Projectile Energy Research Articles

Ultrastretchable Helical Carbon Nanotube-Woven Film.

Helical carbon nanotube (HCNT) is regarded as one of the most promising nanomaterials due to its excellent tensile strength and superhigh stretchability. Here, a novel HCNT-woven film (HWF) is proposed, and its in-plane and out-of-plane mechanical properties are systematically investigated via molecular dynamics (MD) simulation. The MD results show that HWF possesses highly stretchable capability resulting from sliding and straightening of CNT segments, and the maximum tensile strain can reach 2113%. Furthermore, the HWF presents an obvious tensile mechanical anisotropy. The torsion failure is the main fracture mode when the HWF is stretched along the longitudinal direction. However, when the HWF is stretched along the transverse direction, the fracture is mainly caused by intertube compression. On the other hand, the HWF can dissipate large amount of kinetic energy of projectile via sliding and fracture of HCNTs, leading to high specific penetration energy. This work provides a theoretical guidance for designing and fabricating next-generation superstrong two-dimensional CNT-based nanomaterials.

Theoretical analysis of light and heavy-ion induced reactions: production of medically relevant 97Ru

Abstract 97Ru is a key radionuclide sought for diagnostic imaging due to its low-energy and intense γ-rays of 215.7 keV and 324.5 keV. New reaction routes to produce this radionuclide are constantly being investigated. A crucial step in carrying out such reactions is a reliable beforehand estimate of the production cross section of radionuclide and optimization conditions through robust theoretical frameworks. Existing literature on α + 95Mo reaction has been freshly examined to understand the excitation function of 97Ru. The data have been compared to other reactions of different projectiles on medium-mass targets. The reaction codes pace4, empire-3.2.2, and talys-1.96 have been employed to decipher the reaction mechanism and check the predictive ability of underlying theoretical models. The yield of 97Ru at different projectile energies and thick target yield in the optimum energy range has also been determined from the theoretical modeling.

Study of state-selective single-electron capture in slow Ne7+ colliding with He and H2 target

Using the cold target recoil-ion momentum spectroscopy, we measured the state-selective single electron capture in collisions of 3.5–6.3 keV u−1 Ne7+ ions and He and H2. The Q-value spectra and angular distributions as a function of the projectile incident energy were obtained. The results show that the single electron capture into n = 4 states is the dominant reaction channel for the Ne7+-He system, while the capture into n = 4 and n = 5 states both are dominant processes for the Ne7+-H2 system. The molecular coulombic barrier model and the potential energy curves can qualitatively explain the measured state populations for both systems.

Measurement of proton induced absolute production cross-section of 6.13, 6.92 and 7.12 MeV γ-rays from 16O(p,p ′γ )16O reaction

In this article, we report the absolute production cross-section of 6.13, 6.92 and 7.12 MeV γ-rays from the 16O(p,p ′γ )16O reaction for incident proton energy range of 8-16 MeV. Angular distributions of the three γ-rays have been measured for seven angles at 9 MeV proton energy. A detailed phenomenological optical model potential (OMP) was set up to analyse the cross-section data. The OMP parameters were optimised using elastic, polarization and total reaction data available in the literature for protons and neutrons. Low-lying states of 16O were coupled, the optical potential was deformed using deformation parameters, and several resonances were included in the calculations to account for the nuclear structure effects. The potentials so generated have been used to calculate the differential and total cross sections for both 16O(p,p ′ )16O and 16O(p,p ′γ )16O reactions. Our calculated cross-sections are in fairly good agreement with our measured data for 6.13, 6.92 and 7.12 MeV γ-rays. However, there still exist discrepancies in reproduction of the finer details of the cross sections. The comparisons of the calculations with the data bring forth the rather complex roles of channel couplings, resonances in the p+16O system and target deformation in the variation of the cross sections with projectile energy. The increased contribution of nuclear structure effects in light mass nuclei, leads to an apparent loss of predictive power of the theoretical calculation, as we approach the low-energy region of less than 10 MeV projectile energy.

X-ray production cross sections for Ir and Bi M-subshells induced by electron impact

M-subshell X-ray production cross sections were indirectly measured for Ir and Bi targets irradiated with monoenergetic electron beams. The projectile energy range ran from 2.2 to 28 keV, impinging on Ir and Bi pure bulk targets in a scanning electron microscope. The resulting X-ray emission spectra were acquired with an energy dispersive spectrometer, and processed afterwards by means of a robust parameter optimization procedure developed previously. X-ray production cross sections were finally obtained through an approach involving an analytical prediction for the emission spectra, which relies on the ionization depth distribution function. The values obtained by this approach were compared with empirical and theoretical predictions, appealing to different relaxation data taken from the literature.

Hypervelocity impact induced light flash experiments on single and dual layer Kapton targets to develop a time of flight space dust and debris detector

The impact flash from hypervelocity impact on thin (12.5 µm) Kapton film was observed. The projectile sizes ranged from 0.1 to 1 mm, with speeds from 2 to 5 km s−1 and penetrated the Kapton intact, leaving holes the same size as the projectile (to within measurement errors). The flash intensity (normalised to impactor mass) scaled with impact speed to the power 5.5. However, the data also suggest that at constant speed the intensity scales with the area of the hole in the Kapton and not the projectile mass (i.e. with some property of the target and not as a function of the projectile energy or momentum). Using two layers of Kapton, it was possible to construct a Time of Flight (TOF) system, which used the time of the onset of the flash in each layer to produce flight speeds accurate to within typically 1%. When compared to the projectile speed pre-impact, there was no indication of projectile deceleration during passage through the Kapton film. In addition, when PVDF acoustic sensors were placed on the Kapton film, they exhibited an electromagnetic “pick-up” signal from the impact of projectile on the Kapton, confirming suspicions of signal interference from past work with acoustic sensors. The ability of the light flash to provide accurate impact timing signals suggests the TOF system would be suitable for use as a cosmic dust or debris impact detector in space (e.g. Low Earth Orbit).

Dissipation by transfer and its influence on fusion

A new version of the CCQEL code has been developed by upgrading the method of coupling of transfer channels during fusion and backscattering processes. In particular, the number of transfer reactions included has been increased and the dependence of the strength of transfer coupling on the transferred particle and experimental Q-value distribution was introduced. The upgraded code was employed for the investigation of the influence of transfer on the smoothing of the measured quasielastic barrier distribution (Dqe) of the 24Mg + 92Zr and 20Ne + 208Pb systems and found interesting discrepancies with respect to the standard approximations. The study with the upgraded code indicates the transfer responsible for generating strongly excited targets as the leading cause of the smearing of the barrier distribution, even in the case of negative ground state to ground state Q value (Qgg). The smoothing observed in the barrier distribution is dominated rather by one neutron transfer, despite the negative Qgg value for this reaction and the positive Qgg value for two-neutron transfer. Of particular interest is the case of the 20Ne + 208Pb, where the smoothing of the Dqe is mainly influenced by the one neutron pick-up at the beam energy above the barrier, while the one neutron pick-up and one proton stripping transfers are dominant for lower beam energy. These results highlight the importance of the transfer coupling dependence on the experimental Q-value distribution and, consequently, on the projectile kinetic energy.

Sputtering Yields of Beryllium and Tungsten by Various Atoms from Hydrogen to Tungsten

Sputtering yields of targets made of Be and W, promising materials for the first wall and the divertor of the ITER tokamak, are calculated in a wide range of projectile energies from 10 to 100 000 eV by computer simulation. The following atoms were chosen as bombarding particles: H, D, T, He, Be, C, N, O, Ne, Ar, and W. It is demonstrated that the shape of the surface strongly impacts the obtained results. The limiting cases of a planar potential barrier (a smooth surface) and a spherical potential barrier (a rough surface) are analyzed. The data on the average energy and angular distribution of sputtered atoms needed for calculation of the impurity influx into tokamak plasma are obtained. The influx of atoms of the wall material into the ITER tokamak plasma upon wall sputtering by fluxes of fast deuterium and tritium atoms leaving plasma is estimated.

A new experiment on 19F(p, α)16O reaction at low energies and the spectroscopy of 20Ne at large excitation energies

In these proceedings, we present new data for the p + 19F reaction, obtained for the 19F(p, α0)16Ogs and 19F(p, απ)16O6.05 channels. The experiment was performed at the Singletron accelerator in Catania, with proton beam energies in the 1.1-1.3 and 1.6-1.7 MeV energy regions. This allowed us to provide new data for the απ channel around 1.3 MeV projectile energy and to shed light on the ambiguities existing between previous data sets in the absolute value and in the peak shape of a particular resonance, in the α0 channel, at around 1.6 MeV projectile energy.

A review of polymer composite materials in bulletproof vest to defense sector

Personal protection, especially in the context of military protection and security, became a major focus in the development of bulletproof vests. Polymer composite materials offer a wide range of advantages in terms of strength, density, and ability to reduce the kinetic energy of projectiles, making them an attractive choice for such protection applications. This study examines the different types of polymers and composite technologies used in the manufacture of bulletproof vests. This study examines the use of polymer composite materials in the manufacture of bulletproof vests used in the defense sector. We evaluate the mechanical, thermal, and ballistic properties of these materials and investigate the design approaches applied to improve the performance of these protectors. The research proved that the composite was efficient enough to be used as a bulletproof vest material because it was light, flexible and strong.

Failure mechanism of 6252-armor steel under hypervelocity impact by 93W alloy projectile

In this study, we analyzed the fracture mechanism of the 6252-armor steel target exposed to the impact of a kinetic energy projectile made of 93W alloy. By examining the impact pressure, crater morphology, and fracture mechanism at various impact velocities, we established the relationship among these factors. As the impact velocity increased, the ratio of penetration depth to crater diameter initially increased, then stabilized, and ultimately approached 0.7 when impact pressures exceeded 49.78 GPa. For impact pressures below 70.71 GPa, macroscopic cracks were predominantly observed on the side of the crater, with no macroscopic cracks found at the bottom. However, if the pressure exceeded 70.71 GPa, the majority of macroscopic cracks occurred at the bottom of the crater. We also found a decrease in spacing between cracks or shear bands and the recrystallized grain size at the interface when the impact velocity increased. Notably, the fracture patterns demonstrated a mixture of brittle and ductile failure modes simultaneously.

Influence of Tsallis q-entropy on occurrence scattering time in a nonextensive plasma

The essence of Tsallis q-entropy on the occurrence scattering time (OST) process is derived for a nonextensive plasma. The semiclassical eikonal dissection and the nonextensive q-distribution function are used to derive the OST with variables of projectile energy, scattering angle, electron entropic index, ion entropic index, and impact parameter. Our calculations find that the OST advance in a nonextensive plasma decreases with the entropic index. We have seen that the Tsallis q-entropy on the OST advance grows up fast as the scattering angle increases. We also obtained that the nature of Tsallis q-entropy on the OST advance diminishes in forward scattering direction in a nonextensive plasma. Moreover, the authority of the electron q-entropy is found to be greater than the that of ion q-entropy in the cold electron plasma, i.e., when the electron temperature is lower than the ion temperature. However, if the ion temperature is lower than the electron temperature, the authority of the ion q-entropy is more momentous than that of the electron q-entropy.

Preservation of pristine materials under impact craters formed on comet nuclei

Comet nuclei are the most primitive small bodies in the solar system, and would contain highly volatiles and amorphous water ice. However, comet nuclei may lose their primordial properties after high-velocity impacts with other small bodies. Such high-velocity impacts might also cause the characteristic circular structures and pinnacles on the comet-nucleus surface. However, the true origin of these geological structure remains uncertain. We here sought to clarify the shape of impact craters and the effects of post-shock heating on the comet surfaces. We conducted high-velocity impact experiments at velocities of 3–5.8 km s−1 on porous-ice targets with 40%, 50% and 60% porosity, and measured the post-shock temperature around the impact crater. The hard, dense refrozen layer formed on the crater wall resembled the pinnacles and sharp pit rims observed on comet nuclei, suggesting that such structures on comets may originate from impacts. In addition, the crater size scaling law for porous ice targets was successfully obtained in the strength-dominated regime. From the temperature profiles obtained, the energy partition coefficient of the projectile kinetic energy to the post-shock heat, γ, was estimated as follows: γ=0.08, 0.27 and 0.63 for 40%, 50% and 60% porosity at 4.2 km s−1 impact velocity, and γ=0.58 and 0.22 for 50% porosity at 3 km s−1 and 5.8 km s−1 impact velocities. These results, together with our crater size scaling law for porous ice, were used to estimate the temperature distribution induced by post-shock heat on the comet-nucleus surface. Volatile depletion and crystallization of amorphous water ice can occur at distances less than twice the crater radius from the crater center—that is, the post-shock heat effects are confined to the area around the crater. This might suggest that the comet nucleus surface remains relatively primitive after impacts.

Ballistic properties of silicon carbide ceramic under weak support conditions

Ceramic materials play an important role in the composite armor structures used to defend against armor-piercing projectiles. Previous studies have focused on understanding ceramics' energy absorption and ballistic properties under strong constraints. Specifically, this research studied the ballistic properties of silicon carbide (SiC) ceramics under weak support conditions. Ballistic tests were performed to measure the resistance of SiC ceramics with different thicknesses against 7.62×54mmR armor-piercing (AP) projectiles under weak support conditions. The results were then simulated and analyzed using the LS-DYNA software. The study found that even under weak support conditions, the SiC ceramic has a higher ballistic efficiency than the 2024-T351 aluminum alloy. As the thickness of SiC increased from 3 mm to 15mm, the ceramic self-constraint effect on damaged parts was enhanced within ceramics, leading to an increase in energy dissipation during both the dwell and penetration phase, and more projectile kinetic energy transformed into the internal energy of the projectile and the energy of the ceramic. In particular, a 15 mm thick SiC ceramic can effectively defend against 7.62×54mmR AP projectiles. The study highlights the importance of considering the thickness and constraint effect of the ceramic itself when evaluating the ballistic properties of SiC ceramics with poor constraint conditions.

Systematic study of fusion suppression and its dependency on projectile breakup threshold energy

Measurements of the excitation function (EF) of the observed evaporation residues (ERs) populated in the 20Ne + 93Nb reaction at E lab ≈ 91−145 MeV are carried out to explore the systematic of fusion suppression and its dependency on projectile breakup threshold energy, by employing the offline γ-ray detection method. The EF of the observed ERs populated through complete and/or incomplete fusion processes are analysed in the framework of statistical mode code PACE4. The fusion function, derived from the experimentally measured fusion cross section data, is compared with the universal fusion function (UFF) to estimate the degree of fusion incompleteness. Based on the observed results, an empirical formula is proposed to interrelate the degree of fusion suppression and breakup threshold energy of the incident projectile.

Comprehension of breakup fusion reactions using forward recoil range distribution measurements

To understand the break-up fusion reaction dynamics, the forward recoil range distribution (FRRD) measurements of 12C + 165Ho system at the incident projectile energy of ≈ 88 MeV has been performed. The recoil catcher activation technique followed by the off-line gamma ray spectroscopy was implemented. It is observed that the FRRD measurements of the evaporation residues (ERs) populated via xn and pxn channels have a single Guassian peak at large cumulative thickness. This is attributed to complete momentum transfer from the projectile to the target nucleus. However, in case of the FRRD measurements of the ERs populated via αxn, αpxn and 2αxn emitting channels, in addition to peak corresponding to complete momentum transfer, the Gaussian peaks at lower cumulative thicknesses are also observed. This is accredited to the breakup fusion. Moreover, the effect of projectile breakup on complete fusion cross section is also studied. The suppression in fusion cross section is observed when compared with the universal fusion function, thus indicating the breakup probability of 12C projectile.

L-MM Auger electron emission from chlorinated organic molecules under proton impact: Angular distribution and total cross section measurement

We have measured the absolute cross section for L-MM Auger electron emission in chlorinated methanes and benzene chloride molecules in collision with keV energy protons. The measurements have been performed with four different chlorine containing organic molecules viz CCl4, CHCl3, CH2Cl2 and C6H5Cl. We have measured the angular distribution of chlorine L-MM Auger electrons at backward emission angles (90° – 150°). The angular distribution shows an isotropic character. We also studied the projectile energy dependence of the total L-MM Auger yield for proton energy ranging from 125 keV to 275 keV. Carbon K-LL Auger yield was also obtained in the same experiments.

Ar cluster bombardment of phenylalanine deposited on graphene-Effect of kinetic energy and projectile size.

This study investigates the effects of kinetic energy and projectile size on particle emission from a phenylalanine overlayer adsorbed on a graphene bilayer during argon projectile bombardment. Projectiles of various sizes (1-1000 atoms) and kinetic energies (0.5-40keV) are used to study their impact on the ejection efficiency, mass distribution, and kinetic and angular spectra of the emitted substances. Particle ejection mechanisms are discussed in scenarios with and without sample perforation. Additionally, this study investigated the potential use of graphene in secondary ion mass spectrometry or neutral secondary mass spectrometry analyses.

State-selective charge exchange cross sections in collisions of highly-charged sulfur ions with helium and molecular hydrogen

The state-selective cross section data are useful for understanding and modeling the x-ray emission in celestial observations. In the present work, using the cold target recoil ion momentum spectroscopy, for the first time we investigated the state-selective single electron capture processes for S q+–He and H2 (q = 11–15) collision systems at an impact energy of q × 20 keV and obtained the relative state-selective cross sections. The results indicate that only a few principal quantum states of the projectile energy level are populated in a single electron capture process. In particular, the increase of the projectile charge state leads to the population of the states with higher principal quantum numbers. It is also shown that the experimental averaged n-shell populations are reproduced well by the over-barrier model. The database is openly available in Science Data Bank at 10.57760/sciencedb.j00113.00091.

Study on the protective performance of high-performance multi-scale (SiCh-p+B4Cp)/5083Al ceramic array armor with excellent ballistic properties

Ceramic array armor suffers from insufficient constrained capability of ceramic units in the embedded armor structure, leading to weak interfacial bonding at ceramic unit connections, significantly reducing the overall ballistic performance. In this study, centimeter-sized SiC hexagonal prisms and micrometer-sized B4C powders were used as reinforcing materials. A high-strength, high-toughness, and multiscale array (SiCh-p + B4Cp)/5083Al armor with strong interfacial bonding was prepared using pressure infiltration technique. The (SiCh-p + B4Cp)/5083Al armor was combined with ultra-high molecular weight polyethylene and 6252 armor steel to form an integrated armor system. To investigate the effect of constrained material on its ballistic performance, the array structures with epoxy and 5083Al as constrained material were prepared for comparison. Ballistic performance tests were conducted using 12.7 mm Armor-Piercing Incendiary (API). The damage mechanisms of the armor structure were studied through finite element simulation and a combination of macroscopic and microscopic analyses. The results demonstrate excellent overall ballistic performance of the (SiCh-p + B4Cp)/5083Al armor system. The high-strength and high-toughness 55 vol%B4Cp/5083Al composite material exhibits strong interfacial bonding with SiCh-p, providing robust support to the SiCh-p. The armor back deformation was reduced by 50 %, and the ceramic layer dissipated more than 70 % of projectile kinetic energy, The materials prepared in this study exhibit significant potential in ballistic performance.