CN115910746A - Ion migration device, trace explosive detection equipment and X-ray security inspection machine - Google Patents

Abstract

The invention relates to the technical field of ion migration, and discloses an ion migration device, trace explosive detection equipment and an X-ray security inspection machine, which are used for solving the problem that a migration tube in the prior art has poor focusing performance on ions entering a migration area channel to a central area. The ion migration device comprises a base, an inner electrode and an outer electrode; the inner electrode is embedded in the base, and the part of the inner electrode exposed out of the base is of a hemispherical structure; the outer electrode is arranged on the periphery of the base and is provided with a cavity with a hemispherical structure for accommodating the inner electrode, and a gap between the inner wall of the cavity and the inner electrode forms an ion migration channel in a hemispherical crown shape; the outer electrode is provided with an air inlet and an air outlet, an air inlet channel is arranged between the air inlet and the ion migration channel, and an air outlet channel is arranged between the air outlet and the ion migration channel.

Description

Ion migration device, trace explosive detection equipment and X-ray security inspection machine

Technical Field

The invention relates to the technical field of ion migration, in particular to an ion migration device, trace explosive detection equipment and an X-ray security inspection machine.

Background

In recent years, in the field of trace explosive identification by means of gas detection, ion mobility spectrometers based on a high-Field Asymmetric Ion Mobility Spectrometry (FAIMS) are widely applied, and can perform relatively accurate identification on explosives, a mobility tube is an important component of a high-field asymmetric waveform ion mobility spectrometer, the types of the existing high-field asymmetric waveform ion mobility spectrometer mobility tubes are roughly divided into two types, one type is a flat-plate type mobility tube and the other type is a cylindrical type mobility tube, the flat-plate type mobility tube cannot realize an ion focusing function, ions close to the wall surface of a channel of a mobility region are more likely to touch the wall surface of the channel and lose electrons after entering the mobility region, and cannot reach a collecting electrode, so that large ion loss exists, the cylindrical type mobility tube has the ion focusing function, but the focusing performance is poor, the passing rate of the ions in the channel of the mobility region is affected, the loss of the ions in the channel of the mobility region reduces the ion strength received by the collecting electrode, and further the detection performance of the ion mobility spectrometer is affected finally.

Disclosure of Invention

The invention provides an ion migration device, trace explosive detection equipment and an X-ray security inspection machine, which are used for solving the problem that a migration tube in the prior art has poor focusing performance on ions entering a migration area channel to a central area.

In a first aspect, an embodiment of the present invention provides an ion mobility device, including a base, an inner electrode, and an outer electrode;

the inner electrode is embedded in the base, and the part of the inner electrode exposed out of the base is of a hemispherical structure;

the outer electrode is arranged on the periphery of the base and provided with a cavity of a hemispherical structure for accommodating the inner electrode, and a gap between the inner wall of the cavity and the outer wall of the hemispherical structure forms an ion migration channel in a hemispherical crown shape;

the outer electrode is provided with an air inlet and an air outlet, an air inlet channel is arranged between the air inlet and the ion migration channel, and an air outlet channel is arranged between the air outlet and the ion migration channel.

In the above embodiment, an ion migration channel in the shape of a hemispherical crown is arranged between the inner electrode and the outer electrode of the ion migration device, an electric field in the ion migration channel is a non-uniform electric field and has an ion focusing function, and the electric field intensity at any position in the ion migration channel and the R at the position are respectively the same ^-2 In proportion, the electric field can generate larger attenuation along the radius direction, so that the focusing effect of ions is more obvious, the passing rate of the ions passing through the ion migration channel can be improved, and the detection precision and sensitivity of trace explosive substances are further improved.

Optionally, the air inlet channel and the air outlet channel are symmetrically disposed on two sides of the inner electrode, and both extend along a radial direction of the hemispherical structure of the inner electrode.

Optionally, the outer electrode includes a first outer electrode and a second outer electrode, the first outer electrode is disposed on the top of the base, and the first outer electrode has the cavity;

the second outer electrode is connected with the first outer electrode and circumferentially surrounds the base.

Optionally, the first outer electrode faces the surface of the second outer electrode and is provided with a first groove, the second outer electrode faces the surface of the first outer electrode and is provided with a second groove, the surface of the base is provided with a third groove which is connected with the second groove and extends towards the inner electrode, and the first groove, the second groove and the third groove are formed on two sides of the inner electrode and form the air inlet channel and the air outlet channel.

Optionally, the second outer electrode is provided with a stepped hole, the stepped hole includes a first hole section and a second hole section which are sequentially arranged along a direction away from the first outer electrode, the aperture of the first hole section is larger than that of the second hole section, and at least part of the base is located in the stepped hole and is stopped at a stepped surface at a connection position of the first hole section and the second hole section;

the connecting end of the inner electrode penetrates out of the base.

Optionally, the base is provided with a connection hole, the inner electrode includes a first electrode portion and a second electrode portion, the first electrode portion is at least partially exposed from the surface of the base to form the hemispherical structure, the second electrode portion is connected with the first electrode portion, and the second electrode portion is a cylinder penetrating through the connection hole.

Optionally, a sinking groove is formed in the surface of the base, the sinking groove is communicated with the connecting hole, the first electrode portion comprises the hemispherical structure and an assembling structure which are connected, the hemispherical structure is a portion exposed out of the surface of the base, and the assembling structure is accommodated in the sinking groove.

Optionally, an arc transition region is arranged at one end of the air inlet channel and one end of the air outlet channel, which are close to the inner electrode.

In a second aspect, an embodiment of the present invention further provides a trace explosive detection apparatus, where the trace explosive detection apparatus includes an ionization device, the ion migration device in any of the above technical solutions, and an ion detection device, the ionization device is disposed at an air inlet of the ion migration device, and the ion detection device is disposed at an air outlet of the ion migration device.

In the above embodiment, the ion migration device adopted by the trace explosive detection apparatus has the ion migration channel in the shape of a hemispherical crown, so that in the ion screening stage, the focusing effect of the ions is more significant, the passing rate of the ions passing through the ion migration channel can be improved, and the detection accuracy and sensitivity of the trace explosive substances are further improved.

In a third aspect, an embodiment of the present invention further provides an X-ray security inspection machine, where the X-ray security inspection machine includes a security inspection machine body and a trace explosive detection device, the security inspection machine body has a security inspection channel, and the trace explosive detection device is disposed on the security inspection machine body and faces the security inspection channel.

In the embodiment, the trace explosive detection equipment is applied to the X-ray security inspection machine, so that the X-ray security inspection machine can realize the trace detection of explosives on specific suspicious substances in a bag while realizing the traditional X-ray image detection on forbidden articles such as guns, cutters and the like, and realizes one-time bag passing and multiple detections; in addition, in the adopted trace explosive detection equipment, the ion migration device is provided with the ion migration channel in the shape of a hemispherical crown, the ion migration channel in the shape of the hemispherical crown has a good focusing effect on ions, the ion loss of a detected sample can be reduced, and the detection and identification of explosive ions can be better realized.

Drawings

Fig. 1 is a schematic structural diagram of an ion mobility device according to an embodiment of the present invention;

fig. 2 is a cross-sectional view of the ion transfer device shown in fig. 1;

fig. 3 is a schematic cross-sectional view of the ion transfer device shown in fig. 1;

FIG. 4 is a schematic cross-sectional view of a first external electrode of the ion mobility device shown in FIG. 3;

fig. 5 is a schematic cross-sectional view of a second external electrode in the ion mobility device shown in fig. 3;

fig. 6 is a schematic cross-sectional view of an inner electrode in the ion mobility device shown in fig. 3;

fig. 7 is a schematic cross-sectional view of a base in the ion mobility device shown in fig. 3;

FIG. 8 is a schematic view of an ion channel formed by a combination of an inlet channel, an ion transfer channel, and an outlet channel in the ion mobility device shown in FIG. 1;

fig. 9 is a schematic view of an ion channel formed by combining an inlet channel, an ion transfer channel, and an outlet channel in another ion transfer device according to an embodiment of the present invention;

FIG. 10 is a schematic diagram of the trace explosive detection apparatus provided in accordance with an embodiment of the present invention;

fig. 11, fig. 12, fig. 13, fig. 14, and fig. 15 are graphs of scanning voltage waveforms used by the trace explosive detection apparatus provided in the embodiment of the present invention during the test process and graphs of ion signal waveforms of the tested object sample obtained by the test.

Reference numerals:

1-an ion transfer device;

10-a base; 101-connecting hole; 102-sink tank; 103-a third groove;

20-an inner electrode; 201-hemispherical structure; 202-an assembly structure; 21-a first electrode portion; 22-a second electrode portion;

30-an outer electrode; 301-a chamber; 302-an air inlet; 303-air outlet; 31-a first outer electrode; 310-a first groove; 32-a second external electrode; 320-a second groove; 321-a stepped bore; 3211-a first bore section; 3212-a second pore section;

40-ion transport channels; 50-an intake passage; 60-an air outlet channel; 70-an arc transition zone;

2-an ionization device; 3-an ion detection device; 4-asymmetric high voltage generator; 5-compensation voltage generator.

Detailed Description

To make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The embodiment of the invention provides an ion migration device, which is used for solving the problem that a migration tube in the prior art has poor focusing performance on ions entering a migration area channel to a central area.

Referring to fig. 1 to 7 together, the ion transfer device 1 includes a base 10, an inner electrode 20, and an outer electrode 30, wherein the inner electrode 20 is embedded in the base 10, and the exposed portion of the inner electrode 20 from the base 10 is a hemispherical structure 201; the outer electrode 30 is arranged on the periphery of the base 10, the outer electrode 30 is provided with a cavity 301 for accommodating the hemispherical structure 201 of the inner electrode 20, and a gap between the inner wall of the cavity 301 and the outer wall of the hemispherical structure 201 forms an ion migration channel 40 in a hemispherical crown shape; the outer electrode 30 is provided with a gas inlet 302 and a gas outlet 303, and a gas inlet channel 50 is provided between the gas inlet 302 and the ion transfer channel 40, and a gas outlet channel 60 is provided between the gas outlet 303 and the ion transfer channel 40.

Specifically, the base 10 of the ion transfer device 1 is made of an insulating material, and plays a role of supporting the inner electrode 20 and isolating the inner electrode 20 from the outer electrode 30; the inner electrode 20 of the ion transfer device 1 is embedded in the base 10, and includes a hemispherical structure 201, where the hemispherical structure 201 is a portion of the inner electrode 20 exposed from the base 10; the outer electrode 30 of the ion transfer device 1 is disposed outside the base 10, and has a hemispherical cavity 301, the chamber 301 can accommodate the hemispherical structure 201 in which the inner electrode 20 is exposed from the base 10, and there is a gap between the inner wall of the chamber 301 and the outer wall of the hemispherical structure 201, the gap forms an ion transfer channel 40 in the shape of a hemispherical crown, the outer electrode 30 is further provided with a gas inlet 302 and a gas outlet 303, the gas inlet 302 is communicated with the ion transfer channel 40 through a gas inlet channel 50, the gas outlet 303 is communicated with the ion transfer channel 40 through a gas outlet channel 60, in the detection process, a high-voltage, high-frequency asymmetric voltage and a compensation voltage are applied to the inner electrode 20, the outer electrode 30 is grounded, and the compensation voltage is scanned in a certain range, so that a high-frequency asymmetric electric field and a direct current scanning electric field are formed between the inner electrode 20 and the outer electrode 30, ion current generated by ionization sequentially passes through the air inlet 302 and the air inlet channel 50 to enter the ion migration channel 40, in the ion transfer channel 40, different kinds of ions are separated mainly by utilizing the characteristic that the mobility of different kinds of ions under a high electric field is different according to the variation of the electric field intensity, and, under the combined action of the high-frequency asymmetric electric field and the direct-current scanning electric field, only ions meeting a certain scanning voltage can reach the ion detection device 3 through the ion migration channel 40, while other kinds of ions are neutralized by colliding with the inner electrode 20 or the outer electrode 30, and therefore, at the air outlet 303 of the outer electrode 30, a spectrogram of the ion current changing along with the scanning voltage can be obtained through the ion detection device 3, namely, a high-frequency asymmetric waveform ion mobility spectrometry spectrogram, referred to as a FAIMS spectrogram for short, can determine the type of the substance to be detected by using the correspondence between the scanning voltage and the ion type stored in the database based on the obtained FAIMS spectrogram of the substance to be detected.

As can be seen from the foregoing, the ion migration apparatus 1 has the ion migration channel 40 in the shape of a hemispherical crown, in the ion migration channel 40, along the radial direction, the electric field is a non-uniform electric field, the electric field intensity at different positions is different, and shows a trend of gradually decreasing from the inner electrode 20 to the outer electrode 30, under the combined action of the high-frequency asymmetric electric field and the dc scanning electric field, when an ion passes through the ion migration channel 40, if the ion is close to the inner electrode 20, the electric field force will force the ion to move towards the central area between the two electrodes so as to be far away from the inner electrode 20, and if the ion is close to the outer electrode 30, the electric field force will force the ion to move towards the central area between the two electrodes so as to be far away from the outer electrode 30, i.e. a focusing effect of the ion is generated, under the focusing effect of the ion, the ion can be concentrated towards the central area between the two electrodes, so that the ion separation capability is enhanced, and the separated ions are concentrated, which is beneficial to the detection of the subsequent ion detection apparatus 3, and the sensitivity and the accuracy of the ion detection apparatus 3 can be improved.

The effect of the ion focusing effect depends on the gradient change of the electric field in the ion migration channel 40 along the radial direction, the greater the attenuation of the electric field intensity, the more ideal the focusing effect, and the electric field intensity at any position in the ion migration channel 40 can be calculated by the following formula:

in the formula, E is the electric field strength of any position, Q is the total charge amount, ∈ 0 is the dielectric constant, and R is the distance from the center of the circle of the position, and it can be seen that, under the condition that other parameters are not changed, the electric field strength E of any position is in direct proportion to R-2 of the position, which causes the electric field in the ion migration channel 40 in the shape of a hemispherical crown to generate a large attenuation along the radial direction, and the focusing effect of ions is more significant.

In order to more easily understand the advantages of the ion migration apparatus 1 based on the ion focusing effect generated by the ion migration channel 40 in the shape of a hemispherical crown, the present invention is compared with a cylindrical ion migration tube, the cylindrical ion migration tube includes a cylindrical inner electrode and an annular outer electrode, a gap between the cylindrical inner electrode and the annular outer electrode forms the cylindrical ion migration channel, an electric field between the cylindrical inner electrode and the annular outer electrode is also a non-uniform electric field along a radial direction in the ion migration channel, and an electric field strength at any position can be calculated by the following formula:

wherein E is the electric field intensity at any position, Q is the total charge amount, ε 0 is the dielectric constant, R is the distance from the center of the circle, and L is the axial length of the ion migration channel ^-1 Proportional ratio, in the present embodiment, the electric field intensity E at any position and the position R in the ion transfer channel 40 having a hemispherical crown shape ^-2 In proportion to this, the electric field in the ion transfer channel 40 having the hemispherical crown shape is more significantly attenuated than the electric field in the cylindrical ion transfer channel in the radial direction.

Therefore, in the embodiment of the present application, the ion focusing effect generated by the ion migration device 1 based on the ion migration channel 40 in the shape of the hemispherical crown is better than that generated by the cylindrical ion migration tube, so that the probability of collision between ions and the inner electrode 20 or the outer electrode 30 is reduced, the ion loss is reduced, the detection of the ion detection device 3 is facilitated, and the sensitivity and the precision of the ion detection device 3 can be improved.

In the ion migration device 1, the outer electrode 30 forms a coating on the outer part of the inner electrode 20, so that the influence of an external electric field on the internal electric field can be shielded, and meanwhile, the radiation interference of the internal electric field on an external circuit of the system is reduced; in addition, since the ion migration channel 40 has a hemispherical crown structure, the volume of the space is small, which is more beneficial to the overall miniaturization design.

In order to more clearly understand the ion transfer device 1 provided in the embodiment of the present invention, a detailed description will be given with reference to the drawings.

In some embodiments, as shown in fig. 2 and 3, the entrance and exit of the ion transfer channel 40 are located at the bottom edge of the ion transfer channel 40 and are symmetrically disposed on both sides of the hemispherical structure 201 of the inner electrode 20.

Specifically, when the carrier gas pushes ions to travel, the ions move along the shortest path between the inlet and the outlet, and the inlet and the outlet are located at the bottom edge of the ion migration channel 40 and symmetrically arranged at two sides of the hemispherical structure 201 of the inner electrode 20, so that a plurality of ion migration paths which are equal in length and do not influence each other can be formed between the inlet and the outlet, and the migration paths of the ions are close to a half circle, thus detection errors caused by length differences of the ion migration paths can not be caused, meanwhile, the overall flux of the ions can be increased, and detection and identification of trace ions are facilitated.

The inlet of the ion migration channel 40 is located at the intersection of the ion migration channel 40 and the air inlet channel 50, and the outlet of the ion migration channel 40 is located at the intersection of the ion migration channel 40 and the air outlet channel 60, for example, as shown in fig. 8, the air inlet channel 50 and the air outlet channel 60 are symmetrically disposed on two sides of the inner electrode 20, and both extend along the radial direction of the hemispherical structure 201 of the inner electrode 20; alternatively, as shown in fig. 9, the inlet channels 50 and the outlet channels 60 extend in a tangential direction of the hemispherical structure 201.

As for the external electrode 30, in some embodiments, as shown in fig. 1, 2, 3, 4, and 5, the external electrode 30 includes a first external electrode 31 and a second external electrode 32, the first external electrode 31 is disposed on the top of the base 10, and the first external electrode 31 has a hemispherical cavity 301, the cavity 301 can accommodate the hemispherical structure 201 of the internal electrode 20 and form the ion migration channel 40 in the shape of a hemispherical crown with the hemispherical structure 201; the second outer electrode 32 is connected to the first outer electrode 31 and circumferentially disposed around the base 10, and the second outer electrode 32 and the first outer electrode 31 may be welded, flange-connected, or bonded by coating a conductive adhesive on a contact surface therebetween, so that the second outer electrode 32 and the first outer electrode 31 may be electrically connected, and thus, when the second outer electrode 32 is grounded, the first outer electrode 31 may also have a grounding effect.

From the structural point of view, the second external electrode 32 is provided with a hole structure for accommodating the base 10, the base 10 is located in the hole structure so as to be surrounded by the second external electrode 32 in the circumferential direction, for example, as shown in fig. 3 and 5, the second external electrode 32 is provided with a stepped hole 321, the stepped hole 321 includes a first hole segment 3211 and a second hole segment 3212 which are sequentially arranged in the direction away from the first external electrode 31, the hole diameter of the first hole segment 3211 is larger than that of the second hole segment 3212, the base 10 is at least partially located in the stepped hole 321 and stops at the stepped surface of the connecting position of the first hole segment 3211 and the second hole segment 3212; the internal electrode 20 is embedded in the base 10, and the connection end of the internal electrode 20 penetrates out of the base 10.

Specifically, the first hole segment 3211 and the second hole segment 3212 are coaxially disposed, and since the aperture of the first hole segment 3211 is larger than the aperture of the second hole segment 3212, the first hole segment 3211 and the second hole segment 3212 form a step surface at a connection point, the base 10 may be integrally disposed in the first hole segment 3211 of the step hole 321 and stopped at the step surface, or a portion of the base may be disposed in the first hole segment 3211 of the step hole 321 and a portion of the base may be disposed in the second hole segment 3212 of the step hole 321, and a portion of the base 10 located in the first hole segment 3211 is stopped at the step surface, the step surface forms a support and a limit for the base 10, and the step surface and the base 10 may be adhesively fixed by glue.

The top surface of the submount 10 may be flush or substantially flush with the top surface of the second outer electrode 32.

With continued reference to fig. 3 and 5, the stepped hole 321 is a through hole, that is, the stepped hole 321 penetrates through the top surface and the bottom surface of the second external electrode 32, so that when the connection end of the internal electrode 20 penetrates out of the base 10, the penetrated portion will be located in the second hole segment 3212, and in the second hole segment 3212, a wiring harness can be arranged, thereby connecting the internal electrode 20 with the asymmetric high voltage generator 4 and the compensation voltage generator 5.

As can be seen from the foregoing, the air inlet channel 50 may be communicated with the air inlet 302 on the surface of the outer electrode 30 and the ion migration channel 40, the air outlet channel 60 may be communicated with the air outlet 303 on the surface of the outer electrode 30 and the ion migration channel 40, on the basis that the outer electrode 30 includes the first outer electrode 31 and the second outer electrode 32, as shown in fig. 3, fig. 4, fig. 5, and fig. 7, for the formation of the air inlet channel 50 and the air outlet channel 60, as for the surface of the first outer electrode 31 facing the second outer electrode 32, the surface of the second outer electrode 32 facing the first outer electrode 31 is provided with a first groove 310, a second groove 320, and the surface of the base 10 is provided with a third groove 103 connecting the second groove 320 and extending toward the inner electrode 20, and the air inlet channel 50 and the air outlet channel 60 are formed on two sides of the inner electrode 20 by the first groove 310, the second groove 320, and the third groove 103.

As can be seen from the cross-sectional view of the ion transfer device shown in fig. 2, the central axis of the inlet channel 50 coincides with the central axis of the outlet channel 60, and passes through the spherical center of the hemispherical structure 201, so that after the ions enter the ion transfer channel 40 from the inlet channel 50, the movement trajectories of the ions in the ion transfer channel 40 are close to a half circle, and finally the ions are ejected from the outlet channel 60, and the length difference of the movement trajectories of the ions is small.

Alternatively, in other embodiments, the first groove 310 may be disposed only on the surface of the first external electrode 31 facing the second external electrode 32, and the air inlet passage 50 may be formed by the first groove 310, or the second groove 320 may be disposed only on the surface of the second external electrode 32 facing the first external electrode 31, and the third groove 103 connected to the second groove 320 and extending toward the internal electrode 20 may be disposed on the surface of the base 10, and the air inlet passage 50 may be formed by the second groove 320 and the third groove 103.

As shown in fig. 8, when ions enter the ion migration channel 40 from the air inlet channel 50, the motion trajectory of the ions at the intersection of the two will be greatly changed, in order to ensure that the ions can smoothly pass through this region, and reduce the front collision with the surface of the inner electrode 20, an arc transition region 70 is provided at one end of the air inlet channel 50 close to the inner electrode 20, and the arc transition region 70 gradually transitions one end of the air inlet channel 50 close to the inner electrode 20 to the surface of the inner electrode 20 in an arc shape, so that the front collision between the ions and the surface of the inner electrode 20 is reduced, the ions are guided to smoothly pass through, and the ion loss is reduced, and similarly, an arc transition region 70 is also provided at one end of the air outlet channel 60 close to the inner electrode 20.

For the base 10, the base 10 is made of an insulating material, and plays a role in isolation between the inner electrode 20 and the outer electrode 30, and the base 10 may specifically be made of a polytetrafluoroethylene material, which can meet the high-voltage isolation of about 10000V; the base 10 further supports the inner electrode 20, in some embodiments, as shown in fig. 3, 6 and 7, the base 10 is provided with a connection hole 101, the inner electrode 20 includes a first electrode portion 21 and a second electrode portion 22, the first electrode portion 21 is at least partially exposed from the surface of the base 10 to form a hemispherical structure 201, the second electrode portion 22 is connected to the first electrode portion 21, and the second electrode portion 22 is a column penetrating the connection hole 101.

That is, the first electrode portion 21 may include only the hemispherical structure 201, and the hemispherical structure 201 may be exposed from the surface of the base 10, or the first electrode portion 21 may include a portion not exposed from the surface of the base 10 in addition to the hemispherical structure 201, and the portion is embedded in the base 10, thereby enhancing the stability of the hemispherical structure 201.

The second electrode portion 22 is a column and is inserted into the connection hole 101 of the base 10, as shown in fig. 7, the connection hole 101 is a through hole, that is, the connection hole 101 penetrates through the top surface and the bottom surface of the base 10, on the basis that the second external electrode 32 described above is provided with the step hole 321 for accommodating the base 10, the end of the second electrode portion 22 can penetrate out of the connection hole 101 and extend to the second hole segment 3212 of the step hole 321, and in the second hole segment 3212, the second electrode portion 22 of the internal electrode 20 can be connected with the asymmetric high voltage generator 4 and the compensation voltage generator 5 by arranging a wire harness.

With continuing reference to fig. 3, 6 and 7, the bottom base 10 is provided with a sinking groove 102 on the surface thereof, the sinking groove 102 is communicated with the connecting hole 101, the first electrode portion 21 includes a hemispherical structure 201 and a mounting structure 202 connected to each other, wherein the hemispherical structure 201 is a portion exposed from the surface of the bottom base 10, and the mounting structure 202 is accommodated in the sinking groove 102.

The peripheral side surface of the fitting structure 202 may be a portion of a spherical surface having the same curvature as the surface of the hemispherical structure 201, or the peripheral side surface of the fitting structure 202 may be a cylindrical surface. The assembly structure 202 can be accommodated in a sunken groove 102 on the surface of the base 10, wherein the sunken groove 102 and the connecting hole 101 form a step surface at the connection position, the assembly structure 202 stops at the step surface, and the step surface can support and limit the assembly structure 202, so that the inner electrode 20 is relatively stable.

Based on the same technical concept, the embodiment of the invention further provides trace explosive detection equipment, which comprises an ionization device 2, and the ion migration device 1 and the ion detection device 3 in any one of the technical schemes, wherein the ionization device 2 is arranged at the air inlet 302 of the ion migration device 1, and the ion detection device 3 is arranged at the air outlet 303 of the ion migration device 1.

The functional block diagram of the trace explosive detection apparatus is shown in fig. 10, wherein some modules of air pump driving, flow rate detection, temperature detection, ion concentration detection and the like are omitted, the trace explosive detection apparatus can correspondingly complete three core links of generation, screening and detection of ion signals through an ionization device 2, an ion migration device 1 and an ion detection device 3, wherein the ionization device 2 can specifically ionize sample gas possibly containing explosives by using a corona technology, ion current formed after ionization enters the ion migration device 1, in the ion migration device 1, an ion migration channel 40 in a hemispherical crown shape is formed by an inner electrode 20 and an outer electrode 30, after the ion migration channel 40 enters, ions of different types are separated by mainly utilizing the characteristic that the mobility of ions of different types varies with the change of electric field strength under a high electric field, and only the ions conforming to a certain scanning voltage can reach the ion detection device 3 through the ion migration channel 40 without the combined action of a high-frequency asymmetric electric field and a direct-current scanning electric field, and other ions are collided with the inner electrode 20 or the outer electrode 30 and are compared with the ion current field intensity, so that the ion spectrum graph of the ions conforming to a known ion spectrum is obtained by comparing the same with the FAIMS, and if the FAS is determined based on the change of the high-frequency ion spectrum, the FAS, the detected ion spectrogram, and the detected ion spectrum, so that the detected ion spectrum is determined by comparing the FAS.

Moreover, based on the structural characteristics of the ion migration channel 40 in the shape of a hemispherical crown, the ion migration channel 40 has a good ion focusing effect, so that the ion separation capability is enhanced, the separated ions are concentrated, the detection of the subsequent ion detection device 3 is facilitated, and the sensitivity and the precision of the ion detection device 3 can be improved.

To verify the effectiveness of the trace explosive detection device in the case of an ion transport channel 40 having a hemispherical crown shape, the device was tested using the following experimental parameters:

(1) Asymmetric high voltage waveform Vs: vpp =6000V, f =167KHz;

(2) Compensation voltage sweep waveform Vc: the starting voltage is 0V, the ending voltage is 18V, and the triangular wave duration is 500ms;

(3) Air pump: the speed is 30mL/s, and the ion drift speed is 1m/s in a conversion mode;

(4) Corona module: the voltage is-4000V direct current, and the needle point is a carbon needle with the diameter of 0.07 mm;

(5) Test samples: trinitrotoluene (TNT), nitroglycerin (NG), taian (PETN), and hexogen (RDX), with 100NG samples taken for each of the four samples.

Fig. 11 to 15 show graphs of test results, in which, in fig. 11, a line graph is a scanning voltage waveform graph, and a graph is an ion signal waveform graph when the sample to be tested does not contain explosive ions; in fig. 12, a line graph is a scanning voltage waveform graph, a graph is an ion signal waveform graph when trinitrotoluene (TNT) is contained in a sample of a test object, in fig. 13, a line graph is a scanning voltage waveform graph, and a graph is an ion signal waveform graph when Nitroglycerin (NG) is contained in a sample of a test object; in FIG. 14, the line graph is a scanning voltage waveform, and the graph is a waveform of an ion signal when the sample to be measured contains tai-ampere (PETN); in fig. 15, a line graph is a scanning voltage waveform graph, and a graph is an ion signal waveform graph when hexogen (RDX) is contained in a sample of a measured object, and in fig. 11 to 15, the abscissa of the line graph is time, the ordinate is voltage, the abscissa of the line graph is time, and the ordinate is ion signal intensity.

From the test results, it can be seen that the sample molecules to be tested can be effectively ionized by corona ionization, and can be used with the ion migration channel 40 in the shape of a hemispherical crown. As the tested object samples used in the test are all 100ng magnitude and belong to the category of trace detection, the amplitude of the final signal is in the range of 200mV-300mV, which indicates that the focusing effect of the ion migration channel 40 in the shape of a hemisphere crown is good, no great loss of the tested object ions is caused, and the system can better realize the detection and identification of the explosive molecules.

Based on the same technical concept, the embodiment of the invention also provides an X-ray security inspection machine which comprises a security inspection machine body and trace explosive detection equipment, wherein the security inspection machine body is provided with a security inspection channel, and the trace explosive detection equipment is arranged on the security inspection machine body and faces the security inspection channel.

In the trace explosive detection equipment used by the X-ray security inspection machine, the ion migration device 1 is provided with the ion migration channel 40 in the shape of a hemispherical crown, the ion migration channel 40 in the shape of the hemispherical crown has a good focusing effect on ions, and the ion loss of a detected sample can be reduced, so that the detection and identification of explosive ions can be better realized, in addition, the ion migration channel 40 in the shape of the hemispherical crown has a smaller space volume, and is more beneficial to the overall miniaturization design, the volume of an original sensor can be reduced to 1/3, and the trace explosive detection equipment is applied to the X-ray security inspection machine, so that at least two defects of the existing trace explosive device are overcome, firstly, the focusing effect on ions of different types of substances is poor, so that the time difference of the ions of different types of substances reaching a receiving end is too close, and the curve waveform of the generated ion migration map is not obvious, and further the later comparison effect with the previously known FAIMS spectrograms of various explosives is influenced; secondly, the volume is too large, so that the X-ray safety inspection machine is inconvenient to install.

The X-ray security inspection machine applies the non-linear ion mobility spectrometry trace substance detection technology to the inspection of luggage associated articles, so that the X-ray security inspection machine can realize the traditional X-ray image detection of forbidden articles such as guns, cutters and the like, can also realize the trace detection of explosives on specific suspicious substances in the luggage, realizes one-time luggage passing and multiple detections, and has important value in the places such as airports, customs, anti-terrorism departments and the like.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims (10)

1. An ion migration device is characterized by comprising a base, an inner electrode and an outer electrode;

the inner electrode is embedded in the base, and the part of the inner electrode exposed out of the base is of a hemispherical structure;

the outer electrode is arranged on the periphery of the base and is provided with a cavity of a hemispherical structure for accommodating the inner electrode, and a gap between the inner wall of the cavity and the outer wall of the hemispherical structure forms an ion migration channel in a hemispherical crown shape;

the outer electrode is provided with an air inlet and an air outlet, an air inlet channel is arranged between the air inlet and the ion migration channel, and an air outlet channel is arranged between the air outlet and the ion migration channel.

2. The ion transfer arrangement of claim 1, wherein the inlet channel and the outlet channel are symmetrically disposed on either side of the inner electrode and both extend in a radial direction of the hemispherical structure of the inner electrode.

3. The ion transfer device of claim 1, wherein the outer electrodes comprise a first outer electrode and a second outer electrode, the first outer electrode is disposed on top of the base, and the first outer electrode has the cavity;

the second outer electrode is connected with the first outer electrode and arranged around the base along the circumferential direction.

4. The ion transfer assembly of claim 3, wherein a surface of the first outer electrode facing the second outer electrode is provided with a first groove, a surface of the second outer electrode facing the first outer electrode is provided with a second groove, and the base surface is provided with a third groove connecting the second groove and extending toward the inner electrode, the first groove, the second groove, and the third groove forming the inlet channel and the outlet channel on both sides of the inner electrode.

5. The ion transfer assembly of claim 3, wherein the second outer electrode has a stepped bore, the stepped bore comprising a first bore section and a second bore section sequentially arranged in a direction away from the first outer electrode, the first bore section having a larger bore diameter than the second bore section, the base being at least partially located within the stepped bore and stopping at a step surface at a connection location of the first bore section and the second bore section;

the connecting end of the inner electrode penetrates out of the base.

6. The ion transfer unit of any one of claims 1 to 5, wherein the base is provided with a connection hole, the inner electrode comprises a first electrode portion and a second electrode portion, the first electrode portion is at least partially exposed from the surface of the base to form the hemispherical structure, the second electrode portion is connected to the first electrode portion, and the second electrode portion is a column penetrating the connection hole.

7. The ion transfer device of claim 6, wherein the base surface is provided with a sink groove communicating with the connection hole, and the first electrode portion includes the hemispherical structure and a fitting structure connected, wherein the hemispherical structure is a portion exposed from the base surface, and the fitting structure is received in the sink groove.

8. The ion transfer arrangement of any of claims 1 to 5, wherein an arcuate transition region is provided at an end of the inlet and outlet channels adjacent the inner electrode.

9. A trace explosive detection apparatus, comprising an ionization device, an ion transfer device according to any one of claims 1 to 8, and an ion detection device, wherein the ionization device is disposed at an air inlet of the ion transfer device, and the ion detection device is disposed at an air outlet of the ion transfer device.

10. An X-ray security inspection machine comprising a security inspection machine body having a security inspection passageway and the trace explosive detection device of claim 9, disposed on the security inspection machine body and directed toward the security inspection passageway.

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