Biomedical subjects

D Batani

Publications and source records attributed to D Batani.

27 records · Page 2Linked to original sources

PubMed2001

Use of low-density foams as pressure amplifiers in equation-of-state experiments with laser-driven shock waves.

The applicability of foams to equation of state experiments with laser-produced shocks has been studied. The pressure increase due to impedance mismatch at the payload-foam interface was measured experimentally using sub-ns laser pulses smoothed with phase zone plates. Foams of density in the range 5-900 mg/cm(3) and of thicknesses of 50-150 microm were used. A model has been developed to study pressure amplification and the conditions under which the shock is stationary. Two-step two-material targets, allowing simultaneous measurements of the shock velocities in the two materials, were then used to obtain relative equation of state data. Pressures higher than 100 Mbar were achieved in gold.

Journal Article↗

PubMed2000

Explanations for the observed increase in fast electron penetration in laser shock compressed materials

We analyze recent experimental results on the increase of fast electron penetration in shock compressed plastic [Phys. Rev. Lett. 81, 1003 (1998)]. It is explained by a combination of stopping power and electric field effects, which appear to be important even at laser intensities as low as 10(16) W cm-2. An important conclusion is that fast electron induced heating must be taken into account, changing the properties of the material in which the fast electrons propagate. In insulators this leads to a rapid insulator to conductor phase transition.

Journal Article↗

PubMed2000

Foam-induced smoothing studied through laser-driven shock waves

The influence of foams on the uniformity of laser energy deposition has been studied by measuring laser-driven shock waves breakout from foam-aluminum layered targets. Well characterized laser nonuniformities have been produced first by using phase zone plates to get a smooth beam and then by inserting different opaque grids before the foam. Smoothing has been studied as a function of foam density and grid materials (producing different radiative effects).

Journal Article↗

PubMed2000

Experimental evidence of electric inhibition in fast electron penetration and of electric-field-limited fast electron transport in dense matter

Fast electron generation and propagation were studied in the interaction of a green laser with solids. The experiment, carried out with the LULI TW laser (350 fs, 15 J), used K(alpha) emission from buried fluorescent layers to measure electron transport. Results for conductors (Al) and insulators (plastic) are compared with simulations: in plastic, inhibition in the propagation of fast electrons is observed, due to electric fields which become the dominant factor in electron transport.

Journal Article↗

PubMed1999

Chirped pulse reflectivity and frequency domain interferometry in laser driven shock experiments.

We show the simultaneous applicability of the frequency domain interferometry and the chirped pulse reflectometry techniques to measure shock parameters. The experiment has been realized with the laser at the Laboratoire pour l'Utilisation des Lasers Intenses (LULI) with a 550-ps pulse duration and an intensity on target approximately 5 x 10(13) W/cm(2) to produce a shock in a layered aluminum-fused silica target. A second low energy, partially compressed chirped probe beam was used to irradiate the target rear side and the reflected light has been analyzed with a spectrometer, achieving a temporal resolution of the order of 1 ps.

Journal Article↗

PubMed1996