SU529507A1 - Aeroion counter - Google Patents

Description

(54) AEROION COUNTER

one

The invention relates to geophysics and can be applied in instruments for analyzing gases, atmospheric air, and measuring such characteristics as the concentration of positive and positive aero ions.

Various devices for measuring the concentration of air ions are known. The principle of their work is based on the direction of aero-ions on the so-called collecting electrode in the suction condenser and the subsequent measurement of the electric current through this electrode. Such devices operate at high (atmospheric) pressure of the test gas. As the most sensitive current meter, the electrometer with a capacitive vibration transducer is changed (the so-called dynamic electrometer).

The main disadvantage of the known counter 1 is the limited measurement sensitivity. The maximum sensitivity (at the minimum concentration) of this counter is 10 particles in cm with an air flow rate of 4.5 l / s or per 2

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account for a current of 10 A. It should be added

that taking measurements at maximum sensitivity is associated with very large errors (approximately 1%), so the real lower limit of measurement is lower. It also takes considerable time (2-3 minutes) to measure,

A counter of air ions of the SAITGU-65M type is known, which contains a measuring chamber, a voltage source and a recording device. The operation of this meter is based on the fact that the air under study is blown through an aspiration condenser, on the plates of which a constant voltage is applied. One of the plates is connected to the input of the electrometer.

The sensitivity of the counter of air ions is limited both by the noise of the electric elements of the electrometer and by the parasitic currents of the capacitor insulators. The applied voltage to the capacitor must be very well stabilized.

The purpose of the inventive shadow is to increase the sensitivity of the counter with respect to the measured concentration of air ions.

This is achieved by the fact that the meter is equipped with a vacuum unit connected to a measuring chamber with an opening for introducing the gas under investigation, in which an ion acceleration electrode and an ion detector connected respectively to a voltage source and a recording device are placed behind this hole.

The drawing shows the proposed counter.

It contains an electrically conductive chamber 1 with an attached vacuum pump 2, a small hole 3 for introducing the gas under investigation into the chamber, the ion detector 5 accelerating the electrode 4, attached outside the chamber to the recording device 6, the source

A constant voltage, connected by one pole to the body of chamber 1, and the other to the accelerating electrode 4, and insulator 8. The vacuum pump has an input 9

and outlet 10 holes.

The counter works as follows,

8 chamber 1 by means of pump 2 creates a constant low pressure, approximately up to 10 Torr. Through a small opening 3, the gas under investigation is continuously drawn through the chamber, usually containing both electrically charged aero ions and neutral parts.

The electrode 4 from source 7 is supplied with a constant voltage of the order of 1 O with respect to chamber 1, which can be grounded. The polarity of the applied voltage depends on what sign the air ions are currently being recorded. The shape of the electrode 4 does not play a significant role, it may be, for example, cylindrical.

If the ion detector has a metal frame, this can also serve as an accelerating electrode. The few aeroions contained in the test gas under the action of the electric field created by the electrode 4 are accelerated and directed to the ion detector 5. The neutral particles (molecules) in the test gas are sucked through the hole 9 by a vacuum pump 2 and exit through the outlet 1O out.

Ion detector 5 can serve as an ion-electron multiplier in the pulse counting mode or semiconductor

detector in the same mode. The latter has a simpler prog design in operation.

The ions trapped on the ion detector 5 cause electrical impulses, which are recorded by the device 6. The mentioned types of ion detectors provide the entire device with a sensitivity of approximately 10 A current. Due to this, it is possible to significantly reduce the consumption (minimum required volume) of the test gas and at the same time achieve high accuracy and speed of concentration measurement, which cannot be achieved with the known devices by you.

five

During operation, the action of the parasitic current of the insulators is completely eliminated, with this, there is no need for careful stabilization of the DC voltage, which is the case when working

0 devices. Compared to known devices, the measurement speed is significantly increased. When the polarity of the measured ions is changed, there are no polarization phenomena characteristic of the known counters.

formula of invention

Air ion counter containing a measuring chamber, a voltage source and a registering device, characterized in that, in order to increase sensitivity, it is equipped with a vacuum pump connected to the measuring chamber, inside which the accelerating electrode and detector respectively connected to a voltage source and a recording device.

Sources of information taken into account in the examination:

1. USSR author's certificate No. 126287, M Kl.- my 39/26 from 197O

2. Tammet Kh. F. Aspiration method for measuring the spectrum of air ions

Scientific notes of Tartu State University, no. 195, 1967, p. 184 (prototype).