An electrostatic probe driven by positive and negative amplitude modulation pulses and an integrated device for data acquisition and analysis

Abstract

The invention discloses a positive and negative amplitude-modulation pulse driven electrostatic probe and a data acquisition and analysis integrated device. After being amplified, a square wave pulse signal having an adjustable amplitude is used as the bias voltage of a Langmuir probe; a current signal acquisition system rapidly acquires current in a specific current acquisition point on each pulse bias voltage; then, the voltage is decreased to 0; after being naturally cooled, the probe applies and acquires the next pulse square wave; therefore, the self-heating effect of the probe is avoided; furthermore, a soft-switching technology and a large-range current measurement means are adopted in the current signal acquisition system; the precision disadvantage of micro-nano acquisition of ionic current is avoided; finally, after synchronous voltage signals and current signals are processed and calculated through a DSP data processing system, the parameters of the Langmuir probe, such as the V-I characteristic curve, the electronic temperature, the energy distribution, the electron density and the space potential, are obtained; and the parameters are conveniently displayed in an upper computer system.

Description

technical field [0001] The invention relates to the field of plasma science and technology, in particular to an electrostatic probe driven by positive and negative amplitude modulation pulses and an integrated device for data collection and analysis. Background technique [0002] Electrostatic probe technology is one of the necessary tools for the diagnosis of low-pressure plasma parameters. Although the probe measurement theory has been developed and matured 100 years ago, the actual measurement error has been relatively rough, resulting in the probe measurement data only having an order of magnitude reference. significance. We analyze the source of the error. Among them, the electron saturation flow is too large, which makes the error caused by the increase of the internal resistance caused by the self-heating of the probe significant. In actual use, the probe voltage is driven by an external power supply, and the current passes through the measured plasma and the probe t...

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Problems solved by technology

Therefore, the measurement range of current acquisition also needs to span 5 orders of magnitude, which is a difficulty of current measurement methods

Moreover, the price of a probe measurement system that does not eliminate the effect of internal resistance error on the market is more than 50,000 yuan (imported equipment is about 200,000 yuan)

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