A dedicated data acquisition system for ion velocity measurements of laser produced plasmas

122-126This paper describes the design of a multi-channel 25 MSPS (mega samples per second) data acquisition system. The approach is based on a flash analog to digital converter and a FIFO (first in first out) memory. This system is used for acquiring the ion velocity profiles using Langmuir probes in laser plasma in teraction experiments carried out using a high power Nd:glass laser. These profiles are displayed on the personal computer monitor and processed for calculating the ion velocities. The digitized data is stored for further analysis.</span

Equation-of-state studies using a 10-Hz Nd: YAG laser oscillator

A commercial mode locked cavity dumped Nd:YAG dye laser operating at 10 Hz repetition rate is modified to produce a high contrast (>5000:1) single laser pulse while maintaining the energy stability and high beam quality. A trigger generator biases the cavity dumping photodiode, which is triggered externally by a pulse from the microprocessor-based control unit controlling a [similar]2 J/200 ps laser chain. In the laser chain, the high contrast (>5000:1) is achieved by an external pulse selector based on single Pockel's cell to select a single laser pulse of high contrast, which is a prerequisite for experimental study of the equation of state. Laser-induced shock velocity measurement in thin aluminum, gold on aluminum, and copper on aluminum foil targets using this modified laser system are also presented. The equation of state of Al, Au, and Cu obtained using an impedance matching technique are in agreement with the reported results of SESAME and simulation results

Laser driven shock wave experiments for equation of state studies at megabar pressures

We present the results from laser driven shock wave experiments for equation of state (EOS) studies of gold metal. An Nd:YAG laser chain (2 J, 1.06 µ m wavelength, 200 ps pulse FWHM) is used to generate shocks in planar Al foils and Al + Au layered targets. The EOS of gold in the pressure range of 9-13 Mbar is obtained using the impedance matching technique. The numerical simulations performed using the one-dimensional radiation hydrodynamic code support the experimental results. The present experimental data show remarkable agreement with the existing standard EOS models and with other experimental data obtained independently using laser driven shock wave experiments