Projectile Fragmentation Research Articles

Emission characteristics of the target fragments at relativistic energy

In this recent work, we present the characteristic of the emission of the black particles ejected with [Formula: see text] [Formula: see text] [Formula: see text] and [Formula: see text] [Formula: see text][Formula: see text] i.e., in the forward and backward hemispheres, respectively. For the multiplicity variation study of black particles, we have considered the interaction of [Formula: see text]Kr beam with the CNO, AgBr target present in the nuclear emulsion detector. After doing the analysis of the data, we have found that the emission possibility of black particle is greater in the forward hemisphere (FHS) angle whereas in the backward hemisphere (BHS) angle, it is quite low. Along with this, we have also found that the emission probability of black particles does not posses any relation with projectile mass as well as with the incident energy. In this work, we have also studied the characteristics of shower and et al. particles using a new parameter Q (total charge [Formula: see text] of the outgoing projectile fragments emitted in forward cone [Formula: see text], here Z denotes charge, and PF denotes Projectile Fragment) instead of impact parameter to distinguish the different type of collision for two interacting nuclei. The observation from this study suggests that the emission probability of the shower particles as well as gray particles increase as the value of Q decreasing (i.e., as we move from peripheral to central colisions). The results of this work are also compared with the context of other experimental observations and it seems to be relevant.

Nature of seniority symmetry breaking in the semimagic nucleus Ru94

Direct lifetime measurements via γ−γ coincidences using a fast timing detector array consisting of LaBr3(Ce) scintillators has been applied to determine the lifetime of low-lying states in the semimagic (N=50) nucleus Ru94. The experiment was carried out as the first in a series of “FAIR-0” experiments with the DESPEC experimental setup at the Facility for Antiproton and Ion Research (FAIR). Excited states in Ru94 were populated primarily via the β-delayed proton emission of Pd95 nuclei, produced in the projectile fragmentation of an 850 MeV/nucleon Xe124 beam impinging on a 4 g/cm2Be9 target. While the deduced E2 strength for the 2+→0+ transition in the yrast cascade follows the expected behavior for conserved seniority symmetry, the intermediate 4+→2+ transition exhibits a drastic enhancement of transition strength in comparison with pure-seniority model predictions as well as standard shell model predictions in the fpg proton hole space with respect to doubly magic Sn100. The anomalous behavior is ascribed to a subtle interference between the wave function of the lowest seniority ν=2, Iπ=4+ state and that of a close-lying ν=4 state that exhibits partial dynamic symmetry. In addition, the observed strongly prohibitive 6+→4+ transition can be attributed to the same mechanism but with a destructive interference. It is noted that such effects may provide stringent tests of the nucleon-nucleon interactions employed in state-of-the-art theoretical model calculations.Received 17 October 2021Revised 17 January 2022Accepted 11 March 2022DOI:https://doi.org/10.1103/PhysRevC.105.L031304Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by Bibsam.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasIsomer decaysProton emissionProperties90 ≤ A ≤ 149Nuclear bindingTechniquesGamma ray spectroscopyNuclear structure & decaysRadiation detectorsRadioactive beamsSpectrometers & spectroscopic techniquesNuclear PhysicsAccelerators & Beams

Measurement of fragments generated by hypervelocity impacts of micron-sized iron particles at grazing incidents

• Fragments of hypervelocity dust impacts are measured using a Delay Line Detector. • Majority of fragments created at grazing incidences are composed of dust projectile. • Fragmentation of projectiles increase with impact speed for grazing incidences. • The fragment speeds are distributed around 80% of the projectile impact speed. In this study, we present results from hypervelocity impacts of iron particles onto smooth surfaces under shallow incidence. For the first time, the submicron fragments of the projectiles were measured using a delay-line detector combined with a multichannel plate. Micron-sized spherical iron particles with speeds between 4–40 km/s are fired by a dust accelerator facility and impact on an optical mirror target at grazing angles of 2 ° , 4 ° , and 6 ° from the horizontal. Individual fragments generated in each impact event have been measured and analyzed including their speeds, masses, and trajectories. The total mass and momentum of fragments are comparable to their parent projectile. It is observed that most fragments have speeds exceeding 80 % of pre-impact velocities. Fragments generated at incident angle of 2 ° leave the target surface with even lower elevation angles of around 1 ° . The majority of impact fragments generated under incident angles of 4 ° and 6 ° form a spatial distribution centered an axis of 5 ° elevation, which increases with increasing impact speed. Furthermore, azimuthal scattering occurs with a distribution concentrated within ± 10 ° .

Fluctuations of the largest fragment charge in projectile fragmentation and its nonequilibrium effect

Background: The projectile fragmentation is associated with the liquid-gas phase transition in the finite nuclear system. Recent experimental data and calculations by the statistical multifragmentation model indicated that the higher-order fluctuations of the largest fragment charge exhibit the signatures of the second-order phase transition [PLB809(2020)135763]. However, these higher-order fluctuations calculated by the dynamical model are still not reported.Purpose: This work is proposed to investigate dynamically this signature and emphasize the nonequilibrium effect.Methods: The isospin-dependent quantum molecular dynamics (IQMD) model is used to study the nonequilibrium thermalization and fragmentation in the $^{124}\mathrm{Sn} + ^{120}\mathrm{Sn}$ collisions at 600 MeV/nucleon. The minimum spanning tree algorithm is applied to distinguish the hot projectile-like system during the dynamics evolution.Results: The fluctuations of the largest fragment charge ${Z}_{\mathrm{max}}$ up to the fourth order by the IQMD model reproduce the experimental data. The pseudocritical point indicated by zero of skewness (third-order fluctuation) together with minimum of kurtosis excess (fourth-order fluctuation) is found at impact parameter $b=8.7$ fm, where the multifragmentation and nucleon evaporation are well balanced. Two observables are defined to describe the asymmetry of temperature and density in the projectile-like system. The nonequilibrium of the projectile-like system is verified by the distributions of these two observables. By comparing the distributions of the largest fragment charge for the equilibrium and nonequilibrium systems, it is found that the nonequilibrium of the hot projectile-like system influences the competitive relation between the multifragmentation and nucleon evaporation.Conclusions: It is proposed that the nonequilibrium effect should be considered when study the pseudocritical point from the projectile fragmentation.

Production of proton-rich nuclei in the vicinity of 100Sn via multinucleon transfer reactions

The production of new proton-rich nuclei in the vicinity of 100Sn is investigated via multinucleon transfer reactions within the framework of microscopic time-dependent Hartree-Fock (TDHF) and statistical model GEMINI++. The TDHF+GEMINI method has demonstrated the reliable description in the multinucleon transfer dynamics and the agreement between theoretical results and experimental data is quite satisfactory in the observed transfer reactions. We reveal the production cross sections of proton-rich nuclei in 100Sn region via multinucleon transfer reactions to be several orders of magnitude higher than those measured via fusion-evaporation and projectile fragmentation experiments. About 19 new proton-rich isotopes with cross sections of larger than 1 nb are predicted to be produced in multinucleon transfer reaction of 58Ni with 112Sn. The reaction mechanisms are discussed to lead the experimental production of these previously unreported nuclei. Multinucleon transfer reactions provide a fascinating possibility to reach the proton drip-line in 100Sn region and beyond.

Determination of neutron-skin thickness using configurational information entropy

Configurational information entropy (CIE) theory was employed to determine the neutron skin thickness of neutron-rich calcium isotopes. The nuclear density distributions and fragment cross-sections in 350 MeV/u $^{40-60}$Ca + $^{9}$Be projectile fragmentation reactions were calculated using a modified statistical abrasion-ablation model. CIE quantities were determined from the nuclear density, isotopic, mass, and charge distributions. The linear correlations between the CIE determined using the isotopic, mass, and charge distributions and the neutron skin thickness of the projectile nucleus show that CIE provides new methods to extract the neutron skin thickness of neutron-rich nuclei.

Features of the ejection and topography of the distribution of metal particles of a destroyed projectile after overcoming an obstacle made of triplex glass of a car

BACKGROUND: The article describes experimental studies aimed at studying the features of post-retrograde gunshot trauma using the latest modern methods of forensic medical research.
 AIMS: The aim of the work was to study the nature of the distribution of metal particles of a destroyed firearm projectile after passing through an obstacle ― triplex glass.
 MATERIAL AND METHODS: As a barrier, car windshield triplex windows are used, located at an angle of 60 to the aiming line. The shots were fired from the Saiga-MK carbine with 5.4539 BPZ FMJ cartridges. During the experiments, shots were fired from a distance of 10 m (a total of 30 shots were fired). White cotton fabric (calico) with dimensions of 100150 cm, fixed on a chipboard, was used as targets. The distance between the target and the barrier was 100 cm. The targets were studied using a scanning electron microscope Hitachi FlexSem 1000 II and an energy-dispersive X-ray spectrometer Bruker Quantax 80. In the course of the experiment, high-speed video shooting was carried out with a Sony RX0 video camera with a frequency of 1000 fps.
 RESULTS: A frame-by-frame study of the obtained video recordings showed that the deviation of the flight of the projectile fragments from the original trajectory was up to 10 side of the normal to the back surface of the glass. The fragments of the projectile, having overcome the barrier, moved in stages, in 3 phases: overcoming the barrier, ejecting fragments in the form of a cone, breaking through the target and retrograde movement of the fragments of the barrier. The scanning electron microscope and energy dispersive spectroscopy studies showed that the topography and morphology of the distribution of metals on the target surface correspond to the data of the analysis of the movement of parts of a firearm during high-speed video shooting. The metal alloy found on the target contained the following elements: plumbum (Pb), cuprum (Cu), antimony (Sb), and kalium (K).
 CONCLUSION: When conducting an experimental study, it was found that various types of particles that were destroyed during the passage of the barrier, a firearm projectile, are registered on the surface of the target. The nature of the particle distribution and their morphology are very specific, and most likely a qualitative assessment of the projectile particles on the target will allow us to determine the distance of the shot beyond the barrier.

An extensive study of depth dose distribution and projectile fragmentation cross-section for shielding materials using Geant4

Geant4 Monte Carlo simulation was executed for 16O beam in various elemental and hydrogenous materials for assessment of ion characteristics and shielding efficacy. In the energy-dependent comparison, at energies 200–594 MeV/n, the peak to entrance ratio decrement up to 78.6% in water target validates the substantial increase in fragmentation factor. Further, hydrogenous materials and low Z elements (C, Al) demonstrate a low peak-to-entrance ratio (0.92–1.66) compared to heavy element (Cu, Sn, Pb) ratio (2.73–3.54), at 594 MeV/n, indicating the high fragmentation properties of hydrogenous and low Z elements. Accordingly, the depth dose reduction percentage was found to be significantly higher for hydrogenous materials (0.92–1.72%) having 4.20–14.37 H wt.% than non-hydrogenous targets (0.09–0.82%). LiH was found to exhibit the lowest peak-to-entrance ratio and highest depth dose reduction. The high shielding effectiveness of LiH (12.59%) irrespective of having a low H fraction compared to polyethylene (14.37%) which is widely used shielding material, suggests the contribution of low Z element Li (87.41 wt%) over the C (85.63 wt%) element in the material. Also, simulated results of fragmentation for high Z materials were compared with the experimental data for the reliability of Geant4. Finally, the comparison of these properties recommends the use of hydrogenous materials with low Z elements for effective space radiation shielding.

Production of the most neutron-deficient Zn isotopes by projectile fragmentation of Kr78

The cross sections for the production of three most neutron-deficient zinc isotopes, Zn54–56, in the projectile fragmentation of Kr78 at 345 MeV/nucleon on a beryllium target, were measured. Although the results are smaller by over an order of magnitude from those obtained with a Ni58 beam at 75 MeV/nucleon on a nickel target, the rates of reaction products are found to be larger in the case of high-energy fragmentation of Kr78. The experimental cross sections for the most neutron-deficient isotopes of even-Z nuclei between zinc and krypton were analyzed in the framework of the abrasion-ablation model. A very good agreement with the data was found when the nuclear masses predicted by a particular variant of the Hartree-Fock-Bogoliubov mass model were used. The prospects for the observation of more exotic isotopes in this region are discussed in context of 2p radioactivity.Received 29 June 2021Accepted 23 November 2021DOI:https://doi.org/10.1103/PhysRevC.104.064610©2021 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasNuclear fragmentationProton emissionRare & new isotopesNuclear Physics

Isotope and Velocity Distributions in Projectile Fragmentation Reactions at Fermi Energies

Isotope and Velocity Distributions in Projectile Fragmentation Reactions at Fermi Energies

Δ0 (1232) production in n+12C collisions at 4.2GeV/c

For the first time, the production of [Formula: see text] (1232) resonances has been analyzed in minimum bias [Formula: see text]C collisions at 4.2[Formula: see text]GeV/[Formula: see text]. The value of the mass and width of the [Formula: see text] resonances as well as the fraction of the negative pions coming from [Formula: see text] decay obtained in this work in [Formula: see text]C collisions coincide within the uncertainties with those extracted earlier in [Formula: see text]C collisions at 4.2[Formula: see text]GeV/[Formula: see text] per nucleon. The inclusive cross-section for production of [Formula: see text] (1232) resonances in [Formula: see text]C collisions at 4.2[Formula: see text]GeV/[Formula: see text] is estimated to be [Formula: see text][Formula: see text]mb. Production of [Formula: see text] resonances in [Formula: see text]C collisions at 4.2[Formula: see text]GeV/[Formula: see text] has been investigated separately in regions of fragmentation of the target and projectile. The mass of the [Formula: see text] (1232) proved to be the same within the statistical errors in the target and projectile fragmentation regions. The width of the invariant mass spectrum of [Formula: see text] excited in the projectile region proved to be considerably larger than that in the target fragmentation region, coinciding within statistical errors with that obtained in collisions of free nucleons. The results of the previous experiments, in which production of [Formula: see text] resonances is investigated in the whole phase space (without separating the target and projectile fragmentation regions), can be approximately regarded as the mean values of [Formula: see text] parameters, averaged over those in the target and projectile fragmentation regions.

Radioactive Beams for Image-Guided Particle Therapy: The BARB Experiment at GSI.

Several techniques are under development for image-guidance in particle therapy. Positron (β+) emission tomography (PET) is in use since many years, because accelerated ions generate positron-emitting isotopes by nuclear fragmentation in the human body. In heavy ion therapy, a major part of the PET signals is produced by β+-emitters generated via projectile fragmentation. A much higher intensity for the PET signal can be obtained using β+-radioactive beams directly for treatment. This idea has always been hampered by the low intensity of the secondary beams, produced by fragmentation of the primary, stable beams. With the intensity upgrade of the SIS-18 synchrotron and the isotopic separation with the fragment separator FRS in the FAIR-phase-0 in Darmstadt, it is now possible to reach radioactive ion beams with sufficient intensity to treat a tumor in small animals. This was the motivation of the BARB (Biomedical Applications of Radioactive ion Beams) experiment that is ongoing at GSI in Darmstadt. This paper will present the plans and instruments developed by the BARB collaboration for testing the use of radioactive beams in cancer therapy.

Depth-profiling of activity induced by 300 MeV/u 124Xe ions in aluminum: Ranges of heavy projectile fragments

This work is a continuation of a series of publications devoted to the depth-profiling of activity induced by high-energy heavy-ions in selected accelerator-construction materials. An aluminum target in the stacked-foil configuration was irradiated by 300 MeV/u 124Xe ions. Depth-profiles of induced activity of selected nuclides were obtained by gamma-spectroscopy of individual target foils. Special attention was paid to heavy projectile-fragments and their ranges. Main profile-shape categories have been defined to illustrate typical shapes of the measured profiles. A new quantity – an activation depth – has been introduced and its dependence on the fragment atomic and mass number has been found. It is shown that this quantity is fragment-specific and can substitute the range, which is very useful in case of the activation experiments using the stacked-foil targets with depth resolution limited by the foil thickness. Apart from gamma-spectroscopic parameters and fundamental nuclear properties of the nuclides, the activation depth can be used as an additional nuclide-attribute supporting identification of the projectile fragments and verification of the range-calculating computer codes. Although the main attention of this paper is paid to presenting the new experimental results, comparison with supporting simulations with the aid of ATIMA and FLUKA2020 is included, too.

Enhancing the understanding of fragmentation processes in hadrontherapy and radioprotection in space with the FOOT experiment

During proton and carbon ions cancer treatment, nuclear interactions of the beam nuclei with the patient tissues always occur: the former leads to target fragmentation only, the latter to both projectile and target fragments production. In proton therapy the low-energy, high-charge and therefore short-range fragments produced along the beam path in the target fragmentation process may have higher biological effectiveness compared to protons, resulting in a not negligible effect on the delivered dose in a region before the tumor site. In carbon treatments the long range of projectile fragments results in a dose deposition in the healthy tissues behind the tumor site. Therefore, precise fragmentation cross section data would be of great importance to further optimize treatments. At the same time, such data would help improving the design of the shielding of spaceships, especially in view of long distance travels (i.e. Mars human exploration). In fact, nuclear fragmentation occurring between the space background radiation and spacecrafts materials changes the composition of the radiation field and thus the dose received by the astronauts. The FOOT (FragmentatiOn Of Target) experiment has been designed to investigate nuclear fragmentation processes of interest for particle therapy and space radiation protection with a precision in the cross section measurements around 5%. In this work the physics motivations of FOOT and the final design of the experiment will be presented. A performances study of the electronic setup based on FLUKA Monte Carlo simulations and a preliminary analysis of experimental data are reported as well.

Isomeric states in neutron-rich nuclei near N=40

Neutron-rich nuclei in the vicinity of the $N=40$ island of inversion are characterized by shell evolution and exhibit deformed ground states. In several nuclei isomeric states have been observed and attributed to excitations to the intruder neutron $1g_{9/2}$ orbital. In the present study we searched for isomeric states in nuclei around $N=40$, $Z=22$ produced by projectile fragmentation at RIBF. Delayed $\gamma$ rays were detected by the EURICA germanium detector array. High statistics data allowed for an updated decay scheme of $^{60}$V. The lifetime of an isomeric state in $^{64}$V was measured for the first time in the present experiment. A previously unobserved isomeric state was discovered in $^{58}$Sc. The measured lifetime suggests a parity changing transition, originating from an odd number of neutrons in the $1g_{9/2}$ orbital. The nature of the isomeric state in $^{58}$Sc is thus different from isomers in the less exotic V and Sc nuclei.

Isospin effects of projectile fragmentation in a Boltzmann-Langevin approach * *Supported by the National Natural Science Foundation of China (11635003, 11025524, 11161130520), National Basic Research Program of China (2010CB832903) and the European Commissions 7th Framework Programme (FP7-PEOPLE-2010-IRSES) under Grant Agreement Project (269131)

The isospin effects of projectile fragmentation at intermediate energies are investigated using an isospin-dependent Boltzmann-Langevin model. The collisions of mass-symmetric reactions including 58Fe, 58Ni + 58Fe, and 58Ni at intermediate energies, in the 30 to 100 MeV/A range, are studied for different symmetry energies. Yield ratios of the isotopic, isobaric, and isotonic pairs of fragments from the intermediate-mass region using three symmetry energies are extracted as functions of the N/Z ratio of the composite systems in the entrance channel and the incident energies. It is found that the yield ratios are sensitive to symmetry energies, especially for neutron-rich systems, and the calculations using soft symmetry energy are closer to the experimental data. The isospin effect is stronger for the soft symmetry energy, owing to the competition of the repulsive Coulomb force and the symmetry energy attractive force on the proton. For the first time, the splits are presented, revealing a transition from the isospin equilibrium at lower energies to translucency at intermediate energies. The results show a degree of transparency in that intermediate mass fragments undergo a transition from dependence on the composite systems in the entrance channel to reliance on the projectile and target nuclei.

A comparison of contact charging and impact ionization in low-velocity impacts: implications for dust detection in space

Abstract. We investigate the generation of charge due to collision between projectiles with sizes below ∼1 µm and metal surfaces at speeds ∼0.1 to 10 km s−1. This corresponds to speeds above the elastic limit and well below speeds where volume ionization can occur. Impact charge production at these low to intermediate speeds has traditionally been described by invoking the theory of shock wave ionization. By looking at the thermodynamics of the low-velocity solution of shock wave ionization, we find that such a mechanism alone is not sufficient to account for the recorded charge production in a number of scenarios in the laboratory and in space. We propose a model of capacitive contact charging that involves no direct ionization, in which we allow for projectile fragmentation upon impact. Furthermore, we show that this model describes measurements of metal–metal impacts in the laboratory well. We also address contact charging in the context of ice-on-metal collisions and apply our results to rocket observations of mesospheric dust. In general, we find that contact charging dominates at speeds of up to a few kilometres per second and complements shock wave ionization up to speeds where direct ionization can take place. The conditions that we consider can be applied to dust particles naturally occurring in space and in Earth's upper atmosphere and their direct impacts on rockets, spacecraft, and impacts of secondary ejecta.

β-decay and isospin symmetry breaking

<p indent=0mm>The elegant concept of isospin symmetry is of fundamental importance in nuclear and elementary particle physics. As a β-decay process changes an up quark to a down quark or <italic>vice versa</italic>, studies of nuclei with exchanged numbers of neutrons and protons, known as mirror nuclei, can be a powerful means to probe isospin symmetry breaking. A series of β-decay experiments of sd-shell nuclei near the proton drip line produced by projectile fragmentation were performed at the Radioactive Ion Beam Line of the Heavy Ion Research Facility in Lanzhou (HIRFL-RIBLL1) using a silicon array with a high detection efficiency and a low detection threshold. The secondary ions were identified by the combination of Δ<italic>E</italic>-TOF and magnetic rigidity (<italic>Bρ</italic>) in which the time of flight (TOF) was measured by two plastic scintillators at the second and fourth focal planes of the RIBLL1 and the energy loss (Δ<italic>E</italic>) was measured by two silicon detectors in the front of the silicon array. Double-sided silicon strip detectors (DSSDs) in the center of the array served to measure the residual energies of secondary ions on an event-by-event basis and study their decay properties with an implantation-decay correlation. Several quadrant silicon detectors (QSDs) placed behind DSSDs were used for anticoincidences of the penetrating fragments and light particles coming along with the beam, and measurements of β particles and high-energy protons. The β-delayed proton peaks with known energies and their corresponding absolute intensities were used for the energy and detection efficiency calibrations of the DSSDs. The system allows us to measure protons with energies down to about <sc>200 keV</sc> without obvious β background in the proton spectrum and was successful to measure the energies, time, and positions of implanted ions and decay protons efficiently, supporting researchers to study the decay properties of nuclei towards the proton drip line. The β-decay data, together with the large-scale shell-model calculations, allows detailed investigations on the mirror-nuclei systems resulting in the systematic study of isospin symmetry breaking in the sd-shell nuclear region. It was found that the mirror asymmetry parameters become larger due to the smaller separation energies while approaching the proton drip line for the extremely proton-rich sulfur nuclei ^27,28,29S and the Coulomb forces and other isospin-symmetry nonconserving forces acting between protons would lead to extended proton wave functions and cause mirror asymmetries. The properties of ²²Si β-decay for the transitions to the low-lying states of ²²Al were measured, and the reduced transition probabilities were determined. Comparing with the data on the β-decay of the mirror nucleus ²²O, we found a mirror asymmetry of <italic>δ</italic>=209(96)% in the transition to the first 1⁺ excited state of the respective daughters. This is by far the largest value of <italic>δ</italic> observed in the low-lying states. Shell-model calculations with isospin-nonconserving forces, including the <italic>T</italic>=1,<italic> J</italic>=2, 3 interactions related to the s_1/2 orbit that introduces explicitly the isospin-symmetry breaking force and describes the loosely bound nature of the wave functions of the s_1/2 orbit, can reproduce the observed data well and demonstrate that this dramatically large mirror asymmetry is attributed to the significant proton occupation and loosely bound nature of the wave functions of the s_1/2 orbit, which suggests that ²²Al is a proton-halo nucleus.

Fragmentation of carbon on elemental targets at 290AMeV

The total charge-changing cross-sections and the partial cross-sections for projectile fragments (PFs) production for the fragmentation of 12C on C, Al, Cu, Pb and CH2 targets at the highest energy of 290[Formula: see text]A[Formula: see text]MeV were studied. It was found that the total charge-changing reaction cross-sections and the partial reaction cross-sections of PFs production were independent of the beam energy, and increased with increase of mass of target for the same beam energy. The total charge-changing reaction cross-section was the same as the prediction of Bradt–Peters semi-empirical formula, PHITS and NUCFRG2 simulation models. The partial cross-section of PFs production increased with the increase of the mass of target, and it was the same as the prediction of NUCFRG2 models. The mean scattering angle of projectile particle was smaller than the average emission angle of PF, and the width of scattering angle distribution of projectile particle was smaller than that of emission angle distribution of PFs. The mean emission angle of PFs does not obviously depend on the target mass and beam energy in our studied beam energy regions.

Characterization of the non-ideal debris cloud in yaw hypervelocity impact by cylindrical projectile

This work revisits the classical hypervelocity impact problem of a cylindrical projectile impinging upon a thin plate at an attack angle. A methodology is described to identify the potentially dangerous fragments that can perforate the rear plate in a Whipple shield configuration. The attack angle is re-calculated based on the reported orthogonal view angles, followed by numerical modeling of the hypervelocity impact event using the SPH method in AUTODYN-3D, and the qualitative and quantitative post-processing of the debris cloud generated from the hypervelocity impact. The model predictions are compared to results from the experimental data from the literature for two different attack angles – they will be shown to be in good agreement. The concentrated area of dangerous fragments in the debris cloud is quantified in detail, and its damage mechanism to the rear plate is revealed. The majority of the projectile fragments are located inside the inner cone and the cross-wing of the debris cloud, where the latter bridge connecting the inner cone and the outer bubble, and they are defined according to their geometry shapes being as the components of the debris cloud. The accumulative effect of the two structures are shown to attribute to the potential damage in the rear plate. This work aims to help Whipple shield designers seeking a theoretical method to estimate the threat of yaw hypervelocity impact.