An adjustable photoionization sensor

Abstract

The present invention discloses an adjustable photoionization sensor, characterized in that the adjustable photoionization sensor includes: an ultraviolet lamp, a light source baffle, an ionization chamber, and an amplifier circuit; the ultraviolet lamp includes a light source outlet for emitting ultraviolet light; one side of the light source baffle is connected to the light source outlet, and the light source baffle is used to block part of the ultraviolet light; the ionization chamber is connected to the other side of the light source baffle, and the ionization chamber is used to ionize gas in the ionization chamber by ultraviolet light; one end of the amplifier circuit is connected to one end of the ionization chamber, and the other end of the amplifier circuit outputs an amplified signal. The adjustable photoionization sensor of the present invention achieves the effect of changing the ionized gas volume without disassembly or replacement of components through the blocking effect of the light source baffle, thereby changing the gas ion current under the same gas concentration, and further changing the gas concentration measurement range.

Description

Technical Field

[0001] The present invention relates to the field of gas detection, and in particular to an adjustable photoionization sensor. Background Art

[0002] Existing photoionization detectors mostly consist of a vacuum ultraviolet lamp and an ionization chamber. Their operating principle is that the gas being measured absorbs photons emitted by the UV lamp that have a higher ionization energy than the gas molecules, causing it to be ionized into positive and negative ions. Under the influence of an applied electric field, the ions are deflected, generating a weak current. Because this weak current is small, it is typically amplified by a signal amplifier circuit to obtain a readily measurable current value. Furthermore, since the concentration of the gas being measured is linearly related to the photoionization current within a certain range, the concentration of the gas being measured can be determined by measuring the current value detected by the photoionization sensor device and the known gas type, thereby determining whether the organic or toxic gas content in the gas being measured exceeds the specified limit.

[0003] Although photoionization sensors are convenient to use, existing photoionization sensor devices still have many shortcomings. For example, their gas concentration detection range is often fixed, with common ones on the market being 0-20ppm, 0-50ppm, 0-200ppm, etc. With the circuit unchanged, a small range often means high sensitivity and smaller test errors. However, an overly small range will saturate when measuring out-of-range gases, making it impossible to obtain an accurate concentration. To solve this practical problem, it is often necessary to carry multiple photoionization sensor devices with different ranges, test them one by one, and then select the most suitable device. This cumbersome operation consumes a lot of staff time and energy, significantly reducing work efficiency. Summary of the Invention

[0004] The purpose of the present invention is to provide a photoionization sensor that can adjust the range according to the on-site concentration, and realize reversible conversion of the range and perform measurement without disassembling the device or replacing any components.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] An adjustable photoionization sensor comprises: an ultraviolet lamp, a light source baffle, an ionization chamber and an amplifying circuit;

[0007] The light source baffle is located between the ionization chamber and the ultraviolet lamp; the ultraviolet lamp is used to emit ultraviolet light; the ionization chamber is used to ionize the gas in the ionization chamber by the ultraviolet light and output a first current;

[0008] The amplifier circuit is connected to the ionization chamber; the amplifier circuit is used to amplify the first current to form a second current.

[0009] Optionally, the ionization chamber specifically includes: a first electrode, a second electrode and an ultraviolet light window;

[0010] The first electrode and the second electrode have the same external contour structure and are arranged opposite to each other. The area between the first electrode and the second electrode is an ionization area, and there is a potential difference between the first electrode and the second electrode.

[0011] The ultraviolet light window can transmit ultraviolet light and allow it to enter the ionization chamber, so that the gas to be measured is ionized between the first electrode and the second electrode, and the generated ions are collected by the first electrode or the second electrode to generate and output the first current;

[0012] The light source baffle is characterized in that it is parallel to and close to the ultraviolet light window, and can block part of the ultraviolet light through a mechanical structure, changing the cross-sectional area of ​​the ultraviolet light entering the ionization chamber from the ultraviolet light window, thereby changing the total amount of ultraviolet light entering the ionization chamber.

[0013] Optionally, the light source baffle includes: a fixed ring, a first knob, a first scale, and a plurality of aperture blades;

[0014] A plurality of aperture blades surround to form a circular ring structure, the circular ring structure matches the inner circle of the fixed circular ring, and the inner circle through hole of the circular ring structure is used to pass the ultraviolet light;

[0015] The fixed ring is provided with a first scale, and the first scale is used to determine the area of ​​the inner circular through hole;

[0016] The first knob is arranged on the outer circular surface of the fixed ring, and the first knob is used to adjust the area of ​​the inner circular through hole.

[0017] Optionally, the amplifying circuit includes: an operational amplifier and a resistor;

[0018] The inverting input terminal of the operational amplifier is connected to the first electrode or the second electrode, the positive input terminal of the operational amplifier is grounded, and the output terminal of the operational amplifier outputs the second current;

[0019] One end of the resistor is connected to the inverting input end of the operational amplifier, and the other end of the resistor is connected to the output end of the operational amplifier.

[0020] Optionally, the cross section of the ultraviolet light is rectangular.

[0021] Optionally, the light source baffle is a rectangular light source baffle, and the rectangular light source baffle includes: a support column, a second scale, a second knob, a threaded rod, and a light shielding sheet;

[0022] A threaded hole is formed on the support column, the threaded rod passes through the support column through the threaded hole, one end of the threaded rod is connected to the second knob, and the other end of the threaded rod is connected to the light shielding sheet;

[0023] The second scale is parallel to the threaded rod; the second scale is used to measure the displacement of the light shielding sheet;

[0024] Optionally, the area of ​​the light shielding sheet is greater than or equal to the cross-sectional area of ​​the ultraviolet light.

[0025] Optionally, the adjustable photoionization sensor further includes: a limiting column, wherein the limiting column is parallel to the supporting column and is used to limit the maximum displacement of the light shielding sheet.

[0026] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0027] The adjustable photoionization sensor of the present invention has the existing gas concentration measurement range. Through the blocking effect of the light source baffle, the volume of the ionizable gas can be changed without disassembly and replacement of components, thereby changing the gas ion current under the same gas concentration and further changing the gas concentration measurement range. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 This is a structural diagram of an adjustable photoionization sensor provided in Example 1 of the present invention, in which the electrodes are parallel to the ultraviolet light emission direction;

[0030] Figure 2 This is a structural diagram of an adjustable photoionization sensor provided by Example 2 of the present invention, in which the electrodes are perpendicular to the ultraviolet light emission direction;

[0031] Figure 3 This is a structural diagram of the amplifier circuit provided by the present invention;

[0032] Figure 4 A diagram of the first electrode structure provided in Example 1 of the present invention;

[0033] Figure 5 A structural diagram of a light source baffle provided in Example 1 of the present invention;

[0034] Figure 6This is a structural diagram of a rectangular light source baffle provided in Example 2 of the present invention;

[0035] Figure 7 This is a diagram showing the relationship between the number of unobstructed through-hole layers and the saturation range provided by the present invention.

[0036] Explanation of symbols: UV lamp 1, first electrode 2, second electrode 3, light source baffle 4, operational amplifier 5, resistor 6, aperture blade 7, fixed ring 8, first knob 9, first scale 10, support column 11, second scale 12, second knob 13, threaded rod 14, light shielding sheet 15, limit column 16, through hole 17. DETAILED DESCRIPTION

[0037] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0038] The purpose of the present invention is to provide a photoionization sensor that can adjust the range according to the on-site concentration, and realize reversible conversion of the range and perform measurement without disassembling the device or replacing any components.

[0039] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] like Figure 1 or Figure 2 As shown, the adjustable photoionization sensor of the present invention comprises: an ultraviolet lamp 1, a light source baffle 4, an ionization chamber and an amplifying circuit;

[0041] The ultraviolet lamp 1 is located on one side of the ultraviolet light window of the ionization chamber, and the light source baffle 4 is located on the other side of the ultraviolet light window of the ionization chamber; the ultraviolet lamp 1 is used to emit ultraviolet light; the ionization chamber is used to ionize the gas in the ionization chamber by the ultraviolet light and output a first current; the light source baffle 4 is made of the same material as the first electrode 2 and the second electrode 3;

[0042] exist Figure 1 In the embodiment, the UV window is independent, and the shielding material around the through hole 17 of the UV window can be selected from corrosion-resistant metal, gold-plated metal, Teflon, oxide ceramics, etc.; Figure 2 In the embodiment, the ultraviolet light window is realized by manufacturing a through hole 17 on the second electrode 3, and the shielding material around the through hole 17 of the ultraviolet light window can be selected from corrosion-resistant metal, gold-plated metal and other materials.

[0043] The amplifier circuit is connected to the ionization chamber; the amplifier circuit is used to amplify the first current to form a second current.

[0044] In the adjustable photoionization sensor of the present invention, the light source baffle 4 can be implemented in the following two ways:

[0045] First, as Figure 4 The UV window of Example 1 shown and Figure 5 In the structure diagram of the light source baffle 4 of Example 1, the UV window is provided with a plurality of circular light holes, and the light source baffle 4 is provided above the circular light holes. The light source baffle 4 is used to adjust the emission area of ​​the UV light. The outer contour of the light source baffle 4 is greater than or equal to the area of ​​the UV window.

[0046] The first electrode 2 and the second electrode 3 have the same structure.

[0047] The light source baffle comprises: a fixed ring 8, a first knob 9, a first scale 10 and a plurality of aperture blades 7;

[0048] The plurality of aperture blades 7 surround to form a circular ring structure, the circular ring structure matches the inner circle of the fixed circular ring 8, and the inner circle through hole 17 of the circular ring structure is used to pass the ultraviolet light;

[0049] The fixed ring 8 is provided with a first scale 10, and the first scale 10 is used to determine the area of ​​the inner circular through hole 17;

[0050] The first knob 9 is provided on the outer surface of the fixed ring 8 , and the first knob 9 is used to adjust the area of ​​the inner through hole 17 .

[0051] exist Figure 1In the adjustable photoionization sensor shown, in which both the first electrode 2 and the second electrode 3 are parallel to the direction of ultraviolet light emission, a UV lamp 1 emits ultraviolet light. The ultraviolet light passes through the transparent layer of the UV lamp 1 and is emitted vertically upward. It then enters the ionization chamber through the interaction of the light source baffle 4 and the through-hole 17 of the UV window. A gas to be measured is present in the ionization chamber and enters the chamber through micropores in the first electrode 2 or the second electrode 3. The gas to be measured can also flow from top to bottom or from bottom to top, parallel to the direction of the ultraviolet light. The gas to be measured can also flow parallel to the first electrode 2 and the second electrode 3 and perpendicular to the ultraviolet direction. A potential difference exists between the first electrode 2 and the second electrode 3 in the ionization chamber. When ultraviolet light enters the ionization chamber, the potential difference between the first electrode 2 and the second electrode 3 is used to generate an electric field to collect gas molecules ionized by the ultraviolet light. After being ionized by the ultraviolet light, the molecules are accelerated by the electric field and collide with each other, forming a weak ion current on the first electrode 2 and the second electrode 3, thereby achieving detection of the gas molecules. During the detection process, adjusting the light source baffle 4 adjusts the area of ​​the ultraviolet light cross-section passing through the light source baffle 4 and the ultraviolet light window of the ionization chamber, and further adjusts the volume of the ionizable gas, thereby changing the gas ion current intensity at the same concentration, avoiding the possible saturation of the amplifier voltage output, and thus achieving the range of the photoionization sensor. Since the determination method of sensitivity and accuracy is related to the range, when the range is changed, the sensitivity and accuracy will also change with the range change.

[0052] exist Figure 2In the adjustable photoionization sensor shown, in which the electrodes are perpendicular to the direction of ultraviolet light emission, ultraviolet lamp 1 emits ultraviolet light, which is emitted vertically upward through the window layer of ultraviolet lamp 1, enters the ionization chamber through the light hole in the second electrode 3, and is partially blocked by the light source baffle 4 before irradiating into the ionization chamber. A gas to be measured is present in the ionization chamber and enters the chamber through the through hole 17 in the first electrode 2 or the second electrode 3. The gas to be measured can also flow in any direction perpendicular to the direction of the ultraviolet light and parallel to the plane of the two electrode sheets. There is a potential difference between the first electrode 2 and the second electrode 3 in the ionization chamber. When the ultraviolet light enters the ionization chamber, the potential difference between the first electrode 2 and the second electrode 3 is used to generate an electric field and collect the gas molecular ions ionized by the ultraviolet light. After the molecules are ionized by the ultraviolet light, they are accelerated by the electric field and collided. The gas molecules below the light source baffle 4 will be ionized, but because they are blocked by the light source baffle 4, these electrons are accelerated and collected by the light source baffle 4, and will not be collected by the first electrode 2 or the second electrode 3. Only in the unblocked direction of the light source baffle 4 will the ultraviolet light and the photoionized molecular ions not be blocked, and the gas ions in this direction will be collected. If the gas between the first electrode 2 and the light source baffle 4 is not in the unblocked direction, it will not be ionized, and thus no ions will be generated. Therefore, for Figure 1 or Figure 2 In this embodiment, by changing the light-transmitting area, the ion current value can be approximately proportionally changed by varying the number of through-holes 17 blocked, while other detection conditions remain unchanged. This allows adjustment of the volume of ionizable gas, and at the same concentration, the gas ion current intensity also varies accordingly, avoiding potential saturation of the amplifier voltage output, thereby adjusting the range of the photoionization sensor.

[0053] Second, when the outlet of the ultraviolet light source is rectangular, the light source baffle 4 can use a rectangular structure, such as Figure 6 In the rectangular light source baffle structure diagram of Example 2 shown, the cross-section of the ultraviolet light is rectangular or circular; the light source outlet of the ultraviolet lamp should be larger than or equal to the light hole of the rectangular light source baffle in at least one dimension direction.

[0054] The light source baffle 4 is a rectangular light source baffle, which includes: a support column 11, a second scale 12, a second knob 13, a threaded rod 14 and a light shielding sheet 15;

[0055] The support column 11 is provided with a threaded hole, and the threaded rod 14 passes through the support column 11 through the threaded hole. One end of the threaded rod 14 is connected to the second knob 13, and the other end of the threaded rod 14 is connected to the light shielding sheet 15.

[0056] The second scale 12 is parallel to the threaded rod 14; the second scale 12 is used to measure the displacement of the light shielding sheet 15;

[0057] The area of ​​the light shielding sheet 15 is equal to the area of ​​the cross section of the ultraviolet light.

[0058] The rectangular light source baffle further includes a limiting column 16 . The limiting column 16 is parallel to the supporting column 11 . The limiting column 16 is used to limit the maximum displacement of the light shielding sheet 15 .

[0059] In practical applications, the ionization chamber specifically includes: a first electrode 2 and a second electrode 3;

[0060] In such Figure 2 In the embodiment shown in which the electrode is perpendicular to the emission direction of the ultraviolet light, a plurality of circular light holes are provided on the first electrode 2;

[0061] The first electrode 2 and the second electrode 3 have the same structure and are arranged opposite to each other. The area between the first electrode 2 and the second electrode 3 is an ionization area, and there is a potential difference between the first electrode 2 and the second electrode 3.

[0062] exist Figure 1 or Figure 2 After the adjustable photoionization sensor outputs the detected weak ion current, as shown Figure 3 The amplifier circuit shown performs signal amplification processing on the weak current and obtains a voltage signal on the resistor 6 in the amplifier circuit. The voltage signal is processed to obtain the gas concentration information to be measured.

[0063] like Figure 3 As shown, the amplifying circuit includes: an operational amplifier 5 and a resistor 6;

[0064] The reverse input terminal of the operational amplifier 5 is connected to any one of the two electrodes, the forward input terminal of the operational amplifier 5 is grounded, and the output terminal of the operational amplifier 5 outputs the second current;

[0065] One end of the resistor 6 is connected to the inverting input end of the operational amplifier 5 , and the other end of the resistor 6 is connected to the output end of the operational amplifier 5 .

[0066] In the prior art, after the ion current collected from the first electrode 2 or the second electrode 3 enters point A, it is amplified by resistor 6. Based on the relationship IR = U, the voltage between points A and B is measured, which is the amplified voltage. This method generates a low-resistance voltage that can be used for external circuit output. However, this voltage has an upper limit, namely the op amp input voltage, and thus reaches saturation. For a given circuit, the op amp voltage cannot be adjusted significantly, and the resistance value of resistor 6 is also difficult to adjust. Therefore, it is difficult to adjust the current-to-voltage conversion amplification ratio over a wide range, and the output of the photoionization sensor will reach a saturation voltage value.

[0067] Therefore, the method used by the adjustable photoionization sensor of the present invention is to adjust the magnitude of the current value to achieve the ion current intensity value generated by a certain concentration of gas, thereby adjusting the IR value, and adjusting the signal output value without exceeding the operational amplifier input voltage value (when the voltage at point AB is not saturated), thereby achieving the adjustment of the range, sensitivity and accuracy. On the other hand, since the operational amplifier voltage is fixed, that is, the highest saturation voltage of the device is fixed, the ion current required to achieve the same voltage also changes inversely. When the size of the through hole 17 of the light source baffle 4 remains unchanged, the ion current is positively correlated with the concentration. Then, the size of the through hole 17 to achieve the saturated output value of the photoionization sensor is inversely proportional to the concentration. According to the above analysis, the change in the area of ​​the through hole 17 can simultaneously change the sensitivity and saturation concentration of the device, while achieving accurate measurement of gases of different concentrations.

[0068] exist Figure 1 In the embodiment, the first electrode 2 and the second electrode 3 are parallel to the direction of ultraviolet light emission. Figure 2 In the embodiment, the first electrode 2 and the second electrode 3 are both perpendicular to the direction of ultraviolet light emission. Figure 1 In the embodiment, a plurality of through holes 17 are provided on the ultraviolet window of the ionization chamber. Figure 2 The first electrode 2 and the second electrode 3 are provided with a plurality of through holes 17, and the structures thereof are as follows. Figure 4 As shown. The method of opening the through hole 17 is as follows: on the metal material used for the electrode or the electroplated metal layer on the surface, a through hole 17 with a diameter of A is opened at the center. This hole is the first layer of through holes, and the number of holes on this layer is n1=1. Then, a circle at a distance from its center B is divided into n2 equal parts (B≥2×A), and n2 through holes 17 with a diameter of A are opened with the equal division point as the center of the circle. The above n2 through holes 17 are the second layer of through holes 17. Subsequently, n through holes 17 are opened on the circumference of the i-th layer in this way. i Through holes 17 with a diameter of A are formed until the next layer of through holes 17 of the m-layer through holes 17 exceeds the range of the ultraviolet light exit window of the ultraviolet lamp 1, and then no further through holes 17 are formed. At this time, the total number of holes is recorded as m.

[0069] The total number of openings is The total area is Among them D i The diameter of the pores in each layer can be further adjusted by adjusting the diameter of the micropores in each layer to D i and density n i Adjust the total open area of ​​each layer.

[0070] The ionization chamber ultraviolet window with through hole 17 is located at Figure 1 The lower part of the light source baffle 4 is located Figure 2 The light source baffle 4 has a structure as follows Figure 5 As shown, the light source baffle 4 is used to adjust the amount of ultraviolet light that can pass through the through hole 17. When the amount of ultraviolet light that can pass through the through hole 17 decreases, the sensitivity of the photoionization sensor decreases and the gas concentration range increases; when the number of open through holes 17 increases, the sensitivity of the photoionization sensor increases and the gas concentration range decreases.

[0071] When calibrating the first electrode 2, the light source baffle is adjusted to the maximum through hole 17. At this time, the sensitivity is S, the overall range is M, and the number of layers of through holes 17 that are not blocked is the maximum number of layers m, and the hole diameter of each layer is the same. During use, as the light source baffle is adjusted, the number of layers of through holes 17 that are not blocked by the light source baffle is calculated to be p (m>p), and the sensitivity S' at this time is The overall measuring range is M*S / S'.

[0072] When calibrating the rectangular light source baffle in Example 2 of the adjustable photoionization sensor of the present invention, the light hole is first adjusted to the maximum. At this time, the sensitivity is S and the gas concentration range is M. At this time, the length of the light hole is L. The area of ​​the light hole is gradually reduced, and the length of the light hole is reduced to L'. At this time, the sensitivity is S×L' / L, and the gas concentration range is M×L / L'. It can be concluded that when the area of ​​the light hole on the rectangular light source baffle is reduced, the sensitivity of the adjustable photoionization sensor of the present invention is reduced and the gas concentration range is improved.

[0073] Figure 7 The relationship between the actual range of the adjustable photoionization sensor of the present invention and the overall range and the number of unobstructed layers is shown in Figure 2. i =7*i-8. When the light source baffles are all open, m=5, M=50ppm, with different levels of shielding, the number of through holes 17 layers p that are not shielded by the light source baffles decreases, and the saturation range increases. iThe range of the calculation formula is calculated and compared (the lines between the points are only used to assist in observing the trend of the points and have no practical significance), which proves that the measured results are in good agreement with the theory, indicating that the adjustable photoionization sensor of the present invention has increased the saturation range by nearly 100 times through this method.

[0074] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0075] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. An adjustable photoionization sensor, characterized in that: The adjustable photoionization sensor includes: an ultraviolet lamp, a light source baffle, an ionization chamber and an amplifying circuit; The light source baffle is located between the ionization chamber and the ultraviolet lamp; the ultraviolet lamp is used to emit ultraviolet light; the ionization chamber is used to ionize the gas in the ionization chamber by the ultraviolet light and output a first current; The ionization chamber includes: a first electrode, a second electrode, and an ultraviolet light window; the ultraviolet light window is provided with a plurality of circular light holes, and the circular light holes are provided with a light source baffle, the light source baffle being used to adjust the emission area of ​​the ultraviolet light; the light source baffle is parallel to and close to the ultraviolet light window, and can block part of the ultraviolet light through a mechanical structure, thereby changing the cross-sectional area of ​​the ultraviolet light entering the ionization chamber through the ultraviolet light window, thereby changing the total amount of ultraviolet light entering the ionization chamber; the shielding material around the through holes of the ultraviolet light window is corrosion-resistant metal, gold-plated metal, Teflon, or oxide ceramic; The amplifier circuit is connected to the ionization chamber; the amplifier circuit is used to amplify the first current to form a second current; The light source baffle comprises: a fixed circular ring, a first knob, a first scale, and a plurality of aperture blades; the plurality of aperture blades are arranged around a circular ring structure, the circular ring structure matches the inner circle of the fixed circular ring, and the inner circular through hole of the circular ring structure is used to pass the ultraviolet light; the fixed circular ring is provided with a first scale, the first scale is used to determine the area of ​​the inner circular through hole; the first knob is provided on the outer circular surface of the fixed circular ring, and the first knob is used to adjust the area of ​​the inner circular through hole; Or the light source baffle is a rectangular light source baffle, which includes: a support column, a second scale, a second knob, a threaded rod and a light shielding plate; a threaded hole is provided on the support column, the threaded rod passes through the support column through the threaded hole, one end of the threaded rod is connected to the second knob, and the other end of the threaded rod is connected to the light shielding plate; the second scale is parallel to the threaded rod; the second scale is used to measure the displacement of the light shielding plate; the area of ​​the light shielding plate is greater than or equal to the cross-sectional area of ​​the ultraviolet light; the rectangular light source baffle also includes: a limit column, which is parallel to the support column and is used to limit the maximum displacement of the light shielding plate.

2. The adjustable photoionization sensor according to claim 1, characterized in that The first electrode and the second electrode have the same external contour structure and are arranged opposite to each other. The area between the first electrode and the second electrode is an ionization area, and there is a potential difference between the first electrode and the second electrode. The ultraviolet light window can transmit ultraviolet light and allow it to enter the ionization chamber, so that the gas to be measured is ionized between the first electrode and the second electrode, and the generated ions are collected by the first electrode or the second electrode to generate and output the first current.

3. The adjustable photoionization sensor according to claim 2, characterized in that The amplifying circuit includes: an operational amplifier and a resistor; The inverting input terminal of the operational amplifier is connected to the first electrode or the second electrode, the positive input terminal of the operational amplifier is grounded, and the output terminal of the operational amplifier outputs the second current; One end of the resistor is connected to the inverting input end of the operational amplifier, and the other end of the resistor is connected to the output end of the operational amplifier.

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