Types Of Projectiles Research Articles

Local lifetime control by light ion irradiation: impact on blocking capability of power P–i–N diode

The impact of local lifetime control by 1H+ and 4He2+ irradiation on blocking characteristics of power P–i–N diodes was studied in the dose range up to 5×1012cm−2. Energies and doses for both types of projectiles were chosen in a way to create a comparable damage in three qualitatively different regions close to the anode junction. Blocking capabilities of irradiated diodes were measured, compared and simulated. The results show that there is no difference between hydrogen and helium irradiation if the damage is located inside the anode area. When the damage peak is placed into the N-base side of the anode junction and the dose of protons exceeds 1012cm−2, blocking capability of the diode drastically decreases while it stays at the same level for analogous irradiation by helium ions.

Probing inelastic interactions of ions moving in solids by electron spectroscopy

We have measured energy distributions of electrons emitted from clean aluminum surfaces by 20 keV/amu H+, He+ and He0 projectiles. Ratios of energy distributions obtained from two types of projectiles carry information on differences in the electron excitation collisions. We discuss these differences in terms of screening of the projectile by valence electrons, Auger capture and projectile ionization, with the aid of linear response theory. We find the shapes of secondary electron energy spectra are dominated by the energy dependence of the electron escape depth and of the binary ion–electron interaction. The latter must be determined by considering the screened potential of the projectile and its changing charge state as it penetrates the solid.

The applications of unsteady, multi-dimensional studies of detonation waves to ram accelerators

Since much of the early work on the concepts on which ram accelerators are based dates back to the 1960s, although many of these are still being actively pursued, it is difficult to formulate a completely logical approach. This situation is compounded by the use of presently unacceptable treatments of unidimensional detonations in the early work and unfortunately extended to some of the more modern treatments. My approach has been to start by dealing with the early work and recent work impinging upon it, then to re-emphasise recent work on detonations, particularly that dealing with the influence of changes in confinement on quenching and re-initiation of detonations. However, some knowledge of this is inferred in suggestions made in Part 2 for possible improvements in the techniques. Latter sections cover the development of the ram accelerator, the use of various types of projectiles, developments in experimental techniques and finally on areas in space flight where the results from ram accelerators might be utilised.

Penetration of 6061-T6511 aluminum targets by ogive-nose steel projectiles with striking velocities between 0.5 and 3.0 km/s

Summary We performed a series of depth-of-penetration experiments using 7.11-mm-diameter, 71.12-mm-long, ogive-nose steel projectiles and 254-mm-diameter, 6061-T6511 aluminum targets. The projectiles were made from vacuum-arc remelted (VAR) 4340 steel (Rc 38) and AerMet 100 steel (Rc 53), had a nominal mass of 0.021 kg, and were launched using a powder gun or a two-stage, light gas gun to striking velocities between 0.5 and 3.0 km/s. Since the tensile yield strength of AerMet 100 (Rc 53) steel is about 1.5 times greater than VAR 4340 (Rc 38) steel, we were able to demonstrate the effect of projectile strength on ballistic performance. Post-test radiographs of the targets showed three different regions of penetrator response as the striking velocity increased: (1) the projectiles remained rigid and visibly undeformed; (2) the projectiles deformed during penetration without nose erosion, deviated from the target centerline, and exited the side of the target or turned severely within the target; and (3) the projectiles eroded during penetration and lost mass. To show the effect of projectile strength, we present depth-of-penetration data as a function of striking velocity for both types of steel projectiles at striking velocities ranging from 0.5 and 3.0 km/s. In addition, we show good agreement between the rigid-projectile penetration data and a cavityexpansion model.

Numerical simulation of space debris impacts on the Whipple shield

The authors carried out three series of experimental tests of the first bumper perforation and main wall cratering processes directly caused by three types of projectiles with about 2, 4 and 7 km s −1 impact velocities but comparable initial kinetic energies, by using three different accelerators (one-stage powder gun, two-stage light-gas gun and rail gun), for the purpose of investigating space debris hypervelocity impacts onto single-walled Whipple bumper shields [1]. In the present study, after reviewing the numerical simulation method of hydrocode for both Eulerian and Lagrangian descriptions, a number of parametric numerical simulation analyses using multiple material Eulerian methods were performed in order to optimize the material properties of bumper and main wall materials through comparison with experimental results of single target impacts by the projectiles. In particular, the material data on the dynamic fracture phenomena are discussed in detail in the first part. Then a couple of numerical calculations using the interactive Lagrangian rezoning method to simulate the overall impact process against the single walled Whipple shield were performed and compared with the corresponding experimental results. Both results indicated fairly good agreement with each other. Moreover, it was demonstrated that the present method is helpful and efficient in understanding the impact phenomena and fracture mechanism in the space debris hypervelocity impact problem. Finally the multiple material Eulerian method was applied to the same problems modeled by the interactive Lagrangian rezoning method used previously, because the former is much easier to use for almost all users, although it is more diffusive and unclear of material boundaries than the latter. Those two kinds of numerical results also indicated fairly good agreements with each other.

Tracks in MoS 2 irradiated with 20 MeV fullerene and 1 GeV lead ions

The first results of a Transmission Electron Microscopy study of Molybdenite (MoS 2) irradiated with 20 MeV fullerene and 1 GeV lead ions are presented. It is shown that the energy deposited by electronic excitation by both types of projectiles leads to track formation. Although the value of the linear rate of energy deposition is comparable for 20 MeV C 60 clusters and 1 GeV Pb ions, the diameters of the tracks created by the clusters is two times greater than the diameter of the tracks induced by 1 GeV Pb ions. Furthermore, the tracks in the sample irradiated with fullerene ions present specific contrast features.

A numerical simulation method and its validation for debris impact against the whipple bumper shield

The authors carried out three series of experiments of the first bumper perforation and main wall cratering processes directly caused by three different types of projectiles with about 2, 4 and 7 km/s impact velocities but comparable kinetic energies, for the purpose of investigating the space debris hypervelocity impact against the single walled Whipple bumper system [1]. In the present study, a number of parametric numerical simulation analyses were performed in order to optimize the material properties of bumper and main wall materials through the comparison with the experimental results of the single target impacts by the projectiles. Then a couple of numerical calculations to simulate the whole impact process were performed and compared with the corresponding experimental results. This paper offers a numerical simulation method applicable to the space debris impact against the Whipple bumper shield, after providing the optimized material models through the comparison of the results for several single target impact tests between the experimental and parametric numerical analyses.

Order Declaring Certain Types of Ammunition to be Prohibited Weapons (Prohibited Weapons Order No. 10): Some Anticipated Problems for Canadian Firearms Examiners

Prohibited Weapons Order No. 10, is a regulation made under the Criminal Code of Canada, which bans possession of certain types of ammunition. It came into effect on October 1, 1992. Because of certain undefined terms in the Order and in the Criminal Code, and some overlapping regulation of ammunition and its components under the Explosives Act (R.S.C.), it can be anticipated that there will be problems for the police, Crown prosecutors, firearms examiners and firearms/ammunition owners. Since the mid-1800s, there have been no uniform, internationally-recognized standards for marking ammunition, projectiles or the packages in which they are shipped from the factory; since commercial and military cartridges and their components are often stored, traded and sold loose and unlabelled, there are many avenues for error open to all concerned. The Prohibition Order only covers certain types of ammunition and projectiles. These are: handgun cartridges whose projectiles are capable of penetrating body armour fabric; projectiles which ignite on impact; projectiles which explode on impact; and, shotgun cartridges containing flechettes. Unintentionally, it appears to have also included certain types of veterinary “tranquilizer dart” projectiles, containing a component which explodes on impact. This article analyzes the elements of the Order, and some areas of uncertainty in applying its legal language to evidence which may be seized and submitted for examination. It also examines techniques and procedures that can assist the firearms examiner in making a more precise determination of the status of suspect ammunition and projectiles.

Reactive ion–surface collisions: Application of ionized acetone‐d6, DMSO‐d6 and pyridine‐d5 as probes for the characterization of self‐assembled monolayer films on gold

AbstractLow‐energy collisions of ionized acetone‐d6, DMSO‐d6 and pyridine‐d5 with alkanethiolate self‐assembled monolayer (SAM) surfaces prepared on gold were investigated. These experiments can be used to monitor routinely the condition of the surfaces and to determine whether a surface is acceptable for a given application. In addition to the surface‐induced dissociation of the molecular ions, intense peaks corresponding to the addition of H (or D) to the ionized molecules are observed in the ion–surface collision spectra. The relative abundance of the [M + H(D)]+ reaction products was found to be dependent on several variables, including (i) the chemical composition of the monolayers (alkanethiolate, perdeuteroalkanethiolate, fluorinated alkanethiolate), (ii) the chain length of the alkanethiolate monolayers, (iii) the time for which the vapor‐deposited Au surfaces are exposed to the thiol solution during surface preparation and (iv) the degree of deliberate damage of the SAM film (70 eV Ar+˙ beam bombardment). The variation in [M + H(D)]+ abundance with induced surface changes illustrates the utility of these adduct ions for the characterization of the quality of the monolayers. The general trend observed is an increase in the [M + H]+ peak with the increased presence of hydrocarbon adsorbates, which in turn is believed to be directly related to increased disorder (inherent or induced) of the monolayer film. The increase in [M + H]+ is seen with a decrease in chain length, with shorter monolayer preparation times, and with an increase in surface damage. In general, a fluorinated surface that has been intentionally damaged by an Ar+˙ beam retains its highenergy deposition characteristics and is appropriate for use as a collision target for many types of projectiles.

Segmented Penetrators

AbstractThis paper analyses the terminal ballistic performance of segmented rod penetrators in semi‐infinite, spaced as well as reactive targets. The model scaled projectiles with a mass of about 10 g are launched by a light gas gun of caliber 30 mm at velocities up to 4 km/s. To keep the initial acceleration low enough, the junction between the first and the second stage of the gun was appropriately modified. The projectiles are composed of a series of tungsten alloy segments guided by a thin light metal tube. Between the segments with a L/D‐ratio of one there are cylinders made of plastics or aluminium. Usually the space is in the order of one or two projectile diameters. The perforation power of such segmented rods is compared with two types of homogeneous projectiles of equal mass and velocity. One reference projectile has equal length but lower diameter, the other one has the same diameter but a lower length. Experiments against semi‐inifite targets show an increase in penetration depth of about 20 %, compared with homogeneous projectiles of the same diameter. This advantage vanishes if the reference projectile has equal length. In the four‐plate target as well as in the reactive armour, segmented rods are significantly less efficient due to their low stiffness and greater length.

Local damage of reinforced concrete slabs by impact of deformable projectiles

This study is to get informations about the local damage of reinforced concrete slabs by the impact of deformable projectiles. Five types of projectiles with different magnitudes of axial strength were employed for the impact tests. The target specimen were 0.6 m square reinforced concrete slabs with different thickness ranging from 7.0 to 15.0 cm. The striking velocity was kept at 200 m/s in all tests. And the effects of the projectile nose shape on the extent of local damage were also investigated experimentally.

Reference stopping cross sections for hydrogen and helium ions in selected elements

This article presents new fits to all the available published experimental data on electronic stopping for hydrogen projectiles (10 to 2500 keV/nucleon) on Au, Ag, Cu, Ni, and Al, and for helium projectiles (60 to 7500 keV) on Au and Ag. In all of these cases, we also have data measured in our own group. The data from 13 (Out of 123) publications are rejected a priori, mostly because the measurements are relative. We use a least-squares fit to a four-parameter function of the energy, and we reject discrepant data using two statistical criteria. Our fit results are shown graphically together with all the data points and with various fits by other authors. For hydrogen projectiles, we find that the stopping maximum has a lower value than given by Andersen and Ziegler, except in the case of Al, where almost all the fits agree well. For helium projectiles, the agreement of the various data sets and of the fits is generally better. For both types of projectiles, the fitted cross sections for Ag and Au do not cross in the energy region considered, which is not true of fits by other authors.

Amorphization of crystalline Auln 2 films by low-temperature ion irradiation

The intermetallic compound Auln 2 (CaF 2 type) can be forced into an amorphous (a-) phase by vapour quenching onto a liquid-nitrogen-cooled substrate. Thus, according to a previously stated empirical rule, the a-phase should be obtainable also by suitable ion irradiation experiments. To test this prediction, crystalline Auln 2 films were irradiated at T s < 10 K and T s = 125 K with He + and Ar + ions (350 keV) and the corresponding changes of the electrical resistances and the superconducting transition temperatures were monitored. It is found that at T s < 10 K both types of projectiles lead to complete amorphization, while at 125 K heavy ions are necessary to obtain the a-phase. These results, which confirm the above empirical rule, are discussed within a qualitative model taking into account the role of spikes as well as the process of defect accumulation to obtain an amorphous phase.

Surface characterization with keV clusters and MeV ions

Desorption of atomic and molecular species from solids can be achieved by bombardment with keV and MeV projectiles. In the studies described here, the secondary ions (SIs) are identified by time-of-flight mass spectrometry (TOF-MS) in an event-by-event counting mode. In this paper, desorption induced by two types of projectiles, viz. particle desorption mass spectrometry (PDMS) and secondary-ion mass spectrometry with keV clusters as projectiles (cluster-SIMS), is discussed. PDMS uses fast heavy ions as projectiles (i.e., ions of E ≥ 0.1 MeV/amu and m ≥ 40 amu fission fragments are well suited for PDMS). The features of PDMS can be summarized as follows: it is suitable for isotopic and molecular analysis by virtue of the TOF-MS procedure; the desorption yield (ratio [%] of ions desorbed vs primary projectiles) can reach and even exceed 100%; thus mass spectra are obtained with a very low total primary-ion dose of ≤ 10 6 ions. PDMS has a shallow sampling depth (5–100 monolayers, depending on the target), i.e. the technique is suitable for outermost-surface analysis without interference from the substrate. Cluster-SIMS opens new perspectives for surface characterization. Clusters are attractive as projectiles because they are quasineutral, yet they can be accelerated, steered and focused. Their size, mass velocity and chemical composition can be selected to yield maximum SI emission. A new experimental approach has been devised to implement cluster-SIMS. We have observed up to 30-fold enhancement in the SI yield for cluster- vs monoatomic projectiles of equal velocities. Generally, the SI yields increase with the mass of the projectile and its velocity. The technique has particular promise for the surface mapping of organics. Event-by-event coincidence counting can be combined with TOF-MS. This allows one to determine which masses are desorbed together from a primary impact size. Surface homogeneity is thus revealed with high planar resolution.

Influence of the charge state of 1.16 MeV/u incident ions on the desorption process

The heavy ion linear accelerator of the Institut de Physique Nucleaire has been used to study the influence of the projectile charge state q i on secondary ion emission. Ions of Ne, Ar or Kr with a velocity of 1.16 MeV/u bombarded thin films of organic and inorganic solids. The experimental arrangement is described. The ion emission yield is strongly dependent on the charge state of the incident ion qi and of its atomic number (nature of the projectile). The emission yield between the three types of projectiles varies as q4eq where q eq is the equilibrium charge state within the material for each projectile.

Wounding mechanism of projectiles striking at more than 1.5 km/sec.

In 1976 Charters and Charters (2) described experiments intended to study effects of projectiles with a striking velocity greater than 1 km/sec. They postulated that the projectiles at higher velocity would cause shallow wounds with wide tissue destruction on the surface, especially when striking velocity exceeded the speed of sound in tissue (about 1.5 km/sec). We found no other studies reported dealing with projectiles in this velocity range, the conclusions and assumptions of Charters and Charters have been quoted by others and accepted as fact. We designed and performed experiments to test the hypothesis of Charters and Charters by comparing temporary cavity morphology and penetration in gelatin. We fired two types of blunt projectiles over a velocity range from 650 m/sec (2,137 ft/sec) to 2,016 m/sec (6,614 ft/sec). In these studies we found no evidence to indicate that shape and characteristics of the disruption in ordnance gelatin change significantly when missile striking velocity exceeds sonic speed in the target.

Amorphization of AlAu by low temperature ion irradiation

Crystalline Al 0.67Au 0.33-(Al 2Au)-films were irradiated at low temperatures ( T<10 K) with Ar- and He-ions, respectively. The resulting structure was analyzed by in situ electron diffraction and resistivity measurements. Both types of projectiles lead to an amorphous (a-) phase, which is identical to the one found after vapour quenching at temperatures below 80 K. Irradiation at 80 K resulted in the amorphous phase only for Ar-ions, not for He. The results will be discussed within the picture of spikes.