Dislocation based high-rate plasticity model and its application to plate-impact and ultra short electron irradiation simulations

Short-duration high-intensity pulsed electron beams have been used to anneal ion-implantation damage in silicon and to electrically activate the dopant species. Lattice regrowth and dopant activation were determined using He(+)-4 backscattering, SEM, TEM, and device performance characteristics as diagnostic techniques. The annealing mechanism is believed to be liquid-phase epitaxial regrowth initiating from the substrate. The high-temperature transient pulse produced by the electron beam causes the dopant to diffuse rapidly in the region where the liquid state is achieved.

Pulsed-electron-beam annealing of ion-implantation damage

The various laser-interferometer instrumentation techniques which have been applied to the study of plane-stress-wave propagation in solids are reviewed and discussed. The capabilities and limitations of present systems are described.

Laser interferometry in shock-wave research

Pulsed electron beams are formed by the slow charge of a pulse forming network (microseconds to D. C.) and the fast discharge (10 - 100 ns) onto a field emission diode. The resultant beams of kiloamps to megamps at hundreds of keV to ten MeV are passed through a window into the drift region. Ionization in the drift section allows the beam to be confined by its own magnetic field. Secondary electron currents in the plasma tend to neutralize this effect, Recent work on guiding intense beams with auxiliary fields has utilized applied Bz and B? (z-pinch) fields. Application of these beams extends from shock studies to ion acceleration.

Dynamics of Pulsed High Current Relativistic Electron Beams

Experimental results are reported for the transport characteristics of relativistic electron beams in high‐pressure atomic and molecular gases. Experimental results obtained with two different accelerators (ν/γ ∼ 0.05 and 1) are reported. It was found that the highest pressure at which efficient transport occurred was determined by two different physical processes for the two different intensity electron beams. The lower‐intensity beam propagated efficiently throughout a large pressure range, and was attenuated at high pressure by Coulomb scattering of the beam electrons in the screened Coulomb field of the nuclei of the background gas atoms. The more intense electron beam was attenuated at a gas pressure which varied with different gases approximately inversely with the high‐energy ionization cross section. A radial breakdown mechanism is proposed which may explain the loss process of the intense electron beam.

Relativistic Electron Beam Propagation in Low‐Pressure Gases

The first measurements of free surface displacement and velocity induced by the absorption of a pulse of electrons in a solid are reported. The laser‐interferometric measurements demonstrate that the dynamic response of materials induced by charged particle interaction can be observed in detail.

The dynamic response of solids exposed to a pulsed‐electron‐beam

A new technique for the direct measurement of the Gruneisen parameter of elastic materials is presented. The technique employs the measurement of the one‐dimensional thermoelastic response of materials exposed to a pulsed electron beam. The measured values of the Gruneisen parameter for single crystals of both metals and semiconductors are in excellent agreement with thermal values.

Grüneisen data from the one‐dimensional thermoelastic response of elastic materials

Measurements of the dynamic response of a solid induced by charged particle interaction are presented. The measurements were made using a laser interferometric technique to determine the free surface motion of silicon and germanium exposed to a pulsed electron beam. The results show that the free surface displacement and velocity can be determined in detail. The measured displacement and velocity histories are directly related to the energy spectrum of the incident electron beam and proportional to the electron fluence. The measurements are compared with the motion predicted by a thermoelastic calculation using known material properties. The difference between the predicted and measured response is discussed with respect to the coupling between the absorbed energy and the acoustic phonons.

D. R. Schallhorn

Papers

The dynamic response of solids exposed to a pulsed‐electron‐beam

Grüneisen data from the one‐dimensional thermoelastic response of elastic materials

Laser Interferometric Determination of the Dynamic Response of Solids