JPH058790B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to an apparatus for measuring slow electrons using gas discharge in the atmosphere.

BACKGROUND ART Conventionally, as a low-speed electronic measuring device, one described, for example, in Japanese Unexamined Patent Publication No. 159168/1983 is known. This device includes a case that serves as a cathode and has a space inside that communicates with the atmosphere, and an anode that is housed within the case and to which a high voltage is applied.

In the case of the aforementioned low-speed electronic measurement device, since the gas discharge is performed in the atmosphere, it is affected by atmospheric conditions, and for example, when humidity increases, the counting rate increases as shown in Figure 3. There is a problem with that. It is inferred that this is because gas discharge, which becomes background noise, occurs due to the adhesion of water vapor to the anode. Furthermore, when the temperature and pressure change, there is a problem in that errors occur in the measurement results as shown in FIGS. 4 and 5, respectively.
Conventionally, as described in Japanese Patent Publication No. Sho 58-6159, a method has been known in which to prevent a gas discharge causing background noise by heating an anode in response to an increase in humidity. On the other hand, in response to changes in temperature and pressure, it is possible to measure the temperature and pressure at the time of measurement and correct the measurement results by calculation after measurement, but such correction requires a lot of effort and time. The problem is that it requires

Problems to be Solved by the Invention The present invention solves the conventional problem of requiring a great deal of effort and time to correct measurement errors due to fluctuations in temperature, pressure, etc.

Means to Solve the Problems These problems are solved by a low-speed battery that is equipped with a cathode case that has a space inside that communicates with the atmosphere, and an anode that is housed inside the case and has a high voltage applied to it. Solved by providing a heating means in the electronic measurement device that heats the anode and controls the heating temperature based on the output of at least one of a temperature sensor and a pressure sensor that measure the temperature and pressure of the atmosphere. can do.

Function First, when low-speed electrons pass through the space between the case and the anode, a gas discharge occurs near the anode, and this gas discharge is detected. In this way, slow electrons are measured, and during this measurement,
Since the space of the case communicates with the atmosphere, this space is directly affected by the atmosphere. Therefore, when atmospheric conditions, ie, humidity, temperature, pressure, etc., change, the rate of occurrence of gas discharge changes accordingly, and as a result, it is thought that errors occur in the measurement results. However, in this invention, the anode is heated by the heating means, and the heating temperature is controlled based on the output of at least one of the temperature and pressure sensors.
The temperature around the anode can be freely controlled so that the rate of occurrence of gas discharge always remains constant, thereby making it possible to compensate for variations in atmospheric conditions. In this way, the correction can be made simply by controlling the heating temperature of the anode, so the correction can be made very easily and simply.

Embodiment Hereinafter, an embodiment of the present invention will be described based on the drawings.

In FIG. 1, 1 is a case in which a space 3 communicating with the atmosphere via an opening 2 is formed inside.
This case 1 is grounded and becomes a cathode. A ring-shaped anode 4 with ends is provided in the case 1, and one end of the anode 4 is connected to a 3.4KV high-voltage power source 5, which is optimal for measuring slow electrons, which will be described later, at room temperature and pressure, for example. There is. In addition, a first grid electrode 6 as a grid electrode to which a voltage of 100V is applied, for example, is installed inside the case 1, and between this first grid electrode 6 and a sample 7 provided at the bottom of the case 1. A second grid electrode 8 to which a voltage of, for example, 80V is applied is installed. The sample 7 collects low-velocity electrons from its surface, that is, electrons with low energy below a number + eV that do not cause primary ionization when passing through the gas, such as photoelectrons, thermoelectrons, and exoelectrons. discharge. When these low-speed electrons pass through the space 3, the anode 4
Causes gas discharge in the vicinity. Reference numeral 13 denotes an amplifier connected to the anode 4, and a first pulse generator 14 is provided between the amplifier 13 and the first grid electrode 6. This first pulse generator 14 sends a square wave pulse to the first grid electrode 6 to increase the voltage of the first grid electrode 6 when a gas discharge occurs, that is, when an electron pulse is generated at the anode 4. . Further, a second pulse generator 15 is provided between the amplifier 13 and the second grid electrode 8, and when an electron pulse is generated at the anode 4, the second pulse generator 15 generates a second rectangular wave pulse. The voltage is supplied to the grid electrode 8 and the voltage of the second grid electrode 8 is lowered. 16 is a counting means connected to the amplifier 13, and this counting means 16 counts the electron pulses generated at the anode 4. The output signal from this counting means 16 is
After being sent to a display means 18 such as a CRT or printer, the measured number of low-speed electrons is displayed on the display means 18, for example, a CRT or a printer. An AC heating power source 20 is connected to the anode 4 as a heating means that can adjust the power supplied. As a result, the anode 4 is heated to, for example, about 100°C by the Joule heat of the electric power supplied from the heating power source 20.
This heating temperature is controlled by increasing or decreasing the power from the heating power source 20. 21 is a temperature sensor that measures the temperature of the atmosphere, and 23 is a pressure sensor that measures the pressure of the atmosphere. Outputs from the temperature sensor 21 and pressure sensor 23 are sent to the heating power source 20 via the heating power control circuit 22.
The power supplied from the heating power source 20 is changed.

Next, the operation of one embodiment of the present invention will be explained.

First, as shown in FIG. 2a, a high voltage of, for example, 3.4 KV is applied to the anode 4 from the high voltage power source 5, and a predetermined electric power is supplied from the heating power source 20. Thereby, the anode 4 is heated to, for example, about 100°C. At this time, low-velocity electrons are emitted from the surface of the sample 7. Electrons emitted from the sample 7 pass through the second grid electrode 8 and the first grid electrode 6 and are attracted to the anode 4. When the electrons reach the vicinity of the anode 4, the electrons are accelerated by a strong electric field near the anode 4, causing a gas discharge. Due to this gas amplification effect, the potential of the voltage applied to the anode 4 decreases as shown in FIG. 2a, and an electron pulse is generated. The electron pulse generated at the anode 4 is passed through the amplifier 13 to the first pulse generator 14.
and sent to the second pulse generator 15. The first pulse generator 14 generates a rectangular wave pulse with a voltage of 300V and a time width of Te, and sends it to the first grid electrode 6 to adjust the voltage of the first grid electrode 6 as shown in FIG. 2b.
Increase Te time from 100V to 400V. As a result, the potential difference between the anode 4 and the first grid electrode 6 increases.
The voltage drops by 300V, and as a result, secondary electrons from light and positive ions generated by the gas amplification effect cannot reach the discharge voltage, and the gas discharge disappears.
On the other hand, the second pulse generator 15 sends a rectangular wave pulse with a time width Te and a voltage of -110V to the second grid electrode 8, and changes the voltage of the second grid electrode 8 from 80V to -110V as shown in FIG. Reduce to 30V. As a result, cations generated by the gas amplification effect are captured by the second grid electrode 8 and neutralized. Then, after a period of time Te has elapsed, the voltages of the first and second grid electrodes 6 and 8 are restored to their original voltages, and the low-speed electron measuring device is in a state where it can detect electrons again. The electron pulses generated at the anode 4 are simultaneously sent to the counting means 16 via the amplifier 13, and after counting the number of electron pulses, the counting means 16
The output signal is sent to calculation means 17. This calculation means 1
7 corrects for missing counts when the discharge is stopped, and then sends the counting results, for example, the counting rate, to the display means 18 for displaying the counting results. The number of emitted electrons is measured in this way, but the humidity, temperature, pressure, etc. during this measurement vary depending on the location, time, etc. For example, when the temperature is higher than normal temperature or the pressure is lower than normal pressure, the distance between molecules in the atmosphere increases, making it easier for electrons or anions to pass through. Therefore, the probability that electrons or anions will be scattered by gas molecules decreases, making gas discharge more likely to occur. In order to prevent such a situation, in this embodiment, the temperature and pressure of the measurement atmosphere (atmospheric air) are detected by a temperature sensor 21 and a pressure sensor 23, and the signals from these sensors 21 and 23 are converted into heating power. Control circuit 2
2 to the heating power source 20, and the power supplied from the heating power source 20 to the anode 4 is reduced by a value corresponding to the increase in temperature from normal temperature or the decrease in pressure from normal pressure. As a result, the temperature of the anode 4 decreases, and the temperature of the atmosphere around the anode 4 also decreases, and the distance between air molecules becomes smaller. As a result, the rate of occurrence of gas discharge is maintained constant and variations in environmental conditions are compensated for. Further, the anode 4 is, for example,
Since it is heated to 100℃, the relative humidity around the anode 4 is always low even when the atmospheric humidity is high, and as shown in Figure 3, it is used in areas where there is a small amount of gas discharge that causes background noise due to water vapor. can do. Further, by keeping the anode 4 at a high temperature, the operating voltage of the gas discharge can be lowered.

In addition, in the above-mentioned embodiment, the heating power source 20
Although an AC power source is used in this embodiment, a DC power source may also be used in this invention. Further, in the present invention, the temperature of the anode 4 may be changed by indirectly heating the anode 4 with a heater and controlling the temperature of the heater. Also,
In the embodiment described above, the temperature and pressure sensor 2
1 and 23 to measure both the temperature and pressure of the atmosphere, and the temperature of the anode 4 is controlled based on the measurement results. However, in this invention, either the temperature sensor 21 or the pressure sensor 23 The temperature of the anode may be controlled based on one of the measurement results.

Effects of the Invention As explained above, according to the present invention, measurement errors based on fluctuations in atmospheric conditions can be corrected very easily and easily.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing a part of a circuit showing an embodiment of the present invention, Fig. 2 is a graph showing voltage changes of a low-speed electronic measuring device, and Fig. 3 is a counting rate when humidity changes. FIG. 4 is a graph showing changes in the counting rate as the temperature changes, and FIG. 5 is a graph showing changes in the counting rate as the pressure changes. 1... Case, 3... Space, 4... Anode, 5... High voltage power supply, 6... Grid electrode, 7... Sample, 20... Heating power supply.

Claims (1)

[Claims] 1. In a low-speed electronic measurement device equipped with a case that serves as a cathode and has a space inside that communicates with the atmosphere, and an anode that is housed in the case and has a high voltage applied to it, the anode is heated and the atmosphere is 1. A low-speed electronic measuring device comprising a heating means for controlling the heating temperature based on the output of at least one of a temperature sensor and a pressure sensor that measure temperature and pressure.