applied for the identification of nuclear charge number and mass of heavy relativistic projectile fragments. In the experiment the production cross sections of very neutron-rich nuclei by fragmentation of 136 Xe projectiles in the reaction 76A.MeV 136 Xe on 27 Al were determined. From the measured production erates for the production of the double-magic nucleus 132 Zn in this reaction a cross section of σ=(0.4± 0.3 0.6 ) μbarn can be extrapolated. (orig./HSI) [de

States of high energy density

International Nuclear Information System (INIS)

Murray, M.

1988-02-01

The transverse energy, E/sub tau/ spectra for O 16 and S 32 incident for various elements at 200 GeVnucleon are shown. The target and projectile dependencies of the data are discussed. The energy density achieved is estimated. For O 16 on Tungsten the multiplicity spectrum is also presented as well as the pseudorapidity spectra as a function of the transverse energy. The multiplicity cross section dσdN as measured in the backward hemisphere (0.9 < /eta/ < 2.9/ is found to be very similar in shape to the transverse energy distribution dσdE/tau/ reflecting the particular geometry of nucleus nucleus nucleus collisions. The dependence on the atomic mass of the target, A/sub tau/ and projectile A/sub p/ is not what one would expect from naive considerations

Effect of a Bore Evacuator on Projectile In-Bore Dynamics

National Research Council Canada - National Science Library

Carlucci, Donald

2004-01-01

Projectile base pressure measurements were taken in a 155-mm M284 gun tube using an Armament Research, Development and Engineering Center-designed instrumentation package incorporated into a modified...

Study of momentum distributions for projectile fragments of 22Ne and 28Si nuclei in collisions with emulsion

International Nuclear Information System (INIS)

Abou-Steit, S.A.H.

2000-01-01

The charge and mass yield curves and the momentum distributions of the projectile fragments produced in the interactions of 4.1 A GeV/c 22 Ne and 4.5 A GeV/c 28 Si with emulsion have been studied. The overall charge distributions of the projectile fragments resulting from these interactions are presented. The dependence of the mass yield distributions of the projectile fragments on the impact parameter has been tested. The momentum distributions for the considered reactions have been investigated by two methods. First, the projected momentum distributions in the plane of the microscope have been achieved by fitting the projected angular distributions to gaussian ones. It has been found that the width of the distribution changes with the charge of the projectile fragment and it decreases with the increase of the projectile fragment charge. Secondly, the transverse momentum distributions have been compared with previous studies. The momentum distribution, in the forward cone, is a typically narrow gaussian one

Modeling Fragment Simulating Projectile Penetration into Steel Plates Using Finite Elements and Meshfree Particles

Directory of Open Access Journals (Sweden)

James O’Daniel

2011-01-01

Full Text Available Simulating fragment penetration into steel involves complicated modeling of severe behavior of the materials through multiple phases of response. Penetration of a fragment-like projectile was simulated using finite element (FE and meshfree particle formulations. Extreme deformation and failure of the material during the penetration event were modeled with several approaches to evaluate each as to how well it represents the actual physics of the material and structural response. A steel Fragment Simulating Projectile (FSP – designed to simulate a fragment of metal from a weapon casing – was simulated for normal impact into a flat square plate. A range of impact velocities was used to examine levels of exit velocity ranging from relatively small to one on the same level as the impact velocity. The numerical code EPIC, used for all the simulations presented herein, contains the element and particle formulations, as well as the explicit methodology and constitutive models needed to perform these simulations. These simulations were compared against experimental data, evaluating the damage caused to the projectile and the target plates, as well as comparing the residual velocity when the projectile perforated the target.

Energy loss of argon in a laser-generated carbon plasma.

Science.gov (United States)

Frank, A; Blazević, A; Grande, P L; Harres, K; Hessling, T; Hoffmann, D H H; Knobloch-Maas, R; Kuznetsov, P G; Nürnberg, F; Pelka, A; Schaumann, G; Schiwietz, G; Schökel, A; Schollmeier, M; Schumacher, D; Schütrumpf, J; Vatulin, V V; Vinokurov, O A; Roth, M

2010-02-01

The experimental data presented in this paper address the energy loss determination for argon at 4 MeV/u projectile energy in laser-generated carbon plasma covering a huge parameter range in density and temperature. Furthermore, a consistent theoretical description of the projectile charge state evolution via a Monte Carlo code is combined with an improved version of the CasP code that allows us to calculate the contributions to the stopping power of bound and free electrons for each projectile charge state. This approach gets rid of any effective charge description of the stopping power. Comparison of experimental data and theoretical results allows us to judge the influence of different plasma parameters.

PET attenuation coefficients from CT images: experimental evaluation of the transformation of CT into PET 511-keV attenuation coefficients.

Science.gov (United States)

Burger, C; Goerres, G; Schoenes, S; Buck, A; Lonn, A H R; Von Schulthess, G K

2002-07-01

The CT data acquired in combined PET/CT studies provide a fast and essentially noiseless source for the correction of photon attenuation in PET emission data. To this end, the CT values relating to attenuation of photons in the range of 40-140 keV must be transformed into linear attenuation coefficients at the PET energy of 511 keV. As attenuation depends on photon energy and the absorbing material, an accurate theoretical relation cannot be devised. The transformation implemented in the Discovery LS PET/CT scanner (GE Medical Systems, Milwaukee, Wis.) uses a bilinear function based on the attenuation of water and cortical bone at the CT and PET energies. The purpose of this study was to compare this transformation with experimental CT values and corresponding PET attenuation coefficients. In 14 patients, quantitative PET attenuation maps were calculated from germanium-68 transmission scans, and resolution-matched CT images were generated. A total of 114 volumes of interest were defined and the average PET attenuation coefficients and CT values measured. From the CT values the predicted PET attenuation coefficients were calculated using the bilinear transformation. When the transformation was based on the narrow-beam attenuation coefficient of water at 511 keV (0.096 cm(-1)), the predicted attenuation coefficients were higher in soft tissue than the measured values. This bias was reduced by replacing 0.096 cm(-1) in the transformation by the linear attenuation coefficient of 0.093 cm(-1) obtained from germanium-68 transmission scans. An analysis of the corrected emission activities shows that the resulting transformation is essentially equivalent to the transmission-based attenuation correction for human tissue. For non-human material, however, it may assign inaccurate attenuation coefficients which will also affect the correction in neighbouring tissue.

Electromagnetic compression gun for hypervelocity projectile acceleration

International Nuclear Information System (INIS)

Woo, J.T.

1987-01-01

The rapid acceleration of projectiles to very high velocities has applications in many areas. The general requirements for an effective system is simplicity, reliability, compactness and good efficiency. The authors developed a concept by using electromagnetic forces to compressionally heat a plasma to high temperature and pressure to serve as the propellant for the acceleration of projectiles. The concept shares the simplicity of the light gas gun, but because of the high temperature of the propellant, is capable of significantly higher performance. Unlike the electrothermal gun approach to raise the propellant temperature by resistive heating, the electromagnetic concept is more efficient at higher temperatures. Operationally, the concept resembles a railgun in requiring a large pulsed current to drive the system. However, the current flow in this case is entirely external to the gun barrel and is axisymmetric. Therefore, many of the problems associated with railgun operations are avoided. Furthermore, because the current channel is external, there is also greater flexibility in the choice of load impedance to match to the power supply. The concept can also be generalized to a multi-stage regenerative system driven by a pulse forming network to resemble a coaxial accelerator

Morphology and chemistry of projectile residue in small experimental impact craters

Science.gov (United States)

Horz, F.; Fechtig, H.; Janicke, J.; Schneider, E.

1983-01-01

Small-scale impact craters (5-7 mm in diameter) were produced with a light gas gun in high purity Au and Cu targets using soda lime glass (SL) and man-made basalt glass (BG) as projectiles. Maximum impact velocity was 6.4 km/s resulting in peak pressures of approximately 120-150 GPa. Copious amounts of projectile melts are preserved as thin glass liners draping the entire crater cavity; some of this liner may be lost by spallation, however. SEM investigations reveal complex surface textures including multistage flow phenomena and distinct temporal deposition sequences of small droplets. Inasmuch as some of the melts were generated at peak pressures greater than 120 GPa, these glasses represent the most severely shocked silicates recovered from laboratory experiments to date. Major element analyses reveal partial loss of alkalis; Na2O loss of 10-15 percent is observed, while K2O loss may be as high as 30-50 percent. Although the observed volatile loss in these projectile melts is significant, it still remains uncertain whether target melts produced on planetary surfaces are severely fractionated by selective volatilization processes.

Charged projectile spectrometry using solid-state nuclear track detector of the PM-355 type

Directory of Open Access Journals (Sweden)

Malinowska Aneta

2015-09-01

Full Text Available To use effectively any radiation detector in high-temperature plasma experiments, it must have a lot of benefits and fulfill a number of requirements. The most important are: a high energy resolution, linearity over a wide range of recorded particle energy, high detection efficiency for these particles, a long lifetime and resistance to harsh conditions existing in plasma experiments and so on. Solid-state nuclear track detectors have been used in our laboratory in plasma experiments for many years, but recently we have made an attempt to use these detectors in spectroscopic measurements performed on some plasma facilities. This paper presents a method that we used to elaborate etched track diameters to evaluate the incident projectile energy magnitude. The method is based on the data obtained from a semiautomatic track scanning system that selects tracks according to two parameters, track diameter and its mean gray level.

Reply to projectile- and target-charge dependent effects in ionizing collisions of H sup + and He sup 2+ with He, Ne and Ar atoms

Energy Technology Data Exchange (ETDEWEB)

Bernardi, G.; Suarez, S.; Fainstein, P.; Garibotti, C.; Meckbach, W.; Focke, P. (Comision Nacional de Energia Atomica, San Carlos de Bariloche (Argentina). Centro Atomico Bariloche)

1990-12-28

The consistency of our previous results, for He ionization by H{sup +} and He{sub 3}{sup 2+} impact, with recent theoretical calculations is briefly commented upon. The results do not support the hypothesis of an independent saddle-point mechanism at the projectile energies studied. (author).

A simulation of low energy channeling of protons in silicon

International Nuclear Information System (INIS)

Sabin, J.R.

1994-01-01

The authors present early results from the CHANNEL code, which simulates the passage of ionized projectiles through bulk solids. CHANNEL solves the classical equations of motion for the projectile using the force obtained from the gradient of the quantum mechanically derived coulombic potential of the solid (determined via a full potential augmented plane wave FLAPW calculation on the bulk) and a quantum mechanical energy dissipation term, the stopping power, as determined from the local electron density, using the method of Echenique, Nieminen, and Ritchie. The code then generates the trajectory of the ionic projectile for a given initial velocity and a given incident position on the unit cell face. For each incident projectile velocity, the authors generate trajectories for incidence distributed over the channel face. The distribution of ranges generates an implantation profile. In this paper, they report ion (proton) implantation profiles for low energy protons with initial velocity along the (100) and (110) channel directions of diamond structured Silicon

The measurement of attenuation coefficients at low photon energies using fluorescent x-radiation

International Nuclear Information System (INIS)

Peaple, L.H.J.; White, D.R.

1978-03-01

A rapid and accurate method has been developed to measure low energy attenuation coefficients for materials of importance in radiation dosimetry. It employs a collimated beam of fluorescent x-rays from which the required radiation is selected by means of a high resolution germanium detector and multi-channel analyser. The method is described in detail and its accuracy and application outlined with reference to the results from nine different materials. (author)

Migration spontanee de projectile intracranien: presentation clinique ...

African Journals Online (AJOL)

Les traumatismes crâniens par arme à feu sont graves. Les manifestations cliniques sont variables et peuvent présenter quelques particularités. Les auteurs rapportent un cas de migration spontané de projectile intracérébral survenue après un traumatisme crânien par arme à feu au cours d'une partie de chasse. Elle a été ...

Projectile Motion in the "Language" of Orbital Motion

Science.gov (United States)

Zurcher, Ulrich

2011-01-01

We consider the orbit of projectiles launched with arbitrary speeds from the Earth's surface. This is a generalization of Newton's discussion about the transition from parabolic to circular orbits, when the launch speed approaches the value [image omitted]. We find the range for arbitrary launch speeds and angles, and calculate the eccentricity of…

Failure mechanism of monolayer graphene under hypervelocity impact of spherical projectile

Science.gov (United States)

Xia, Kang; Zhan, Haifei; Hu, De'An; Gu, Yuantong

2016-09-01

The excellent mechanical properties of graphene have enabled it as appealing candidate in the field of impact protection or protective shield. By considering a monolayer graphene membrane, in this work, we assessed its deformation mechanisms under hypervelocity impact (from 2 to 6 km/s), based on a serial of in silico studies. It is found that the cracks are formed preferentially in the zigzag directions which are consistent with that observed from tensile deformation. Specifically, the boundary condition is found to exert an obvious influence on the stress distribution and transmission during the impact process, which eventually influences the penetration energy and crack growth. For similar sample size, the circular shape graphene possesses the best impact resistance, followed by hexagonal graphene membrane. Moreover, it is found the failure shape of graphene membrane has a strong relationship with the initial kinetic energy of the projectile. The higher kinetic energy, the more number the cracks. This study provides a fundamental understanding of the deformation mechanisms of monolayer graphene under impact, which is crucial in order to facilitate their emerging future applications for impact protection, such as protective shield from orbital debris for spacecraft.

Calculation of projectile velocity in an electromagnetic mass driver

International Nuclear Information System (INIS)

Ikuta, K.

1986-08-01

The formula for the velocity increase of a projectile accelerated by the single z-pinch between the cylindrical electrodes is established. This formula enables one to consider the necessary stages in the cylindrical electrode array of the accelerator for a required velocity. (author)

X-ray yields by low energy heavy ion excitation in alkali halide solid targets

International Nuclear Information System (INIS)

Kurup, M.B.; Prasad, K.G.; Sharma, R.P.

1981-01-01

Solid targets of the alkali halides KCl, NaCl and KBr are bombarded with ion beams of 35 Cl + , 40 Ar + and 63 Cu + in the energy range 165 keV to 320 keV. The MO and characteristic K X-ray yields resulting from the ion-atom collision have been systematically studied. Both MO and Cl K X-ray yields are enhanced by factors 3.5 and 2 respectively in KCl targets as compared to that in NaCl when bombarded with either Cl + or Ar + projectiles. An intercomparison of MO and K X-ray yields for a given projectile-target combination has shown that the latter increases ten times faster than the former as the energy of the projectile is increased from 165 to 320 keV indicating a correspondingly stronger velocity dependence of the K X-ray production process. The X-ray yields observed in the symmetric Cl-Cl collision are identical to those observed in the asymmetric Ar-Cl collision for the same projectile velocities in both KCl and NaCl targets. It is inferred that the multiple ionization of the projectile resulting in an increase in the binding energy of its inner shells offsets the expected enhancement in the X-ray yields in a symmetric collision. The same projectiles, Ar or Cl, incident on KBr targets have produced only Br L X-rays. Using substantially heavier projectiles than the target atoms (Na, K and Cl), like 63 Cu + ions, the inner shell excitation by recoiling atoms is shown. (orig.)

Absence of the threshold anomaly in the elastic scattering of the weakly bound projectile 7Li on 27Al

International Nuclear Information System (INIS)

Figueira, J.M.; Abriola, D.; Niello, J.O. Fernandez; Arazi, A.; Capurro, O.A.; Barbara, E. de; Marti, G.V.; Martinez Heimann, D.; Pacheco, A.J.; Testoni, J.E.; Padron, I.; Gomes, P.R.S.; Lubian, J.

2006-01-01

To study the conditions leading to the appearance of the threshold anomaly in systems involving weakly bound projectiles we measured elastic scattering cross sections for the 7 Li+ 27 Al system at ten different bombarding energies. The results were exhaustively analyzed using different optical model potentials. The similar behavior observed in all these analyses allows us to conclude that no threshold anomaly is found for the present system

High speed photography of the plasma flow and the projectiles in the T.U.M. hypervelocity accelerator

International Nuclear Information System (INIS)

Igenbergs, E.; Kuczera, H.; Schroeder, B.

1979-01-01

The hypervelocity accelerator at the Technische Universitaet Muenchen, FRG, accelerates small projectiles (0.1 to 1.0 mm diameter) to velocities around 20 km/s. The photographic equipment consists of two Cordin single-frame image converter cameras and one TRW image converter camera with streak units and multiple-frame units. They are used for plasma flow diagnostics and the measurement of the position and the velocity of the projectiles. The single-frame cameras are triggered with a Laser light bar and the photographic measurement of the projectile velocity will be compared with Doppler-Radar. (author)

Influence of the target surface contamination on UHV screening energies

Energy Technology Data Exchange (ETDEWEB)

Targosz-Sleczka, N; Czerski, K; Kilic, A I [Institute of Physics, University of Szczecin, Szczecin (Poland); Huke, A; Martin, L; Heide, P [Institut fuer Atomare Physik und Optik, Technische Universitaet Berlin, Berlin (Germany); Blauth, D; Winter, H, E-mail: natalia.targosz@wmf.univ.szczecin.p [Institut fuer Physik, Humboldt-Universitaet zu Berlin, Berlin (Germany)

2010-01-01

The d + d fusion reactions have been investigated in the Zirconium environment under ultra high vacuum (UHV) conditions for projectile energies below 30 keV. The experimentally determined screening energy value of 497 {+-} 7 eV is larger than the previous results by a factor of almost two. Despite the UHV conditions a small deviation between experimental data and the theoretical curve arising from the target surface contamination could be still observed at the lowest projectile energies. Calculations made under the assumption of formation of a Zirconium oxide contamination, show that every atomic monolayer reduces the estimated screening energy significantly.

Influence of the target surface contamination on UHV screening energies

International Nuclear Information System (INIS)

Targosz-Sleczka, N; Czerski, K; Kilic, A I; Huke, A; Martin, L; Heide, P; Blauth, D; Winter, H

2010-01-01

The d + d fusion reactions have been investigated in the Zirconium environment under ultra high vacuum (UHV) conditions for projectile energies below 30 keV. The experimentally determined screening energy value of 497 ± 7 eV is larger than the previous results by a factor of almost two. Despite the UHV conditions a small deviation between experimental data and the theoretical curve arising from the target surface contamination could be still observed at the lowest projectile energies. Calculations made under the assumption of formation of a Zirconium oxide contamination, show that every atomic monolayer reduces the estimated screening energy significantly.

Wound Ballistics Modeling for Blast Loading Blunt Force Impact and Projectile Penetration.

Energy Technology Data Exchange (ETDEWEB)

Taylor, Paul A. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

2015-11-01

Light body armor development for the warfighter is based on trial-and-error testing of prototype designs against ballistic projectiles. Torso armor testing against blast is nonexistent but necessary to protect the heart and lungs. In tests against ballistic projectiles, protective apparel is placed over ballistic clay and the projectiles are fired into the armor/clay target. The clay represents the human torso and its behind-armor, permanent deflection is the principal metric used to assess armor protection. Although this approach provides relative merit assessment of protection, it does not examine the behind-armor blunt trauma to crucial torso organs. We propose a modeling and simulation (M&S) capability for wound injury scenarios to the head, neck, and torso of the warfighter. We will use this toolset to investigate the consequences of, and mitigation against, blast exposure, blunt force impact, and ballistic projectile penetration leading to damage of critical organs comprising the central nervous, cardiovascular, and respiratory systems. We will leverage Sandia codes and our M&S expertise on traumatic brain injury to develop virtual anatomical models of the head, neck, and torso and the simulation methodology to capture the physics of wound mechanics. Specifically, we will investigate virtual wound injuries to the head, neck, and torso without and with protective armor to demonstrate the advantages of performing injury simulations for the development of body armor. The proposed toolset constitutes a significant advance over current methods by providing a virtual simulation capability to investigate wound injury and optimize armor design without the need for extensive field testing.

High accuracy experimental determination of copper and zinc mass attenuation coefficients in the 100 eV to 30 keV photon energy range

Science.gov (United States)

Ménesguen, Y.; Gerlach, M.; Pollakowski, B.; Unterumsberger, R.; Haschke, M.; Beckhoff, B.; Lépy, M.-C.

2016-02-01

The knowledge of atomic fundamental parameters such as mass attenuation coefficients with low uncertainties, is of decisive importance in elemental quantification using x-ray fluorescence analysis techniques. Several databases are accessible and frequently used within a large community of users. These compilations are most often in good agreement for photon energies in the hard x-ray ranges. However, they significantly differ for low photon energies and around the absorption edges of any element. In a joint cooperation of the metrology institutes of France and Germany, mass attenuation coefficients of copper and zinc were determined experimentally in the photon energy range from 100 eV to 30 keV by independent approaches using monochromatized synchrotron radiation at SOLEIL (France) and BESSY II (Germany), respectively. The application of high-accuracy experimental techniques resulted in mass attenuation coefficient datasets determined with low uncertainties that are directly compared to existing databases. The novel datasets are expected to enhance the reliability of mass attenuation coefficients.

Factorization of secondary particle multiplicities in nucleus-nucleus collisions at energy of some GeV on the projectile nucleon; Faktorizatsiya mnozhestvennostej vtorichnykh chastits v yadro-yadernykh soudareniyakh pri ehnergii neskol`ko GehV na nuklon snaryada

Energy Technology Data Exchange (ETDEWEB)

Basova, E S; Zhumanov, A; Nasrullaeva, Kh; Nasyrov, Sk Z; Petrov, N V; Sadykov, N O; Svechnikova, L N; Trofimova, T P; Tuleeva, U I; Tursunov, B P

1992-03-01

The nuclear photographic emulsion method was used to study multiplicity of secondaries in interaction of some GeV on nucleon of {sup 132} Xe nucleus with photoemulsion. The formulas suggested describing the experimental data of normalized, mean and specific secondary particle multiplicity in nucleus-nucleus collisions at given energy. These formulas have evidence for the factorization of mean and specific multiplicities relatively the target and projectile nucleus mass number. (author). 10 refs., 5 figs., 4 tabs.

Comparative parametric numerical simulations of materials used as liners in the explosively formed projectiles (EFPs)

International Nuclear Information System (INIS)

Hussain, G.; Sanaullah, K.

2009-01-01

A conventional shaped charge comprises a conical metal liner projecting a hyper velocity jet of metal that is able to penetrate to great depths into steel armour. However, misalignment problems exist in tandem with jet break up and spewing particles that greatly diminish its penetration power. An EFP, on the other hand, has a liner in the shape of a geometrical recess. The force of the blast molds the liner into a number of configurations, depending on the geometry and the explosive detonation characteristics. This paper presents comparative parametric numerical simulations of materials used as liners in the explosively formed projectiles EFPs. Numerical simulations are carried out using AUTODYN 2D hydrocode to study effects of liner's materials on the shape, velocity, traveled distance, time, pressure, internal energy, temperature, yield stress, divergence or stability, density, compression, and length to diameter (L/D) ratio of EFPs. These parameters are estimated at the instants of maximum as well as at stable velocities. The parametric study reveals that aluminum has maximum velocity in shortest time among the liner materials. From this reason, it was concluded effective standoff was greater for aluminum than more denser metals. Maximum velocity and traveled distance of Tantalum EFP is found to be minimum which may be due to low thermal softening exponent and larger hardening exponent. The simulated yield stress and pressure developed in the Fe EFP reaches at maximum. The L/D ratio for Copper is found to be maximum which supports maximum penetration. From the stability point of view, 1006 MS is found to be the most reliable liner material due to minimum divergence. Generally all liner materials have similar effects of all parameters like pressure, internal energy, temperature, yield stress, divergence or stability, density, compression at the instants of maximum as well as at stable velocities except L/D ratio of EFPs. At the instant of maximum velocity, L

Bringing solid fuel ramjet projectiles closer to application - An overview of the TNO/RWMS technology demonstration programme

NARCIS (Netherlands)

Veraar, R.G.; Giusti, G.

2005-01-01

TNO executed a technology demonstration programme in co-operation with RWMS on the application of solid fuel ramjet propulsion technology to medium calibre air defence projectiles. From 2000 to 2004 a complete and integrated structural and aero-thermodynamic projectile design was conceived

Bibliographic survey of medium energy inclusive reaction data

International Nuclear Information System (INIS)

Arthur, E.D.; Madland, D.G.; McClellan, D.M.

1986-04-01

A bibliographic survey of inclusive reaction data (experimental and theoretical) for several projectile types having energies between 50 and 1000 MeV has been completed. Approximately one thousand references selected from this survey describe the current state of knowledge for particle-induced inclusive reaction data. The search covered data for the following projectiles: p, d, t, 3 He, 4 He, and lithium ions

Energy dependence of the stopping power of MeV 16O ions in a laser-produced plasma

International Nuclear Information System (INIS)

Sakumi, A.; Shibata, K.; Sato, R.; Tsubuku, K.; Nishimoto, T.; Hasegawa, J.; Ogawa, M.; Oguri, Y.; Katayama, T.

2001-01-01

The energy dependence of the stopping power of 16 O ions in a laser-produced plasma target was experimentally investigated in the projectile energy range of 150-350 keV/u. In order to produce the target plasma a Q-Switched Nd-glass laser was focused onto a small lithium hydride (LiH) pellet. The plasma electron temperature and the electron line density were 15 eV and 2x10 17 cm -2 , respectively. The energy loss of 16 O ions in the plasma was measured by a time-of-flight (TOF) method. We found that the stopping power in the plasma agreed with the theoretical estimation based on a modified Bohr equation with correction at low velocities. In this evaluation, the effective charge of the projectile was calculated by means of rate equations on the loss and capture of electrons. It has been also found that in this projectile energy range the stopping power of the 16 O ions in the plasma still increases with decreasing projectile energy, while it decreases in cold equivalent

CFD Simulations of a Finned Projectile with Microflaps for Flow Control

Directory of Open Access Journals (Sweden)

Jubaraj Sahu

2017-01-01

Full Text Available This research describes a computational study undertaken to determine the effect of a flow control mechanism and its associated aerodynamics for a finned projectile. The flow control system consists of small microflaps located between the rear fins of the projectile. These small microflaps alter the flow field in the aft finned region of the projectile, create asymmetric pressure distributions, and thus produce aerodynamic control forces and moments. A number of different geometric parameters, microflap locations, and the number of microflaps were varied in an attempt to maximize the control authority generated by the flaps. Steady-state Navier-Stokes computations were performed to obtain the control aerodynamic forces and moments associated with the microflaps. These results were used to optimize the control authority at a supersonic speed, M=2.5. Computed results showed not only the microflaps to be effective at this speed, but also configurations with 6 and 8 microflaps were found to generate 25%–50% more control force than a baseline 4-flap configuration. These results led to a new optimized 8-flap configuration that was further investigated for a range of Mach numbers from M=0.8 to 5.0 and was found to be a viable configuration effective in providing control at all of these speeds.

Computation of the mass attenuation coefficient of polymeric materials at specific gamma photon energies

Science.gov (United States)

Mirji, Rajeshwari; Lobo, Blaise

2017-06-01

The gamma ray mass attenuation coefficients of ten synthetic polymeric materials, namely, polyethylene (PE), polystyrene (PS), polycarbonate (PC), polyvinyl alcohol (PVA), polyvinyl chloride (PVC), Polyethylene terephthalate (PET), Polyvinyl pyrrolidone (PVP), Polytetrafluoroethylene (PTFE), Polypropylene (PP) and Polymethyl methacrylate (PMMA) have been calculated using second order polynomial equation and logarithmic interpolation formula at selected gamma photon energies, in the energy range starting from 14.4 keV up to 1332 keV. It is important to note that second order polynomial equation fits very well with NIST data for all the polymeric materials considered here, for gamma photon energies ranging from 300 keV up to 2000 keV. Third order polynomial fitting is best suited for lower gamma photon energies (from 10 keV up to 200 keV).

Study of Relativistic Nucleus-nucleus Coll.Induced by 16O Projectiles

CERN Multimedia

2002-01-01

A double experiment in which two detector systems (Streamer Chamber, Plastic Ball Calorimeter), running concurrently via a beam split (West Area H3, X5), search for quark matter formation in violent collisions of |1|6O or |2|0Ne with target nuclei between |4|0Ca and |2|0|6Pb. The acceleration of |1|6O will be facilitated by a high charge state injector, consisting of an ECR source and an RFQ pre-accelerator, installed by GSI and LBL at the PS Linac 1. Experimental equipment will be a streamer chamber installed in the Vertex Magnet of experiment WA75 together with beam hodoscopes and a downstream trigger calorimeter selecting violent events by the absence of energy flow to the projectile fragmentation region. Observed particles will be p, @p, K|0, @L and @L. In addition there will be the Plastic Ball, 800-fold @DE-E particle identifier system, covering the target fragmentation and backward fireball regions. Together with a multisegmented large solid angle (@+~9|0 of beam) energy calorimeter and a trigger calor...

Gamma-rays attenuation of zircons from Cambodia and South Africa at different energies: A new technique for identifying the origin of gemstone

Science.gov (United States)

Limkitjaroenporn, P.; Kaewkhao, J.

2014-10-01

In this work, the gamma-rays interaction properties of zircons from Cambodia and South Africa have been studied. The densities of Cambodian and South African's zircons are 4.6716±0.0040 g/cm3 and 4.5505±0.0018 g/cm3, respectively. The mass attenuation coefficient and the effective atomic number of gemstones were measured with the gamma-ray in energies range 223-662 keV using the Compton scattering technique. The mass attenuation coefficients of both zircons decreased with the increasing of gamma-rays energies. The different mass attenuation coefficients between the two zircons observed at gamma-ray energies below 400 keV are attributed to the differences in the photoelectric interaction. The effective atomic number of zircons was decreased with the increasing of gamma-ray energies and showed totally different values between the Cambodia and South Africa sources. The origins of the two zircons could be successfully identified by the method based on gamma-rays interaction with matter with advantage of being a non-destructive testing.

Ultrasonic attenuation in superconducting zinc

International Nuclear Information System (INIS)

Auluck, S.

1978-01-01

The differences in the Zn ultrasonic attenuation data of different workers are analyzed. The superconducting energy gaps deduced from our analysis of the ultrasonic-attenuation data of Cleavelin and Marshall are consistent with the gaps deduced from the knowledge of the Fermi surface and the electron-phonon mass enhancement factor

Devices for launching 0.1-g projectiles to 150 km/s or more to initiate fusion. Part 1. Magnetic-gradient and electrostatic accelerators

International Nuclear Information System (INIS)

Brittingham, J.N.

1979-01-01

The feasibility of using magnetic-gradient and electrostatic accelerators to launch a 0.1-g projectile to hypervelocities (150 km/s or more) is studied. Such hypervelocity projectiles could be used to ignite deuterium-tritium fuel pellets in a fusion reactor. For the magnetic-gradient accelerator, several types of projectile were studied: shielded and unshielded copper, ferromagnetic, and superconducting. The calculations revealed the superconducting projectile to be the best of those materials. It would require a 3.2-km-long magnetic-gradient accelerator and achieve a 92% efficiency. This accelerator-projectile combination would be the one most likely to launch a 0.1-g projectile to 150 km/s or more. Its components would cost $58.9 million. The electrostatic accelerator was found to be impractical because of its excessive length of 23 km

Aerodynamic Jump: A Short Range View for Long Rod Projectiles

Directory of Open Access Journals (Sweden)

Mark Bundy

2001-01-01

Full Text Available It is shown that aerodynamic jump for a nonspinning kinetic energy penetrator is not – as conventional definitions may infer – a discontinuous change in the direction of motion at the origin of free flight, nor is it the converse, a cumulative redirection over a domain of infinite extent. Rather, with the aid of an alternative kinematical definition, it is shown that aerodynamic jump for such a projectile is a localized redirection of the center-of-gravity motion, caused by the force of lift due to yaw over the relatively short region from entry into free flight until the yaw reaches its first maximum. A rigorous proof of this statement is provided, but the primary objective of this paper is to provide answers to the questions: what is aerodynamic jump, what does it mean, and what aspects of the flight trajectory does it refer to, or account for.

Research on Ground Motion Metal Target Based on Rocket Projectile by Using Millimeter Wave Radiometer Technology

Directory of Open Access Journals (Sweden)

Zhang Dongyang

2014-06-01

Full Text Available How to detect the ground motion metal target effectively is an important guarantee for precision strike in the process of Rocket Projectile flight. Accordingly and in view of the millimeter- wave radiation characteristic of the ground motion metal target, a mathematical model was established based on Rocket Projectile about millimeter-wave detection to the ground motion metal target. Through changing various parameters in the process of Rocket Projectile flight, the detection model was studied by simulation. The parameters variation and effective range of millimeter wave radiometer were obtained in the process of rotation and horizontal flight. So a certain theoretical basis was formed for the precision strike to the ground motion metal target.

Fusion of a polarized projectile with a polarized target

International Nuclear Information System (INIS)

Christley, J.A.; Johnson, R.C.; Thompson, I.J.

1995-01-01

The fusion cross sections for a polarized target with both unpolarized and polarized projectiles are studied. Expressions for the observables are given for the case when both nuclei are polarized. Calculations for fusion of an aligned 165 Ho target with 16 O and polarized 7 Li beams are presented

Penetration of a Small Caliber Projectile into Single and Multi-layered Targets

Directory of Open Access Journals (Sweden)

Riad A.M.

2010-06-01

Full Text Available The normal penetration of armor-piercing projectiles into single and multi-layered steel plates has been investigated. An experimental program has been conducted to study the effect of spaced and in-contact layered targets on their ballistic resistance. Armor piercing projectiles with caliber of 7.62 mm were fired against a series of single and multi-layered steel targets. The projectile impact velocities were ranged from 300-600 m/s, whereas the total thicknesses of the tested single, spaced and in-contact layered steel targets were 3 mm. The penetration process of different tested target configurations has been simulated using Autodayn-2D hydrocode. The experimental measurements of the present work were used to discuss the effect of impact velocity, target configurations and number of layers of different spaced and in-contact layered steel targets on their ballistic resistance. In addition, the post-firing examination of the tested targets over the used impact velocity range showed that the single and each layer of spaced and in-contact laminated steel targets were failed by petalling. Finally, the obtained experimental measurements were compared with the corresponding numerical results of Autodyn-2D hydrocode, good agreement was generally obtained.

Estimates of the Attenuation Rates of Baroclinic Tidal Energy Caused by Resonant Interactions Among Internal Waves based on the Weak Turbulence Theory

Science.gov (United States)

Onuki, Y.; Hibiya, T.

2016-02-01

The baroclinic tides are thought to be the dominant energy source for turbulent mixing in the ocean interior. In contrast to the geography of the energy conversion rates from the barotropic to baroclinic tides, which has been clarified in recent numerical studies, the global distribution of the energy sink for the resulting low-mode baroclinic tides remains obscure. A key to resolve this issue is the resonant wave-wave interactions, which transfer part of the baroclinic tidal energy to the background internal wave field enhancing the local energy dissipation rates. Recent field observations and numerical studies have pointed out that parametric subharmonic instability (PSI), one of the resonant interactions, causes significant energy sink of baroclinic tidal energy at mid-latitudes. The purpose of this study is to analyze the quantitative aspect of PSI to demonstrate the global distribution of the intensity of resonant wave interactions, namely, the attenuation rate of low-mode baroclinic tidal energy. Our approach is basically following the weak turbulence theory, which is the standard theory for resonant wave-wave interactions, where techniques of singular perturbation and statistical physics are employed. This study is, however, different from the classical theory in some points; we have reformulated the weak turbulence theory to be applicable to low-mode internal waves and also developed its numerical calculation method so that the effects of stratification profile and oceanic total depth can be taken into account. We have calculated the attenuation rate of low-mode baroclinic tidal waves interacting with the background Garrett-Munk internal wave field. The calculated results clearly show the rapid attenuation of baroclinic tidal energy at mid-latitudes, in agreement with the results from field observations and also show the zonal inhomogeneity of the attenuation rate caused by the density structures associated with the subtropical gyre. This study is expected

Nuclear interactions of high energy heavy ions and applications in astrophysics

International Nuclear Information System (INIS)

Wefel, J.P.

1992-01-01

This program was established for the purpose of studying projectile fragmentation; (1) as a function of energy, focusing first on the intermediate energy region, < 1 GeV/nucleon, where there have been few previous measurements and no systematic studies, and (2) as a function of projectile mass, starting with light beams and proceeding to species as heavy as nickel (and possibly beyond). The intermediate energy region is important as the transition between the lower energy data, where the interaction appears to be dominated by collective effects and the decay of excited nuclei, and the highest energy results, where nucleon-nucleon interactions are fundamental, ''limiting fragmentation'' applies, and the nucleus may well break-up before any de-excitation. The mass dependence of projectile fragmentation is largely unknown since most detailed work has involved light ion beams. Nuclear structure effects, for example, may well be quite prominent for heavier beams. Furthermore, the nuclear excitation functions for the production of different fragment isotopes have immediate application to the astrophysical interpretation of existing isotopic datasets obtained from balloon and satellite measurements of galactic cosmic rays

Projectile electron loss in collisions of light charged ions with helium

International Nuclear Information System (INIS)

Yin Yong-Zhi; Chen Xi-Meng; Wang Yun

2014-01-01

We investigate the single-electron loss processes of light charged ions (Li 1+,2+ , C 2+,3+,5+ , and O 2+,3+ ) in collisions with helium. To better understand the experimental results, we propose a theoretical model to calculate the cross section of projectile electron loss. In this model, an ionization radius of the incident ion was defined under the classical over-barrier model, and we developed ''strings'' to explain the processes of projectile electron loss, which is similar with the molecular over-barrier model. Theoretical calculations are in good agreement with the experimental results for the cross section of single-electron loss and the ratio of double-to-single ionization of helium associated with one-electron loss. (atomic and molecular physics)

Absence of reionization in low-energy N a+ scattering from Al surfaces

Science.gov (United States)

Riccardi, P.; Cosimo, F.; Sindona, A.

2018-03-01

Inner-shell excitation during low-energy atomic collisions in the gas phase is driven by the formation of transient molecules, in which some electronic levels are promoted to higher energies. For collisions occurring in solids, it is commonly believed that electrons are promoted into the empty conduction states of the embedding system. To verify this assumption, we scattered slow, singly charged neon and sodium ions from polycrystalline aluminum surfaces, focusing on the Auger decay of projectiles excited in the 2 p level, during a binary collision with a target atom. We observed double promotion of 2 p electrons in collisions involving neon projectiles and neonlike sodium ions. Double 2 p excitation is anticipated also for neutralized sodium projectiles, but only single excitation is observed. This implies that the collision-induced excitation is governed by the occupancy of the 3 s level of the sodium projectile, with the electrons being excited into the Rydberg states of the collision system, rather than being transferred to the solid.

ENHANCEMENTS TO NATURAL ATTENUATION: SELECTED CASE STUDIES

Energy Technology Data Exchange (ETDEWEB)

Vangelas, K; W. H. Albright, W; E. S. Becvar, E; C. H. Benson, C; T. O. Early, T; E. Hood, E; P. M. Jardine, P; M. Lorah, M; E. Majche, E; D. Major, D; W. J. Waugh, W; G. Wein, G; O. R. West, O

2007-05-15

In 2003 the US Department of Energy (DOE) embarked on a project to explore an innovative approach to remediation of subsurface contaminant plumes that focused on introducing mechanisms for augmenting natural attenuation to achieve site closure. Termed enhanced attenuation (EA), this approach has drawn its inspiration from the concept of monitored natural attenuation (MNA).

Mean excitation energies for molecular ions

DEFF Research Database (Denmark)

Jensen, Phillip W.K.; Sauer, Stephan P.A.; Oddershede, Jens

2017-01-01

The essential material constant that determines the bulk of the stopping power of high energy projectiles, the mean excitation energy, is calculated for a range of smaller molecular ions using the RPA method. It is demonstrated that the mean excitation energy of both molecules and atoms increase...

Radiative electron capture into the K-, L-, and M-shell of decelerated, hydrogenic Ge projectiles

International Nuclear Information System (INIS)

Stoehlker, T.; Kozhuharov, C.; Livingston, A.E.; Mokler, P.H.; Stachura, Z.; Warczak, A.

1991-12-01

Radiative Electron Capture (REC) in 4 to 12 MeV/u Ge 31+ →H 2 collisions has been studied using an X-ray/particle coincidence technique. This technique allowed a systematic investigation of K-shell REC as well as a separation of REC into the projectile L- and M-shells. The cross sections are discussed within a general scaling picture based on the reduced projectile velocity. (orig.)

Assessment of empirical formulae for local response of concrete structures to hard projectile impact

International Nuclear Information System (INIS)

Buzaud, E.; Cazaubon, Ch.; Chauvel, D.

2007-01-01

The outcome of the impact of a hard projectile on a reinforced concrete structure is affected by different parameters such as the configuration of the interaction, the projectile geometry, mass and velocity and the target geometry, reinforcement, and concrete mechanical properties. Those parameters have been investigated experimentally during the last 30 years, hence providing a basis of simplified mathematical models like empirical formulae. The aim of the authors is to assess the relative performances of classical and more recent empirical formulae. (authors)

The LCLS Gas Attenuator Revisited

International Nuclear Information System (INIS)

Ryutov, D

2005-01-01

In the report ''X-ray attenuation cell'' [1] a preliminary analysis of the gas attenuator for the Linac Coherent Light Source (LCLS) was presented. This analysis was carried out for extremely stringent set of specifications. In particular, a very large diameter for the unobstructed beam was set (1 cm) to accommodate the spontaneous radiation; the attenuator was supposed to cover the whole range of energies of the coherent radiation, from 800 eV to 8000 eV; the maximum attenuation was set at the level of 10 4 ; the use of solid attenuators was not allowed, as well as the use of rotating shutters. The need to reach a sufficient absorption at the high-energy end of the spectrum predetermined the choice of Xe as the working gas (in order to have a reasonable absorption at a not-too-high pressure). A sophisticated differential pumping system that included a Penning-type ion pump was suggested in order to minimize the gas leak into the undulator/accelerator part of the facility. A high cost of xenon meant also that an efficient (and expensive) gas-recovery system would have to be installed. The main parameter that determined the high cost and the complexity of the system was a large radius of the orifice. The present viewpoint allows for much smaller size of the orifice, r 0 = 1.5 mm. (1) The use of solid attenuators is also allowed (R.M. Bionta, private communication). It is, therefore, worthwhile to reconsider various parameters of the gas attenuator for these much less stringent conditions. This brief study should be considered as a physics input for the engineering design. As a working gas we consider now the argon, which, on the one hand, provides a reasonable absorption lengths and, on the other hand, is inexpensive enough to be exhausted into the atmosphere (no recovery). The absorption properties of argon are illustrated by Fig.1 where the attenuation factor A is shown for various beam energies, based on Ref. [2]. The other relevant parameters for argon are

Experiment evaluation of impact attenuator for a racing car under static load

Science.gov (United States)

Imanullah, Fahmi; Ubaidillah, Prasojo, Arfi Singgih; Wirawan, Adhe Aji

2018-02-01

The automotive world is a world where one of the factors that must be considered carefully is the safety aspect. In the formula student car one of the safety factor in the form of impact attenuator. Impact attenuator is used as anchoring when a collision occurs in front of the vehicle. In the rule of formula society of automotive engineer (FSAE) student, impact attenuator is required to absorb the energy must meet or exceed 7350 Joules with a slowdown in speed not exceeding 20 g average and peak of 40 g. The student formula participants are challenged to pass the boundaries so that in designing and making the impact attenuator must pay attention to the strength and use of the minimum material so that it can minimize the expenditure. In this work, an impact attenuator was fabricated and tested using static compression. The primary goal was evaluating the actual capability of the impact attenuator for impact energy absorption. The prototype was made of aluminum alloy in a prismatic shape, and the inside wall was filled with rooftop plastic slices and polyurethane hard foam. The compression test has successfully carried out, and the load versus displacement data could be used in calculating energy absorption capability. The result of the absorbent energy of the selected impact attenuator material. Impact attenuator full polyurethane absorbed energy reach 6380 Joule. For impact attenuator with aluminum polyurethane with a slashed rooftop material as section absorbed energy reach 6600 Joule. Impact attenuator with Aluminum Polyurethane with aluminum orange peel partitions absorbed energy reach 8800 Joule. From standard student formula, energy absorbed in this event must meet or exceed 7350 Joules that meet aluminum polyurethane with aluminum orange peel partitions with the ability to absorb 8800 Joule.

Distributed energy store railguns experiment and analysis

International Nuclear Information System (INIS)

Holland, L.D.

1984-01-01

Electromagnetic acceleration of projectiles holds the potential for achieving higher velocities than yet achieved by any other means. A railgun is the simplest form of electromagnetic macroparticle accelerator and can generate the highest sustained accelerating force. The practical length of conventional railguns is limited by the impedance of the rails because current must be carried along the entire length of the rails. A railgun and power supply system called the distributed energy store railgun was proposed as a solution to this limitation. The distributed energy store railgun used multiple current sources connected to the rails of a railgun at points distributed along the bore. These current sources (energy stores) are turned on in sequence as the projectile moves down the bore so that current is fed to the railgun from behind the armature. In this system the length of the rails that carry the full armature current is less than the total length of the railgun. If a sufficient number of energy stores is used, this removes the limitation on the length of a railgun. An additional feature of distributed energy store type railguns is that they can be designed to maintain a constant pressure on the projectile being accelerated. A distributed energy store railgun was constructed and successfully operated. In addition to this first demonstration of the distributed energy store railgun principle, a theoretical model of the system was also constructed

Study of secondary electron emission from thin carbon targets with swift charged particles: heavy ions, hydrogen ions; Etude experimentale de l`emission electronique secondaire de cibles minces de carbone sous l`impact de projectiles rapides: ions lourds, ions hydrogene (atomiques, moleculaires ou sous forme d`agregats)

Energy Technology Data Exchange (ETDEWEB)

Billebaud, A

1995-07-12

The main subject of this work is the study of electron emission from the two surfaces of thin solid targets bombarded with swift charged particles. The slowing down of swift ions in matter is mainly due to inelastic interaction with target electrons (ionization, excitation): the energy transfer to target electrons is responsible for the secondary electron emission process. The phenomenological and theoretical descriptions of this phenomena are the subject of the first chapter. We focused on secondary electron emission induced by different kind of projectiles on thin carbon foils. In chapter two we describe hydrogen cluster induced electron emission measurement between 40 and 120 keV/proton. These projectiles, composed of several atoms, allowed us to study and highlight collective effects of the electron emission process. We extended our study of electron emission to molecular (H{sub 2}{sup +}, H{sub 3}{sup +}) and composite (H{sup -}, H{sup 0}) projectiles at higher energies (<= 2 MeV): we have designed an experimental set-up devoted to electron emission statistics measurements which allowed us to study, among others things, the role of projectile electrons in secondary electron emission. This experiment is described in the third chapter. Finally, the fourth chapter describes new measurements of electron emission induced by energetic (13 MeV/u) and highly charged argon ion provided by the medium energy beam line (SME) of GANIL (Caen), which have been analyzed in the framework of a semi-empirical model of secondary electron emission. This set of experiments brings new results on composite projectile interaction with matter, and on the consequences of high energy deposition in solids. (author).

Single capture and transfer ionization in collisions of Clq+ projectile ions incident on helium

International Nuclear Information System (INIS)

Wong, K.L.; Ben-Itzhak, I.; Cocke, C.L.; Giese, J.P.; Richard, P.

1995-01-01

The Kansas State University linac has been used to measure the ratio of the cross sections for the processes of transfer ionization (TI) and single capture (SC) for 2 MeV/amu Cl q+ where q=7, 9, 13, 14, and 15 projectile ions incident on a helium target. The ratio was determined using a helium gas jet target by measuring coincidences between projectile-ion and recoil-ion final charge states. The σ TI /σ SC for Cl q+ were compared to measurements of bare F 9+ and hydrogenlike F 8+ and O 7+ taken at the same velocity. The ratios deviate from a q 2 scaling which is predicted in the perturbative regime. This deviation is attributed to screening by the projectile electrons for low q=7 and 9, and to the collision being non-perturbative for high q. A possible saturation effect in the ratio was observed for q similar 14. (orig.)

Occult lawn mower projectile injury presenting with hemoptysis

Directory of Open Access Journals (Sweden)

Patric J. Darvie, BS

2017-12-01

Full Text Available We present the case of a 72-year-old man with hemoptysis after a thoracic projectile injury, which occurred while mowing the lawn. Chest radiograph followed by a computed tomography angiogram revealed a metallic foreign body in the right middle lobe of the lung. The patient underwent a right anterolateral thoracotomy where the object was successfully retrieved. The patient had an uneventful postoperative recovery.

Occult lawn mower projectile injury presenting with hemoptysis.

Science.gov (United States)

Darvie, Patric J; Ballard, David H; Harris, Nicholas; Bhargava, Peeyush; Rao, Vyas R; Samra, Navdeep S

2017-12-01

We present the case of a 72-year-old man with hemoptysis after a thoracic projectile injury, which occurred while mowing the lawn. Chest radiograph followed by a computed tomography angiogram revealed a metallic foreign body in the right middle lobe of the lung. The patient underwent a right anterolateral thoracotomy where the object was successfully retrieved. The patient had an uneventful postoperative recovery.

Occult lawn mower projectile injury presenting with hemoptysis

OpenAIRE

Patric J. Darvie, BS; David H. Ballard, MD; Nicholas Harris, MD; Peeyush Bhargava, MD, MBA; Vyas R. Rao, MD; Navdeep S. Samra, MD

2017-01-01

We present the case of a 72-year-old man with hemoptysis after a thoracic projectile injury, which occurred while mowing the lawn. Chest radiograph followed by a computed tomography angiogram revealed a metallic foreign body in the right middle lobe of the lung. The patient underwent a right anterolateral thoracotomy where the object was successfully retrieved. The patient had an uneventful postoperative recovery.

A parameterization scheme for the x-ray linear attenuation coefficient and energy absorption coefficient.

Science.gov (United States)

Midgley, S M

2004-01-21

A novel parameterization of x-ray interaction cross-sections is developed, and employed to describe the x-ray linear attenuation coefficient and mass energy absorption coefficient for both elements and mixtures. The new parameterization scheme addresses the Z-dependence of elemental cross-sections (per electron) using a simple function of atomic number, Z. This obviates the need for a complicated mathematical formalism. Energy dependent coefficients describe the Z-direction curvature of the cross-sections. The composition dependent quantities are the electron density and statistical moments describing the elemental distribution. We show that it is possible to describe elemental cross-sections for the entire periodic table and at energies above the K-edge (from 6 keV to 125 MeV), with an accuracy of better than 2% using a parameterization containing not more than five coefficients. For the biologically important elements 1 coefficients. At higher energies, the parameterization uses fewer coefficients with only two coefficients needed at megavoltage energies.

Gamma-rays attenuation of zircons from Cambodia and South Africa at different energies: A new technique for identifying the origin of gemstone

International Nuclear Information System (INIS)

Limkitjaroenporn, P.; Kaewkhao, J.

2014-01-01

In this work, the gamma-rays interaction properties of zircons from Cambodia and South Africa have been studied. The densities of Cambodian and South African’s zircons are 4.6716±0.0040 g/cm 3 and 4.5505±0.0018 g/cm 3 , respectively. The mass attenuation coefficient and the effective atomic number of gemstones were measured with the gamma-ray in energies range 223–662 keV using the Compton scattering technique. The mass attenuation coefficients of both zircons decreased with the increasing of gamma-rays energies. The different mass attenuation coefficients between the two zircons observed at gamma-ray energies below 400 keV are attributed to the differences in the photoelectric interaction. The effective atomic number of zircons was decreased with the increasing of gamma-ray energies and showed totally different values between the Cambodia and South Africa sources. The origins of the two zircons could be successfully identified by the method based on gamma-rays interaction with matter with advantage of being a non-destructive testing. - Highlights: • Gamma-rays interaction of zircons from Cambodia and South Africa studied. • Measured energy is during 223–662 keV. • Different μ m between the two zircons observed at gamma-ray energies below 400 keV. • The origins the two zircons could be successfully identified

Secondary electron emission of thin carbon foils under the impact of hydrogen atoms, ions and molecular ions, under energies within the MeV range; Multiplicite des electrons secondaires emis par des cibles minces de carbone sous l'impact de projectiles H0, H2+, H3+ d'energie de l'ordre du MeV

Energy Technology Data Exchange (ETDEWEB)

Vidovic, Z

1997-06-15

This work focuses on the study of the emission statistics of secondary electrons from thin carbon foils bombarded with H{sup 0}, H{sub 2}{sup +} and H{sub 3}{sup +} projectiles in the 0.25-2.2 MeV energy range. The phenomenon of secondary electron emission from solids under the impact of swift ions is mainly due to inelastic interactions with target electrons. The phenomenological and theoretical descriptions, as well as a summary of the main theoretical models are the subject of the first chapter. The experimental set-up used to measure event by event the electron emission of the two faces of a thin carbon foil traversed by an energetic projectile is described in the chapter two. In this chapter are also presented the method and algorithms used to process experimental spectra in order to obtain the statistical distribution of the emitted electrons. Chapter three presents the measurements of secondary electron emission induced by H atoms passing through thin carbon foils. The secondary electron yields are studied in correlation with the emergent projectile charge state. We show the peculiar role of the projectile electron, whether it remains or not bound to the incident proton. The fourth chapter is dedicated to the secondary electron emission induced by H{sub 2}{sup +} and H{sub 3}{sup +} polyatomic ions. The results are interpreted in terms of collective effects in the interactions of these ions with solids. The role of the proximity of the protons, molecular ion fragments, upon the amplitude of these collective effects is evidenced from the study of the statistics of forward emission. These experiences allowed us to shed light on various aspects of atom and polyatomic ion inter-actions with solid surfaces. (author)

Numerical simulation of 3-D incompressible, multi-phase flows over cavitating projectiles

Energy Technology Data Exchange (ETDEWEB)

Owis, F.M.; Nayfeh, A.H. [Blacksburg State University, Dept. of Engineering Science and Mechanics, MC 0219, Virginia Polytechnic Institute, VA (United States)

2004-04-01

The hydrodynamic cavitation over axisymmetric projectiles is computed using the unsteady incompressible Navier-Stokes equations for multi-fluid elements. The governing equations are discretized on a structured grid using an upwind difference scheme with flux limits. A preconditioning dual-time stepping method is used for the unsteady computations. The Eigen-system is derived for the Jacobian matrices. This Eigen-system is suitable for high-density ratio multi-fluid flows and it provides high numerical stability and fast convergence. This method can be used to compute single- as well as multi-phase flows. Cavitating flows over projectiles with different geometries are computed and the results are in good agreement with available experimental data and other published computations. (authors)

When Does Air Resistance Become Significant in Projectile Motion?

Science.gov (United States)

Mohazzabi, Pirooz

2018-01-01

In an article in this journal, it was shown that air resistance could never be a significant source of error in typical free-fall experiments in introductory physics laboratories. Since projectile motion is the two-dimensional version of the free-fall experiment and usually follows the former experiment in such laboratories, it seemed natural to…

Systematic studies of binding energy dependence of neutron-proton momentum correlation function

International Nuclear Information System (INIS)

Wei, Y B; Ma, Y G; Shen, W Q; Ma, G L; Wang, K; Cai, X Z; Zhong, C; Guo, W; Chen, J G; Fang, D Q; Tian, W D; Zhou, X F

2004-01-01

Hanbury Brown-Twiss (HBT) results of the neutron-proton correlation function have been systematically investigated for a series of nuclear reactions with light projectiles with the help of the isospin-dependent quantum molecular dynamics model. The relationship between the binding energy per nucleon of the projectiles and the strength of the neutron-proton HBT at small relative momentum has been obtained. Results show that neutron-proton HBT results are sensitive to the binding energy per nucleon

Simulations of the Penetration of 6061-T6511 Aluminum Targets by Spherical-Nosed VAR 4340 Steel Projectiles

Energy Technology Data Exchange (ETDEWEB)

Tabbara, M.R.; Warren, T.L.

1998-10-21

In certain penetration events it is proposed that the primary mode of deformation of the target can be approximated by known analytical expressions. In the context of an analysis code, this approximation eliminates the need for discretizing the target as well as the need for a contact algorithm. Thus, this method substantially reduces the computer time and memory requirements. In this paper a forcing function which is derived from a spherical-cavity expansion (SCE) analysis has been implemented in a transient dynamic finite element code. This irnplementation is capable of computing the structural and component responses of a projectile due to a three dimensional penetration event. Simulations are presented for 7.1 l-mm-diameter, 74.7-mm-long, spherical-nose, vacuum- arc-remelted (VAR) 4340 steel projectiles that penetrate 6061-T6511 aluminum targets. Final projectile configurations obtained from the simulations are compared with post-test radiographs obtained from the corresponding experiments. It is shown that the simulations accurately predict the permanent projectile deformation for three dimensional loadings due to incident pitch and yaw over a wide range of striking velocities.

Comparison of high speed movie and flash x-ray measurement of the translational and rotational motions of projectiles penetrating gelatin

International Nuclear Information System (INIS)

Roecker, E.T.

1979-01-01

Projectiles penetrating a gelatin block were simultaneously measured by a high speed movie camera, Dynafax, and by a sequential, orthogonal, flash x-ray system. The eight orthogonal views of the x-ray system provided position and orientation of the projectiles vs. time. From onset of tumble in the gelatin, owing to gyroscopic instability, the growth of yaw was the same for each round in a replicated set. This phenomenon provided a legitimate procedure for pooling the x-ray data, giving well determined curves of velocity decay and yaw growth. The movie camera observed the progress of the cavity formed by the projectile. The resulting velocity decay of the cavity tip was compared to that of the projectile as measured by the x-ray technique. (author)

Angular distributions of projectiles following electron capture from C60 by 2.5-keV Ar8+

International Nuclear Information System (INIS)

Walch, B.; Thumm, U.; Stoeckli, M.; Cocke, C.L.; Klawikowski, S.

1998-01-01

Experimental measurements of the projectile angular distributions for 2.5-keV Ar 8+ ions capturing one to five electrons from a gas-phase C 60 target are presented. The number of captured electrons was determined by demanding a coincidence between the scattered projectile and a charge-state-analyzed intact C 60 recoil ion. The results are compared to calculations based on a dynamical classical overbarrier model. Good agreement is obtained only if the influence on the projectile trajectory by the large polarizability of the C 60 target is taken into account, thereby making the collective dielectric response of the cluster target observable in a scattering experiment. copyright 1998 The American Physical Society

Measurement of projectile-like fragments produced by 80. 6 MeV /sup 16/O on /sup 27/Al

Energy Technology Data Exchange (ETDEWEB)

Wen-Qing, SHEN; Shu-Zhi, YIN; Zhong-Yan, GUO; Wen-Long, ZHAN; Yong-Tai, ZHU; Gen-Ming, JIN; Wei-Min, QIAO; En-Chiu, WU; Cheng-Lie, JIANG

1985-05-01

The projectile-like fragments produced by 80.6 MeV /sup 16/O on /sup 27/Al were measured using the large area position sensitive ionization chamber. The energy spectra, angular distributions, contour plots of d/sup 2/sigma/d..cap omega..dE in the E-theta plane of the reaction products from Li to Na and the Z-distribution were obtained. The cross sections of the quasi and deep inelastic scattering were introduced. A brief discussion of the experimental results is also given.

Measurement of attenuation coefficients for bone, muscle, fat and water at 140, 364 and 662keV γ-ray energies

International Nuclear Information System (INIS)

Akar, A.; Baltas, H.; Cevik, U.; Korkmaz, F.; Okumusoglu, N.T.

2006-01-01

The half-value thicknesses, linear and mass attenuation coefficients of biological samples such as bone, muscle, fat and water have been measured at 140, 364 and 662keV γ-ray energies by using the ATOMLAB TM -930 medical spectrometer. The γ-rays were obtained from 99m Tc, 131 I and 137 Cs γ-ray point sources. Also theoretical calculations have been performed in order to obtain the half-value thicknesses and, mass and linear attenuation coefficients at photon energies 0.001keV-20MeV for bone, muscle and water samples. The calculated value and the experimental results of this work and the other results in literature are found to be in good agreement

Universality of spectator fragmentation at relativistic bombarding energies

International Nuclear Information System (INIS)

Schuettauf, A.; Woerner, A.

1996-06-01

Multi-fragment decays of 129 Xe, 197 Au, and 238 U projectiles in collisions with Be, C, Al, Cu, In, Au, and U targets at energies between E/A=400 MeV and 1000 MeV have been studied with the ALADIN forward-spectrometer at SIS. By adding an array of 84 Si-CsI(Tl) telescopes the solid-angle coverage of the setup was extended to θ lab =16 . This permitted the complete detection of fragments from the projectile-spectator source. The dominant feature of the systematic set of data is the Z bound universality that is obeyed by the fragment multiplicities and correlations. These observables are invariant with respect to the entrance channel if plotted as a function of Z bound , where Z bound is the sum of the atomic numbers Z i of all projectile fragments with Z i ≥2. No significant dependence on the bombarding energy nor on the target mass is observed. The dependence of the fragment multiplicity on the projectile mass follows a linear scaling law. The reasons for and the limits of the observed universality of spectator fragmentation are explored within the realm of the available data and with model studies. It is found that the universal properties should persist up to much higher bombarding energies than explored in this work and that they are consistent with universal features exhibited by the intranuclear cascade and statistical multifragmentation models. (orig.)

Influence of Energy and Temperature in Cluster Coalescence Induced by Deposition

Directory of Open Access Journals (Sweden)

J. C. Jiménez-Sáez

2012-01-01

Full Text Available Coalescence induced by deposition of different Cu clusters on an epitaxial Co cluster supported on a Cu(001 substrate is studied by constant-temperature molecular dynamics simulations. The degree of epitaxy of the final system increases with increasing separation between the centres of mass of the projectile and target clusters during the collision. Structure, roughness, and epitaxial order of the supported cluster also influence the degree of epitaxy. The effect of energy and temperature is determinant on the epitaxial condition of the coalesced cluster, especially both factors modify the generation, growth and interaction among grains. A higher temperature favours the epitaxial growth for low impact parameters. A higher energy contributes to the epitaxial coalescence for any initial separation between the projectile and target clusters. The influence of projectile energy is notably greater than the influence of temperature since higher energies allow greater and instantaneous atomic reorganizations, so that the number of arisen grains just after the collision becomes smaller. The appearance of grain boundary dislocations is, therefore, a decisive factor in the epitaxial growth of the coalesced cluster.

Study of atomic excitations in sputtering with the use of N, O, F, Ne, Na, Cl, and Ar projectiles

International Nuclear Information System (INIS)

Jensen, H.K.; Veje, E.

1985-01-01

Solid magnesium has been bombarded with 80 keV ions of N, O, F, Ne, Na, Cl, and Ar, and excitation of sputtered magnesium atoms and ions has been studied. Relative level excitation probabilities depend strongly on the projectile, the dependences for Mg I levels being different from those for Mg II levels. With all projectiles, the resonance level in Mg II is excited stronger than the resonance level in Mg I. Very little radiation is observed from the projectiles except for sodium. The results are discussed. (orig.)

Total fragmentation cross section of 158A GeV lead projectiles in Cu target

International Nuclear Information System (INIS)

Mukhtar Ahmed Rana; Shahid Manzoor

2008-01-01

Total fragmentation cross section for the reaction 158A Pb ions + Cu target is measured using the most sensitive track detector CR-39. Measured values are compared with calculations. Exposures of target-detector stack with 158A Pb projectiles are made at CERN-SPS beam facility. Results of calibration of CR-39 detector in a charge region (63≤Z≤83) are also reported, which can be used for high energy particle identification using CR-39 and in determination of partial charge changing cross sections. The charge resolution σ Z achieved by this technique is about 0.2e. A systematic dependence of total fragmentation cross section on target properties is revealed and the corresponding results are presented. (authors)

Critical impact energy for the perforation of metallic plates

International Nuclear Information System (INIS)

Aly, S.Y.; Li, Q.M.

2008-01-01

This paper investigates the empirical formulae used in engineering practice to predict the critical perforation energy of metallic plates struck by rigid projectiles in the sub-ordnance regime. Main factors affecting the critical perforation energy are identified and valid conditions for each empirical formula are compared. Dimensional analysis is conducted to show the dependence of the non-dimensional critical impact energy on other influential non-dimensional numbers. Available empirical formulae are re-expressed in non-dimensional forms. A modified Jowett/AEA equation is proposed to predict the critical perforation energy of a flat-ended short projectile. The present work increases the confidence of using these empirical formulae and can be regarded as a quick guide for ballistic protection design of metallic shields and steel armour plates

Energy shifts of the binary encounter peak (BEP) in 1 MeV/uSiq+ + H2

International Nuclear Information System (INIS)

Hidmi, H.I.; Sanders, J.M.; Zouros, T.J.M.; Richard, P.

1993-01-01

The double differential cross section of the BEP for 1 MeV/u Si q+ on H 2 was measured at 0 degrees observation angle for q = 5-13. The data were fitted to the theoretical prediction of the impulse approximation (IA) using a two parameter model. The first parameter was a scaling factor which corresponds to the enhancement ratio between the ion of charge state q and the bare ion. The second was an open-quote energy correction close-quote which enters into the calculation of the energy of the bound target electron in the projectile rest frame. The observed enhancement ratio increases with increasing number of electrons on the projectile, in agreement with previously reported data. The energy correction parameter required to fit the BEP energy decreases with increasing number of electrons on the projectile ion

SSNTD studies of lead nuclei fission induced by relativistic p, d, He and sup 1 sup 2 C projectiles inside massive Pb and U targets

CERN Document Server

Perelygin, V P; Krivopustov, M I; Petrova, R I; Abdullaev, I G; Bradnova, V; Knjazeva, G P; Brandt, R; Ochs, M; Wan, J S; Vater, P

1999-01-01

A series of experiments was carried out with relativistic protons, deuterons, helium and carbon-12 projectiles accelerated at SYNCHOPHASOTRON LHE, Dubna which hit massive Pb and U targets. The beam profiles and intensities of both primary particles and secondary fast neutrons were measured using plastic SSNTD inside the massive cylinder blocks of Cu, Pb and U by counting of fission fragment tracks due to the induced fission of Pb nuclei. The beam diameter increases typically by 20-30% at the depth 10 and 20 cm. With increasing the energy of projectiles the number of secondary neutrons rises with the depth for protons, deuterons and helium ions. Nevertheless, for sup 1 sup 2 C ions beams with changing the energy from 18 GeV to 44 GeV we first observe the effect of significant increase both the yield of secondary fast neutrons and the half-width of the beam. The observed enhanced yield of secondary fast neutrons confirms unusual behavior of nuclear interaction cross section of 44 GeV sup 1 sup 2 C ions observed...

Attenuation coefficients of soils

International Nuclear Information System (INIS)

Martini, E.; Naziry, M.J.

1989-01-01

As a prerequisite to the interpretation of gamma-spectrometric in situ measurements of activity concentrations of soil radionuclides the attenuation of 60 to 1332 keV gamma radiation by soil samples varying in water content and density has been investigated. A useful empirical equation could be set up to describe the dependence of the mass attenuation coefficient upon photon energy for soil with a mean water content of 10%, with the results comparing well with data in the literature. The mean density of soil in the GDR was estimated at 1.6 g/cm 3 . This value was used to derive the linear attenuation coefficients, their range of variation being 10%. 7 figs., 5 tabs. (author)

L and M shell coulomb ionization by heavy charged projectiles

International Nuclear Information System (INIS)

Karmaker, R.

1980-01-01

Universal cross sections for L and M shell ionization have been extracted from the semiclassical approximation (SCA) model in the straight line path approximation of the projectile. It has been shown that it is possible to organise the calculation of the SCA in a suitable way so that it is not necessary to calculate the cross section for different targets. The agreement between the theoretical curve in the SCA model and the available experimental data for different target elements, is reasonably good. Cross sections for L and M shell ionization in the straight line path of the projectile in the SCA model for Pb, Au and U targets by the impact of protons have been calculated. The results have been compared with those calculated in the Binary Encounter Approximation (BEA) and the Plane Wave Born Approximation (PWBA) as well as with the available experimental results. The present calculations are in good agreement with the existing theoretical and the experimental results. (author)

Charge-transfer collisions of multicharged ions with atomic and molecular hydrogen: measurements with low-energy accelerators

International Nuclear Information System (INIS)

Phaneuf, R.A.; Meyer, F.W.; Crandall, D.H.

1977-01-01

Electron-capture cross sections for O/sup +q/ + H → O/sup +q-1/ + H + and O/sup +q/ + H 2 → O/sup +q-1/ + H 2 + are shown for projectile energies from 10 to 1300 keV. At low energies the cross sections are determined by details of the quasi-molecule potential; at higher energies momentum transfer becomes the dominant mechanism, and the cross sections fall off similarly. Results with other projectiles are described briefly. 1 figure

Devices for launching 0.1-g projectiles to 150 km/s or more to initiate fusion. Part 2. Railgun accelerators

International Nuclear Information System (INIS)

Hawke, R.S.

1979-01-01

The possibility of using a railgun accelerator to launch 0.1-g projectiles to hypervelocities (150 km/s or more) to initiate thermonuclear fusion is studied. The analysis revealed that a railgun with a plasma-arc armature is a viable approach to the goal. When calculating the railgun's probable performance, it was discovered that this launch system might possibly be designed to avoid adverse effects from boundary layer drag. An appendix provided by A.C. Buckingham summarizes his calculations that predict the amount of erosive drag between projectile and rail. Finally, it was found that certain properties of railgun and projectile materials can impose operational limits. Using these limits, single- and multistage accelerators were designed. Within such limits, a railgun could accelerate a 0.1-g projectile to hypervelocities

Research on a wavefront aberration calculation method for a laser energy gradient attenuator

International Nuclear Information System (INIS)

Dong, Tingting; Han, Xu; Chen, Chi; Fu, Yuegang; Li, Ming

2013-01-01

When a laser energy gradient attenuator is working, there is an inhomogeneous temperature distribution in the whole of the glass because of the non-uniform light energy absorption. This will lead to optical performance reduction. An integrated opto-thermal–mechanical method is proposed to calculate the wavefront aberration for analysis of the thermal effect of the system. Non-sequential optical analysis is used for computing the absorbed energy distribution. The finite element analysis program solves the temperature distribution and the deformations of nodes on the surfaces. An interface routine is created to fit the surface shape and the index field, and extended Zernike polynomials are introduced to get a higher fitting precision. Finally, the parameters are imported to the CodeV optical design program automatically, and the user defined gradient index material is ray traced to obtain the wavefront aberration. The method can also be used in other optical systems for thermal effect analysis. (letter)

Technological cost-reduction pathways for attenuator wave energy converters in the marine hydrokinetic environment.

Energy Technology Data Exchange (ETDEWEB)

Bull, Diana L; Ochs, Margaret Ellen

2013-09-01

This report considers and prioritizes the primary potential technical costreduction pathways for offshore wave activated body attenuators designed for ocean resources. This report focuses on technical research and development costreduction pathways related to the device technology rather than environmental monitoring or permitting opportunities. Three sources of information were used to understand current cost drivers and develop a prioritized list of potential costreduction pathways: a literature review of technical work related to attenuators, a reference device compiled from literature sources, and a webinar with each of three industry device developers. Data from these information sources were aggregated and prioritized with respect to the potential impact on the lifetime levelized cost of energy, the potential for progress, the potential for success, and the confidence in success. Results indicate the five most promising costreduction pathways include advanced controls, an optimized structural design, improved power conversion, planned maintenance scheduling, and an optimized device profile.

Evaluation of various energy windows at different radionuclides for scatter and attenuation correction in nuclear medicine.

Science.gov (United States)

Asgari, Afrouz; Ashoor, Mansour; Sohrabpour, Mostafa; Shokrani, Parvaneh; Rezaei, Ali

2015-05-01

Improving signal to noise ratio (SNR) and qualified images by the various methods is very important for detecting the abnormalities at the body organs. Scatter and attenuation of photons by the organs lead to errors in radiopharmaceutical estimation as well as degradation of images. The choice of suitable energy window and the radionuclide have a key role in nuclear medicine which appearing the lowest scatter fraction as well as having a nearly constant linear attenuation coefficient as a function of phantom thickness. The energy windows of symmetrical window (SW), asymmetric window (ASW), high window (WH) and low window (WL) using Tc-99m and Sm-153 radionuclide with solid water slab phantom (RW3) and Teflon bone phantoms have been compared, and Matlab software and Monte Carlo N-Particle (MCNP4C) code were modified to simulate these methods and obtaining the amounts of FWHM and full width at tenth maximum (FWTM) using line spread functions (LSFs). The experimental data were obtained from the Orbiter Scintron gamma camera. Based on the results of the simulation as well as experimental work, the performance of WH and ASW display of the results, lowest scatter fraction as well as constant linear attenuation coefficient as a function of phantom thickness. WH and ASW were optimal windows in nuclear medicine imaging for Tc-99m in RW3 phantom and Sm-153 in Teflon bone phantom. Attenuation correction was done for WH and ASW optimal windows and for these radionuclides using filtered back projection algorithm. Results of simulation and experimental show that very good agreement between the set of experimental with simulation as well as theoretical values with simulation data were obtained which was nominally less than 7.07 % for Tc-99m and less than 8.00 % for Sm-153. Corrected counts were not affected by the thickness of scattering material. The Simulated results of Line Spread Function (LSF) for Sm-153 and Tc-99m in phantom based on four windows and TEW method were

Secondary electron emission of thin carbon foils under the impact of hydrogen atoms, ions and molecular ions, under energies within the MeV range; Multiplicite des electrons secondaires emis par des cibles minces de carbone sous l'impact de projectiles H0, H2+, H3+ d'energie de l'ordre du MeV

Energy Technology Data Exchange (ETDEWEB)

Vidovic, Z

1997-06-15

This work focuses on the study of the emission statistics of secondary electrons from thin carbon foils bombarded with H{sup 0}, H{sub 2}{sup +} and H{sub 3}{sup +} projectiles in the 0.25-2.2 MeV energy range. The phenomenon of secondary electron emission from solids under the impact of swift ions is mainly due to inelastic interactions with target electrons. The phenomenological and theoretical descriptions, as well as a summary of the main theoretical models are the subject of the first chapter. The experimental set-up used to measure event by event the electron emission of the two faces of a thin carbon foil traversed by an energetic projectile is described in the chapter two. In this chapter are also presented the method and algorithms used to process experimental spectra in order to obtain the statistical distribution of the emitted electrons. Chapter three presents the measurements of secondary electron emission induced by H atoms passing through thin carbon foils. The secondary electron yields are studied in correlation with the emergent projectile charge state. We show the peculiar role of the projectile electron, whether it remains or not bound to the incident proton. The fourth chapter is dedicated to the secondary electron emission induced by H{sub 2}{sup +} and H{sub 3}{sup +} polyatomic ions. The results are interpreted in terms of collective effects in the interactions of these ions with solids. The role of the proximity of the protons, molecular ion fragments, upon the amplitude of these collective effects is evidenced from the study of the statistics of forward emission. These experiences allowed us to shed light on various aspects of atom and polyatomic ion inter-actions with solid surfaces. (author)

Geometrical aspects of reaction cross sections for {sup 3}He, {sup 4}He and {sup 12}C projectiles

Energy Technology Data Exchange (ETDEWEB)

Ingemarsson, A. [Uppsala Univ. (Sweden). Dept. of Radiation Sciences; Lantz, M. [Uppsala Univ. (Sweden). The Svedberg Laboratory

2003-04-01

A black-disc model combined with accurate matter densities has been used for an investigation of reaction cross sections for {sup 3}He, {sup 4}He and {sup 12}C projectiles. A simple relation is derived between the energy dependence of the reaction cross sections and the strength of the nucleon-nucleon interaction. A comparison is also made of the reaction cross sections for {sup 3}He and {sup 4}He for six different nuclei {sup 12}C, {sup 16}O, {sup 40}Ca, {sup 58,60}Ni and {sup 208}Pb.

Behind armour blunt trauma--an emerging problem.

Science.gov (United States)

Cannon, L

2001-02-01

Behind Armour Blunt Trauma (BABT) is the non-penetrating injury resulting from the rapid deformation of armours covering the body. The deformation of the surface of an armour in contact with the body wall arises from the impact of a bullet or other projectile on its front face. The deformation is part of the retardation and energy absorbing process that captures the projectile. In extreme circumstances, the BABT may result in death, even though the projectile has not perforated the armour. An escalation of the available energy of bullets and the desire of armour designers to minimise the weight and bulk of personal armour systems will increase the risk of BABT in military and security forces personnel. In order to develop materials that can be interposed between the armour and the body wall to attenuate the transfer of energy into the body, it is essential that the mechanism of BABT is known. There is a great deal of activity within UK and NATO to unravel the interactions; the mechanism is likely to be a combination of stress (pressure) waves generated by the rapid initial motion of the rear of the armour, and shear deformation to viscera produced by gross deflection of the body wall. Physical and computer model systems are under development to characterise the biophysical processes and provide performance targets for materials to be placed between armours and the body wall in order to attenuate the injuries (trauma attenuating backings-TABs). The patho-physiological consequences of BABT are being clarified by research, but the injuries will have some of the features of blunt chest trauma observed in road traffic accidents and other forms of civilian blunt impact injury. The injuries also have characteristics of primary blast injury. An overview diagnosis and treatment is described.

Effects of dust-charge fluctuations on the potential of an array of projectiles in a partially ionized dusty plasma

International Nuclear Information System (INIS)

Ali, S.; Nasim, M.H.; Murtaza, G.

2003-01-01

The expressions for the Debye and the wake potential are derived by incorporating dust-charge fluctuations of a single projectile, as well as of an array of dust grain projectiles, propagating through a partially ionized dusty plasma with a constant velocity. Numerically, the effects of the dust-charge fluctuations and the dust-neutral collisions on the electrostatic potential for a single, three, six and ten projectiles are examined. The dust-charge relaxation rate modifies the shape of the Debye as well as the wake potential. For smaller values of the relaxation rates a potential well is formed instead of Debye potential

Self-attenuation correction factors for bioindicators measured by γ spectrometry for energies <100keV

International Nuclear Information System (INIS)

Manduci, L.; Tenailleau, L.; Trolet, J.L.; De Vismes, A.; Lopez, G.; Piccione, M.

2010-01-01

The mass attenuation coefficients for a number of marine and terrestrial bioindicators were measured using γ spectrometry for energies between 22 and 80 keV. These values were then used to find the correction factor k for the apparent radioactivity. The experimental results were compared with a Monte Carlo simulation performed using PENELOPE in order to evaluate the reliability of the simplified calculation and to determine the correction factors.

Projectile fragmentation of neutron-rich nuclei on light target (momentum distribution and nucleon-removal cross section)

International Nuclear Information System (INIS)

Kobayashi, T.; Tanihata, I.; Suzuki, T.

1992-01-01

Transverse momentum distributions of the projectile fragments from β-unstable nuclei have been measured with various projectile and target combinations. The momentum correlation of two neutrons in the neutron halo is extracted from the P c t distribution of 9 Li and hat of the neutrons. It is found that the two neutrons are moving in the same direction on average and thus strongly suggests the formation of a di-neutron in 11 Li. (Author)

Projectile deformation effects in the breakup of 37Mg

Directory of Open Access Journals (Sweden)

Shubhchintak

2016-01-01

Full Text Available We study the breakup of 37Mg on Pb at 244MeV/u with the recently developed extended theory of Coulomb breakup within the postform finite range distorted wave Born approximation that includes deformation of the projectile. Comparing our calculated cross section with the available Coulomb breakup data we determine the possible ground state configuration of 37Mg.

Nuclear Fragmentation Induced by Relativistic Projectiles Studied in the 4$\\pi$ Configuration of Plastic Track Detectors

CERN Multimedia

2002-01-01

% EMU19 \\\\ \\\\ The collisions of heavy ions at relativistic energies have been studied to explore a number of questions related with hot and dense nuclear matter in order to extend our knowledge of nuclear equation-of-state. There are other aspects of these interactions which are studied to expound the process of projectile and/or target disintegrations. The disintegrations in question could be simply binary fissions or more complex processes leading to spallation or complete fragmentation. These important aspects of nuclear reactions are prone to investigations with nuclear track detectors. \\\\ \\\\One of the comparatively new track detector materials, CR-39, is sensitive enough to record particles of Z~$\\geq$~6 with almost 100\\% efficiency up to highly relativistic energies. The wide angle acceptance and exclusive measurements possible with plastic track detectors offer an opportunity to use them in a variety of situations in which high energy charged fragments are produced. The off-line nature of measuring tra...

Impact Vibration Attenuation for a Flexible Robotic Manipulator through Transfer and Dissipation of Energy

Directory of Open Access Journals (Sweden)

Yushu Bian

2013-01-01

Full Text Available Due to the presence of system flexibility, impact can excite severe large amplitude vibration responses of the flexible robotic manipulator. This impact vibration exhibits characteristics of remarkable nonlinearity and strong energy. The main goal of this study is to put forward an energy-based control method to absorb and attenuate large amplitude impact vibration of the flexible robotic manipulator. The method takes advantage of internal resonance and is implemented through a vibration absorber based on the transfer and dissipation of energy. The addition of the vibration absorber to the flexible arm generates a coupling effect between vibration modes of the system. By means of analysis on 2:1 internal resonance, the exchange of energy is proven to be existent. The impact vibrational energy can be transferred from the arm to the absorber and dissipated through the damping of the absorber. The results of numerical simulations are promising and preliminarily verify that the method is feasible and can be used to combat large amplitude impact vibration of the flexible manipulator undergoing rigid motion.

Investigation of incomplete linear momentum transfer in heavy ion reactions at intermediate energies

International Nuclear Information System (INIS)

Leray, S.

1986-07-01

At intermediate energies, heavy ion central collisions lead to the incomplete fusion of the incident nuclei while part of the initial linear momentum is carried away by fast light particles. Experiments were performed with 30 MeV per nucleon neon and 20, 35 and 44 MeV per nucleon argon projectiles bombarding heavy targets. Results obtained with 30 MeV per nucleon neon and 20 MeV per nucleon argon beams are in good agreement with an empirical law established with lighter projectiles. On the contrary, 35 and 44 MeV per nucleon argon projectiles do not follow the same law and fission fragments progressively disappear. A simple model explains the evolution of the amount of transferred linear momentum versus incident energy. The disappearance of the fusion products of the composite system observed with argon projectiles beyond 35 MeV per nucleon is explained by a limitation of the excitation energy per nucleon which can be deposited in a nucleus. The limit is evaluated from nucleon binding energy in nuclei and probability to emit clusters and is in good agreement with experimental data. Because of the coupling between intrinsic motion of nucleons and relative motion of nuclei, some nucleons have a kinetic energy high enough to be emitted: a theoretical model is proposed which rather well fits the data concerning fast nucleons but cannot explain the measured amounts of transferred linear momentum. This is attributed to the existence of other mechanisms [fr

Characteristics of intermediate-energy nucleons emitted from 50 GeV

International Nuclear Information System (INIS)

Goyal, D.P.; Singh, S.; Arya, N.S.

1984-01-01

The multiplicity and angular distributions of intermediate-energy (grey) nucleons are studied from 50 GeV π - -nucleus data and compared with those available from π - -nucleus and p-nucleus interactions at other energies. The value of is found to be dependent both on the energy as well as on the projectile. The former variation is attributable to kinematics and the latter explainable on the basis of the additive quark model. The angular distribution of grey particles is found to be independent of energy, projectile and target, which supports the view that grey particles are chiefly due to knock-on recoiling protons. The various versions of the cascade model, however, are unable to explain any of the observed features of grey-particle distributions

''Theta gun,'' a multistage, coaxial, magnetic induction projectile accelerator

International Nuclear Information System (INIS)

Burgess, T.J.; Duggin, B.W.; Cowan, M. Jr.

1985-11-01

We experimentally and theoretically studied a multistage coaxial magnetic induction projectile accelerator. We call this system a ''theta gun'' to differentiate it from other coaxial accelerator concepts such as the mass driver. We conclude that this system can theoretically attain railgun performance only for large caliber or very high injection velocity and, even then, only for long coil geometry. Our experiments with a three-stage, capactor bank-driven accelerator are described. The experiments are modeled with a 1-1/2 dimensional equivalent circuit-hydrodynamics code which is also described. We derive an expression for the conditions of coaxial accelerator-railgun ''velocity breakeven'' in the absence of ohmic and hydrodynamic effects. This, in conjunction with an expression for the magnetic coupling coefficient, defines a set of geometric relations which the coaxial system must simultaneously satisfy. Conclusions concerning both the existence and configuration of a breakeven coaxial system follow from this requirement. The relative advantages and disadvantages of the coaxial induction projectile accelerator, previously cited in the literature, are critiqued from the viewpoint of our analysis and experimental results. We find that the advantages vis-a-vis the railgun have been overstated. 13 refs., 17 figs

Total Fragmentation Cross Section of 158A GeV Lead Projectiles in Cu Target

International Nuclear Information System (INIS)

Rana, Mukhtar Ahmed

2008-01-01

Total fragmentation cross section for the reaction 158 A Pb ions + Cu target is measured using the most sensitive track detector CR-39. Measured values are compared with calculations. Exposures of target-detector stack with 158A Pb projectiles are made at CERN-SPS beam facility. Results of calibration of CR-39 detector in a charge region (63 ≤ Z ≤ 83) are also reported, which can be used for high energy particle identification using CR-39 and in determination of partial charge changing cross sections. The charge resolution σ z achieved by this technique is about 0.2e. A systematic dependence of total fragmentation cross section on target properties is revealed and the corresponding results are presented. (nuclear physics)

On the Horizontal Deviation of a Spinning Projectile Penetrating into Granular Systems

Directory of Open Access Journals (Sweden)

Waseem Ghazi Alshanti

2017-01-01

Full Text Available The absence of a general theory that describes the dynamical behavior of the particulate materials makes the numerical simulations the most current powerful tool that can grasp many mechanical problems relevant to the granular materials. In this paper, based on a two-dimensional soft particle discrete element method (DEM, a numerical approach is developed to investigate the consequence of the orthogonal impact into various granular beds of projectile rotating in both clockwise (CW and counterclockwise (CCW directions. Our results reveal that, depending on the rotation direction, there is a significant deviation of the x-coordinate of the final stopping point of a spinning projectile from that of its original impact point. For CW rotations, a deviation to the right occurs while a left deviation has been recorded for CCW rotation case.

Self-attenuation factors in gamma-ray spectrometry

International Nuclear Information System (INIS)

Korun, M.

1999-01-01

The relation between the self-attenuation factors and the distribution function describing the number of photons detected in the full-energy peaks, as a function of their path length in the sample is presented. The relations between the self-attenuation factor and the moments of the distribution function, the average path length and the variance are also presented. The use of these relations is illustrated by applying them to self-attenuation factors describing attenuation in cylindrical samples. The results of the calculations are compared with the measured average path lengths and discussed in terms of the properties of the distribution function. (author)

A simple nonbinary scattering model applicable to atomic collisions is crystals at 1ow energies

DEFF Research Database (Denmark)

Andersen, Hans Henrik; Sigmund, Peter

1966-01-01

the asymptotic velocities of the ring atoms as well as the energy loss of the projectile. Furthermore, it can be decided whether the projectile is reflected by the ring. Both the feasibility of assumptions specifying the problem and the validity of different approximations made in the transformation from...... previously. Inelastic contributions to the energy loss can easily be included. The oscillator forces binding lattice atoms turn out to influence the scattering process only at very small energies. The validity of the so-called momentum approximation and a related perturbation method are also investigated....

Electron Effective-Attenuation-Length Database

Science.gov (United States)

SRD 82 NIST Electron Effective-Attenuation-Length Database (PC database, no charge)   This database provides values of electron effective attenuation lengths (EALs) in solid elements and compounds at selected electron energies between 50 eV and 2,000 eV. The database was designed mainly to provide EALs (to account for effects of elastic-eletron scattering) for applications in surface analysis by Auger-electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS).

Calculation of forces arising from impacting projectiles upon yielding structures

International Nuclear Information System (INIS)

Drittler, K.; Gruner, P.; Krivy, J.

1977-01-01

Calculations concerning the impact of airplanes upon nuclear power plant buildings usually imply that the building 'acts' as a rigid target. This assumption is justified for considerations concerning the structural integrity of the building being hit. However, for investigating induced vibrations of components within the structure, this approach might -in general- be too conservative. It is expected, that yielding of the structure during impact reduces the peak values of the loads and changes the temporal behavior of the load function which is obtained for a rigid target. To calculate the changes of the load function which are due to deformations of the structure, Riera's method is extended for the case of a yielding target. In view of the applications of the calculations to the impact of airplanes upon buildings which are constructed to withstand loads of this kind without serious damage and without large deformations, it is possible to simplify the calculations to some extent. That is, the investigations need not take into account in detail the behavior of the target during impact. The calculations are performed with a one-dimensional model for the projectile. The direction of impact is perpendicular to the target surface; direction of impact and projectile axis coincide. The calculations were performed for several initial velocities of the projectiles simulating a fast flying military airplane. Variations of the peak values of the load functions as compared to corresponding values for a rigid target do not exceed about 10%. The overall temporal behavior of the load curves turns out to be not very sensitive to the yielding of the target, though, in some cases displacements in time of the peak positions within a single load curve do arise

The motion of an arbitrarily rotating spherical projectile and its application to ball games

International Nuclear Information System (INIS)

Robinson, Garry; Robinson, Ian

2013-01-01

In this paper the differential equations which govern the motion of a spherical projectile rotating about an arbitrary axis in the presence of an arbitrary ‘wind’ are developed. Three forces are assumed to act on the projectile: (i) gravity, (ii) a drag force proportional to the square of the projectile's velocity and in the opposite direction to this velocity and (iii) a lift or ‘Magnus’ force also assumed to be proportional to the square of the projectile's velocity and in a direction perpendicular to both this velocity and the angular velocity vector of the projectile. The problem has been coded in Matlab and some illustrative model trajectories are presented for ‘ball-games’, specifically golf and cricket, although the equations could equally well be applied to other ball-games such as tennis, soccer or baseball. Spin about an arbitrary axis allows for the treatment of situations where, for example, the spin has a component about the direction of travel. In the case of a cricket ball the subtle behaviour of so-called ‘drift’, particularly ‘late drift’, and also ‘dip’, which may be produced by a slow bowler's off or leg-spin, are investigated. It is found that the trajectories obtained are broadly in accord with those observed in practice. We envisage that this paper may be useful in two ways: (i) for its inherent scientific value as, to the best of our knowledge, the fundamental equations derived here have not appeared in the literature and (ii) in cultivating student interest in the numerical solution of differential equations, since so many of them actively participate in ball-games, and they will be able to compare their own practical experience with the overall trends indicated by the numerical results. As the paper presents equations which can be further extended, it may be of interest to research workers. However, since only the most basic principles of fundamental mechanics are employed, it should be well within the grasp of first

The motion of an arbitrarily rotating spherical projectile and its application to ball games

Science.gov (United States)

Robinson, Garry; Robinson, Ian

2013-07-01

In this paper the differential equations which govern the motion of a spherical projectile rotating about an arbitrary axis in the presence of an arbitrary ‘wind’ are developed. Three forces are assumed to act on the projectile: (i) gravity, (ii) a drag force proportional to the square of the projectile's velocity and in the opposite direction to this velocity and (iii) a lift or ‘Magnus’ force also assumed to be proportional to the square of the projectile's velocity and in a direction perpendicular to both this velocity and the angular velocity vector of the projectile. The problem has been coded in Matlab and some illustrative model trajectories are presented for ‘ball-games’, specifically golf and cricket, although the equations could equally well be applied to other ball-games such as tennis, soccer or baseball. Spin about an arbitrary axis allows for the treatment of situations where, for example, the spin has a component about the direction of travel. In the case of a cricket ball the subtle behaviour of so-called ‘drift’, particularly ‘late drift’, and also ‘dip’, which may be produced by a slow bowler's off or leg-spin, are investigated. It is found that the trajectories obtained are broadly in accord with those observed in practice. We envisage that this paper may be useful in two ways: (i) for its inherent scientific value as, to the best of our knowledge, the fundamental equations derived here have not appeared in the literature and (ii) in cultivating student interest in the numerical solution of differential equations, since so many of them actively participate in ball-games, and they will be able to compare their own practical experience with the overall trends indicated by the numerical results. As the paper presents equations which can be further extended, it may be of interest to research workers. However, since only the most basic principles of fundamental mechanics are employed, it should be well within the grasp of first

Supercavitating flow around high-speed underwater projectile near free surface induced by air entrainment

Directory of Open Access Journals (Sweden)

Chang Xu

2018-03-01

Full Text Available Cavitating flow near free surface is a complicated issue and may provide new inspiration on high-speed surface cruising. This study observes stable supercavitating flow as a new phenomenon in a launch experiment of axisymmetric projectile when the upper side of the projectile coincides with the free surface. A numerical approach is established using large eddy-simulation and volume-of-fluid methods, and good agreements are achieved between numerical and experimental results. Supercavity formation mechanism is revealed by analyzing the experiment photographs and the iso-surface of 90% water volume fraction in numerical results. The entrainment of a large amount of air into the cavity can cause the pressure inside the cavity to similarly increase with the pressure outside the cavity, which makes the actual cavitation number close to zero and is similar to supercavitation. Cases with various headforms of the projectile and cavitation numbers on the cavitating flow, as well as the drag reduction effects are further examined. Results indicate that the present strategy near the free surface could possibly be a new effective approach for high-speed cruising after vigorous design optimization in the future.

Numerical Simulation of Projectile Impact on Mild Steel Armour Platesusing LS-DYNA, Part II: Parametric Studies

OpenAIRE

M. Raguraman; A. Deb; N. K. Gupta; D. K. Kharat

2008-01-01

In Part I of the current two-part series, a comprehensive simulation-based study of impact of jacketed projectiles on mild steel armour plates has been presented. Using the modelling procedures developed in Part I, a number of parametric studies have been carried out for the same mild steel plates considered in Part I and reported here in Part II. The current investigation includes determination of ballistic limits of a given target plate for different projectile diameters and impact velociti...

Determination of beta attenuation coefficients by means of timing method

International Nuclear Information System (INIS)

Ermis, E.E.; Celiktas, C.

2012-01-01

Highlights: ► Beta attenuation coefficients of absorber materials were found in this study. ► For this process, a new method (timing method) was suggested. ► The obtained beta attenuation coefficients were compatible with the results from the traditional one. ► The timing method can be used to determine beta attenuation coefficient. - Abstract: Using a counting system with plastic scintillation detector, beta linear and mass attenuation coefficients were determined for bakelite, Al, Fe and plexiglass absorbers by means of timing method. To show the accuracy and reliability of the obtained results through this method, the coefficients were also found via conventional energy method. Obtained beta attenuation coefficients from both methods were compared with each other and the literature values. Beta attenuation coefficients obtained through timing method were found to be compatible with the values obtained from conventional energy method and the literature.

Mean excitation energy of polystyrene extracted from proton-stopping-power measurements

International Nuclear Information System (INIS)

Porter, L.E.

1980-01-01

The measured stopping power of polystyrene for 2.2- to 5.9-MeV protons has been analyzed with the Bloch projectile-z 4 correction term and a modified low-velocity projectile-z 3 term included in the Bethe-Bloch formula. When the full-strength Walske K-shell correction was utilized, the mean excitation energy corresponding to the best fit of the measurements was (71.1 +- 1.8) eV. This result was obtained for a value of the free parameter of the low-velocity projectile-z 3 effect formalism of 1.90 +- 0.05, whether or not a Walske L-shell correction was included

Systematic experimental survey on projectile fragmentation and fission induced in collisions of 238U at 1 A GeV with lead

International Nuclear Information System (INIS)

Enqvist, T.; Benlliure, J.; Farget, F.; Schmidt, K.H.; Armbruster, P.; Bernas, M.; Tassan-Got, L.; Boeckstiegel, C.; Jong, M. de; Dufour, J.P.

1999-03-01

Projectile fragmentation and fission, induced in collisions of 238 U at 1 A GeV with lead, have systematically been studied. A complete survey on the isotopic production cross sections of all elements between vanadium (Z = 23) and rhenium (Z = 75) down to a cross section of 0.1 mb is given. About 600 isotopes produced in fragmentation and about 600 isotopes produced in fission were identified in the GSI fragment separator FRS from magnetic rigidities, time-of-flight values, and the energy loss in an ionisation chamber. In addition, the velocity distributions of all these reaction products have been mapped, and the products are unambiguously attributed to the different reaction mechanisms due to their kinematical properties. The results are compared with empirical systematics and previous data. The velocity of the fragments obtained in the fission process by the Coulomb repulsion allows to reconstruct the TKE-value of the break-up and to identify the atomic number of the fissioning nucleus in hot fission. The mean velocities of light projectile fragments were found to be higher than the beam velocity. (orig.)

Rapid Assessment of Small Changes to Major Gun and Projectile Dynamic Parameters

National Research Council Canada - National Science Library

Erline, Thomas

1997-01-01

The U.S. Navy's 5-in 54-cal. (5"/54) gun system Mark (Mk) 45 was subjected to first-order dynamic analysis tools that allowed rapid assessment of ballistic dispersion of a typical naval high explosive projectile...

The Physics of Protoplanetesimal Dust Agglomerates. IX. Mechanical Properties of Dust Aggregates Probed by a Solid-projectile Impact

Science.gov (United States)

Katsuragi, Hiroaki; Blum, Jürgen

2017-12-01

Dynamic characterization of mechanical properties of dust aggregates has been one of the most important problems to quantitatively discuss the dust growth in protoplanetary disks. We experimentally investigate the dynamic properties of dust aggregates by low-speed (≤slant 3.2 m s-1) impacts of solid projectiles. Spherical impactors made of glass, steel, or lead are dropped onto a dust aggregate with a packing fraction of ϕ = 0.35 under vacuum conditions. The impact results in cratering or fragmentation of the dust aggregate, depending on the impact energy. The crater shape can be approximated by a spherical segment and no ejecta are observed. To understand the underlying physics of impacts into dust aggregates, the motion of the solid projectile is acquired by a high-speed camera. Using the obtained position data of the impactor, we analyze the drag-force law and dynamic pressure induced by the impact. We find that there are two characteristic strengths. One is defined by the ratio between impact energy and crater volume and is ≃120 kPa. The other strength indicates the fragmentation threshold of dynamic pressure and is ≃10 kPa. The former characterizes the apparent plastic deformation and is consistent with the drag force responsible for impactor deceleration. The latter corresponds to the dynamic tensile strength to create cracks. Using these results, a simple model for the compaction and fragmentation threshold of dust aggregates is proposed. In addition, the comparison of drag-force laws for dust aggregates and loose granular matter reveals the similarities and differences between the two materials.

Role of hexadecapole deformation of projectile 28Si in heavy-ion fusion reactions near the Coulomb barrier

Science.gov (United States)

Kaur, Gurpreet; Hagino, K.; Rowley, N.

2018-06-01

The vast knowledge regarding the strong influence of quadrupole deformation β2 of colliding nuclei in heavy-ion sub-barrier fusion reactions inspires a desire to quest the sensitivity of fusion dynamics to higher order deformations, such as β4 and β6 deformations. However, such studies have rarely been carried out, especially for deformation of projectile nuclei. In this article, we investigated the role of β4 of the projectile nucleus in the fusion of the 28Si+92Zr system. We demonstrated that the fusion barrier distribution is sensitive to the sign and value of the β4 parameter of the projectile, 28Si, and confirmed that the 28Si nucleus has a large positive β4. This study opens an indirect way to estimate deformation parameters of radioactive nuclei using fusion reactions, which is otherwise difficult because of experimental constraints.

Coincidence measurement between α-particles and projectile-like fragments in the reaction of 82.7 MeV 16O on 27Al

International Nuclear Information System (INIS)

Shen Wenqing; Zhan Wenlong; Zhu Yongtai

1988-01-01

In a coincidence measurement between α-particles and projectile-like fragments in the reaction of 82.7 MeV 16 O on 27 Al, the contour plot of Galilean-invariant cross section of the coincidence between C-fragments and α-particles in the velocity plane, and the coincident angular correlation have been obtained. The correlated α-particles measured at positive angles (on the same side of the beam as the projectile-like fragments) were emitted mainly from the projectile-like fragments;the α-particles at large negative angles were emitted from the target-like fragments;the α-particles at small negative angles came from the fragmentation of the 16 O projectile. A possible reaction mechanism in which the residue produced in the fragmentation of the projectile continues the dissipation process during the interaction with the target has been discussed. It is also pointed out that in the large yield of C-fragments observed in the inclusive experiment, the contribution of C-fragments produced by the excited 16 O of DIC product via α-emission is quite small

Tissue simulant response at projectile impact on flexible fabric armour systems

NARCIS (Netherlands)

Bree, J.L.M.J. van; Volker, A.; Heiden, N. van der

2006-01-01

Behind Armour Blunt Trauma is a phenomenon which has been studied extensively for rigid personal protective armour systems. These systems used in e.g. bullet proof vests manage to defeat high velocity small arms projectiles. Tissue simulants are used to study behind armour effects. At high velocity

Charm production yield from target nuclei filtering intrinsic projectile charm

International Nuclear Information System (INIS)

Quack, E.; Nemes, M.C.

1990-01-01

Estimating the process of filtering an intrinsic projectile charm component by a target nucleus as proposed earlier, we obtain upper limits for the cross sections of open charm and J/Ψ. Comparing with experiment, we conclude that this filtering mechanism is not sufficient to explain the observed A α-dependence at large final state momenta. (author)

Projectile General Motion in a Vacuum and a Spreadsheet Simulation

Science.gov (United States)

Benacka, Jan

2015-01-01

This paper gives the solution and analysis of projectile motion in a vacuum if the launch and impact heights are not equal. Formulas for the maximum horizontal range and the corresponding angle are derived. An Excel application that simulates the motion is also presented, and the result of an experiment in which 38 secondary school students…

On the Trajectories of Projectiles Depicted in Early Ballistic Woodcuts

Science.gov (United States)

Stewart, Sean M.

2012-01-01

Motivated by quaint woodcut depictions often found in many late 16th and 17th century ballistic manuals of cannonballs fired in air, a comparison of their shapes with those calculated for the classic case of a projectile moving in a linear resisting medium is made. In considering the asymmetrical nature of such trajectories, the initial launch…

Management of in-tube projectiles using acoustic channel

Science.gov (United States)

Kostina, M. A.; Bortalevich, S. I.; Loginov, E. L.; Shinyakov, Y. A.; Sukhorukov, M. P.

2018-03-01

The article describes the method of measuring the distance from the operator's console installed outside the pipe to the in-tube projectile. A method for measuring distance in the absence of an echo signal is proposed. To do this, two identical ultrasonic locators operating at different frequencies were installed inside and outside the pipeline. The change in the duration of an acoustic pulse propagating in a circular waveguide with rigid walls is shown, which leads to a decrease in the data transfer rate.

Excitation and ionization of ethylene by charged projectiles

International Nuclear Information System (INIS)

Wang Zhiping; Wang Jing; Zhang Fengshou

2010-01-01

Using the time dependent local density approximation, applied to valence electrons, coupled non-adiabatically to molecular dynamics of ions, the collision process between ethylene and fast charged projectiles is studied in the microscopic way. The impact of ionic motion on the ionization is explored to show the importance of treating electronic and ionic degrees of freedom simultaneously. The number of escaped electrons, ionization probabilities are obtained. Furthermore, it is found that the ionic extensions in different directions show the different patterns. (authors)

Fission of spin-aligned projectile-like nuclei in the interactions of 29 MeV/nucleon 208Pb with 197Au

International Nuclear Information System (INIS)

Bresson, S.; Morjean, M.; Jastrzebski, J.; Skulski, W.; Kordyasz, A.; Lott, B.

1992-01-01

Binary fission of projectile-like nuclei was investigated in the interaction of 29 MeV/nucleon Pb on Au, together with the associated neutron multiplicity. Fission is only observed in rather peripheral collisions and represents approximately 20% of the total reaction cross-section. The fission process occurs after collisions in which up to 550 MeV have been dissipated. The angular and energy distribution of the fragments can be accounted for by assuming a noticeable spin alignment of the fissioning nuclei. (author) 18 refs.; 3 figs

["Bolt projectiles" discharged from modified humane killers (author's transl)].

Science.gov (United States)

Pollak, S; Reiter, C

1981-01-01

Some common types of "humane killers" are supplied with rubber bushings and recoil springs holding back the bolt, which afterwards is rebound into the barrel. Removal of the rubber bush and withdrawal spring before firing can cause the bolt to break and become a free projectile. A suicide case is reported, in which a livestock stunner discharged a steel bolt penetrating the forehead and getting stuck in the skull.

Fragmentation and mean kinetic energy release of the nitrogen molecule

International Nuclear Information System (INIS)

Santos, A.C.F.; Melo, W.S.; Sant'Anna, M.M.; Sigaud, G.M.; Montenegro, E.C.

2007-01-01

Ionization and fragmentation of the N 2 molecule in coincidence with the final projectile charge state have been measured for the impact of 0.188-0.875 MeV/amu He + projectiles. The average kinetic energy release (KER) of the target ionic fragments is derived from the peak widths of their time-of-flight distributions. It is shown that the KER's for singly-charged products follow scaling laws irrespectively to the collision channel

Transparency in high-energy nuclear collisions

International Nuclear Information System (INIS)

Karol, P.J.

1992-01-01

Problems associated with transparency schemes based on sharp cutoff models are discussed. The soft spheres model of hadron-nucleus and nucleus-nucleus collisions has been used to explore the influence of the realistic nuclear density geometry on transparency. An average nuclear transparency and an average reaction transparency are defined and their dependence on target and projectile dimensions and on the hadron-nucleon collision cross section are described. The results are expected to be valid for projectile energies above several hundred MeV/nucleon through the ultrarelativistic regime. For uniform (hard sphere) nuclear profiles, methods for obtaining effective total transparencies are suggested

An intranuclear cascade calculation of high-energy heavy-ion interactions

International Nuclear Information System (INIS)

Yariv, Y.; Fraenkel, Z.

1979-01-01

The intranuclear cascade model of Chen is extended to high-energy reactions between two heavy ions. The results of the calculations are compared with experimental results for the inclusive proton and pion cross sections, two-particle correlations, particle multiplicity distributions and spallation cross section distributions from light ( 12 C+ 12 C) to heavy( 40 Ar + 238 U) projectile-target systems in the laboratory bombarding energy range E/A=250-1000 MeV. The comparison shows that the model is fairly successful in reproducing the various aspects of high-energy reactions between heavy ions. It is also shown that the assumption that high particle multiplicities are indicative of ''central'' (small impact parameter) collisions are well founded for heavy projectile-target systems. (B.G.)