CN204652766U - Based on the Langmuir probe diagnostic device of pulse modulation scanning power supply - Google Patents

Abstract

The utility model relates to a kind of Langmuir probe diagnostic device based on pulse modulation scanning power supply, this device can be used for the parameter such as density, space potential, electron temperature diagnosing plasma, it is characterized in that using pulse modulated probe bias voltage to replace traditional zigzag triangle wave voltage.The utility model is made up of probe, operational amplifier, data collecting card and PC.Utilize data collecting card to generate bias voltage by PC, be loaded on probe after being amplified to-50V ~+50V by operational amplifier, be linked into afterwards on plasma and can diagnose.

Description

Langmuir probe diagnostic device based on pulse-modulated scanning power supply

technical field

The utility model belongs to the field of plasma diagnosis science and technology, in particular to a Langmuir probe diagnosis device based on a pulse modulation scanning power supply.

Background technique

The Langmuir probe is one of the diagnostic methods of plasma properties. The traditional Langmuir probe diagnostic method is to insert a very small electrode into the plasma to be tested, and then load the probe on the probe generated by the signal generator. The saw-tooth triangular wave, by measuring the current and voltage on the probe, and drawing a voltage-current characteristic curve, and then using the special points on the characteristic curve to obtain parameters such as plasma density, space potential and electron temperature; this method The disadvantage is: in one cycle, the sawtooth triangular wave always acts on the probe. When the probe reaches the electronic saturation current, the probe current is very large, which causes the probe to heat up seriously, and the self-resistance increases, resulting in the measurement of plasma parameters. Inaccurate.

Contents of the invention

The technical problem to be solved by the utility model is to overcome the shortcomings of the traditional Langmuir probe, use the pulse modulated probe bias voltage instead of the traditional sawtooth triangular wave voltage, and construct a Langmuir probe based on the pulse modulated scanning power supply The diagnostic device provides a more efficient and rapid diagnostic method for plasma properties.

The technical solution adopted by the utility model to solve the technical problem is to propose a Langmuir probe diagnostic device based on pulse modulation scanning power supply. The Langmuir probe diagnostic device based on pulse modulation scanning power supply comprises a probe (1), an operational amplifier (2), a data acquisition card (3) and a PC (4). It is characterized in that the probe bias voltage of pulse modulation is used to replace the traditional sawtooth triangular wave voltage, wherein the probe bias voltage of pulse modulation is composed of signals in the form of amplitude modulation pulse voltage sequence, and the data acquisition is controlled by means of a PC (4) The card generates pulse modulation probe bias voltage and samples and analyzes the current and voltage of the probe.

The beneficial effect of the utility model is that the structured Langmuir probe diagnostic device based on the pulse modulation scanning power supply can solve the problem of severe heating of the probe caused by the large probe current when the Langmuir single probe is saturated with electrons. Effect of increased self-resistance on plasma characteristics. The range of plasma measured by the device can be adjusted according to actual conditions.

Description of drawings

Fig. 1 is a schematic diagram of the principle of the utility model.

Fig. 2 is a schematic diagram of the principle of the pulse modulation probe bias voltage of the present invention.

Fig. 3 is a schematic diagram of the voltage-current sampling point area after the pulse amplification of the utility model.

Detailed ways

Describe the specific embodiment of the utility model in detail below in conjunction with accompanying drawing of description

In the PC in Figure 1, the Labview program is written by Labview2009 developed by NI Company. The data acquisition card uses the USB-2085 series products with analog output developed by Beijing Altai Company. The operational amplifier uses a 3538AM high-voltage power operational amplifier. , the probe is the same as that used in the traditional Langmuir single probe.

In Figure 2, the pulse modulation probe bias voltage is composed of amplitude modulation pulse sequence, the pulse size presents a monotonically increasing trend, the voltage value between each pulse is 0, and the time interval between each pulse is the same and the size can be adjusted. Adjustment, the pulse is from -50V to +50V as a cycle; when the bias voltage of the pulse modulation probe is loaded on the probe, due to the effect of the pulse interval, the thermal effect of the probe can be reduced, thereby reducing the temperature caused by the electron saturation current. Diagnosis of various plasmas due to heating problems of the probe.

In the embodiment of Fig. 3, the collected voltage and the corresponding current point must be controlled in area 1 during current-voltage collection, and the sampling program is designed by Labview according to the actual situation.

Claims (1)

1. A Langmuir probe diagnostic device based on pulse modulation scanning power supply, characterized in that the probe bias voltage using pulse modulation replaces traditional sawtooth triangular wave voltage; its structural feature is that PC (4) and data acquisition The cards (3) are connected, the data acquisition card (3) is connected with the operational amplifier (2), and the operational amplifier (2) is connected with the probe (1).