A vacuum cavity detector

Abstract

The present invention relates to the field of neutron detection technology, and specifically discloses a vacuum chamber detector, which includes a vacuum chamber, a detection mechanism, and a drive mechanism. Neutrons are injected from a neutron inlet and then emitted from a neutron outlet. During this process, the drive mechanism drives two detection mechanisms to move radially along the neutron inlet, thereby causing the detection ends of the two detectors to face the neutron inlet respectively. The detection ends of the detectors can then detect the beam intensity and beam spot size of the neutron beam injected from the neutron inlet. During this process, when the drive mechanism drives the two detection mechanisms to move together, one detection mechanism is subjected to a tensile force within the accommodating chamber, while the other detection mechanism is subjected to a compressive force within the accommodating chamber. The two forces are equal in magnitude and opposite in direction and cancel each other out, thereby not causing a pulling force on the drive mechanism, making the drive mechanism more stable.

Description

Technical Field

[0001] The present invention relates to the technical field of neutron detection, and in particular to a vacuum cavity detector. Background Art

[0002] Small-angle neutron scattering is an experimental platform that uses a strictly collimated neutron beam to study the internal microscopic structure (1 nanometer to hundreds of nanometers) of matter. It has a wide range of applications in new drug development, new energy, new materials, etc.

[0003] Two neutron beam monitors are installed in the incident light path of the small-angle neutron scattering spectrometer (SANS) near the sample to measure and calibrate the incident neutron beam intensity or spot size. After the measurements are completed, the beam monitors need to be moved out of the beam center. Furthermore, to reduce air spurious neutrons, a sample vacuum chamber is typically placed in the neutron incident light path before the sample. The neutron detectors must be placed within this chamber. Since neutron detectors typically operate at voltages exceeding 1,000 volts, and high voltages can easily spark in a vacuum, the detectors' electrical connectors cannot operate in a vacuum environment. These connectors must be connected to the atmosphere outside the vacuum chamber through connectors such as bellows. The main detector body remains in the vacuum environment, and since the detectors' electrical connectors are relatively large, they require large bellows for connection. Moving the detectors in and out of the neutron beam path requires a motorized mechanism. Due to the vacuum pressure within the bellows, a motor with high torque is required to move the detectors.

[0004] In the prior art, detector switching structures that can be used in a vacuum primarily use a motor to directly drive the detector connected to a long rod to lift or move horizontally. The motor and drive mechanism are located outside the vacuum chamber, and the long rod connects to the detector inside the vacuum chamber. The motion is transmitted to the vacuum chamber through a bellows and the long rod. The bellows acts to isolate the vacuum and transmit the motion. For example, a sample changer for a white-light neutron source charged particle detection spectrometer, published as CN109459457A, uses a motor to directly drive the bellows to move up and down. However, the bellows is subject to high vacuum pressure, requiring a large torque to lift the detector upward. However, when moving the detector downward, the vacuum force pulls the detector downward, which can easily cause the motor to lose steps, leading to damage. Summary of the Invention

[0005] The purpose of the present invention is to provide a vacuum chamber detector to solve the problem in the related art that since the driving mechanism of the detector is usually arranged outside the vacuum chamber, when the detection mechanism is located in the vacuum chamber, the detection mechanism will be affected by the pull or pressure in the vacuum chamber, which may easily cause damage to the driving mechanism.

[0006] The present invention provides a vacuum cavity detector, which includes:

[0007] A vacuum chamber, wherein the vacuum chamber is provided with a receiving chamber and a neutron inlet and a neutron outlet communicating with the receiving chamber, the neutron inlet and the neutron outlet are coaxially arranged, and the vacuum chamber is provided with a detection hole along the radial direction of the neutron inlet;

[0008] a detection mechanism, the detection mechanism being slidably disposed in the detection hole and being sealed with the detection hole, the detection mechanism comprising a detector, a detection end of the detector being located in the accommodating cavity, and a connection end of the detector being located outside the accommodating cavity;

[0009] There are two detection holes, the axes of the two detection holes are located in a plane where the axis of the neutron inlet is located, and there are two detection mechanisms, the two detection mechanisms correspond to the two detection holes one by one;

[0010] The driving mechanism is arranged in the accommodating cavity and simultaneously drives the two detection mechanisms in the same direction to have two states of sliding relative to the vacuum cavity and being fixed relative to the vacuum cavity.

[0011] As an optimal technical solution for the vacuum chamber detector, the detection mechanism also includes an electrical cavity and a sealing tube group. The electrical cavity is penetrated through the corresponding detection hole and slides with the corresponding hole wall of the detection hole. The electrical cavity is provided with an installation cavity and a first hole and a second hole connected to the installation cavity along the axis of the detection hole. The first hole is located in the accommodating cavity, and the second hole is located outside the accommodating cavity. The wiring terminal of the detector extends into the first hole, and the detector is sealed and connected to the hole wall of the first hole. The detection end of the detector is arranged along the radial direction of the neutron inlet. The sealing tube group is sleeved on the part of the electrical cavity located outside the vacuum cavity. One end of the sealing tube group is sealed and connected to the outer wall of the vacuum cavity, and the other end of the sealing tube group is sealed and connected to the second hole. The sealing tube group is retractable along the sliding direction of the electrical cavity.

[0012] As an optimal technical solution for the vacuum cavity detector, the sealing tube group includes a sealing tube and a bellows. The sealing tube is sleeved on the portion of the electrical cavity located outside the accommodating cavity. The end of the sealing tube close to the vacuum cavity is sealed and connected to the vacuum cavity. The second hole is sealed and connected to one end of the bellows, and the other end of the bellows is sealed and connected to the end of the sealing tube away from the vacuum cavity.

[0013] As a preferred technical solution of the vacuum chamber detector, the detection mechanism further includes a threading tube, one end of which is passed through the bellows and fixedly connected to the inner wall of the second hole.

[0014] As an optimal technical solution for the vacuum cavity detector, the driving mechanism includes a driving assembly and a slide. The slide is fixedly connected to the two electrical cavities at the same time. The driving assembly drives the slide to slide along the axial direction of the detection hole.

[0015] As an optimal technical solution for the vacuum chamber detector, the driving mechanism also includes a fixed plate, which is fixed to the inner wall of the vacuum chamber. One of the fixed plate and the slide is provided with a slide rail, and the other is provided with a slide groove, and the slide rail and the slide groove are slidably matched.

[0016] As an optimal technical solution for the vacuum chamber detector, the driving assembly includes a driver, a screw and a nut, the nut is fixedly connected to the slide, the driver is fixed to the fixed plate, the screw is threadedly connected to the nut, and the driver drives the screw to rotate.

[0017] As an optimal technical solution for the vacuum cavity detector, the driver is a vacuum stepping motor.

[0018] As a preferred technical solution for the vacuum cavity detector, the slide plate is fixedly provided with a grating ruler, and the fixed plate is fixedly provided with a reading head, and the reading head is opposite to the grating ruler.

[0019] As an optimal technical solution for the vacuum cavity detector, it also includes two beam tubes, which are respectively coaxial with the neutron inlet and are arranged at intervals along the axis of the neutron inlet on the inner wall of the vacuum cavity. When the detection end of the detector is opposite to the neutron inlet, the detection end of the detector is located between the two beam tubes.

[0020] The beneficial effects of the present invention are:

[0021] The present invention provides a vacuum cavity detector, which includes a vacuum cavity, a detection mechanism and a driving mechanism. The vacuum cavity is provided with a accommodating cavity and a neutron inlet and a neutron outlet connected to the accommodating cavity, the neutron inlet and the neutron outlet are coaxially arranged, and the vacuum cavity is provided with a detection hole along the radial direction of the neutron inlet; the detection mechanism is slidably arranged in the detection hole and is sealed with the detection hole, the detection mechanism includes a detector, the detection end of the detector is located in the accommodating cavity, and the connection end of the detector is located outside the accommodating cavity; there are two detection holes, the axes of the two detection holes are both located in a plane where the axis of the neutron inlet is located, there are two detection mechanisms, and the two detection mechanisms correspond one to one to the two detection holes; the driving mechanism is arranged in the accommodating cavity and simultaneously drives the two detection mechanisms in the same direction to have two states of sliding relative to the vacuum cavity and being fixed relative to the vacuum cavity. When the vacuum chamber detector is in operation, neutrons enter through the neutron inlet and are then emitted through the neutron outlet. During this process, the driving mechanism drives the two detection mechanisms to move radially along the neutron inlet, thereby causing the detection ends of the two detectors to face the neutron inlet, so that the detection ends of the detectors can detect the beam intensity and beam spot size of the neutron beam entering through the neutron inlet. When the detectors complete detection, the driving mechanism drives the two detection mechanisms to move radially along the neutron inlet, thereby causing the detection ends of the detectors to move away from the neutron beam. During this process, the connection terminals of the detectors are always located outside the accommodating chamber, thereby avoiding the problem of electric sparks that are easily generated when the connection terminals of the detectors are arranged in a vacuum environment. Because the driving mechanism is located within the accommodating chamber, when the driving mechanism drives the two detection mechanisms to move together, one detection mechanism is subjected to a tensile force within the accommodating chamber, while the other detector is subjected to a compressive force within the accommodating chamber. The two forces are equal in magnitude and opposite in direction and cancel each other out, thereby preventing any pulling force on the driving mechanism and making the driving mechanism more stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the structure of a vacuum cavity detector in an embodiment of the present invention;

[0023] Figure 2 for Figure 1 Cross-sectional view at AA in the middle;

[0024] Figure 3 for Figure 2 Cross-sectional view at the middle BB;

[0025] Figure 4 Schematic diagram of the structure of the drive mechanism, detector and electrical cavity in the embodiment of the present invention Figure 1 ;

[0026] Figure 5 Schematic diagram of the structure of the drive mechanism, detector and electrical cavity in the embodiment of the present invention Figure 2 ;

[0027] Figure 6for Figure 5 sectional view of .

[0028] In the picture:

[0029] 1. Vacuum chamber; 11. Accommodation chamber; 12. Neutron inlet; 13. Neutron outlet;

[0030] 2. Detection mechanism; 21. Detector; 22. Electrical cavity; 221. Mounting cavity; 231. Sealing tube; 232. Bellows; 24. Threading tube;

[0031] 3. Driving mechanism; 311. Driver; 312. Screw; 313. Nut; 32. Slide plate; 33. Fixing plate;

[0032] 4. Beam tube. DETAILED DESCRIPTION

[0033] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0034] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions, and the first feature being "above", "above" and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature includes the first feature being directly below and obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0035] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0036] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0037] like Figures 1 to 6As shown, this embodiment provides a vacuum chamber detector, which includes a vacuum chamber 1, a detection mechanism 2 and a driving mechanism 3. The vacuum chamber 1 is provided with a accommodating chamber 11 and a neutron inlet 12 and a neutron outlet 13 connected to the accommodating chamber 11. The neutron inlet 12 and the neutron outlet 13 are coaxially arranged, and the vacuum chamber 1 is provided with a detection hole along the radial direction of the neutron inlet 12; the detection mechanism 2 is slidably arranged in the detection hole and is sealed with the detection hole, the detection mechanism 2 includes a detector 21, the detection end of the detector 21 is located in the accommodating chamber 11, and the connection end of the detector 21 is located outside the accommodating chamber 11; there are two detection holes, the axes of the two detection holes are both located in a plane where the axis of the neutron inlet 12 is located, there are two detection mechanisms 2, and the two detection mechanisms 2 correspond one to one to the two detection holes; the driving mechanism 3 is arranged in the accommodating chamber 11 and simultaneously drives the two detection mechanisms 2 in the same direction to have two states of sliding relative to the vacuum chamber 1 and being fixed relative to the vacuum chamber 1. When the vacuum chamber detector is working, neutrons are injected from the neutron inlet 12 and then emitted from the neutron outlet 13. During this process, the driving mechanism 3 drives the two detection mechanisms 2 to move radially along the neutron inlet 12, so that the detection ends of the two detectors 21 are respectively opposite to the neutron inlet 12, and then the detection ends of the detectors 21 can detect the beam intensity and beam spot size of the neutron beam injected from the neutron inlet 12. When the detection of the detector 21 is completed, the driving mechanism 3 drives the two detection mechanisms 2 to move radially along the neutron inlet 12, so that the detection ends of the detectors 21 are away from the neutron beam. During this process, the connection terminal of the detector 21 is always located outside the accommodating cavity 11, thereby avoiding the problem of electric sparks that are prone to occur when the connection terminal of the detector 21 is set in a vacuum environment. Since the driving mechanism 3 is located in the accommodating cavity 11, when the driving mechanism 3 drives the two detection mechanisms 2 to move together, one detection mechanism 2 is subjected to tension in the accommodating cavity 11, and the other detector 21 is subjected to pressure in the accommodating cavity 11. The two forces are equal in magnitude and opposite in direction and cancel each other out, and thus will not cause pulling force on the driving mechanism 3, making the driving mechanism 3 work more stably.

[0038] Optionally, the detection mechanism 2 also includes an electrical cavity 22 and a sealing tube group. The electrical cavity 22 is penetrated into the corresponding detection hole and slides with the hole wall of the corresponding detection hole. The electrical cavity 22 is provided with an installation cavity 221 and a first hole and a second hole connected to the installation cavity 221 along the axis of the detection hole. The first hole is located in the accommodating cavity 11, and the second hole is located outside the accommodating cavity 11. The wiring terminal of the detector 21 extends into the first hole, and the detector 21 is sealed and connected to the hole wall of the first hole. The detection end of the detector 21 is arranged along the radial direction of the neutron inlet 12. The sealing tube group is sleeved on the part of the electrical cavity 22 located outside the vacuum cavity 1. One end of the sealing tube group is sealed and connected to the outer wall of the vacuum cavity 1, and the other end of the sealing tube group is sealed and connected to the second hole. The sealing tube group is retractable along the sliding direction of the electrical cavity 22. In this embodiment, one end of the detector 21 is the detection portion, and the other end of the detector 21 is the wiring portion. An annular flange is protruded from the peripheral wall of the middle position of the detector 21. The annular flange is screwed to the electrical cavity 22 by bolts. To ensure that the detector 21 is sealed to the first hole, a sealing ring is provided between the annular flange and the electrical cavity 22. One end of the sealing tube assembly is sealed to the vacuum cavity 1 via a flange, and the other end of the sealing tube assembly is sealed to the second hole via a flange. This arrangement can maintain a sealed fit between the vacuum cavity 1 and the detection mechanism 2. Since the sealing tube assembly is elastic, it will not interfere with the sliding of the electrical cavity 22 relative to the vacuum cavity 1.

[0039] Optionally, the sealing tube assembly includes a sealing tube 231 and a bellows 232. The sealing tube 231 is sleeved on the portion of the electrical cavity 22 located outside the accommodating cavity 11. The end of the sealing tube 231 close to the vacuum cavity 1 is sealedly connected to the vacuum cavity 1. The second hole is sealedly connected to one end of the bellows 232. The other end of the bellows 232 is sealedly connected to the end of the sealing tube 231 away from the vacuum cavity 1. In this embodiment, since the bellows 232 is elastic, when the bellows 232 is sealedly connected to the electrical cavity 22, the bellows 232 will not interfere with the sliding of the electrical cavity 22 relative to the vacuum cavity 1. Specifically, the sealing tube 231 is a two-stage stepped tube, and the diameter of the portion close to the vacuum cavity 1 is larger than the diameter of the portion away from the vacuum cavity 1. Therefore, when the electrical cavity 22 slides out of the vacuum cavity 1, the electrical cavity 22 can slide to the sealing tube 231 close to the vacuum cavity 1.

[0040] Optionally, the detection mechanism 2 further includes a wire tube 24, one end of which is passed through the corrugated tube 232 and fixedly connected to the inner wall of the second hole. In this embodiment, the connection line extends into the electrical cavity 22 through the wire tube 24, and is then electrically connected to the terminal of the detector 21 located in the electrical cavity 22.

[0041] Optionally, the drive mechanism 3 includes a drive assembly and a slide 32. The slide 32 is fixedly connected to both electrical cavities 22. The drive assembly drives the slide 32 to slide along the axis of the detection hole. In this embodiment, the slide 32 is located between the two electrical cavities 22 and is fixedly connected to the two electrical cavities 22 by bolts.

[0042] Optionally, the drive mechanism 3 further includes a fixed plate 33, which is fixed to the inner wall of the vacuum chamber 1. The fixed plate 33 and the slide plate 32 are provided with a slide rail on one side and a slide groove on the other side, and the slide rails and the slide grooves slidably engage with each other. In this embodiment, the fixed plate 33 is fixed to the inner wall of the vacuum chamber 1 by bolts. The fixed plate 33 is provided with two slide rails at intervals along the sliding direction of the slide plate 32. The slide plate 32 is provided with two slide grooves at intervals, and the two slide grooves correspond to the two slide rails one-to-one and slidably engage with each other.

[0043] Optionally, the drive assembly includes a driver 311, a lead screw 312, and a nut 313. The nut 313 is fixedly connected to the slide 32. The driver 311 is fixed to the fixed plate 33. The lead screw 312 is threadedly connected to the nut 313. The driver 311 drives the lead screw 312 to rotate. In this embodiment, one end of the lead screw 312 is rotatably engaged with the slide 32 via a bearing, and the other end of the lead screw 312 is coaxially fixedly connected to the output end of the driver 311. Specifically, the driver 311 is a vacuum stepping motor.

[0044] Optionally, the slide 32 is fixed with a grating ruler, and the fixed plate 33 is fixed with a reading head, which is opposite to the grating ruler. In this embodiment, the reading head can read the position of the grating ruler, thereby determining the sliding position of the slide 32 and the respective positions of the detection parts of the two detectors 21.

[0045] Optionally, the vacuum chamber detector further includes two beam tubes 4, each coaxial with the neutron inlet 12 and spaced apart on the inner wall of the vacuum chamber 1 along the axis of the neutron inlet 12. When the detection end of the detector 21 faces the neutron inlet 12, the detection end of the detector 21 is located between the two beam tubes 4. In this embodiment, the beam tubes 4 function to reduce neutron stray light.

[0046] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A vacuum cavity detector, characterized in that: include: A vacuum cavity (1), the vacuum cavity (1) being provided with a receiving cavity (11) and a neutron inlet (12) and a neutron outlet (13) communicating with the receiving cavity (11), the neutron inlet (12) and the neutron outlet (13) being coaxially arranged, and the vacuum cavity (1) being provided with a detection hole along the radial direction of the neutron inlet (12); a detection mechanism (2), the detection mechanism (2) being slidably disposed in the detection hole and being sealedly connected to the detection hole, the detection mechanism (2) comprising a detector (21), a detection end of the detector (21) being located in the accommodating cavity (11), and a connection end of the detector (21) being located outside the accommodating cavity (11); There are two detection holes, the axes of the two detection holes are both located in a plane where the axis of the neutron inlet (12) is located, and there are two detection mechanisms (2), the two detection mechanisms (2) correspond one to one with the two detection holes; A driving mechanism (3), the driving mechanism (3) being arranged in the accommodating cavity (11) and simultaneously driving the two detection mechanisms (2) in the same direction to have two states: sliding relative to the vacuum cavity (1) and being fixed relative to the vacuum cavity (1); The detection mechanism (2) further comprises an electrical cavity (22) and a sealing tube group, wherein the electrical cavity (22) is provided in the corresponding detection hole and is slidably matched with the hole wall of the corresponding detection hole, the electrical cavity (22) is provided with a mounting cavity (221) and a first hole and a second hole connected to the mounting cavity (221) along the axis of the detection hole, the first hole being located in the accommodating cavity (11), the second hole being located outside the accommodating cavity (11), the wiring terminal of the detector (21) extending into the first hole, the detector (21) being sealedly connected to the hole wall of the first hole, the detection end of the detector (21) being arranged along the radial direction of the neutron inlet (12), the sealing tube group being sleeved on the portion of the electrical cavity (22) located outside the vacuum cavity (1), one end of the sealing tube group being sealedly connected to the outer wall of the vacuum cavity (1), the other end of the sealing tube group being sealedly connected to the second hole, and the sealing tube group being retractable along the sliding direction of the electrical cavity (22).

2. The vacuum chamber detector according to claim 1, characterized in that: The sealing tube assembly comprises a sealing tube (231) and a bellows (232), wherein the sealing tube (231) is sleeved on a portion of the electrical cavity (22) located outside the accommodating cavity (11), one end of the sealing tube (231) close to the vacuum cavity (1) is sealedly connected to the vacuum cavity (1), the second hole is sealedly connected to one end of the bellows (232), and the other end of the bellows (232) is sealedly connected to one end of the sealing tube (231) away from the vacuum cavity (1).

3. The vacuum chamber detector according to claim 2, characterized in that: The detection mechanism (2) further comprises a threading tube (24), one end of which is passed through the corrugated tube (232) and fixedly connected to the inner wall of the second hole.

4. The vacuum chamber detector according to claim 1, wherein: The driving mechanism (3) comprises a driving assembly and a slide plate (32), wherein the slide plate (32) is fixedly connected to the two electrical cavities (22) at the same time, and the driving assembly drives the slide plate (32) to slide along the axial direction of the detection hole.

5. The vacuum chamber detector according to claim 4, characterized in that: The driving mechanism (3) further comprises a fixed plate (33), wherein the fixed plate (33) is fixed to the inner wall of the vacuum chamber (1), and one of the fixed plate (33) and the slide plate (32) is provided with a slide rail, and the other is provided with a slide groove, and the slide rail and the slide groove are slidably matched.

6. The vacuum chamber detector according to claim 5, characterized in that: The driving assembly comprises a driver (311), a lead screw (312) and a nut (313), wherein the nut (313) is fixedly connected to the slide plate (32), the driver (311) is fixedly arranged on the fixed plate (33), the lead screw (312) is threadedly connected to the nut (313), and the driver (311) drives the lead screw (312) to rotate.

7. The vacuum chamber detector according to claim 6, characterized in that: The driver (311) is a vacuum stepping motor.

8. The vacuum chamber detector according to claim 5, characterized in that: The slide plate (32) is fixedly provided with a grating ruler, and the fixed plate (33) is fixedly provided with a reading head, and the reading head is opposite to the grating ruler.

9. The vacuum chamber detector according to any one of claims 1 to 8, characterized in that: The invention also includes two beam tubes (4), the two beam tubes (4) are respectively coaxial with the neutron inlet (12) and are arranged at intervals on the inner wall of the vacuum chamber (1) along the axis of the neutron inlet (12); when the detection end of the detector (21) is opposite to the neutron inlet (12), the detection end of the detector (21) is located between the two beam tubes (4).

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