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A single rf-compensated cylindrical Langmuir probe has been developed in order to characterise a plasma RF discharge. A circuit using radiofrequency filtering and the passive compensation method was employed to minimize the probe curve distortions. The effect of the rfcompensation on the probe measurements was discussed. The latter were performed at power and pressure of 50 W and 510-2–1.2 mbar, respectively. Compensated measurements of the electron energy distribution function (EEDF) and plasma parameters were conducted at powers ranging from 5 to 120 W and pressure of 0.3 mbar. They exhibit a transition between the stochastic electron heating mode operating at low powers and the secondary-electron emission heating mode (γ) operating at high powers. The electronic density increases from 1.5×109 to 3.2×1010 cm-3 while the effective electron temperature decreases from 3.7 to 2.3 eV. The EEDFs were found to be Druyvesteyn-like in the range of 5–80W and then evolve to the Maxwellian beyond 90W.

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In order to optically pump pulsed solid-state lasers like Nd: YAG laser, one needs a power supply that basically contains a trigger circuit, a main discharge circuit and a simmer circuit. These circuits must be synchronized by a command. In this communication we will present the synchronization circuit of the system. This circuit is a quartz oscillator known for its good frequency stability, followed by a frequency divider in order to have different repetition rates of the laser. We will also present the simmer circuit which was modelled using a voltage multiplier and a switch mode power supply. The same circuits were also simulated by using Pspice software, thus giving results in good agreement with those of modelling. Experimental proof of modelling has been obtained through the successful use of the command and simmer circuits to control the main discharge into a flash lamp operated at both 1 and 10 Hz frequencies.

Abstract. The power supply of flash lamp-pumped a Nd: YAG solid-state laser basically consists of a trigger circuit which initiate the ionization of the gas into the lamp, a simmer circuit that keeps the ionized gas with a low-level dc current and a main discharge circuit where a storage capacitor is discharged into a flash lamp to pump the Nd:YAG laser. The impedance of the flash lamp presents a nonlinear variation and the gas deionization which can occur between two pulses laser, leading to another manual triggering operation. To overcome this operation, we give in this paper a new automated trigger circuit activated by a delivered signal from the simmer circuit. This circuit is simple for implementation and need just few components. It has been simulated by PSpice software and validated by experimental results.