TPC detector applied to white light neutron beam experiment

Abstract

The application discloses a TPC detector applied to a white light neutron beam flow experiment and belongs to the technical field of detectors. The TPC detector comprises a field cage, a cathode plate, a cathode preamplifier and an anode plate. The field cage comprises a plurality of support columns and a plurality of PCB plates. The outer circle of the PCB plate is circular, the inner circle is a regular N-polygon, each side of the inner circle of the PCB plate is provided with a spacing hole, and the support column penetrates through the spacing hole to space the plurality of PCB plates which are stacked and placed. The cathode plate is located on the side of the field cage close to the emission of the neutron beam flow. The cathode preamplifier is located on the side of the cathode plate close to the emission of the neutron beam flow. The anode plate is located on the side of the field cage far from the emission of the neutron beam flow, comprises an inner side and an outer side, the inner side faces the field cage and comprises a readout pixel area which is a regular N-polygon with the same size as the inner circle of the PCB plate, and the outer side of the anode plate faces an electronic module. The application can measure the time of flight of the neutron beam flow and meet the signal-to-noise ratio and accuracy requirements of the cathode signal.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of detectors, in particular to a TPC detector applied to white light neutron beam experiment. BACKGROUND

[0002] In nuclear physics and particle physics experiments, TPC (Time Projection Chamber) is an important detector that can measure the three-dimensional position and energy information of charged particles simultaneously. The traditional TPC detector is mainly used for high-energy particle measurement, and the outgoing particles are mainly large transverse momentum particles. Therefore, in general, the design of the TPC detector mainly considers the transverse resolution capability, and the longitudinal requirement is not high. Moreover, in the existing TPC detector design scheme, there is a lack of technical scheme for providing high-precision cathode timing signals. SUMMARY

[0003] The present application provides a TPC detector applied to white light neutron beam experiment, which can measure the time of flight of neutron beam while meeting the signal-to-noise ratio and accuracy requirements of cathode signals. The technical scheme is as follows:

[0004] On the one hand, a TPC detector applied to white light neutron beam experiment is provided, which includes a field cage, a cathode plate, a cathode preamplifier, an anode plate and an electronic module.

[0005] The field cage includes a plurality of support columns and a plurality of PCBs (Printed Circuit Boards). The outer circle of the PCB is circular, and the PCB also has a hollow inner circle. The inner circle is a regular N-polygon, and the midpoint of the outer side of each side of the inner circle of the PCB has a spacing hole, and the spacing hole is located on the inner side of the outer circle of the PCB. The support column passes through the spacing hole to space the plurality of stacked PCBs. Wherein, N is a multiple of 6.

[0006] The cathode plate is located on the side of the field cage close to the emission of the neutron beam. The size of the cathode plate is equal to the size of the PCB, and the center of the cathode plate is collinear with the centers of the plurality of PCBs.

[0007] The cathode preamplifier is located on the side of the cathode plate close to the emission of the neutron beam. The cathode preamplifier is used to measure the time of flight of the neutron beam.

[0008] The anode plate is located on the side of the field cage far from the neutron beam emission, the anode plate comprises an inner side and an outer side, the size of the anode plate is larger than that of the PCB plate; the inner side faces the field cage, the inner side comprises a readout pixel area, the readout pixel area is a regular N-polygon with the same size as the inner circle of the PCB plate, and the center of the readout pixel area is collinear with the centers of the plurality of PCB plates; the outer side of the anode plate faces the electronics module;

[0009] The electronics module is used for signal processing and recording waveform information.

[0010] Optionally, the inner circle is a regular hexagon.

[0011] Optionally, the cathode preamplifier comprises:

[0012] An input circuit comprising a first end and a second end, the first end is used for receiving a beam current signal, the input circuit is used for introducing a beam current signal into the cathode preamplifier, the beam current signal is a signal corresponding to the neutron beam current;

[0013] A first amplification circuit, the input end of the first amplification circuit is connected with the second end of the input circuit, used for improving the signal-to-noise ratio of the received beam current signal, and outputting the processed beam current signal from the output end of the first amplification circuit;

[0014] A second amplification circuit, the input end of the second amplification circuit is connected with the output end of the first amplification circuit, used for enabling the cathode preamplifier to remain stable operation at high frequency;

[0015] An output circuit, the input end of the output circuit is connected with the output end of the second amplification circuit, used for maintaining the stability of the cathode preamplifier.

[0016] Optionally, the readout pixel area comprises:

[0017] A plurality of readout pixels, each readout pixel in the plurality of readout pixels has the same shape and size, and the shape of the readout pixel is a regular hexagon;

[0018] The first pixel and the second pixel in the plurality of readout pixels are separated by a first distance, the first pixel is any one pixel in the plurality of readout pixels, and the second pixel is any one pixel in the plurality of readout pixels except the first pixel.

[0019] Optionally, the anode plate further comprises:

[0020] a spacing region, the spacing region is located outside the readout pixel region, the shape and size of the spacing region are the same as the shape and size of the outer circle of the PCB board, and the center of the spacing region is the same as the center of the readout pixel region;

[0021] a connection region, the connection region is located outside the spacing region, the outer circle shape of the connection region is a regular hexagon, and the center of the connection region is the same as the center of the readout pixel region, the connection region is used to connect with the field cage and / or the electronics module.

[0022] Optionally, the connection region comprises:

[0023] at least one electronics interface, the electronics interface is located in the center of any one or more edges of the connection region, the electronics interface penetrates the inner side and the outer side of the anode plate, and the electronics interface is used to connect with the electronics module;

[0024] a high-voltage interface, the high-voltage interface is located on the inner side of the anode plate, and is used to provide voltage.

[0025] Optionally, the TPC detector further comprises:

[0026] a micro-grid structure, the micro-grid structure is located between the field cage and the anode plate, the shape and size of the micro-grid structure are the same as the shape and size of the readout pixel region, and the center of the micro-grid structure is collinear with the center of the readout pixel region;

[0027] there is a spacing region between the micro-grid structure and the readout pixel region, and the spacing region is an avalanche region.

[0028] Optionally, the connection region further comprises:

[0029] a grid preamplifier, the grid preamplifier is located on the outer side of the anode plate, is used to receive signals after passing through the avalanche region, and amplifies the signals to enable the electronics module to process corresponding signals and record waveform information;

[0030] a cathode signal transmission interface, the cathode signal transmission interface is located on the inner side of the anode plate, is used to receive signals after being amplified by the cathode preamplifier, to enable the electronics module to process corresponding signals and record waveform information.

[0031] Optionally, the input circuit comprises a junction field effect transistor to introduce the input signal into the cathode preamplifier;

[0032] the first amplification circuit comprises a differential amplification sub-circuit, and the differential amplification sub-circuit comprises a plurality of transistors in symmetrical cascade connection;

[0033] The second amplification circuit comprises a common-shoot common-base amplification sub-circuit to perform Walmanization.

[0034] Optionally, the electronics module comprises:

[0035] At least one connection port matched with the electronics interface of the connection area to connect the electronics module and the anode plate.

[0036] The technical scheme provided by the embodiments of the present application can bring at least the following beneficial effects:

[0037] The embodiments of the present application can ensure the uniformity of the electric field in the drift region by making the inner circle shape of the PCB board in the field cage a regular N-polygon, and N is a multiple of 6, that is, the inner circle shape of the field cage is a regular N-polygon uniform compression structure; and the cathode preamplifier is located on the side of the cathode plate close to the emission of the neutron beam, which can directly receive the neutron beam, thereby reducing the damage of the cathode signal, improving the signal-to-noise ratio of the cathode signal, and further realizing the measurement of the neutron time of flight and the electron drift time; in addition, the shape and size of the readout pixel area on the anode plate are the same as the inner circle shape of the PCB board, so that the structure of the anode plate can meet the resolution requirements in the horizontal and vertical directions, and the shape inside the field cage can be strictly matched with the readout pixel area. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 is a structure schematic diagram of a TPC detector applied to a white light neutron beam experiment provided by the embodiments of the present application;

[0039] Figure 2 is a structure schematic diagram of a PCB board provided by the embodiments of the present application;

[0040] Figure 3 is a structure schematic diagram of a cathode preamplifier provided by the embodiments of the present application;

[0041] Figure 4 is a structure schematic diagram of another cathode preamplifier provided by the embodiments of the present application

[0042] Figure 5 is a schematic diagram of a readout pixel area provided by the embodiments of the present application;

[0043] Figure 6 is a structure schematic diagram of an anode plate provided by the embodiments of the present application;

[0044] Figure 7 is a structure schematic diagram of another anode plate provided by the embodiments of the present application;

[0045] Figure 8 is a position schematic diagram of a micro-grid structure and an anode plate provided by the embodiments of the present application;

[0046] Figure 9 Fig. 1 is a schematic diagram of a structure of an anode plate according to an embodiment of the present application. DETAILED DESCRIPTION

[0047] The application will be further described in details through specific embodiments and with reference to the drawings. In different embodiments, similar elements are denoted by similar reference numerals. In the following embodiments, many details are described in order to make the application better understood. However, one skilled in the art can easily recognize that some features can be omitted in different cases, or can be replaced by other elements, materials, methods. In some cases, some operations related to the application are not shown or described in the specification, in order to avoid the core of the application being overwhelmed by too much description, and it is not necessary to describe these related operations in detail for one skilled in the art, who can fully understand the related operations according to the description in the specification and general technical knowledge in the art.

[0048] In addition, the features, operations or characteristics described in the specification can be combined in any appropriate manner to form various embodiments. Meanwhile, the steps or actions in the method description can also be sequentially adjusted or adjusted in a manner that one skilled in the art can easily see. Therefore, the order in the specification and the drawings is only for the purpose of clearly describing a certain embodiment, and does not mean that it is the necessary order, unless otherwise stated that a certain order must be followed.

[0049] The serial numbers of components in this paper, such as "first", "second", etc., are only used to distinguish the described objects, and do not have any order or technical meaning. Unless otherwise specified, "connection" and "coupling" in this application include direct and indirect connection (coupling).

[0050] In nuclear and particle physics experiments, TPC detector is an important detector that can simultaneously measure the three-dimensional position and energy information of charged particles. The traditional TPC detector is mainly used for high-energy particle measurement, and the outgoing particles are mainly large transverse momentum particles, so the design of the TPC detector mainly considers the transverse resolution capability, and the longitudinal requirement is not high. The outgoing particles of neutron nuclear reactions have a large probability distribution in the 4π range, which requires the TPC detector to have high resolution requirements for both the transverse and momentum, so the structure of the anode plate needs to consider the resolution requirements of both the transverse and longitudinal directions.

[0051] The inner ring shape of the field cage in the existing TPC detector is usually circular or square. However, in the white neutron source experiment, because the sensitive area of the anode plate is a polygonal structure, if the inner ring shape of the equalizing ring is circular or square, the electric field of the anode plate will be distorted, and therefore a new equalizing ring structure needs to be designed to meet the requirement of the electric field uniformity.

[0052] In addition, in the particle physics experiment, the T0 starting time is provided by the accelerator beam collision or target signal, and the cathode of the TPC detector does not need to provide the T0 signal. However, in the white neutron source experiment, the cathode signal of the TPC detector needs to be recorded to measure the neutron flight time. At the same time, the cathode signal also serves as the T0 signal of the electron drift. Therefore, in the white neutron source experiment, the signal-to-noise ratio and the accuracy of the cathode signal of the TPC detector are required to be high.

[0053] Based on this, the embodiment of the present application provides a TPC detector applied to a white neutron beam experiment, wherein the structure of the anode plate can meet the requirements of the transverse and longitudinal resolution, the field cage can meet the requirement of the electric field uniformity, and in addition, the TPC detector can meet the requirements of the signal-to-noise ratio and the accuracy of the cathode signal while measuring the neutron beam flight time.

[0054] Next, the TPC detector applied to the white neutron beam experiment provided by the embodiment of the present application will be introduced in detail.

[0055] Please refer to Figure 1 , Figure 1 is a structure schematic diagram of the TPC detector applied to the white neutron beam experiment provided by the embodiment of the present application, please refer to Figure 1The TPC detector comprises a field cage 1, a cathode plate 2, a cathode preamplifier 3, an anode plate 4 and an electronics module 5. The field cage 1 comprises a plurality of support columns 11 and a plurality of PCB plates 12; the outer ring of the PCB plate 12 is circular, and the PCB plate 12 further has a hollow inner ring which is a regular N-sided polygon, and the midpoint of the outer side of each side of the inner ring of the PCB plate 12 has a spacing hole, and the spacing hole is located on the inner side of the outer ring of the PCB plate 12; the support column 11 passes through the spacing hole to space the plurality of PCB plates 12 stacked one above another; wherein N is a multiple of 6. The cathode plate 2 is located on the side of the field cage 1 close to the emission of the neutron beam, and the size of the cathode plate 2 is equal to the size of the PCB plate 12, and the center of the cathode plate 2 is collinear with the center of the plurality of PCB plates 12. The cathode preamplifier 3 is located on the side of the cathode plate 1 close to the emission of the neutron beam, and the cathode preamplifier 3 is used to measure the time of flight of the neutron beam. The anode plate 4 is located on the side of the field cage 1 away from the emission of the neutron beam, and the anode plate 4 comprises an inner side and an outer side, and the size of the anode plate 4 is greater than the size of the PCB plate 12; the inner side faces the field cage 1, and the inner side comprises a readout pixel area which is a regular N-sided polygon with the same size as the inner ring of the PCB plate 12, and the center of the readout pixel area is collinear with the center of the plurality of PCB plates 12; the outer side of the anode plate 4 faces the electronics module 5. The electronics module 5 is used for signal processing and recording waveform information.

[0056] Since the internal shape of the field cage 1 is a regular N-sided polygon, and N is a multiple of 6, the uniformity of the electric field in the drift region can be ensured; and the cathode preamplifier 3 is located on the side of the cathode plate 2 close to the emission of the neutron beam, which can directly receive the neutron beam, thereby reducing the damage of the cathode signal, improving the signal-to-noise ratio of the cathode signal, and further realizing the measurement of the neutron time of flight and the electron drift time; in addition, the shape and size of the readout pixel area on the anode plate 4 are the same as the shape of the inner ring of the PCB plate 12, so that the shape of the inside of the field cage 1 can be strictly matched with the readout pixel area.

[0057] In some embodiments, the field cage 1 comprises a plurality of stacked PCB plates 12, and the shape of the PCB plate 12 can be as shown in Figure 2 As can be seen from Figure 2 , the PCB plate 12 has an outer ring and an inner ring, and the inner ring is a hollow regular N-sided polygon, and N is a multiple of 6, and the PCB plate 12 further has a plurality of spacing holes, so that the support column can pass through the plurality of PCB plates 12 to be neatly stacked and spaced. It can be seen that the inner ring shape of the field cage 1 is a regular N-sided polygon voltage equalizing ring structure, which can ensure the uniformity of the electric field in the drift region.

[0058] In addition, in some embodiments, please refer to Figure 2The inner circle of the PCB board 12 can be a regular hexagon. Since the shape of the inner part of the conventional field cage is a circle or a square, and the readout pixel area of the anode plate 4 is mostly a polygon, the conventional field cage cannot be strictly matched with the readout pixel area in the anode plate 1, which will cause the electric field in the anode plate 4 area to be uneven. Therefore, the shape of the inner circle of the PCB board 12 can be a regular hexagon, so that the shape of the inner part of the field cage 1 is a regular hexagonal column, to be accurately matched with the readout pixel area in the anode plate 4.

[0059] In some embodiments, the outer part of the PCB board 12 can also be insulated, that is, the plurality of PCB boards 12 can be separated by an insulating material to form a stable electric field environment. Moreover, each layer of the PCB board of the field cage 1 is designed to have uniformly distributed electrodes, which are powered by an external power supply and can generate a stable electric field.

[0060] In addition, in some embodiments, the field cage 1 can also have connecting devices on both sides, so that the two sides of the field cage can be connected with the cathode plate 2 and the anode plate 3, thereby forming a complete detection system.

[0061] It should be noted that the number of layers of the PCB board in the field cage 1 can be adjusted according to actual conditions, so as to change the height of the drift region to adapt to different ranges of incident ions; the spacing between the above-mentioned plurality of PCB boards 12 can also be adjusted according to requirements, so as to realize accurate adjustment of the height of the drift region by adjusting the spacing between the layers of the PCB board 12. That is, the number of the PCB boards 12 in the field cage 1 and the spacing between the PCB boards 12 are not limited in the embodiments of the present application.

[0062] The cathode plate 2 is located on the side of the field cage close to the emission of the neutron beam, so that the cathode plate in the TPC detector can first receive the neutron beam. The size of the cathode plate 2 is the same as that of the PCB board 12, that is, the area of the cathode plate 2 is equal to that of the PCB board 12, and the center of the cathode plate 2 is collinear with the centers of the plurality of PCB boards, so that the cathode plate can be connected with the field cage 1 in order.

[0063] The cathode preamplifier 3 is located on the cathode plate 2 and close to the side of the emission of the neutron beam, so that the cathode preamplifier 3 can directly receive the neutron beam, thereby reducing the damage of the cathode signal and realizing the measurement of the neutron time of flight.

[0064] In some embodiments, please refer to Figure 3, the cathode preamplifier 3 comprises: an input circuit 31, the input circuit 31 comprises a first end and a second end, the first end is used for receiving a beam current signal, the input circuit 31 is used for introducing the beam current signal into the cathode preamplifier 3, the beam current signal is a signal corresponding to a neutron beam current; a first amplification circuit 32, an input end of the first amplification circuit 32 is connected with the second end of the input circuit 31, for improving the signal-to-noise ratio of the received beam current signal, and outputting the processed beam current signal from an output end of the first amplification circuit 32; a second amplification circuit 33, an input end of the second amplification circuit 33 is connected with the output end of the first amplification circuit 32, for enabling the cathode preamplifier 3 to still work stably at high frequency; and an output circuit 34, an input end of the output circuit 34 is connected with an output end of the second amplification circuit 33, for maintaining the stability of the cathode preamplifier 3.

[0065] In addition, in some embodiments, referring to Figure 4 , the input circuit 31 comprises a junction field effect transistor 311, for introducing an input signal into the cathode preamplifier 3; the first amplification circuit 32 comprises a differential amplification sub-circuit 321, the differential amplification sub-circuit 321 comprises a plurality of symmetrically cascaded transistors; and the second amplification circuit 33 comprises a common-emitter common-base amplification sub-circuit 331, for performing Whitmanization.

[0066] The junction field effect transistor is used as an input stage, and the low-noise characteristic thereof is utilized to introduce the beam current signal into the cathode preamplifier 3 and reduce the introduction of noise as much as possible. In addition, the differential amplification sub-circuit 321 comprises a plurality of symmetrically cascaded transistors, and an active load end can also be formed by using an emitter follower circuit, which can effectively improve the common-mode rejection ratio and the inherent noise of the circuit, and improve the signal-to-noise ratio of the signal. Moreover, by means of the common-emitter common-base amplification sub-circuit 331, the cathode preamplifier 3 can be subjected to Whitmanization processing, and a high-gain amplification loop can also be formed by using a reverse emitter follower and an active load, and a frequency compensation capacitor can be added at the input end of the emitter follower circuit, which can expand the frequency characteristic, so that the cathode preamplifier 3 can still work stably at high frequency.

[0067] In addition, in some embodiments, the output circuit 34 can also use a constant current source to replace a traditional output resistor, which can realize high-gain second-stage output while maintaining the stability of the circuit.

[0068] In some embodiments, the related components mentioned in the above content can be selected from low-noise and high-stability electronic components, such as high-precision resistors, capacitors and transistors, to ensure the overall performance of the cathode preamplifier.

[0069] It should be noted that the above description assumes the input circuit includes a junction field-effect transistor (JFET), the first amplifier circuit includes a differential amplifier sub-circuit comprising multiple symmetrically cascaded transistors, and the second amplifier circuit includes a common-emitter, common-base amplifier sub-circuit. Alternatively, in applications, the input circuit, the first amplifier circuit, and the second amplifier circuit may also include other components. This application does not limit these components.

[0070] The anode plate 4 is located on the side of the field cage 1 away from the neutron beam emission, and has inner and outer surfaces. The inner surface faces the field cage 1 and has a readout pixel area. Since the inner circle of the PCB board 12 in the field cage 1 is a regular N-gon, in order to ensure a strict match between the readout pixel area and the shape inside the field cage 1, the size and shape of the readout pixel area must be the same as the size and shape of the inner circle of the PCB board 12. That is, the area of ​​the readout pixel area is the same as the area of ​​the inner circle of the PCB board 12, and the shape of the readout pixel area is also a regular N-gon. For example, as... Figure 5 As shown, the readout pixel area is a regular hexagon, and its area is the same as the area of ​​the inner circle of the PCB board 12. For another example, the anode plate 4 is a regular hexagon with a side length of 270mm, and the central area is a readout pixel area with a side length of 68.5mm.

[0071] In some embodiments, please refer to Figure 5 The readout pixel area includes: multiple readout pixels, each of which has the same shape and size, and the shape of the readout pixel is a regular hexagon; a first distance between the first pixel and the second pixel of the multiple readout pixels, wherein the first pixel is any one of the multiple readout pixels, and the second pixel is any one of the multiple readout pixels other than the first pixel.

[0072] For example, such as Figure 5 The readout pixels in the readout pixel area can be regular hexagons with a side length of 1.63 mm, and each readout pixel can be spaced 0.2 mm apart; that is, the first spacing distance can be 0.2 mm. As another example, the readout pixel area may include 1519 readout pixels distributed as described above.

[0073] In some embodiments, please refer to Figure 6 The anode plate 4 further includes: a spacing region 41, which is located outside the readout pixel region. The shape and size of the spacing region 41 are the same as the outer ring shape and size of the PCB board 12, and the center of the spacing region 41 is the same as the center of the readout pixel region; and a connection region 42, which is located outside the spacing region 41. The outer ring shape of the connection region 42 is a regular hexagon, and the center of the connection region 42 is the same as the center of the readout pixel region. The connection region 42 is used to connect with the field cage 1 and / or the electronics module 5.

[0074] The shape and size of the interval region 41 are the same as the shape and size of the outer ring of the PCB 12, so that the shape of the anode plate 4 is more consistent with the shape of the field cage 1. In addition, the connection region 42 with the outer ring shape of a regular hexagon is further arranged outside the interval region 41, so that the anode plate 4 can be connected to other elements (such as the electronic module 5) through the connection region 42 in addition to the field cage 1.

[0075] It should be noted that the outer ring shape of the connection region 42 is a regular hexagon, or in applications, the outer ring of the connection region can also have other shapes. The embodiments of the present application do not limit this.

[0076] In some embodiments, referring to Figure 7 , the connection region 42 includes at least one electronic interface 421, the electronic interface 421 is located at the center of any one or more edges of the connection region 42, the electronic interface 421 penetrates the inner side and the outer side of the anode plate 4, and the electronic interface 421 is used to connect with the electronic module 5; and a high-voltage interface 422, the high-voltage interface 422 is located on the inner side of the anode plate 4 and is used to provide voltage.

[0077] Since the electronic interface 421 penetrates the inner side and the outer side of the anode plate 4, the anode plate 4 can be directly connected with the electronic module 5. In addition, the electronic interface 421 can include multiple channels to transmit the sensing signals on the TPC detector to the electronic module 5. For example, the electronic interface 421 can include 64 channels.

[0078] In some embodiments, the high-voltage interface 422 can include multiple different sub-interfaces. For example, the high-voltage interface 422 can include a cathode high-voltage sub-interface and a grid high-voltage sub-interface, wherein the cathode high-voltage sub-interface is used to provide voltage to the cathode, and the cathode voltage can be provided through internal wiring of the anode plate 4 to leave a pad inside the field cage 1, and after the field cage 1 is installed, the high-voltage line is connected with the cathode to provide high voltage to the cathode; in the case that the TPC detector includes a micro-grid structure, the high voltage provided by the grid high-voltage sub-interface can be connected with the micro-grid structure through the welding point to provide voltage for it.

[0079] In addition, in some embodiments, in the case that the inner side of the anode plate 4 also includes the cathode preamplifier 3, the connection region 42 can further include a low-voltage power supply interface for providing working voltage to the cathode preamplifier 3 inside the gas chamber, i.e., inside the field cage 1. The cathode preamplifier 3 is placed inside the gas chamber because the cathode signal is a signal generated during the drift of the ionized electrons in the field cage 1, which has not been amplified by avalanche, and the signal amplitude is small. The inside of the gas chamber can reduce noise and improve signal-to-noise ratio. In addition, the connection region 42 can output the signal passing through the cathode preamplifier 3 to the electronic module 5 through internal wiring, so as to know the working state of the preamplifier inside the gas chamber through the electronic module 5.

[0080] In some embodiments, referring to Figure 8 , the TPC detector further comprises: a micro-lattice structure 6, the micro-lattice structure 6 is located between the field cage 1 and the anode plate 4, the shape and size of the micro-lattice structure 6 are the same as the shape and size of the readout pixel area, and the center of the micro-lattice structure 6 is collinear with the center of the readout pixel area; there is a spacing area between the micro-lattice structure 6 and the readout pixel area, and the spacing area is an avalanche area.

[0081] For example, as Figure 8 shown, the shape of the micro-lattice structure 6 can also be a regular hexagon, and the spacing between the micro-lattice structure 6 and the anode plate 4 can be 100 μm.

[0082] In addition, in some embodiments, there can also be a working gas in the avalanche area.

[0083] In some embodiments, referring to Figure 9 , the connection area 42 further comprises: a grid preamplifier 423, the grid preamplifier 423 is located on the outer side of the anode plate 4, and is used to receive the signal after passing through the avalanche area, and amplify it to make the electronics module 5 process the corresponding signal and record the waveform information; a cathode signal transmission interface 424, the cathode signal transmission interface 424 is located on the inner side of the anode plate, and is used to receive the signal after being amplified by the cathode preamplifier 3, so that the electronics module 5 processes the corresponding signal and records the waveform information.

[0084] Since the grid preamplifier 423 is arranged outside the anode plate 1 gas chamber (i.e. not in the field cage 1), the grid signal is the signal after avalanche amplification after passing through the avalanche area, and the amplitude is larger than that of the cathode signal. The grid signal can be introduced to the grid preamplifier 423 through the internal wiring of the anode plate 4, amplified, and then viewed by the electronics module 5.

[0085] In some embodiments, the micro-lattice structure can be made by hot pressing technology, and the avalanche area has a spacing between the micro-lattice structure 6 and the anode plate 4. The TPC detector generates an electric field of the order of kV / cm in the avalanche area in the working state, so it is easy to have a sparking phenomenon. In order to reduce the sparking strength and probability of the micro-lattice structure 6, and improve the working voltage of the micro-lattice structure 6 and the gain of the avalanche area, the anode plate 4 can also be designed as a resistive layer, that is, a resistive germanium layer with a thickness of 400 nm is plated in the readout pixel area of the anode plate 4, thereby effectively reducing the sparking probability and improving the working voltage and gain of the micro-lattice structure 6.

[0086] In addition, in some embodiments, the electronics module 5 comprises at least one connection port 51 matching the electronics interface 421 of the connection area 42, so as to connect the electronics module 6 and the anode plate 4. That is, in order for the electronics module 5 to receive signals from the anode plate 4, it needs to comprise at least one interface matching the interface of the anode plate 4, so as to enable the electronics module 5 to be connected with the anode plate.

[0087] The embodiments of the present application can ensure the uniformity of the electric field in the drift region by making the inner circle shape of the PCB board in the field cage a regular N-polygon, and N being a multiple of 6, i.e., the inner circle shape of the field cage is a regular N-polygon uniform compression structure; and the cathode preamplifier is located on the side of the cathode plate close to the neutron beam emission, which can directly receive the neutron beam, thereby reducing the damage of the cathode signal, improving the signal-to-noise ratio of the cathode signal, and further realizing the measurement of the neutron time of flight and the electron drift time; in addition, the shape and size of the readout pixel area on the anode plate are the same as the inner circle shape of the PCB board, so that the structure of the anode plate can meet the resolution requirements in the horizontal and vertical directions, and the shape inside the field cage can be strictly matched with the readout pixel area. Moreover, the cathode preamplifier can realize low-noise signal input and transmission by the combination of the junction field effect tube input stage and the differential circuit, can realize high-gain second-stage output by using a constant current source to replace an output resistor, can improve the amplification multiple of the signal, and can broaden the frequency characteristics and improve the stability and response speed of the circuit by performing the Wollmanization processing on the circuit; the anode plate also has a connection area, which can realize efficient and stable connection of the TPC detector and the electronics module through various designed interfaces.

[0088] The above application of specific examples is used to help understand the present application and does not limit the present application. For those skilled in the art to which the present application belongs, according to the idea of the present application, a number of simple deductions, deformations or substitutions can be made.

Claims

1. A TPC detector applied to a white light neutron beam experiment, characterized in that, The field cage, the cathode plate, the cathode preamplifier, the anode plate and the electronics module are included. The field cage includes a plurality of support columns and a plurality of PCB boards; the outer ring of the PCB board is circular, the PCB board further has a hollow inner ring, the inner ring is a regular N-polygon, the midpoint of the outer side of each side of the inner ring of the PCB board has a spacing hole, and the spacing hole is located on the inner side of the outer ring of the PCB board; the support column passes through the spacing hole to space the plurality of PCB boards stacked together; wherein the N is a multiple of 6; The cathode plate is located on the side of the field cage close to the emission of the neutron beam, the size of the cathode plate is equal to the size of the PCB board, and the center of the cathode plate is collinear with the centers of the plurality of PCB boards; The cathode preamplifier is located on the side of the cathode plate close to the emission of the neutron beam, and the cathode preamplifier is used for measuring the time of flight of the neutron beam; The anode plate is located on the side of the field cage away from the emission of the neutron beam, the anode plate includes an inner side and an outer side, the size of the anode plate is greater than the size of the PCB board; the inner side faces the field cage, the inner side includes a readout pixel area, the readout pixel area is a regular N-polygon with the same size as the inner ring of the PCB board, and the center of the readout pixel area is collinear with the centers of the plurality of PCB boards; the outer side of the anode plate faces the electronics module; The electronics module is used for signal processing and recording waveform information.

2. The TPC probe of claim 1, wherein, The inner ring is a regular hexagon.

3. The TPC probe of claim 1, wherein, The cathode preamplifier includes: An input circuit, the input circuit includes a first end and a second end, the first end is used for receiving a beam current signal, the input circuit is used for introducing the beam current signal into the cathode preamplifier, the beam current signal is a signal corresponding to the neutron beam; A first amplification circuit, the input end of the first amplification circuit is connected with the second end of the input circuit, used for improving the signal-to-noise ratio of the received beam current signal, and outputting the processed beam current signal from the output end of the first amplification circuit; A second amplification circuit, the input end of the second amplification circuit is connected with the output end of the first amplification circuit, used for enabling the cathode preamplifier to remain stable operation under high frequency; An output circuit, the input end of the output circuit is connected with the output end of the second amplification circuit, used for maintaining the stability of the cathode preamplifier.

4. The TPC probe of claim 1, wherein, The readout pixel area includes: A plurality of readout pixels, the shape and size of each readout pixel in the plurality of readout pixels are the same, and the shape of the readout pixel is a regular hexagon; The first pixel and the second pixel in the plurality of readout pixels are spaced apart by a first distance, the first pixel is any one of the plurality of readout pixels, and the second pixel is any one of the plurality of readout pixels except the first pixel.

5. The TPC probe of any one of claims 1-4, wherein, The anode plate further includes: A spacing area, the spacing area is located on the outer side of the readout pixel area, the shape and size of the spacing area are the same as the shape and size of the outer ring of the PCB board, and the center of the spacing area is the same as the center of the readout pixel area; A connection region, which is located outside the interval region, the outer circle of the connection region is a regular hexagon, and the center of the connection region is the same as the center of the readout pixel region, the connection region is used to connect with the field cage and / or the electronic module.

6. The TPC probe of claim 5, wherein, The connection region includes: At least one electronic interface, which is located in the center of any one or more edges of the connection region, the electronic interface penetrates the inner and outer sides of the anode plate, and is used to connect with the electronic module; A high-voltage interface, which is located on the inner side of the anode plate, and is used to provide voltage.

7. The TPC probe of claim 5, wherein, The TPC detector further includes: A micro-grid structure, which is located between the field cage and the anode plate, the shape and size of the micro-grid structure are the same as those of the readout pixel region, and the center of the micro-grid structure is collinear with the center of the readout pixel region; There is an interval region between the micro-grid structure and the readout pixel region, which is an avalanche region.

8. The TPC probe of claim 7, wherein, The connection region further includes: A grid preamplifier, which is located on the outer side of the anode plate, and is used to receive signals after passing through the avalanche region, and amplify them to enable the electronic module to process and record waveform information of the corresponding signals; A cathode signal transmission interface, which is located on the inner side of the anode plate, and is used to receive signals after being amplified by the cathode preamplifier, to enable the electronic module to process and record waveform information of the corresponding signals.

9. The TPC probe of claim 3, wherein, The input circuit includes a junction field effect transistor to introduce the beam current signal into the cathode preamplifier; The first amplification circuit includes a differential amplification sub-circuit, which includes a plurality of symmetrically cascaded transistors; The second amplification circuit includes a common-emitter common-base amplification sub-circuit to perform walmanization.

10. The TPC probe of claim 6, wherein, The electronic module includes: At least one connection port matched with the electronic interface of the connection region, to enable the electronic module and the anode plate to be connected.

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