Development of picosecond time resolution optical and X-ray streak cameras

Abstract

We describe the development of an optical and an X-ray streak camera with picosecond time resolution. The entire peripheral electronics and testing systems have been developed indigenously. Both the streak cameras provide ~ 15 ram/1 ns streak rate with a sweep voltage of ~ 1 kV amplitude and rise time of 1 ns. The time and spatial resolution of the optical streak camera have been found to be ~ 17 ps and 100 #m respectively. The sweep pulse generator developed for this purpose provides a step pulse of rise time ~< 1 ns and amplitude ~ 2 kV. The laser diode used for testing the optical streak camera provides multiple pulsation when the pump current is increased beyond a critical threshold.

High speed plasma diagnostics for laser plasma interaction and fusion studies

“…which remain for a longer time > 20ns, whereas in the latter case (presence of Zapon and aluminum filter) it is sensitive only to soft and hard X-rays, which show the time duration of the pulse as ~ 3 ns, which is again limited by the oscilloscope sampling rate (L&T Gould Model 7074). The time durations of UV and X-ray emissions recorded using photodiodes are in agreement with the measurements made using an X-ray streak camera (Rai et al 1995a) where ultraviolet and X-rays emissions last for > 20 ns (without filter) and soft X-rays last for 1.5 ns (with Zapon filter) (Rai et al 1998a). During these experiments, photodiodes are biased to ~ 700 volts (optimum voltage) and signals are recorded across 50~2 termination.…”

“…The streak camera is one of the most versatile instruments (Schelev et al 1972;Campillo & Shapiro 1983;Tsuchiya 1983;Stradling et al 1983;Kinoshita et al 1983;Rai et al 1995a) today for high-speed photometry in the field of physics, chemistry, biology and nonlinear optics. Particularly, hydrodynamic and radiative processes in laser-produced plasma and inertial confinement fusion experiments with rapid time variations demand detailed studies of time resolved X-ray and optical emission from laser-produced plasma.…”

A simple and compact high-voltage switch mode power supply for streak cameras

“…All the components used in these supplies are readily available. The SMPSs operate well in the streak camera [2] and x-ray imaging device [3] built in our laboratory. The design is so simple that it can be made very easily in any laboratory.…”

“…Self oscillating SMPSs of 1-25 W are more suitable for a streak camera because they require fewer components which then reduces the size and price of the supply drastically. These SMPSs consist of an oscillator operating at a desired frequency, a high-frequency pulse system [2] and an x-ray imaging device based on the combination of a phosphor screen and an image intensifier tube [3]. The switch mode oscillator, which is common to all the above mentioned power supplies, works on the principle of gain limited switching [1].…”

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

“…The shock luminosity signal at the rear surface of the target during shock unloading is recorded with a visible (s-20) streak camera having temporal and spatial resolution of 20 ps and 100 µm respectively [6]. When the shock unloads at the rear free surface thermal radiation is generated.…”