Ultra-compact photoionization imager with time slicing capability

Abstract

The present invention discloses an ultra-small photoion imager with a time-slicing function, comprising an electrostatic field region, a micro-focusing ion free-flight tube, an MCP detection screen, and a CCD image acquisition system arranged in sequence, with an electromagnetic shielding shell provided on the outside of the photoion imager; a plurality of electrodes with different inner diameters are provided within the electrostatic field region to form a slowly changing electrostatic field; the electrostatic field region is a laser action zone; the micro-focusing ion free-flight tube is a single-lens focusing system containing a plurality of micro-focusing electrodes for micro-focusing ions and adjusting the focus point; the MCP detection screen is a single-chip MCP structure or a double-chip MCP structure for multiplying electrons and achieving time slicing by loading a pulse voltage signal; and the CCD image acquisition system is used to collect ion images. The ion imager of the present invention is small in size, easy to assemble, and highly adjustable, and can meet the detection needs of high-precision and cutting-edge fields.

Description

Technical Field

[0001] The invention relates to a photoion imager, and more specifically to an ultra-small photoion imager with a time slicing function. Background Art

[0002] Ion imaging technology is an indispensable tool in experimental research on photolysis dynamics and chemical processes. It can provide information on the kinetic energy and angular distribution of ions throughout a 4π solid angle, and has great potential for applications in the study of material evolution in interstellar space, the atmospheric ionosphere, and plasmas. High-tech applications require ion imagers with easily adjustable focusing accuracy, compact size, and lightweight to meet the requirements of airborne and spaceborne exploration.

[0003] The commonly used ion imager currently is a triode-based photoelectron imager developed by Eppink, Parker and others. By adding an ion lens plate and changing the electric field shape, high image resolution is effectively achieved, but the length of the ion imager is greater than 450mm; Liu Yuzhu and others used a hexapole structure combined with a hollow cylindrical free-flight tube to invent a low-electric-field photoelectron imager, but the focusing ability is weak, resulting in the focal point of the entire ion imager being far away from the laser action area, and the size of the ion imager is greater than Φ1000mm×1000mm.

[0004] In summary, it is difficult for the currently developed ion imagers to simultaneously achieve good velocity focusing imaging and a small size, which limits their application in the field of photolysis dynamics in interstellar space and the atmospheric ionosphere. Summary of the Invention

[0005] The purpose of the present invention is to address the problem that currently developed ion imagers are difficult to achieve both good velocity focusing imaging and small size, and to provide an ultra-small photoion imager with time slicing function, in which the velocity imaging voltage is easily adjusted and the overall size is small.

[0006] The present invention is achieved through the following technical solutions:

[0007] An ultra-small photoion imager with a time slicing function, the photoion imager comprises an electrostatic field region, a micro-focused ion free-flight tube, an MCP detection screen and a CCD image acquisition system arranged in sequence, and an electromagnetic shielding shell is provided on the outside of the photoion imager;

[0008] The electrostatic field region is provided with a plurality of electrode sheets with different inner diameters for forming a slowly changing electrostatic field; the electrostatic field region is the laser action region;

[0009] The micro-focusing ion free flight tube is a single lens focusing system comprising a number of micro-focusing electrodes, which is used to micro-focus ions and adjust the focus point;

[0010] The MCP detection screen is a single-chip MCP structure or a double-chip MCP structure, which is used to multiply electrons and realize time slicing by loading pulse voltage signals;

[0011] The CCD image acquisition system is used to collect ion imaging;

[0012] The electromagnetic shielding shell is used to reduce the impact of the environment on ion imaging.

[0013] To optimize the above technical solutions, specific limitations also include:

[0014] The electrode sheets in the electrostatic field region are coaxially arranged hollow cylindrical electrodes, and the outer diameters of the electrode sheets are equal, while the inner diameters of the electrode sheets are different. The electrode sheets include at least a first electrode sheet at the entrance of the electrostatic field region, a second electrode sheet with an inner diameter larger than that of the first electrode sheet on the rear side of the first electrode sheet, and a last electrode sheet with an inner diameter larger than that of the first electrode sheet and smaller than that of the second electrode sheet at the exit of the electrostatic field region.

[0015] Furthermore, the electrode sheets in the electrostatic field region further include a plurality of electrode sheets which are sequentially arranged between the second electrode sheet and the last electrode sheet and have an inner diameter which is the same as or larger than that of the second electrode sheet.

[0016] The micro-focusing electrodes of the micro-focusing ion free flight tube are coaxially arranged cylindrical electrodes, including at least two first micro-focusing electrodes and third micro-focusing electrodes arranged at intervals and having the same inner diameter and outer diameter, and a second micro-focusing electrode arranged at the interval between the first micro-focusing electrode and the third micro-focusing electrode, with an inner diameter larger than the outer diameters of the first micro-focusing electrode and the third micro-focusing electrode.

[0017] The electrode sheets in the electrostatic field region, the micro-focused ion free flight tube and the MCP detection screen are connected in sequence through ceramic rings.

[0018] The single-chip MCP structure includes a first single-chip MCP electrode serving as the input electrode of the MCP detection screen, a channel with secondary electron emission characteristics, a second single-chip MCP electrode serving as the output electrode of the MCP screen, a phosphor screen and an electromagnetic shielding shell of the single-chip MCP structure; the double-chip MCP structure includes a first double-chip MCP electrode serving as the MCP1 input electrode of the MCP detection screen, a second double-chip MCP electrode serving as the MCP1 output electrode and the MCP2 input electrode of the MCP detection screen, a secondary electron multiplication channel of MCP1, a secondary electron multiplication channel of MCP2, a third double-chip MCP electrode serving as the MCP2 output electrode of the MCP detection screen, a phosphor screen and an electromagnetic shielding shell of the double-chip MCP structure.

[0019] The inner radius of the first electrode sheet is 8mm~12mm, and the outer radius is 76mm~84mm. The inner radius of the second electrode sheet is 55mm~65mm, and the outer radius is 75mm~85mm. The spacing between the second electrode sheet and the first electrode sheet along the direction of ion movement is 11mm~15mm; the inner radius of the last electrode sheet is 35mm~45mm, and the outer radius is 75mm~85mm. The spacing between the last electrode sheet and the adjacent electrode sheet along the direction of ion movement is 26mm~30mm.

[0020] Several electrode sheets arranged between the second electrode sheet and the last electrode sheet, with an inner diameter equal to or larger than that of the second electrode sheet, have an inner radius of 55mm to 65mm and an outer radius of 75mm to 85mm. 2-6 electrode sheets are arranged between the second electrode sheet and the last electrode sheet; the length of each electrode sheet in the electrostatic field region along the direction of ion movement is 1 to 2mm.

[0021] The potential difference between the second micro-focusing electrode and the first and third micro-focusing electrodes is 50V to 150V; the inner radius of the first and third micro-focusing electrodes is 60mm to 64mm, the outer radius is 68mm to 72mm, and the length along the direction of ion movement is 105mm to 115mm; the spacing between the first micro-focusing electrode and the last electrode sheet along the direction of ion movement is 26mm to 30mm; the spacing between the third micro-focusing electrode and the first micro-focusing electrode along the direction of ion movement is 57mm to 63mm; the inner radius of the second micro-focusing electrode is 70mm to 74mm, the outer radius is 78mm to 82mm, and the length along the direction of ion movement is 193mm to 205mm.

[0022] When using a single-chip MCP, the potential difference between the first single-chip MCP electrode and the second single-chip MCP electrode is 600V~800V, and slicing is achieved by loading a pulse voltage signal; when using a double-chip MCP, the potential difference between the second double-chip MCP electrode and the first double-chip MCP electrode is 600V~800V, and the potential difference between the third double-chip MCP electrode and the first double-chip MCP electrode is 1500V~1600V.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention adopts an electrostatic focusing system combined with a single-lens micro-focusing ion free-flight tube, which greatly improves the focusing performance of the photoion imager and can flexibly adjust the voltage to achieve different degrees of focusing;

[0025] The present invention can realize different gains by reasonably designing the detection screen MCP parameters; and can realize the time slicing function by adopting the pulse voltage signal to drive the MCP.

[0026] The present invention achieves a small size, easy assembly, and strong voltage adjustability through reasonable design of the electrode structure and potential distribution, which can meet the detection needs of high-precision fields, such as airborne and satellite-borne detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the structure of an ultra-small photoion imager with time slicing function;

[0028] Figure 2 This is a schematic diagram of the structure of a single-lens micro-focusing ion free-flight tube;

[0029] Figure 3 It is a schematic diagram of the single-chip MCP structure;

[0030] Figure 4 It is a schematic diagram of the double-chip MCP structure;

[0031] Figure 5 Schematic diagram of pulse voltage signal for single or double MCP;

[0032] Figure 6 This is the electric field distribution diagram of the ultra-small photoion imager with time slicing function;

[0033] Figure 7 The focusing effect of ions with the same speed (including size and direction) at different positions;

[0034] Figure 8 The focusing effect of ions with different speeds (including size and direction) at the same position (electron trajectory diagram);

[0035] Figure 9 The focusing effect of ions with different velocities (including size and direction) at the same position (front view);

[0036] Figure 10 is the gain of the monolithic MCP structure;

[0037] Figure 11 is the gain of the two-chip MCP structure;

[0038] The reference numerals in the figure are: 1-first electrode sheet, 2-second electrode sheet, 3-third electrode sheet, 4-fourth electrode sheet, 5-fifth electrode sheet, 6-sixth electrode sheet, 7-seventh electrode sheet, 8-microfocusing ion free flight tube, 81-first microfocusing electrode, 82-second microfocusing electrode, 83-third microfocusing electrode, 9-MCP detection screen, 911-monolithic MCP input electrode, 912-monolithic MCP electron multiplying channel, 913-monolithic MCP output electrode, 914-monolithic Phosphor screen, 915-single-chip MCP electromagnetic shielding shell, 921-double-chip MCP1 input electrode, 922-double-chip MCP1 electron multiplying channel, 923-double-chip MCP1 output electrode (i.e., MCP2 input electrode), 924-double-chip MCP2 electron multiplying channel, 925-double-chip MCP2 output electrode, 926-double-chip MCP2 phosphor screen, 927-double-chip MCP electromagnetic shielding shell, 10-electromagnetic shielding shell, 11-laser action area, 12-CCD image acquisition system. DETAILED DESCRIPTION

[0039] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0040] The structure of the ultra-small photoionization imager with time slicing function of the present invention is shown in FIG. Figure 1 , including a first electrode sheet 1, a second electrode sheet 2, a third electrode sheet 3, a fourth electrode sheet 4, a fifth electrode sheet 5, a sixth electrode sheet 6, a seventh electrode sheet 7, a micro-focused ion free flight tube 8, an MCP detection screen 9, an electromagnetic shielding shell 10, a laser action area 11 and a CCD image acquisition system 12.

[0041] The first electrode sheet 1, the second electrode sheet 2, the third electrode sheet 3, the fourth electrode sheet 4, the fifth electrode sheet 5, the sixth electrode sheet 6, and the seventh electrode sheet 7 are all hollow cylinders with the same outer diameter. The first electrode sheet 1 has the smallest inner diameter. The second electrode sheet 2, the third electrode sheet 3, the fourth electrode sheet 4, the fifth electrode sheet 5, and the sixth electrode sheet 6 have the same inner diameter and are all larger than the inner diameter of the first electrode sheet 1. The inner diameter of the seventh electrode sheet 7 is larger than the inner diameter of the first electrode sheet 1 and smaller than the inner diameter of the second electrode sheet 2. The micro-focused ion free flight tube 8 is a single lens focusing system, and its structure is as follows: Figure 2As shown, the device comprises a first micro-focusing electrode 81, a second micro-focusing electrode 82, and a third micro-focusing electrode 83 arranged sequentially along the direction of ion propagation. Each of the first, second, and third micro-focusing electrodes 81, 82, 83 is cylindrical. The inner and outer radii and axial lengths of the first and third micro-focusing electrodes 81, 83 are equal. The inner diameter of the second micro-focusing electrode 82 is larger than the outer diameter of the first micro-focusing electrode 81. The second micro-focusing electrode 82 is positioned between the first and third micro-focusing electrodes 81, 83. The first, second, third, fourth, fourth, fifth, sixth, and seventh electrodes 7 are connected to the micro-focusing ion free flight tube 8 in sequence via ceramic rings. The MCP detector screen 9 is a single-chip MCP or a dual-chip MCP.

[0042] The potential difference between the first micro-focusing electrode 81 and the third micro-focusing electrode 83 is 0V, and the potential difference between the third micro-focusing electrode 83 and the second micro-focusing electrode 82 is 50V to 150V. The potential difference between the second electrode sheet 2 and the first electrode sheet 1 is -280V, and the potential difference between the third electrode sheet 3 and the first electrode sheet 1 is -400V to -300V; the potential difference between the fourth electrode sheet 4 and the first electrode sheet 1 is -700V to -600V; the potential difference between the fifth electrode sheet 5 and the first electrode sheet 1 is -1350V to -1250V; the potential difference between the sixth electrode sheet 6 and the first electrode sheet 1 is -1750V to -1650V; and the voltage of the seventh electrode sheet 7 is 0V.

[0043] The inner radius of the first electrode sheet 1 is 8mm to 12mm, with an optional 10mm; the outer radius is 76mm to 84mm, with an optional 80mm; and the length along the direction of ion movement is 2mm. The inner radius of the second electrode sheet 2 is 55mm to 65mm, with an optional 60mm; the outer radius is 75mm to 85mm, with an optional 80mm; the length along the direction of ion movement is 1mm, and the spacing between the second electrode sheet 2 and the first electrode sheet 1 along the direction of ion movement is 11mm to 15mm, with an optional 13mm. The inner radius of the third electrode sheet 3 is 55mm to 65mm, with an optional 60mm; the outer radius is 75mm to 85mm, with an optional 80mm; the length along the direction of ion movement is 2mm, and the spacing between the third electrode sheet 3 and the second electrode sheet 2 along the direction of ion movement is 12mm to 16mm, with an optional 14mm. The fourth electrode sheet 4 has an inner radius of 55 mm to 65 mm, optionally 60 mm; an outer radius of 75 mm to 85 mm, optionally 80 mm; a length along the direction of ion movement of 2 mm, and a spacing between the fourth electrode sheet 4 and the third electrode sheet 3 along the direction of ion movement of 26 mm to 30 mm, optionally 28 mm. The fifth electrode sheet 5 has an inner radius of 55 mm to 65 mm, optionally 60 mm; an outer radius of 75 mm to 85 mm, optionally 80 mm; a length along the direction of ion movement of 2 mm, and a spacing between the fifth electrode sheet 5 and the fourth electrode sheet 4 along the direction of ion movement of 26 mm to 30 mm, optionally 28 mm. The sixth electrode sheet 6 has an inner radius of 55 mm to 65 mm, optionally 60 mm; an outer radius of 75 mm to 85 mm, optionally 80 mm; a length along the direction of ion movement of 2 mm, and a spacing between the sixth electrode sheet 6 and the fifth electrode sheet 5 along the direction of ion movement of 26 mm to 30 mm, optionally 28 mm. The inner radius of the seventh electrode sheet 7 is 35 mm to 45 mm, with 40 mm being an option; the outer radius is 75 mm to 85 mm, with 80 mm being an option; the length along the ion travel direction is 2 mm, and the spacing between the seventh electrode sheet 7 and the sixth electrode sheet 6 along the ion travel direction is 26 mm to 30 mm, with 28 mm being an option. The major diameters of the third electrode sheet 3, the fourth electrode sheet 4, the fifth electrode sheet 5, and the sixth electrode sheet 6 are all 0.0444 to 0.0571, with 0.05 being an option.The micro-focusing ion free flight tube 8 is a single lens focusing system. The inner radius of the first micro-focusing electrode 81 is 60mm-64mm, and 62mm is optional. The outer radius is 68mm-72mm, and 70mm is optional. The length along the ion running direction is 105mm-115mm, and 110mm is optional. The spacing between the first micro-focusing electrode 81 and the seventh electrode sheet 7 along the ion running direction is 26mm-30mm, and 28mm is optional. The inner radius of the second micro-focusing electrode 82 is 70mm-74mm, and 72mm is optional. The outer radius is 68mm-72mm, and 70mm is optional. The diameter is 78mm~82mm, and 80mm is optional; the length along the direction of ion movement is 193mm~205mm, and 200mm is optional; the inner radius of the third micro-focusing electrode 83 is 60mm~64mm, and 62mm is optional; the outer radius is 68mm~72mm, and 70mm is optional; the length along the direction of ion movement is 105mm~115mm, and 110mm is optional; the spacing between the third micro-focusing electrode 83 and the first micro-focusing electrode 81 along the direction of ion movement is 57mm~63mm, and 60mm is optional.

[0044] The radius of the single-chip MCP input electrode 911 is 45 mm to 50 mm, and 50 mm is optional. The radius of the output electrode 913 is 45 mm to 50 mm, and 50 mm is optional. The spacing between the output electrode 913 and the input electrode 911 is 400 μm to 500 μm, and 500 μm is optional. The inclination angle of the electron multiplier channel 912 is 6°, the channel aperture is 6 μm to 8 μm, and 6 μm is optional. The number of channels is 3×10 7 Alternatively, the radius of the first MCP1 input electrode 921 of the double-chip MCP is 45 mm to 50 mm, and 50 mm is optional; the radius of the MCP1 output electrode 923 is 45 mm to 50 mm, and 50 mm is optional; the spacing between the output electrode 923 and the input electrode 921 is 400 μm to 500 μm, and 500 μm is optional; the inclination angle of the electron multiplication channel 922 of the MCP1 is 6°, and the channel aperture is 6 μm to 8 μm, and 6 μm is optional; the number of channels is 3×10 7 The radius of the second MCP2 input electrode 923 is 45 mm to 50 mm, and 50 mm is optional. The radius of the phosphor screen 925 is 45 mm to 50 mm, and 50 mm is optional. The spacing between the phosphor screen 925 and the MCP1 output electrode 923 is 400 μm to 500 μm, and 500 μm is optional. The inclination angle of the electron multiplication channel 924 of MCP2 is 6°, and the channel aperture is 6 μm to 8 μm, and 6 μm is optional. The number of channels is 3×10 7 indivual.

[0045] The specific working process of the present invention is as follows (taking electronic signals as an example)

[0046] Photodissociated electrons are accelerated in the slowly varying electric field formed by the first, second, third, fourth, fifth, sixth, and seventh electrodes 7. They then pass through a microfocused ion free-flight tube 8 and travel to the MCP 9 for signal amplification. When the electron signal reaches the MCP input, a pulsed high voltage with a width of 60 to 80 nanoseconds and an amplitude of 1500 volts is instantaneously applied to the MCP, bringing it to its normal operating voltage to amplify the weak electron signal after photodissociation and achieving time slicing. The narrower the pulsed high voltage time width, the better the time slicing effect. The amplified signal is collected by a CCD image acquisition system 12. During this process, electrons at the same position but different velocities form a ring on the MCP detector input surface, which is multiplied by the MCP to form a ring with enhanced brightness. Electrons with the same velocity but different directions land at different positions within the ring. Electrons at different positions but the same velocity can be focused onto the same point on the MCP detection screen. In this way, the distribution of the electron ball's speed and angular size can be observed intuitively from the images collected by the CCD.

[0047] The focusing characteristics of an ultra-compact photoionization imager with time slicing capability were evaluated using the following process:

[0048] First, it is necessary to calculate the electromagnetic field distribution inside the ultra-small photoion imager, combine the actual experimental experience parameters, give the ion velocity, energy and other information, and then track the ion trajectory. According to the electron velocity focusing situation, the structural parameters and electrical parameters are optimized, and finally the optimal voltage parameters are determined. The discretized electromagnetic field distribution is calculated using three-dimensional electromagnetic simulation software, such as Figure 6 shown.

[0049] Secondly, the focusing effect of electrons with the same speed (including size and direction) at different positions is simulated. Given the symmetry of the ultra-small photoionization imager with time slicing function, five beams of electrons with the same speed are emitted within the laser action area at intervals of 7.5 mm along the x direction (the overall laser action area is Φ30 mm). The electron trajectories are tracked and the focusing of the electrons on the phosphor screen is observed, as shown in Figure 2. Figure 7 shown.

[0050] Simulate the electron effect of ions with different speeds (including size and direction) at the same position. Emit 8 electron beams with different speeds (including size and direction) at the center of the laser action area, track the electron trajectory, and observe the focusing of the electrons on the phosphor screen, such as Figure 8 and Figure 9 shown.

[0051] Finally, the electrons enter the MCP multiplication system for number multiplication. Given the small aperture of the MCP channel, each channel only multiplies the electrons at the corresponding position. Therefore, the ultra-small photoion imager has position resolution capability. The gain of the simulated single-chip MCP is as follows: Figure 10 As shown; the gain of the dual-chip MCP is as follows Figure 11 shown.

[0052] The single-lens micro-focusing ion free-flight tube of the present invention employs a single-lens electrostatic focusing system, wherein the potential difference between the first micro-focusing electrode and the third micro-focusing electrode is 0V. Therefore, the imager's focus point can be well adjusted simply by adjusting the voltages of the first and third micro-focusing electrodes. After ions are accelerated out of the ion lens system, they enter the MCP detection system through a free-flight region with a length of 308mm. The total distance between the ion reaction center and the MCP detector is only 430mm. The entire ultra-small photoion imager with a time-slicing function has an outer dimension of only approximately 80mm x 460mm.

[0053] The above description is only a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Any simple modification, equivalent replacement and improvement made by any technician familiar with the profession to the above embodiment without departing from the scope of the technical solution of the present invention and based on the technical essence of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. An ultra-small photoionization imager with a time slicing function, characterized by: The photoion imager includes an electrostatic field region, a micro-focused ion free-flight tube, an MCP detection screen and a CCD image acquisition system arranged in sequence, and an electromagnetic shielding shell is provided on the outside of the photoion imager; The electrostatic field region is provided with a plurality of electrode sheets with different inner diameters for forming a slowly changing electrostatic field; the electrostatic field region is the laser action region; The micro-focusing ion free flight tube is a single lens focusing system comprising a number of micro-focusing electrodes, which is used to micro-focus ions and adjust the focus point; The MCP detection screen is a single-chip MCP structure or a double-chip MCP structure, which is used to multiply electrons and realize time slicing by loading pulse voltage signals; The CCD image acquisition system is used to collect ion imaging; The electromagnetic shielding shell is used to reduce the impact of the environment on ion imaging; The micro-focusing electrodes of the micro-focusing ion free flight tube are coaxially arranged cylindrical electrodes, including at least two first micro-focusing electrodes and third micro-focusing electrodes arranged at intervals and having the same inner diameter and outer diameter, and a second micro-focusing electrode arranged at the interval between the first micro-focusing electrode and the third micro-focusing electrode, with an inner diameter larger than the outer diameters of the first micro-focusing electrode and the third micro-focusing electrode.

2. The ultra-small photoionization imager with time slicing function according to claim 1, characterized in that: The electrode sheets in the electrostatic field region are coaxially arranged hollow cylindrical electrodes, and the outer diameters of the electrode sheets are equal, while the inner diameters of the electrode sheets are different. The electrode sheets include at least a first electrode sheet at the entrance of the electrostatic field region, a second electrode sheet with an inner diameter larger than that of the first electrode sheet on the rear side of the first electrode sheet, and a last electrode sheet with an inner diameter larger than that of the first electrode sheet and smaller than that of the second electrode sheet at the exit of the electrostatic field region.

3. The ultra-small photoionization imager with time slicing function according to claim 2, characterized in that: The electrode sheets in the electrostatic field region further include a plurality of electrode sheets which are sequentially arranged between the second electrode sheet and the last electrode sheet and have an inner diameter which is the same as or larger than that of the second electrode sheet.

4. The ultra-small photoionization imager with time slicing function according to claim 1, characterized in that: The electrode sheets in the electrostatic field region, the micro-focused ion free flight tube and the MCP detection screen are connected in sequence through ceramic rings.

5. The ultra-small photoionization imager with time slicing function according to claim 1, characterized in that: The single-chip MCP structure includes a first single-chip MCP electrode serving as the input electrode of the MCP detection screen, a channel with secondary electron emission characteristics, a second single-chip MCP electrode serving as the output electrode of the MCP screen, a phosphor screen and an electromagnetic shielding shell of the single-chip MCP structure; the double-chip MCP structure includes a first double-chip MCP electrode serving as the MCP1 input electrode of the MCP detection screen, a second double-chip MCP electrode serving as the MCP1 output electrode and the MCP2 input electrode of the MCP detection screen, a secondary electron multiplication channel of MCP1, a secondary electron multiplication channel of MCP2, a third double-chip MCP electrode serving as the MCP2 output electrode of the MCP detection screen, a phosphor screen and an electromagnetic shielding shell of the double-chip MCP structure.

6. The ultra-small photoionization imager with time slicing function according to claim 2, characterized in that: The inner radius of the first electrode sheet is 8mm~12mm, and the outer radius is 76mm~84mm. The inner radius of the second electrode sheet is 55mm~65mm, and the outer radius is 75mm~85mm. The spacing between the second electrode sheet and the first electrode sheet along the direction of ion movement is 11mm~15mm; the inner radius of the last electrode sheet is 35mm~45mm, and the outer radius is 75mm~85mm. The spacing between the last electrode sheet and the adjacent electrode sheet along the direction of ion movement is 26mm~30mm.

7. The ultra-small photoionization imager with time slicing function according to claim 3, characterized in that: Several electrode sheets arranged between the second electrode sheet and the last electrode sheet, with an inner diameter equal to or larger than that of the second electrode sheet, have an inner radius of 55mm~65mm and an outer radius of 75mm~85mm. 2-6 electrode sheets are arranged between the second electrode sheet and the last electrode sheet; the length of each electrode sheet in the electrostatic field region along the direction of ion movement is 1~2mm.

8. The ultra-small photoionization imager with time slicing function according to claim 1, characterized in that: The potential difference between the second micro-focusing electrode and the first and third micro-focusing electrodes is 50 V to 150 V; the inner radius of the first and third micro-focusing electrodes is 60 mm to 64 mm, the outer radius is 68 mm to 72 mm, and the length along the ion movement direction is 105 mm to 115 mm; the spacing between the first micro-focusing electrode and the last electrode sheet along the ion movement direction is 26 mm to 30 mm; the spacing between the third micro-focusing electrode and the first micro-focusing electrode along the ion movement direction is 57 mm to 63 mm; the inner radius of the second micro-focusing electrode is 70 mm to 74 mm, the outer radius is 78 mm to 82 mm, and the length along the ion movement direction is 193 mm to 205 mm.

9. The ultra-small photoionization imager with time slicing function according to claim 6, characterized in that: When using a single-chip MCP, the potential difference between the first single-chip MCP electrode and the second single-chip MCP electrode is 600V~800V, and slicing is achieved by applying a pulse voltage signal; When using a double-chip MCP, the potential difference between the second double-chip MCP electrode and the first double-chip MCP electrode is 600V~800V, and the potential difference between the third double-chip MCP electrode and the first double-chip MCP electrode is 1500V~1600V.

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