Energy spectrum data reading circuit and X-ray detector

Abstract

The utility model provides an energy spectrum data reading circuit and an X-ray detector. The energy spectrum data reading circuit comprises an acquisition circuit, the acquisition circuit comprises a plurality of sub-channels, and each sub-channel is used for receiving a current pulse signal generated based on X-rays and generating a detection signal based on the current pulse signal; the trigger circuit is connected with the plurality of sub-channels and is used for responding to an over-threshold channel in the plurality of sub-channels, generating a global trigger signal and a channel gating signal and outputting the address of the over-threshold channel, and the over-threshold channel is the sub-channel of which the amplitude of the generated detection signal exceeds a preset threshold value; the multiplexer is connected with the plurality of sub-channels and the trigger circuit, and is used for selecting an over-threshold channel from the plurality of sub-channels according to a channel gating signal provided by the trigger circuit to output a detection signal; and the control circuit is connected with the trigger circuit of the acquisition circuit and the multiplexer, and is used for reading the detection signal output by the multiplexer and the address output by the trigger circuit in response to the global trigger signal from the trigger circuit.

Description

Technical Field

[0001] The utility model relates to the field of a detector readout circuit, and more specifically, to an energy spectrum data readout circuit. Background Art

[0002] At present, X-ray diffraction technology is usually used in aviation, railway, logistics and other security inspection sites to inspect suitcases, parcels, etc. After X-rays are irradiated on the inspected items, the detector can detect and form a diffraction energy spectrum that changes with the X-ray energy distribution, so as to obtain the material molecular structure information of the inspected items based on the diffraction energy spectrum, thereby realizing the identification of crystalline contraband.

[0003] In the process of obtaining the diffraction energy spectrum, the detector first interacts with the X-ray to generate a current pulse signal and extract the voltage amplitude information. However, the detector imaging module has multiple channels, and there will only be one or more channels that generate voltage amplitudes through X-rays at the same time. Therefore, it is necessary to obtain the voltage amplitude and the channel position that generates the voltage amplitude. The existing methods need to read and analyze the voltage amplitudes of a large number of channels, and the next cycle of reading can only be performed after all the read channel information is analyzed, resulting in a long time in a reading cycle, which has certain limitations in the use scenario. Summary of the invention

[0004] The utility model provides an energy spectrum data readout circuit and an X-ray detector.

[0005] According to one aspect of the utility model, the utility model provides an energy spectrum data readout circuit, including: an acquisition circuit, the acquisition circuit including: multiple sub-channels, each sub-channel is used to receive a current pulse signal generated based on X-rays, and generate a detection signal based on the current pulse signal; a trigger circuit, connected to the multiple sub-channels, for generating a global trigger signal and a channel selection signal in response to the existence of an over-threshold channel among the multiple sub-channels, and outputting the address of the over-threshold channel, wherein the over-threshold channel is a sub-channel whose generated detection signal has an amplitude exceeding a preset threshold; a multiplexer, connected to the multiple sub-channels and the trigger circuit, for selecting an over-threshold channel from the multiple sub-channels to output a detection signal according to the channel selection signal provided by the trigger circuit; and a control circuit, connected to the trigger circuit and the multiplexer of the acquisition circuit, for reading the detection signal output by the multiplexer and the address output by the trigger circuit in response to the global trigger signal from the trigger circuit.

[0006] According to an embodiment of the utility model, each sub-channel includes: a charge-sensitive amplifier, used to receive a current pulse signal generated based on X-rays and convert it into a voltage signal; a signal amplitude measurement circuit, connected to the charge-sensitive amplifier, used to generate a detection signal based on the voltage signal, and the detection signal carries voltage amplitude information that is proportional to the received X-ray energy; an over-threshold mark generating circuit, connected to the charge-sensitive amplifier, used to generate an over-threshold mark based on the relationship between the amplitude of the voltage signal and a preset threshold.

[0007] According to an embodiment of the utility model, the signal amplitude measurement circuit includes: a first shaping circuit, connected to the charge sensitive amplifier, for amplifying and filtering the voltage signal output by the charge sensitive amplifier; a peak sampling and holding circuit, connected to the first shaping circuit, for performing peak sampling and holding on the amplified and filtered signal output by the first shaping circuit to obtain a detection signal.

[0008] According to an embodiment of the utility model, the over-threshold flag generating circuit includes: a second shaping circuit, connected to the charge-sensitive amplifier, and used to filter and shape the voltage signal output by the charge-sensitive amplifier, wherein the shaping time of the second shaping circuit is shorter than the shaping time of the first shaping circuit; a comparator, connected to the second shaping circuit, and used to compare the signal amplitude output by the second shaping circuit with a preset threshold value, and generate an over-threshold flag based on the comparison result.

[0009] According to an embodiment of the utility model, the trigger circuit includes: a global trigger signal generating circuit, which is connected to the output end of the threshold value identification generating circuit of each sub-channel, and is used to determine whether there is an over-threshold channel among multiple sub-channels based on the over-threshold identification output by the threshold value identification generating circuit, and generate a global trigger signal when there is an over-threshold channel; an address output circuit, which is connected to the threshold value identification generating circuit of each sub-channel, the global trigger signal generating circuit and the control end of the multiplexer, and is used to select the address of the over-threshold channel from the multiple sub-channels according to the threshold value identification of each sub-channel and the global trigger signal for output, and output a channel selection signal indicating the over-threshold channel to the control end of the multiplexer.

[0010] According to an embodiment of the utility model, the global trigger signal generating circuit includes: an OR gate, wherein multiple input ends of the OR gate are respectively connected to the output ends of the threshold value marking generating circuits of multiple sub-channels, and the output end of the OR gate is connected to the control circuit.

[0011] According to an embodiment of the utility model, the address output circuit includes: multiple triggers, the input ends of the multiple triggers are respectively connected to the output ends of the threshold value identification generating circuits of the multiple sub-channels, the control ends of the multiple triggers are all connected to the output end of the global trigger signal generating circuit, and each trigger is configured to output a channel trigger signal at the output end according to the signals of the input end and the control end; a priority encoder, the multiple input ends of the priority encoder are respectively connected to the output ends of the multiple triggers, the first output end of the priority encoder is connected to the control end of the multiplexer, the second output end of the priority encoder is used to output the address, and the priority encoder is configured to determine the over-threshold channel from the multiple sub-channels according to the channel trigger signals output by the multiple triggers, and output the channel selection signal indicating the over-threshold channel at the first output end, and output the address of the over-threshold channel at the second output end.

[0012] According to an embodiment of the utility model, the priority encoder is also configured to select an address of an over-threshold channel from the multiple over-threshold channels for output according to a preset priority when there are multiple over-threshold channels, and output a channel selection signal indicating the selected over-threshold channel.

[0013] According to an embodiment of the utility model, the address output circuit also includes: a parallel-to-serial conversion circuit, wherein the first input end of the parallel-to-serial conversion circuit is connected to the second output end of the priority encoder to receive the address of the over-threshold channel, the address of the over-threshold channel is n1-bit parallel data, and the output end of the parallel-to-serial conversion circuit is connected to the control circuit.

[0014] According to an embodiment of the utility model, the acquisition circuit also includes a configuration register, which is connected to the second input end of the parallel-to-serial conversion circuit in the address output circuit, and is used to provide an identification of the acquisition circuit to the second input end of the parallel-to-serial conversion circuit, and the identification of the acquisition circuit is n2-bit parallel data; the parallel-to-serial conversion circuit is used to convert the n1+n2-bit parallel data received at the first input end and the second input end into serial data and output it at the output end of the parallel-to-serial conversion circuit.

[0015] According to an embodiment of the utility model, the energy spectrum data readout circuit includes multiple acquisition circuits; the control circuit is also used to respond to receiving a global trigger signal from at least two acquisition circuits among the multiple acquisition circuits, select an acquisition circuit from the at least two acquisition circuits according to a preset priority, and read the voltage amplitude information and address output by the selected acquisition circuit.

[0016] According to the embodiment of the utility model, the acquisition circuit is implemented as an application specific integrated circuit ASIC.

[0017] According to an embodiment of the utility model, the control circuit is implemented as a field programmable gate array FPGA.

[0018] According to another aspect of the present invention, the present invention provides an X-ray detector, comprising the energy spectrum data readout circuit in any one of the above embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above contents and other purposes, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0020] Figure 1A The structure block diagram of the energy spectrum data readout circuit according to the embodiment of the utility model is schematically shown;

[0021] Figure 1B The structure block diagram of the acquisition circuit in the energy spectrum data readout circuit according to the embodiment of the utility model is schematically shown;

[0022] Figure 1C A schematic diagram shows a structural block diagram of a sub-channel of an acquisition circuit in an energy spectrum data readout circuit according to an embodiment of the utility model;

[0023] Figure 2 The structure block diagram of the trigger circuit in the acquisition circuit in the energy spectrum data readout circuit according to the embodiment of the utility model is schematically shown;

[0024] Figure 3 The flowchart of the data reading method executed by the energy spectrum data reading circuit according to the embodiment of the utility model is schematically shown. DETAILED DESCRIPTION

[0025] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present invention. In the following detailed description, for ease of explanation, many specific details are described to provide a comprehensive understanding of the embodiments of the present invention. However, it is obvious that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present invention.

[0026] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The terms "include", "comprises", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0027] All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner.

[0028] When using expressions such as "at least one of A, B, and C, etc.", they should generally be interpreted according to the meaning of the expression commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0029] In the technical solution of the present utility model, the collection, storage, use, processing, transmission, provision, disclosure and application of the data involved (including but not limited to user personal information) shall comply with the relevant laws and regulations, take necessary confidentiality measures, and shall not violate public order and good morals.

[0030] An embodiment of the utility model provides an energy spectrum data readout circuit.

[0031] Figure 1A The structure block diagram of the energy spectrum data readout circuit according to the embodiment of the utility model is schematically shown. Figure 1B The structure block diagram of the acquisition circuit in the energy spectrum data readout circuit according to the embodiment of the utility model is schematically shown.

[0032] like Figure 1A and 1B As shown, the energy spectrum data readout circuit 100 of this embodiment includes an acquisition circuit 110 and a control circuit 120. The acquisition circuit 110 may include a plurality of sub-channels 111_0, 111_1, . . . , 111_127, a trigger circuit 112 and a multiplexer 113.

[0033] The acquisition circuit 110 includes a plurality of sub-channels 111_0 , 111_1 , . . . , 111_127 , a trigger circuit 112 , and a multiplexer 113 .

[0034] Each of the multiple sub-channels 111_0, 111_1, ..., 111_127 (hereinafter collectively referred to as sub-channel 111) can receive the current pulse signal generated after the X-ray enters the semiconductor detector, and generate a detection signal for determining the type of substance based on the current pulse signal, wherein the detection signal includes voltage amplitude information proportional to the X-ray energy. When the X-ray irradiates the substance and coherent scattering occurs, the scattered coherent light interferes inside the substance, and the angle and wavelength of the emitted diffracted light will vary depending on the type of substance. By measuring the energy spectrum of the emitted light and inverting the crystal structure inside the substance according to the Bragg formula, the type of substance can be determined.

[0035] In some embodiments, after the X-ray passes through the object to be inspected, it interacts with the pixels of the semiconductor detector (such as a cadmium zinc telluride detector) to generate a current signal, and then further extracts the voltage amplitude information through analog front-end electronics (including charge sensitive amplifiers, filter shaping circuits, peak sampling and holding circuits, etc.), and the voltage amplitude is proportional to the energy of the X-ray photons. Based on the voltage amplitude information, a perspective image that can reflect the internal structure of the object to be inspected can be generated.

[0036] The number of sub-channels can be set as needed. In some embodiments, the acquisition circuit may include 128 sub-channels, and the output end of each sub-channel is connected to the multiplexer 113.

[0037] The trigger circuit 112 is connected to a plurality of sub-channels 111_0, 111_1, ..., 111_127. The trigger circuit 112 can generate a global trigger signal and a channel selection signal in response to the presence of an over-threshold channel among the plurality of sub-channels, and output the address of the over-threshold channel. The over-threshold channel may include a sub-channel whose voltage amplitude information of the detection signal exceeds a preset threshold value. When the voltage amplitude information exceeds the preset threshold value, it indicates that the sub-channel is triggered. In some embodiments, since the utility model is mainly applied to low count rate scenarios, in most cases, only one sub-channel is triggered at the same time. The global trigger signal can be used to send to the control circuit 120, indicating that the sub-channel in the acquisition circuit 110 is triggered and there is an over-threshold channel. The channel selection signal can be used to send to the multiplexer 113 to indicate the location of the over-threshold channel in the acquisition circuit 110 so that the multiplexer obtains the detection signal of the over-threshold channel.

[0038] The multiplexer 113 is connected to the multiple sub-channels 111_0, 111_1, ..., 111_127 and the trigger circuit 112. The multiplexer 113 can select the detection signal of the over-threshold channel from the multiple sub-channels 111_0, 111_1, ..., 111_127 according to the channel selection signal provided by the trigger circuit 112 for output.

[0039] The control circuit 120 is connected to the trigger circuit 112 and the multiplexer 113 of the acquisition circuit 110. The control circuit 120 can respond to the global trigger signal from the trigger circuit and read the detection signal and address output by the multiplexer. In some embodiments of the present invention, the control circuit 120 can be implemented by a field programmable gate array (FPGA).

[0040] The traditional method reads the detection signals of all sub-channels or all triggered sub-channels in the acquisition circuit. This method has a reading cycle that is too long. In addition, since there are many sub-channels to read and the amount of data read is large, the waiting time of the detection signal is increased, which limits the use scenarios of electronics.

[0041] An embodiment of the utility model provides an energy spectrum data readout circuit. By setting a trigger circuit and a multiplexer, the detection signal and address of the over-threshold channel can be selected from multiple sub-channels for output, which greatly reduces the number of sub-channels read in a single cycle, thereby alleviating the problem of the traditional method of too long a reading cycle and reducing the waiting time of the detection signal.

[0042] In some embodiments, the acquisition circuit 110 can be implemented by an application specific integrated circuit (ASIC). ASIC can integrate the functions of several small-scale circuits on a chip, thereby satisfying the functions that the acquisition circuit in the utility model needs to implement. For example, the acquisition circuit 110 can be implemented as a cadmium zinc telluride detector readout chip, and the chip can include 128 sub-channels. Each sub-channel 111 can include a charge sensitive amplifier, a filter shaping circuit, and a peak sampling and holding circuit, and the output end of each sub-channel is connected to the multiplexer 113. In the case where the sub-channel does not obtain a current pulse signal, the output of the multiplexer is in a high impedance state. When a sub-channel in the chip is triggered, the trigger circuit 112 in the acquisition circuit 110 sends a global trigger signal to the control circuit 120, and the control circuit responds to the global trigger signal and sends an address read clock to the acquisition circuit. After receiving the address read clock, the acquisition circuit trigger circuit sends the address of the over-threshold channel to the control circuit, and the multiplexer receives the channel selection signal sent by the trigger circuit, and obtains and outputs the detection signal of the over-threshold channel.

[0043] In some embodiments of the utility model, the energy spectrum data readout circuit 100 may further include an analog-to-digital conversion circuit 130. The analog-to-digital conversion circuit 130 may be used to receive the detection signal of the threshold channel sent by the acquisition circuit, and convert the voltage amplitude information included in the detection signal from the analog signal to a digital signal. The analog-to-digital conversion circuit 130 outputs a digital signal carrying, which may be provided to a host computer together with the address read by the control circuit 120 as readout data, and the host computer may perform subsequent processing according to the readout data, for example, a perspective image of the detected object may be generated based on the readout data.

[0044] In some embodiments of the present invention, the acquisition circuit 110 may further include a configuration register 114. The configuration register 114 is used to provide configuration information of the acquisition circuit 110, for example, it may provide an identification of the acquisition circuit.

[0045] In some embodiments of the present invention, the acquisition circuit 110 may further include a bias circuit 115 for providing a bias current or a bias voltage to ensure that the entire circuit operates normally.

[0046] In some embodiments of the utility model, the energy spectrum data readout circuit may have a reading cycle. In one reading cycle, the acquisition circuit responds to the presence of a threshold-crossing channel in multiple sub-channels, outputs the address and detection signal of the threshold-crossing channel, and the control circuit reads it. When the control circuit completes the reading, all circuits are reset and the next reading cycle is performed.

[0047] The embodiment of the utility model only reads the detection signal and address of one over-threshold channel in one reading cycle, and the reading cycle time is short, the amount of data is small, and the reading frame rate is high. Compared with the traditional method of reading the detection information of all channels in each reading cycle, the reading efficiency of obtaining the detection signal from multiple channels is improved. In addition, when reading the voltage amplitude information of multiple channels, the traditional method adopts the working mode of channel switching output within one cycle, which is easily interfered by the switching signal and the external load. The technical solution of the embodiment of the utility model is based on the comparison of the amplitude of the detection signal. When the amplitude information is read within one reading cycle, the analog output waveform has reached the peak value, which ensures the stability of the amplitude output of the over-threshold channel and reduces the interference of the digital signal on the analog waveform.

[0048] In some embodiments, the energy spectrum data readout circuit 100 may include a plurality of acquisition circuits, for example, Figure 1AThe two acquisition circuits 110_1 and 110_2 are shown. For example, the energy spectrum data readout circuit 100 may be provided with a 256-pixel CdZnTe detector readout module, which includes two 128-subchannel CdZnTe detector readout chips, which serve as acquisition circuits 110_1 and 110_2, respectively. Each acquisition circuit may send a global trigger signal to the control circuit when detecting an over-threshold channel. The control circuit may respond to the global trigger signal and send a chip selection signal and an address readout clock to each acquisition circuit. The selected acquisition circuit outputs the address of the over-threshold channel according to the address clock and sends the detection information of the over-threshold channel to the analog-to-digital conversion circuit. For example, when the n-th sub-channel in the acquisition circuit 110_1 and the m-th sub-channel in the acquisition circuit 110_2 are triggered, the acquisition circuits 110_1 and 110_2 may both send a global trigger signal to the control circuit 120. In response to receiving the global trigger signal, the control circuit 120 may select one acquisition circuit from the two acquisition circuits 110_1 and 110_2 according to a preset priority as the acquisition circuit from which data is to be read. For example, assuming that the priority of the acquisition circuit 110_1 is higher than that of the acquisition circuit 110_2, the control circuit 120 may select the acquisition circuit 110_1 as the acquisition circuit from which data is to be read. In this case, the control circuit 120 may send a chip selection signal to the acquisition circuits 110_1 and 110_2 to select the detection signal and address of the over-threshold channel to be read from the acquisition circuit 110_1. The control circuit 120 also sends an address read clock to the acquisition circuits 110_1 and 110_2, and the selected acquisition circuit 110_1 may output the address of the over-threshold channel to the control circuit 120 according to the address read clock.

[0049] The embodiment of the utility model provides a multi-channel energy spectrum data readout circuit under low counting rate conditions, wherein the output ends of multiple sub-channels in the acquisition circuit are connected to a multiplexer, and when there is no current pulse signal, the output of the multiplexer is in a high impedance state, so the output ports of multiple chips in the acquisition circuit can be spliced ​​together, and the detection signal is processed through an analog-to-digital conversion circuit. This single-channel triggered working mode has few readout interfaces and strong scalability, and can meet the detection needs of low counting rate scenarios.

[0050] Figure 1C The structural block diagram of a sub-channel of the acquisition circuit in the energy spectrum data readout circuit according to the embodiment of the utility model is schematically shown.

[0051] like Figure 1C As shown, each sub-channel 111 in the acquisition circuit includes a charge sensitive amplifier 1111 , a signal amplitude measurement circuit 1112 and an over-threshold mark generation circuit 1113 .

[0052] The charge sensitive amplifier 1111 is used to receive the current pulse signal generated by the X-ray and convert it into a voltage signal.

[0053] The signal amplitude measurement circuit 1112 is connected to the charge sensitive amplifier 1111 and is used to obtain a detection signal containing voltage amplitude information from the voltage signal.

[0054] In some embodiments of the present invention, the signal amplitude measurement circuit 1112 may include a first shaping circuit 11121 and a peak sampling and holding circuit 11122. The first shaping circuit 11121 is connected to the charge sensitive amplifier 1111, and is used to filter and shape the voltage signal output by the charge sensitive amplifier to obtain, for example, a quasi-Gaussian waveform. The peak sampling and holding circuit 11122 is connected to the first shaping circuit 11121, and is used to perform peak sampling and holding on the quasi-Gaussian waveform output by the first shaping circuit to obtain a detection signal containing voltage amplitude information.

[0055] The threshold value flag generation circuit 1113 is connected to the charge sensitive amplifier 1111, and is used to generate a threshold value flag according to the relationship between the amplitude of the voltage signal and the preset threshold value. When the amplitude of the voltage signal is higher than the preset threshold value, the sub-channel is triggered, and when the amplitude of the voltage signal is lower than or equal to the preset threshold value, the sub-channel is not triggered.

[0056] In some embodiments of the utility model, the threshold value identification generating circuit 1113 may include a second shaping circuit 11131 and a comparator 11132. The second shaping circuit 11131 is connected to the charge sensitive amplifier 1111, and is used to filter and shape the voltage signal output by the charge sensitive amplifier. The comparator 11132 is connected to the second shaping circuit 11131, and is used to compare the signal amplitude output by the second shaping circuit with the preset threshold value, and generate the threshold value identification according to the comparison result. For example, if the signal amplitude exceeds the preset threshold value, the threshold value identification is set to a high level, indicating that the sub-channel is a threshold value channel; otherwise, the threshold value identification is set to a low level, indicating that the sub-channel is not a threshold value channel. In some embodiments, the shaping time of the second shaping circuit can be less than the shaping time of the first shaping circuit, so that the first shaping circuit can retain more waveform information of the signal through slower shaping; the second shaping circuit can quickly extract the peak information in the signal through faster shaping, so as to compare with the threshold value later.

[0057] During operation, after receiving the current pulse signal, the subchannel obtains a voltage signal through the charge sensitive amplifier 1111, and the charge sensitive amplifier 1111 sends the voltage signal to the signal amplitude measurement circuit 1112 and the over-threshold mark generation circuit 1113. The signal amplitude measurement circuit 1112 extracts the voltage amplitude from the voltage signal and converts it into a detection signal containing voltage amplitude information, and the over-threshold mark generation circuit 1113 generates an over-threshold mark according to whether the acquired signal amplitude exceeds a preset threshold.

[0058] Figure 2 The structure block diagram of the trigger circuit in the acquisition circuit in the energy spectrum data readout circuit according to the embodiment of the utility model is schematically shown.

[0059] like Figure 2 As shown, the trigger circuit includes a global trigger signal generating circuit 2121 and an address output circuit 2122 .

[0060] The global trigger signal generating circuit 2121 is connected to the output end of the threshold value identification generating circuit of each sub-channel, and is used to determine whether there is an over-threshold channel among multiple sub-channels based on the over-threshold identification output by the threshold value identification generating circuit, and generate a global trigger signal when there is an over-threshold channel.

[0061] In some embodiments of the present invention, the global trigger signal generating circuit 2121 may include an OR gate 21211, wherein multiple input terminals of the OR gate are respectively connected to the outputs of the threshold value over-marking generating circuits of multiple sub-channels to respectively receive the threshold value over-marking RPB of each sub-channel. <0> , RPB <1> , ..., RPB <127> The output end of the OR gate is connected to the control circuit to provide the global trigger signal TOR to the control circuit. The OR gate can generate a global trigger signal based on the threshold value crossing flag and send the global trigger signal to the control circuit.

[0062] For example, when the nth sub-channel in the acquisition circuit is an over-threshold channel, the over-threshold flag RPB received by the input terminal connected to the over-threshold flag generating circuit of the nth sub-channel <n>The threshold value received by the input end connected to other sub-channels is at a high level, and the over-threshold mark is at a low level. After the OR operation, the OR gate generates a high-level global trigger signal at the output end and sends it to the control circuit.

[0063] The address output circuit 2122 is connected to the threshold value identification generating circuit of each sub-channel, the global trigger signal generating circuit and the control end of the multiplexer, and is used to select the address of the over-threshold channel from multiple sub-channels for output according to the threshold value identification of each sub-channel and the global trigger signal, and output the channel selection signal indicating the over-threshold channel to the control end of the multiplexer.

[0064] In some embodiments of the present invention, the address output circuit 2122 may include a plurality of triggers 21221_0 , 21221_1 , … , 21221_n , … , 21221_127 (hereinafter collectively referred to as triggers 21221 ) and a priority encoder 21222 .

[0065] The input terminals D of the multiple triggers 21221 are respectively connected to the outputs of the threshold value generation circuits of the multiple sub-channels to receive the threshold value RPB of each sub-channel respectively. <0> , RPB <1> , ..., RPB <127> The control terminals CP of the multiple triggers 21221 are all connected to the output terminal of the global trigger signal generating circuit, and each trigger can output a channel trigger signal at the output terminal Q according to the signal of the input terminal D and the control terminal CP.

[0066] For example, when the nth subchannel is an over-threshold channel, the global trigger signal generating circuit 2121 generates a high-level global trigger signal TOR. The over-threshold flag received at the input end of the trigger 21221_n and the global trigger signal TOR received at the control end are both high-level, so 21221_n generates a high-level trigger flag Trig at the output end. <n>Since the threshold value flag received by the input end of other triggers is low level, the trigger flag at the output end is low level. According to the trigger flag output by each trigger, it can be determined that the sub-channel corresponding to the trigger 21221_n is the threshold value channel.

[0067] The multiple input terminals of the priority encoder 21222 are respectively connected to the output terminals of the multiple triggers 21221 to receive the trigger identifier Trig output by each trigger. <1> , Trig <2> , ..., Trig <127> . The first output end of the priority encoder 21222 is connected to the control end of the multiplexer to provide it with a channel selection signal, such as a 128-bit Switch<127:0>, in which one of the 128 bits of the channel selection signal is 1 and the other bits are 0. Under the control of the channel selection signal Switch<127:0>, the multiplexer can select a sub-channel from multiple sub-channels as an over-threshold channel and output a detection signal of the over-threshold channel. The second output end of the priority encoder 21222 is used to output an address to the control circuit, such as a 7-bit address ADDR<6:0>. The priority encoder 21222 can output a channel trigger signal Trig<6:0> according to the channel trigger signal Trig<6:0> output by multiple triggers. <1> , Trig <2> , ..., Trig <127> , determine the over-threshold channel from the multiple sub-channels, and output the channel selection signal Switch<127:0> indicating the over-threshold channel at the first output terminal, and output the address ADDR<6:0> of the over-threshold channel at the second output terminal.

[0068] In some embodiments of the utility model, the priority encoder can also select the address of an over-threshold channel from the multiple over-threshold channels for output according to a preset priority when there are multiple over-threshold channels, and output a channel selection signal indicating the selected over-threshold channel.

[0069] Assume that the priority of the 128 sub-channels CH0 to CH127 of the acquisition circuit is CH0>CH1>......>CH127. If both sub-channels CH0 and CH1 are triggered, the trigger flags Trig corresponding to sub-channels CH0 and CH1 are <1> , Trig <2> are all high level, and the trigger flags of other sub-channels are all low level, then the priority encoder can judge that the priority of sub-channel CH0 is higher than that of sub-channel CH1 according to this preset priority, and thus select the sub-channel CH0 with higher priority as the over-threshold channel between sub-channels CH0 and CH1, and output the channel selection signal Switch<127:0> for selecting sub-channel CH0 at the first output terminal, and output the address of sub-channel CH0 at the second output terminal ADDR. After completing the reading of the address and detection signal of the over-threshold channel CH0, the control circuit ends the current reading cycle and starts the reading of the next cycle. In the next reading cycle, the control circuit can read the address and detection signal of the over-threshold channel CH1 of the next priority, thereby realizing the data reading of all over-threshold channels.

[0070] In some embodiments of the present invention, the address output circuit 2212 may further include a parallel-to-serial conversion circuit 21223. The first input end of the parallel-to-serial conversion circuit is connected to the second output end of the priority encoder 21222 to receive the address of the over-threshold channel, and the address of the over-threshold channel is n1-bit parallel data, for example, it may be a 6-bit address ADDR<6:0>. The output end of the parallel-to-serial conversion circuit 2212 is connected to the control circuit. The parallel-to-serial conversion circuit 2212 may convert the address of the over-threshold channel into serial data to provide to the control circuit.

[0071] In some embodiments, the second input end of the parallel-to-serial conversion circuit 21223 can also be connected to a configuration register to receive an identification of an acquisition circuit, so as to select among these acquisition circuits when there are over-threshold channels in multiple acquisition circuits. The identification of the acquisition circuit can be n2 rows of parallel data, for example, it can be a 5-bit ID number ADDR<11:7>. In this case, the parallel-to-serial conversion circuit 21223 can convert the n1+n2 bits (for example, a 7-bit address and a 5-bit acquisition circuit identification, a total of 12 bits of data) of parallel data received at the first input end and the second input end into serial data and output it at the output end of the parallel-to-serial conversion circuit 21223.

[0072] For example, when the nth sub-channel in the acquisition circuit is an over-threshold channel, the first input end of the priority encoder is connected to obtain the 7-bit channel address ADDR<6:0> of the over-threshold channel, and the second input end of the configuration register is connected to obtain the 5-bit identifier ADDR<11:7> of the acquisition circuit. In response to receiving the global trigger signal, the control circuit sends an address read clock to the acquisition circuit, and the parallel-to-serial conversion circuit obtains 12-bit serial address data ADDR<11:0> according to the address read clock for subsequent imaging processing.

[0073] Figure 3 The flowchart of the data reading method executed by the energy spectrum data reading circuit according to the embodiment of the utility model is schematically shown.

[0074] In step S310 , each of the multiple sub-channels in the acquisition circuit receives a current pulse signal generated based on X-rays, and generates a detection signal based on the current pulse signal.

[0075] Step S320: In response to the existence of an over-threshold channel among the multiple sub-channels, the trigger circuit in the acquisition circuit generates a global trigger signal and a channel selection signal, and outputs the address of the over-threshold channel.

[0076] Step S330: The multiplexer in the acquisition circuit selects a cross-threshold channel from a plurality of sub-channels according to the channel selection signal provided by the trigger circuit to output a detection signal.

[0077] Step S340: the control circuit responds to the global trigger signal from the trigger circuit in the acquisition circuit and reads the detection signal output by the multiplexer in the acquisition circuit and the address output by the trigger circuit.

[0078] The embodiment of the utility model further provides an X-ray detector, comprising the energy spectrum data readout circuit in any embodiment of the utility model. In some embodiments, the X-ray detector can be implemented as a cadmium zinc telluride detector. In some embodiments, the X-ray detector can be a cadmium zinc telluride detector for detecting X-ray photons in the low energy region (<200keV) and low counting rate (<100kfl)s).

[0079] It should also be noted that the directional terms mentioned in the embodiments, such as "upper", "lower", "front", "back", "left", "right", etc., are only used to refer to the directions of the drawings and are not intended to limit the scope of protection of the present invention. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or constructions will be omitted when they may cause confusion in the understanding of the present invention.

[0080] The shapes and sizes of the components in the figures do not reflect the actual size and proportion, but only illustrate the contents of the embodiments of the utility model. In addition, in the claims, any reference symbols between brackets should not be constructed as limitations to the claims.

[0081] Furthermore, the word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

[0082] The ordinal numbers used in the specification and claims, such as "first", "second", "third", etc., to modify the corresponding elements, do not themselves mean that the elements have any ordinal numbers, nor do they represent the order of one element and another element, or the order in the manufacturing method. The use of these ordinal numbers is only used to clearly distinguish a component with a certain name from another component with the same name.

[0083] Those skilled in the art will appreciate that the features described in the various embodiments and / or claims of the present invention may be combined and / or combined in various ways, even if such combinations and / or combinations are not explicitly described in the present invention. In particular, the features described in the various embodiments and / or claims of the present invention may be combined and / or combined in various ways without departing from the spirit and teachings of the present invention. All of these combinations and / or combinations fall within the scope of the present invention.

[0084] The embodiments of the present invention are described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention. Although the embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage. The scope of the present invention is defined by the attached claims and their equivalents. Without departing from the scope of the present invention, a person skilled in the art may make a variety of substitutions and modifications, which should all fall within the scope of the present invention.< / n> < / n>

Claims

1. A spectrum data readout circuit, characterized in that: include: The acquisition circuit comprises: A plurality of sub-channels, each sub-channel being used to receive a current pulse signal generated based on X-rays and to generate a detection signal based on the current pulse signal; a trigger circuit connected to the plurality of sub-channels, for generating a global trigger signal and a channel selection signal in response to the presence of an over-threshold channel among the plurality of sub-channels, and outputting the address of the over-threshold channel, wherein the over-threshold channel is a sub-channel whose detection signal amplitude exceeds a preset threshold value; a multiplexer connected to the plurality of sub-channels and the trigger circuit, and configured to select the over-threshold channel from the plurality of sub-channels according to a channel selection signal provided by the trigger circuit to output a detection signal; and The control circuit is connected to the trigger circuit and the multiplexer of the acquisition circuit, and is used to read the detection signal output by the multiplexer and the address output by the trigger circuit in response to the global trigger signal from the trigger circuit.

2. The energy spectrum data readout circuit according to claim 1, characterized in that: Each subchannel consists of: A charge sensitive amplifier, used for receiving current pulse signals generated by X-rays and converting them into voltage signals; a signal amplitude measurement circuit, connected to the charge sensitive amplifier, for generating a detection signal based on the voltage signal, wherein the detection signal carries voltage amplitude information proportional to the received X-ray energy; The threshold value crossing flag generating circuit is connected to the charge sensitive amplifier and is used to generate a threshold value crossing flag according to the relationship between the amplitude of the voltage signal and the preset threshold value.

3. The energy spectrum data readout circuit according to claim 2, characterized in that: The signal amplitude measurement circuit comprises: A first shaping circuit, connected to the charge sensitive amplifier, for amplifying and filtering the voltage signal output by the charge sensitive amplifier; The peak sampling and holding circuit is connected to the first shaping circuit and is used to perform peak sampling and holding on the amplified and filtered shaped signal output by the first shaping circuit to obtain the detection signal.

4. The energy spectrum data readout circuit according to claim 3, characterized in that: The over-threshold mark generating circuit comprises: a second shaping circuit, connected to the charge sensitive amplifier, and used for filtering and shaping the voltage signal output by the charge sensitive amplifier, wherein a shaping time of the second shaping circuit is shorter than a shaping time of the first shaping circuit; A comparator is connected to the second shaping circuit, and is used to compare the signal amplitude output by the second shaping circuit with the preset threshold value, and generate an over-threshold mark according to the comparison result.

5. The energy spectrum data readout circuit according to claim 2, characterized in that: The trigger circuit comprises: A global trigger signal generating circuit is connected to the output end of the threshold value crossing mark generating circuit of each sub-channel, and is used to determine whether there is an over-threshold channel among the multiple sub-channels according to the threshold value crossing mark output by the threshold value crossing mark generating circuit, and generate the global trigger signal when there is an over-threshold channel; The address output circuit is connected to the threshold value identification generating circuit of each sub-channel, the global trigger signal generating circuit and the control end of the multiplexer, and is used to select the address of the over-threshold channel from the multiple sub-channels for output according to the threshold value identification of each sub-channel and the global trigger signal, and output a channel selection signal indicating the over-threshold channel to the control end of the multiplexer.

6. The energy spectrum data readout circuit according to claim 5, characterized in that: The global trigger signal generating circuit comprises: an OR gate, wherein a plurality of input terminals of the OR gate are respectively connected to output terminals of the threshold value marking generating circuits of the plurality of sub-channels, and an output terminal of the OR gate is connected to the control circuit.

7. The energy spectrum data readout circuit according to claim 5, characterized in that: The address output circuit comprises: A plurality of triggers, wherein input terminals of the plurality of triggers are respectively connected to output terminals of the threshold value-crossing flag generating circuits of the plurality of sub-channels, control terminals of the plurality of triggers are all connected to the output terminal of the global trigger signal generating circuit, and each trigger is configured to output a channel trigger signal at an output terminal according to signals at the input terminal and the control terminal; A priority encoder, wherein the multiple input terminals of the priority encoder are respectively connected to the output terminals of the multiple triggers, the first output terminal of the priority encoder is connected to the control terminal of the multiplexer, the second output terminal of the priority encoder is used to output an address, and the priority encoder is configured to determine an over-threshold channel from multiple sub-channels according to channel trigger signals output by the multiple triggers, and output a channel selection signal indicating the over-threshold channel at the first output terminal, and output the address of the over-threshold channel at the second output terminal.

8. The energy spectrum data readout circuit according to claim 7, characterized in that: The priority encoder is also configured to select an address of an over-threshold channel from the multiple over-threshold channels for output according to a preset priority when there are multiple over-threshold channels, and output a channel selection signal indicating the selected over-threshold channel.

9. The energy spectrum data readout circuit according to claim 7, characterized in that: The address output circuit also includes: a parallel-to-serial conversion circuit, wherein the first input end of the parallel-to-serial conversion circuit is connected to the second output end of the priority encoder to receive the address of the over-threshold channel, the address of the over-threshold channel is n1-bit parallel data, and the output end of the parallel-to-serial conversion circuit is connected to the control circuit.

10. The energy spectrum data readout circuit according to claim 9, characterized in that: The acquisition circuit further includes a configuration register, the configuration register being connected to the second input end of the parallel-to-serial conversion circuit in the address output circuit and being used to provide the identification of the acquisition circuit to the second input end of the parallel-to-serial conversion circuit, wherein the identification of the acquisition circuit is n2-bit parallel data; The parallel-to-serial conversion circuit is used to convert n1+n2 bits of parallel data received at the first input terminal and the second input terminal into serial data and output the serial data at the output terminal of the parallel-to-serial conversion circuit.

11. The energy spectrum data readout circuit according to any one of claims 1 to 10, characterized in that: The energy spectrum data readout circuit includes a plurality of acquisition circuits; The control circuit is also used to select an acquisition circuit from the at least two acquisition circuits according to a preset priority in response to receiving a global trigger signal from at least two acquisition circuits among the multiple acquisition circuits, and read the detection signal and address output by the selected acquisition circuit.

12. The energy spectrum data readout circuit according to any one of claims 1 to 10, characterized in that: The acquisition circuit is implemented as an application specific integrated circuit ASIC.

13. The energy spectrum data readout circuit according to any one of claims 1 to 10, characterized in that: The control circuit is implemented as a field programmable gate array FPGA.

14. An X-ray detector, characterized in that: The method comprises the energy spectrum data readout circuit as claimed in any one of claims 1 to 10.

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