SU633429A1 - Method of determining the temperature of electrons in plasma of active element of he-ne laser - Google Patents

Description

There are 3 electron electrons in active elements with a capillary diameter of 1 mm. The probe introduces perturbation into the plasma, which can substantially distort the measurement result. The introduction of the probe causes significant diffraction losses, which makes it impossible to use this method for measuring the temperature of electrons in thin capillaries of working lasers and, moreover, this method requires relatively long measurements to measure the current-voltage characteristics of the probe. The purpose of the invention is to simplify the method of reducing the time of measurement, elimination of diffraction, 2U, e,., U. ,,.,) - {l j

3oboH l pfl- # pf (if) j

Where:

UQ is the steady-state value of the voltage on the active element;

in - the electron charge;

Cp is the discharge capacity;

1 - the frequency of reactive oscillations in the initial stage;

Ed is the steady-state current through the active element;

bo is the ion mobility at low fields x at P S 1 mm Hg;

Uj - Ionization potential;

/) - differential resistance of the active element;

R - ballast resistance;

k - constant Boltzmann

The drawing shows a block diagram of a device by which the proposed method is implemented.

The anode of the active element 1, in whose plasma the temperature of the electrons is determined, is connected through the ballast resistance 2 to the power source 3. The cathode of active element I is connected to power supply 3 via cathode resistance 4 and milliammeter 5. OftentoMep 6 measuring the frequency of jet oscillations connected to cathode resistance 4. Voltmeter 7 is connected to electrodes of active element 1.

The proposed method is carried out as follows.

The circuit parameters of the power supply source 3 - active element 1 excite reactive oscillations in the initial stage and measure their frequency, the steady-state voltage value on the active element 1, the discharge capacitance, the steady-state current through the active element 1 and the differential resistance of the active element 1.

3-. .-i, i Д „

 l l

Knowledge of these quantities makes it possible to calculate the temperature of the electrons in the active element. Using the expression for the frequency of the initial stage of reactive oscillations, one can obtain a relation connecting the electron temperature in the plasma of the active element with the frequency of reactive oscillations.

For the implementation of the proposed method does not require any structural changes.

in the active element. Using the proposed method, it is possible to measure the electron temperature in almost any active element of a working He-Ne laser, since this does not introduce diffraction losses or disturbances.

into the plasma. The discharge capacitance and the differential resistance of the active element can be determined in advance for each active element.

The time required for the measurement is determined by the counting time of the frequency meter and the measuring time of the steady-state voltage value on the active element. When using, for example, a frequency meter of type 43-34 A and a high-resistance voltmeter, the measurement time may be

no more than a few seconds. This allows measurements to be carried out in cases where, according to experimental conditions, the electron temperature changes over time, for example, when the laser mode changes.

Thus, the proposed method allows to simplify the method of measuring the electron temperature in the plasma of the active element of an He-Ne laser, shorten the measurement time, eliminate diffraction losses, and extend the range

investigated devices.

Claims (1)

DETAILED DESCRIPTION OF THE INVENTION A method for determining the temperature of electrons in a plasma of an active element of a He-Ne laser, which is different in that, in order to simplify the loss of space and to expand the range of devices under study. This is achieved by selecting the power source - active element circuit meters. The pump excites reactive oscillations in the initial stage, measures the frequency of reactive oscillations, the steady-state voltage value on the active element, the discharge capacity, the steady-state current through the active element, the differential resistance of the active element and determine the temperature by the formula: