Position-sensitive time-of-flight detector and method of using the same

Abstract

The present invention relates to the field of nuclear physics, particle physics, and nuclear astrophysics experimental technology, and in particular to a position-sensitive time-of-flight detector and a method for using the same. The time-of-flight detector comprises: a detector field cage, provided with an emission film for generating secondary electrons and a high-voltage wire mesh for providing the electric field required for guiding the secondary electrons; a delay line readout plate, arranged above the emission film in parallel and at intervals; and a conical anode readout, arranged below the emission film in parallel and at intervals; wherein the delay line readout plate and the conical anode readout are each provided with an MCP component on the side facing the emission film; the MCP component cooperates with the delay line readout plate to provide position information, and the MCP component cooperates with the conical anode readout to provide time information. The time-of-flight detector combines a position readout part and a time readout part, which can independently optimize time resolution and position resolution while making the structure compact.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear physics, particle physics and nuclear astrophysics experiments, and in particular to a position-sensitive time-of-flight detector and a method for using the same. Background Art

[0002] Time-of-flight measurements are widely used in experiments such as nuclear physics, particle physics, and nuclear astrophysics. In the mass measurement of nuclear fission fragments, the mass resolution can be indirectly measured according to the following formula:

[0003]

[0004] In this formula, M is the particle mass, E is the particle energy, t is the particle flight time, and l is the length of the particle trajectory. δ represents the uncertainty of a quantity. , which represents the relative uncertainty of mass and is used to quantify the accuracy of mass measurement. , represents the relative uncertainty of energy and is used to quantify the accuracy of energy measurement. , represents the relative uncertainty of time and is used to quantify the accuracy of time measurement. , represents the relative uncertainty of length and is used to quantify the accuracy of length measurement.

[0005] According to this formula, mass resolution is related to energy resolution, time resolution, and position resolution. Improving the time resolution and position resolution of a time-of-flight detector can improve mass resolution.

[0006] In existing technology, a parallel plate avalanche counter (PPAC) is commonly used as a time-of-flight detector to measure the mass of nuclear fission fragments. Because the PPAC is based on the principle of gas amplification, in addition to the equivalent thickness introduced by the PPAC itself, the metal film window and air gap introduced by the vacuum must also be considered. Therefore, the energy loss caused by these intermediate materials to the target isotope increases the energy dispersion of the beam, thereby reducing the energy resolution of the system. Furthermore, according to the above formula, reduced energy resolution will reduce mass resolution. Furthermore, due to the unreasonable structural design of the commonly used microchannel plate (MCP) time-of-flight detector, the position resolution is greater than 1mm (FWHM) and the time resolution is greater than 1ns.

[0007] Therefore, there is an urgent need for a time-of-flight detector that can achieve high energy resolution, high time resolution, and high position resolution. Summary of the Invention

[0008] The present invention aims to address at least one of the technical problems existing in the related art. To this end, the present invention proposes a position-sensitive time-of-flight detector and its use method to address the problems of existing time-of-flight detectors, such as large beam energy loss, low position and time resolution, and inability to meet the requirements for nuclear mass measurement and energy spread measurement of low- and medium-energy heavy ion beams.

[0009] In a first aspect, the present invention provides a position-sensitive time-of-flight detector, the time-of-flight detector comprising:

[0010] A detector field cage is provided with an emission film for generating secondary electrons and a high-voltage wire mesh for providing an electric field required for guiding the secondary electrons;

[0011] a delay line readout board, arranged in parallel and spaced apart above the detector field cage;

[0012] a conical anode readout disposed in parallel and spaced apart below the detector field cage;

[0013] Wherein, the delay line readout plate and the tapered anode readout are each provided with an MCP component on a side facing the emitter film;

[0014] The MCP assembly cooperates with the delay line readout plate to provide position information of particles, and the MCP assembly cooperates with the conical anode readout to provide time information of particles.

[0015] According to a position-sensitive time-of-flight detector provided by the present invention, the MCP assembly is adapted for the tapered anode readout and comprises: an MCP upper electrode, an MCP middle partition, an MCP, an MCP middle electrode, an MCP, an MCP lower electrode, and an MCP voltage divider circuit board, which are sequentially placed from top to bottom;

[0016] When the MCP assembly is adapted to the delay line readout board, it includes: an MCP upper electrode, an MCP middle partition, an MCP, an MCP middle electrode, an MCP, an MCP lower electrode and an MCP voltage divider circuit board, which are placed in sequence from bottom to top.

[0017] According to a position-sensitive time-of-flight detector provided by the present invention, the MCP voltage divider circuit board is provided with a resistor for providing bias voltage to the MCP, and the resistor is connected to the MCP upper electrode, the MCP middle electrode and the MCP lower electrode.

[0018] According to a position-sensitive time-of-flight detector provided by the present invention, the detector field cage comprises: the high-voltage wire mesh is composed of a plurality of gold-plated tungsten wires arranged in two mutually perpendicular directions, and two high-voltage wire meshes are respectively stacked on both sides of the emission film;

[0019] The detector field cage further comprises:

[0020] A partition is provided between the high-voltage wire mesh and the emission film;

[0021] A support assembly vertically penetrates the emission film, the high-voltage wire mesh and the partition and presses them tightly together. The upper end of the support assembly is connected to the delay line readout plate, and the lower end of the support assembly is connected to the conical anode readout.

[0022] According to a position-sensitive time-of-flight detector provided by the present invention, the emission film is a polyester double-sided aluminum-plated film, wherein the polyester film is 0.5 μm thick and the single-sided aluminum-plated film is 0.1 μm thick.

[0023] According to a position-sensitive time-of-flight detector provided by the present invention, the support assembly includes:

[0024] A first stud, both ends of which are set as male plugs, and one end of the first stud is connected to the tapered anode readout, and the other end of the first stud is connected to and protrudes from one side of the high-voltage wire mesh;

[0025] A second stud, one end of which is configured as a female head and connected to a male head of the first stud that passes through and protrudes from the high-voltage wire mesh, and the other end of which is configured as a male head connected to the delay line readout board.

[0026] According to a position-sensitive time-of-flight detector provided by the present invention, the tapered anode readout comprises:

[0027] A conical anode, wherein the large-section end of the conical anode is connected to the MCP assembly, and the small-section end of the conical anode extends downward from the MCP assembly;

[0028] A housing, which is disposed outside the conical anode and is connected to the MCP assembly;

[0029] An SMA feedthrough mounted on the housing;

[0030] Lead-out pins connect the tapered anode and the SMA feedthrough.

[0031] According to the position-sensitive time-of-flight detector provided by the present invention, the impedance of the tapered anode and the SMA feedthrough are both 50Ω.

[0032] A position-sensitive time-of-flight detector provided by the present invention further includes a detector bracket connected to the housing, which is used to fix the emission film, the delay line readout plate and the MCP assembly at a 45° tilt relative to the horizontal plane.

[0033] In a second aspect, the present invention further provides a method for using a time-of-flight detector, which is applied to any of the position-sensitive time-of-flight detectors described above.

[0034] S1. In a high vacuum environment, arrange an experimental target, a first time-of-flight detector, and a second time-of-flight detector in sequence, setting the experimental target and the emitting film of the first time-of-flight detector and the emitting film of the second time-of-flight detector parallel to each other, and making the center of the emitting film coincide with the center of the experimental target on the same straight line;

[0035] S2, making the beam incident on the experimental target from the upper side of the experimental target in a vertical direction;

[0036] S3. Set the beam intensity to less than 1E5pps and the beam structure to be uniform.

[0037] The above one or more technical solutions in the present invention have at least one of the following technical effects:

[0038] 1. By arranging the position readout part and the time readout part on both sides of the emission film, the structure of the time-of-flight detector is compact, the installation and maintenance are simple and reliable, and it can be widely used in the fields of nuclear physics, particle physics and nuclear astrophysics experiments.

[0039] 2. The position readout part and the time readout part are set on both sides of the emitting film through the detector field cage, introducing a two-sided readout method of the emitting film, and at the same time enabling the time-of-flight detector to have high time resolution and high position resolution.

[0040] 3. The advantage of the small thickness of the emission film is fully utilized, which greatly reduces the interference to the beam and improves the energy resolution of the time-of-flight detector.

[0041] In addition to the technical problems solved by the present invention, the technical features of the technical solutions constituted, and the advantages brought about by the technical features of these technical solutions described above, other technical features of the present invention and the advantages brought about by these technical features will be further explained in conjunction with the accompanying drawings, or can be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0043] Figure 1 A schematic diagram of the three-dimensional structure of a time-of-flight detector provided in an embodiment of the present invention.

[0044] Figure 2 This is a cross-sectional structural diagram of a time-of-flight detector provided by an embodiment of the present invention along the longitudinal symmetry plane.

[0045] Figure 3 A schematic diagram of the layout of a time-of-flight detector provided by an embodiment of the present invention when in use.

[0046] Figure 4 Schematic diagram of the layout of the time-of-flight detector in the present invention when calibrating the position resolution.

[0047] Figure 5 for Figure 4 Cross-sectional structural diagram of each device along the longitudinal symmetry plane.

[0048] Figure 6 Schematic diagram of the layout of the time-of-flight detector in the present invention when calibrating the time resolution.

[0049] Figure 7 for Figure 6 Cross-sectional structural diagram of each device along the longitudinal symmetry plane.

[0050] Reference numerals:

[0051] 100, detector field cage; 110, emission film; 120, high-voltage wire mesh; 130, partition; 140, support assembly; 141, first stud; 142, second stud; 200, MCP assembly; 210, MCP upper electrode; 220, MCP middle partition; 230, MCP; 240, MCP middle electrode; 250, MCP lower electrode; 260, MCP voltage divider circuit board; 300, conical anode readout; 310, conical anode; 320, housing; 330, SMA feedthrough; 340, lead pin; 350, insulating support; 400, delay line readout board; 500, detector bracket. DETAILED DESCRIPTION

[0052] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0053] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0054] In the description of the embodiments of the present invention, it should be noted that, unless otherwise specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; and direct connections or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the embodiments of the present invention based on the specific circumstances.

[0055] In the embodiments of the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, a first feature being "above," "above," and "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is at a higher level than the second feature. A first feature being "below," "below," and "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0056] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiments of the present invention. In this specification, the schematic representations of the above terms are not limited to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0057] In the present invention, time of flight measurement is a technology for analyzing the characteristics of charged particles by detecting the time required for charged particles to travel a specific distance in nuclear physics and particle physics experiments, and is used to determine the mass, velocity and energy of the particles.

[0058] A microchannel plate (MCP) is a two-dimensional electron multiplier composed of numerous tiny channels arranged parallel and perpendicular to the plate's surface. When charged particles, photons, or other forms of energy enter these tiny channels, they trigger a series of secondary electron emissions, generating very large current gains. MCPs are widely used in various instruments requiring high-sensitivity detection.

[0059] FWHM (Full Width at Half Maximum) is usually used to describe the width of a function, spectrum line, or signal peak. It is an important parameter for evaluating signal clarity or resolution.

[0060] In an embodiment of the present invention, a position-sensitive time-of-flight detector is introduced to solve the problem that existing time-of-flight detectors are difficult to provide high energy resolution, high time resolution, and high position resolution simultaneously.

[0061] like Figure 1 and Figure 2 As shown, the time-of-flight detector mainly includes: a detector field cage 100 , a delay line readout plate 400 , a conical anode readout 300 and an MCP assembly 200 .

[0062] The detector cage 100 is equipped with an emission film 110 for generating secondary electrons and a high-voltage wire mesh 120 for providing the electric field required to guide the secondary electrons. Delay line readout plates 400 are arranged in parallel and spaced apart above the detector cage 100. Conical anode readout plates 300 are arranged in parallel and spaced apart below the detector cage 100.

[0063] The delay line readout board 400 and the tapered anode readout board 300 are each provided with an MCP assembly 200 on the side facing the emitter film 110. The MCP assembly 200 cooperates with the delay line readout board 400 to provide particle position information. The MCP assembly 200 cooperates with the tapered anode readout board 300 to provide particle timing information.

[0064] like Figure 2As shown, the position readout section is comprised of the emitter film 110, high-voltage screen 120, MCP assembly 200, and delay line readout board 400, located above the emitter film 110. A negative high voltage is applied to the emitter film 110, and a high-voltage screen 120 is added. An even lower negative high voltage is applied to the high-voltage screen 120, generating an electric field that guides secondary electrons toward the MCP assembly 200.

[0065] When fission fragments or beam current act on the emitter film 110, the emitter film 110 generates secondary electrons. Then, under the action of the electric field, the secondary electrons move toward the MCP assembly 200 and the delay line readout plate 400, and the position resolution is obtained using the delay line readout method.

[0066] Located below the emitter film 110: The emitter film 110, high-voltage wire mesh 120, MCP assembly 200, and conical anode readout 300 form the temporal readout section. When fission fragments or beam current strike the emitter film 110, it generates secondary electrons. These electrons are then driven by the electric field toward the MCP assembly 200 and conical anode readout 300, enabling temporal resolution to be achieved using the conical anode readout 300.

[0067] In this embodiment, by respectively arranging a position readout part and a time readout part on both sides of the emission film 110, the time resolution and position resolution can be optimized independently, and the structure of the time-of-flight detector is made compact, and the installation and maintenance are simple and reliable. In addition, the advantage of the small thickness of the emission film 110 is fully utilized, which not only reduces the interference with the beam and improves the energy resolution, but also improves the time resolution and position resolution.

[0068] Based on the above embodiment, another embodiment of the present invention introduces a position-sensitive time-of-flight detector.

[0069] The MCP assembly 200 specifically includes two MCPs 230, one MCP upper electrode 210, one MCP middle electrode 240, one MCP middle partition 220, one MCP lower electrode 250, and one MCP voltage divider circuit board 260. The MCP assembly 200 also includes screws and nuts for fixing the above components.

[0070] In addition, the screws and nuts in the MCP assembly 200 are made of PEEK material.

[0071] PEEK (Polyether Ether Ketone) is the full name of polyether ether ketone, which has a very high glass transition temperature (about 143°C) and melting point (about 343°C), and can maintain good performance under extreme temperature conditions. Figure 1As shown, the MCP assembly 200 installed with the tapered anode readout 300 comprises, from top to bottom, an MCP upper electrode 210, an MCP middle spacer 220, an MCP 230, an MCP middle electrode 240, an MCP 230, an MCP lower electrode 250, and an MCP voltage divider circuit board 260. Correspondingly, in the MCP assembly 200 installed with the delay line readout board 400, the placement order of the aforementioned components is exactly the opposite.

[0072] Furthermore, the MCP voltage divider circuit board 260 is provided with a resistor for providing a bias voltage to the MCP 230 , and the resistor is connected to the MCP upper electrode 210 , the MCP middle electrode 240 , and the MCP lower electrode 250 .

[0073] The MCP upper electrode 210 is provided with a bias pin to provide bias input for the voltage divider circuit on the MCP voltage divider circuit board 260. The MCP lower electrode 250 is connected to a protection resistor and then to ground to ensure the circuit safety of the MCP assembly 200.

[0074] Furthermore, the MCP top electrode 210 is 1 mm thick, the MCP middle electrode 240 is 0.2 mm thick, the MCP 230 is 0.48 mm thick, the MCP middle partition 220 is 0.8 mm thick, and the MCP bottom electrode 250 is 1 mm thick.

[0075] In addition, a bias voltage application method is described: both the emitter film 110 and the high-voltage screen 120 are provided with bias pins. The bias voltage of the emitter film 110 is set to -5000V; the bias voltage of the high-voltage screen 120 is set to -2000V; and the bias voltage of the MCP top electrode 210 is set to -2000V. By setting the voltage difference between the emitter film 110 and the high-voltage screen 120 to be greater than 2000V, the position resolution of the time-of-flight detector can be guaranteed.

[0076] The delay line readout board 400 connects the horizontal strip electrodes using a linear delay mechanism. Similarly, the vertical strip electrodes are also connected using a linear delay mechanism. Furthermore, the delay line readout board 400 is equipped with four signal output ports: two for horizontal and two for vertical directions. This allows the delay line readout board 400 to output two horizontal signals and two vertical signals. The absolute position requires calibration to obtain a conversion coefficient, ultimately enabling the time-of-flight detector to achieve a position resolution of less than 1 mm (FWHM). The tapered anode readout 300 outputs the time signal via an SMA connector, enabling the time-of-flight detector to achieve a resolution of less than 1 ns.

[0077] Based on the above embodiment, another embodiment of the present invention introduces a position-sensitive time-of-flight detector.

[0078] The high-voltage wire mesh 120 is composed of a plurality of gold-plated tungsten wires arranged in two mutually perpendicular directions. This is because the use of a mutually perpendicular mesh structure can effectively reduce the influence of electric field distortion.

[0079] The diameter of the gold-plated tungsten wire is 15 μm, and the distance between adjacent gold-plated tungsten wires is 1 mm. The two high-voltage wire meshes 120 are stacked on both sides of the emission film 110.

[0080] like Figure 2 As shown, the detector cage 100 further includes a partition 130 and a support assembly 140. The partition 130 is disposed between the high-voltage wire mesh 120 and the emission film 110.

[0081] The support assembly 140 vertically penetrates the emission film 110, the high-voltage wire mesh 120 and the partition 130. In addition, the support assembly 140 presses the emission film 110, the high-voltage wire mesh 120 and the partition 130 together.

[0082] The upper end of the support assembly 140 is connected to the delay line readout plate 400. The lower end of the support assembly 140 is connected to the tapered anode readout 300. In this way, the delay line readout plate 400, the tapered anode readout 300, and the emitter film 110 are positioned parallel to each other but spaced apart.

[0083] Preferably, the support assembly 140 comprises a first stud 141 and a second stud 142 connected via a male and female connector having a threaded structure. The male connector comprises a protruding rod with a threaded outer surface, while the female connector comprises a groove with a threaded inner surface. The first stud 141 and the second stud 142 are made of PEEK.

[0084] Specifically, both ends of the first stud 141 are configured as male connectors, and one end of the first stud 141 is connected to the tapered anode readout 300 , while the other end of the first stud 141 is connected to the emitter film 110 .

[0085] One end of the second stud 142 is configured as a female connector connected to the emission film 110 , and the other end of the second stud is configured as a male connector connected to the delay line readout board 400 .

[0086] Furthermore, the two male ends of the first stud 141 respectively penetrate the high-voltage wire mesh 120 and the MCP voltage-dividing circuit board 260. The male end of the first stud 141 protruding from the high-voltage wire mesh 120 is connected to the female end of the second stud 142.

[0087] The male end of the second stud 142 penetrates the delay line readout board 400, and the portion protruding from the delay line readout board 400 is fastened to a nut. Furthermore, the emitter film 110 is made of polyester double-sided aluminum-plated film. The polyester film is 0.5 μm thick, and the single-sided aluminum plating is 0.1 μm thick.

[0088] Preferably, the emitter film 110 may be deposited on its side with a substance that increases the secondary electron yield. For example, cesium iodide. The secondary electron yield refers to the number of secondary electrons emitted by a single particle after passing through the emitter film. In this embodiment, the time-of-flight detector based on microchannel plate (MCP) amplification adopts a structure in which a position readout part and a time readout part are respectively provided on the front and back sides of the emitter film 110. Compared to a parallel plate avalanche counter (PPAC), the emitter film 110 has weak blocking properties because its thickness is only 0.7μm. The reduced thickness of the emitter film 110 can significantly reduce the energy loss caused to the beam, thereby improving the energy resolution of the time-of-flight detector and greatly improving the accuracy of mass measurement.

[0089] Based on the above embodiment, another embodiment of the present invention introduces a position-sensitive time-of-flight detector.

[0090] The tapered anode readout 300 mainly includes a tapered anode 310 , a housing 320 , an SMA feedthrough 330 , and a lead-out needle 340 .

[0091] The large-section end of the conical anode 310 is connected to the MCP assembly 200 , and the small-section end of the conical anode 310 extends downward from the MCP assembly 200 .

[0092] The housing 320 is disposed on the outside of the conical anode 310 . In addition, the open end of the housing 320 is connected to the MCP voltage-dividing circuit board 260 of the MCP assembly 200 .

[0093] The SMA feedthrough 330 is mounted on the housing 320 to transmit signals from the inside of the device to the outside to reduce interference. Preferably, a flange structure is provided on the periphery of the SMA feedthrough 330, and the flange structure is fixed to the housing 320 by four M2.5 screws.

[0094] The lead-out needle 340 connects the tapered anode 310 and the SMA feedthrough 330 on the inner side of the housing 320. Preferably, the outer surface of the lead-out needle 340 is plated with gold.

[0095] The TOF detector further includes an insulating support 350 for securing the conical anode 310. The insulating support 350 is positioned between the small-section end of the conical anode 310 and the housing 320. Furthermore, a through-hole is defined in the center of the insulating support 350. A lead pin 340 is inserted through the through-hole and connects the SMA feedthrough 330 to the conical anode 310.

[0096] The time-of-flight detector further comprises a detector bracket 500 connected to the housing 320 , for making the position readout part and the time readout part thereof form an angle of 45° with the horizontal plane.

[0097] Specifically, if Figure 2 As shown, the emitter film 110 of the detector field cage 100, the delay line readout plate 400, and the MCP assembly 200 are fixed at a 45° angle relative to the horizontal plane. Screw holes are provided on the detector bracket 500. The detector bracket 500 is connected to the outer shell 320 of the conical anode 310 via screws.

[0098] Furthermore, the impedance of the conical anode 310 and the SMA feedthrough 330 are both 50Ω.

[0099] Furthermore, the emitter film 110, the high-voltage wire mesh 120, the spacer 130 and the delay line readout board 400 are made of a base plate made of FR4 material, and the thickness of the base plate is 2 mm.

[0100] The conical anode 310 , the conical anode 310 housing 320 and the detector bracket 500 are made of the same metal material, for example, stainless steel.

[0101] On the other hand, another embodiment of the present invention introduces a method for using a time-of-flight detector, which can help experimenters fully utilize the time-of-flight detector described in the above embodiments.

[0102] like Figure 3 As shown, the method of use includes the following steps: S1. In a high vacuum environment (<1E-6 mbar), sequentially arranging an experimental target, a first time-of-flight detector, and a second time-of-flight detector. The experimental target and the emission films of the first time-of-flight detector and the emission films of the second time-of-flight detector are arranged parallel to each other.

[0103] Furthermore, the center of the emissive film and the center of the experimental target are aligned on the same straight line. Specifically, the emissive film of the time-of-flight detector is a rectangular plane. The experimental target is also a rectangular plane. Mark the center points of the rectangles on the emissive film and the experimental target, respectively, and set the center of the emissive film and the center of the experimental target at the same height. Then, align the emissive film and the experimental target along a horizontal straight line.

[0104] S2. Make the beam incident on the experimental target from the upper side in a vertical direction.

[0105] S3. Set the beam intensity to less than 1E5pps and the beam structure to be uniform.

[0106] Specifically, the separation between the first and second time-of-flight detectors is set to the maximum possible distance. For example, within a vacuum target chamber, the separation between the first and second time-of-flight detectors is set to 1 meter. A uniform beam structure means that at a sampling rate of 10 ksps, the beam duty cycle is greater than 95%.

[0107] In another aspect, embodiments of the present invention also provide a method for calibrating the position resolution of a time-of-flight detector. Prior to on-line installation, the time-of-flight detector is placed in an offline vacuum target chamber. Coincidence measurements of the silicon detector are then used to calibrate the position resolution of the time-of-flight detector.

[0108] Specifically, according to Figure 4 and Figure 5 As shown in Figure 1, the radiation source, time-of-flight detector, and quartz crystal are placed inside the vacuum target chamber, sequentially from upstream to downstream. The vacuum target chamber's containment cavity is designed to be cylindrical. The center of the time-of-flight detector's emissive membrane and the center of the experimental target's surface are aligned with the central axis of the vacuum target chamber's containment cavity, ensuring that the center of the emissive membrane and the center of the experimental target are aligned on the same straight line.

[0109] Apart from Figure 4 and Figure 5 In addition to the equipment shown in the figure, the vacuum target chamber also requires a dry pump, molecular pump, vacuum gauge, and other equipment. The front and rear ends of the vacuum target chamber are blind panels. The sides of the vacuum target chamber are flanged. These flanges accommodate various feedthroughs, including high-voltage feedthroughs with a withstand voltage exceeding 5000V and signal feedthroughs such as SMA feedthrough 330 with a 50Ω impedance.

[0110] Among them, the radiation source adopts α radiation source. For example: 241 A thin film with holes for position calibration must be added in front of the time-of-flight detector to be calibrated. A square silicon detector is a square silicon detector.

[0111] During calibration, the time readout of the TOF detector is matched with the time readout of the silicon wafer to generate a coincidence gate, collecting the TOF detector's position information particle by particle. Through data analysis, the TOF detector's accurate position resolution is finally determined.

[0112] On the other hand, another embodiment of the present invention introduces a method for calibrating the time resolution of a time-of-flight detector. Figure 6 and Figure 7As shown in , the radiation source, the first time-of-flight detector, and the second time-of-flight detector are sequentially arranged inside the vacuum target chamber from upstream to downstream.

[0113] Apart from Figure 6 and Figure 7 In addition to the equipment shown, the vacuum target chamber also requires a dry pump, molecular pump, vacuum gauge, and other equipment. The front and rear ends of the vacuum target chamber are blind panels. The sides of the vacuum target chamber are flanged. These flanges accommodate various feedthroughs, including a high-voltage feedthrough with a withstand voltage exceeding 5000V and a 50Ω SMA feedthrough 330 for signal feedthroughs.

[0114] The same biasing elements in the first time-of-flight detector and the second time-of-flight detector are connected in series and then connected to the high-voltage feedthrough on the flange surface.

[0115] During calibration, the time readouts of the first and second TOF detectors are gated and collected particle by particle. A sufficient amount of data, such as 10,000 events, is collected and analyzed. The time resolution of the TOF detectors is then determined.

[0116] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A position-sensitive time-of-flight detector, characterized in that: include: A detector field cage (100) is provided with an emission film (110) for generating secondary electrons and a high-voltage wire mesh (120) for providing an electric field required for guiding the secondary electrons; Delay line readout plates (400) are arranged above the detector field cage (100) in parallel and at intervals; A conical anode readout (300) is arranged in parallel and spaced apart below the detector field cage (100); The delay line readout plate (400) and the tapered anode readout (300) are each provided with an MCP component (200) on a side facing the emission film (110); The MCP assembly (200) cooperates with the delay line readout plate (400) to provide position information of particles, and the MCP assembly (200) cooperates with the conical anode readout (300) to provide time information of particles; The emission film (110) is a polyester double-sided aluminum-plated film, wherein the thickness of the polyester film is 0.5 μm and the thickness of the aluminum-plated film on one side is 0.1 μm; The high-voltage wire mesh (120) is composed of a plurality of gold-plated tungsten wires arranged in two mutually perpendicular directions, and two high-voltage wire meshes (120) are respectively stacked on both sides of the emission film (110); The detector field cage (100) further comprises: a partition (130) disposed between the high-voltage wire mesh (120) and the emission film (110); A support assembly (140) vertically penetrates the emission film (110), the high-voltage wire mesh (120) and the partition (130) and presses them together, the upper end of the support assembly (140) is connected to the delay line readout plate (400), and the lower end of the support assembly (140) is connected to the conical anode readout (300); The delay line readout plate (400) is provided with strip electrodes in the horizontal direction and the vertical direction respectively, and is provided with two signal lead-out ports in the horizontal direction and the vertical direction respectively, for outputting two horizontal direction signals and two vertical direction signals.

2. The position-sensitive time-of-flight detector according to claim 1, characterized in that When the MCP assembly (200) is adapted to the conical anode readout (300), it comprises: an MCP upper electrode (210), an MCP middle partition (220), an MCP (230), an MCP middle electrode (240), an MCP (230), an MCP lower electrode (250), and an MCP voltage divider circuit board (260) arranged in sequence from top to bottom; When the MCP assembly (200) is adapted to the delay line readout plate (400), it comprises: an MCP upper electrode (210), an MCP middle partition (220), an MCP (230), an MCP middle electrode (240), an MCP (230), an MCP lower electrode (250), and an MCP voltage divider circuit board (260), which are sequentially arranged from bottom to top.

3. The position-sensitive time-of-flight detector according to claim 2, characterized in that The MCP voltage-dividing circuit board (260) is provided with a resistor for providing a bias voltage to the MCP (230), and the resistor is connected to the MCP upper electrode (210), the MCP middle electrode (240), and the MCP lower electrode (250).

4. The position-sensitive time-of-flight detector according to any one of claims 1 to 3, characterized in that: The support assembly (140) includes: a first stud (141), both ends of the first stud (141) being configured as male ends, one end of the first stud (141) being connected to the conical anode readout (300), and the other end of the first stud (141) being connected to the emission film (110); A second stud (142), one end of the second stud (142) is configured as a female connector connected to the emission film (110), and the other end of the second stud (142) is configured as a male connector connected to the delay line readout board (400).

5. The position-sensitive time-of-flight detector according to any one of claims 1 to 3, characterized in that: The tapered anode readout (300) comprises: a conical anode (310), wherein a large-section end of the conical anode (310) is connected to the MCP assembly (200), and a small-section end of the conical anode (310) extends downward from the MCP assembly (200); A housing (320) is disposed outside the conical anode (310) and is connected to the MCP assembly (200); An SMA feedthrough (330) mounted on the housing (320); A lead-out needle (340) connects the tapered anode (310) and the SMA feedthrough (330).

6. The position-sensitive time-of-flight detector according to claim 5, characterized in that The impedance of the conical anode (310) and the SMA feedthrough (330) are both 50Ω.

7. The position-sensitive time-of-flight detector according to claim 6, characterized in that It also includes a detector bracket (500) connected to the housing (320) and used to fix the emission film (110), the delay line readout plate (400) and the MCP assembly (200) at an angle of 45 degrees relative to the horizontal plane.

8. A method for using a time-of-flight detector, characterized in that: Applicable to a position-sensitive time-of-flight detector as claimed in any one of claims 1 to 7, S1. In a high vacuum environment, arrange an experimental target, a first time-of-flight detector, and a second time-of-flight detector in sequence, setting the experimental target and the emitting film of the first time-of-flight detector and the emitting film of the second time-of-flight detector parallel to each other, and making the center of the emitting film coincide with the center of the experimental target on the same straight line; S2, making the beam incident on the experimental target from the upper side of the experimental target in a vertical direction; S3. Set the beam intensity to less than 1E5pps and the beam structure to be uniform.

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