Energy spectrum data readout circuit, x-ray detector, and data readout method

Abstract

The present disclosure provides an energy spectrum data readout circuit, an X-ray detector, and a data readout method. The energy spectrum data readout circuit comprises an acquisition circuit and a control circuit. The acquisition circuit comprises: a plurality of sub-channels used for receiving a current pulse signal generated on the basis of an X-ray, and generating a detection signal on the basis of the current pulse signal; a multiplexer connected to the plurality of sub-channels that selects and outputs a detection signal of at least one channel from among the plurality of sub-channels according to a channel selection signal; and a trigger circuit connected to the plurality of sub-channels and is used for generating a global trigger signal according to an over-threshold identifier received from the plurality of sub-channels, and outputting an address of an over-threshold channel according to an address readout request. The control circuit is connected to the acquisition circuit and is used, in response to a trigger signal from the acquisition circuit, for generating a chip selection signal and an address readout request, and providing the signal and request to the acquisition circuit.

Description

Energy spectrum data readout circuit, X-ray detector and data readout method

[0001] This application claims priority to Chinese patent application No. 202311830350.6, filed on December 28, 2023, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present disclosure relates to the field of detector readout circuits, and more specifically, to an energy spectrum data readout circuit and a data readout method. Background Art

[0003] At present, X-ray diffraction technology is commonly used in security inspection sites such as aviation, railways, and logistics to inspect suitcases, parcels, etc. After X-rays are irradiated on the inspection items, the detector can detect and form a diffraction energy spectrum that changes with the X-ray energy distribution, so as to obtain the molecular structure information of the inspection items based on the diffraction energy spectrum, thereby realizing the identification of crystalline contraband.

[0004] When acquiring a diffraction spectrum, the detector interacts with the X-rays to generate a current pulse signal, from which voltage amplitude information is extracted. However, the detector imaging module has multiple channels, and only one or more channels will generate voltage amplitudes at any given time. Therefore, it is necessary to obtain both the voltage amplitude and the location of the channel generating the voltage amplitude. Existing methods require reading and analyzing the voltage amplitudes of a large number of channels, and only after analyzing all the read channel information can the next reading cycle proceed. This results in a long reading cycle, which has certain limitations in practical scenarios. Summary of the Invention

[0005] The present disclosure provides an energy spectrum data readout circuit, an X-ray detector, and a data readout method.

[0006] According to one aspect of the present disclosure, the present disclosure provides an energy spectrum data readout circuit, comprising: an acquisition circuit, the acquisition circuit comprising: multiple 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 multiple 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 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 the over-threshold channel from the multiple sub-channels to output the 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 a global trigger signal from the trigger circuit.

[0007] According to an embodiment of the present disclosure, each sub-channel includes: a charge-sensitive amplifier, which is used to receive a current pulse signal generated based on X-rays and convert it into a voltage signal; a signal amplitude measurement circuit, which is connected to the charge-sensitive amplifier and is 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 flag generation circuit, which is connected to the charge-sensitive amplifier and is used to generate an over-threshold flag based on the relationship between the amplitude of the voltage signal and a preset threshold.

[0008] According to an embodiment of the present disclosure, 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.

[0009] According to an embodiment of the present disclosure, the over-threshold flag generating circuit includes: a second shaping circuit, connected to the charge-sensitive amplifier, for filtering and shaping the voltage signal output by the charge-sensitive amplifier, wherein the shaping time of the second shaping circuit is less than the shaping time of the first shaping circuit; a comparator, connected to the second shaping circuit, for comparing the signal amplitude output by the second shaping circuit with a preset threshold, and generating an over-threshold flag based on the comparison result.

[0010] According to an embodiment of the present disclosure, 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 an over-threshold channel exists; 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 based on the over-threshold 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.

[0011] According to an embodiment of the present disclosure, the global trigger signal generating circuit includes: an OR gate, wherein multiple input terminals of the OR gate are respectively connected to the output terminals of the threshold value identification generating circuits of multiple sub-channels, and the output terminal of the OR gate is connected to the control circuit.

[0012] According to an embodiment of the present disclosure, the address output circuit includes: multiple triggers, the input ends of the multiple triggers are respectively connected to the output ends of the over-threshold 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.

[0013] According to an embodiment of the present disclosure, the priority encoder is also configured to select the address of an over-threshold channel from the multiple over-threshold channels according to a preset priority for output when there are multiple over-threshold channels, and output a channel selection signal indicating the selected over-threshold channel.

[0014] According to an embodiment of the present disclosure, the address output circuit also includes: a parallel-to-serial conversion circuit, 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 cross-threshold channel, the address of the cross-threshold channel is n1-bit parallel data, and the output end of the parallel-to-serial conversion circuit is connected to the control circuit.

[0015] According to an embodiment of the present disclosure, 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, where 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.

[0016] According to an embodiment of the present disclosure, 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.

[0017] According to an embodiment of the present disclosure, the acquisition circuit is implemented as an application-specific integrated circuit (ASIC).

[0018] According to an embodiment of the present disclosure, the control circuit is implemented as a field programmable gate array (FPGA).

[0019] According to another aspect of the present disclosure, the present disclosure provides an X-ray detector, comprising the energy spectrum data readout circuit in any one of the above embodiments.

[0020] According to another aspect of the present disclosure, the present disclosure provides a data readout method performed by an energy spectrum data readout circuit, including: multiple sub-channels in the acquisition circuit each receive a current signal generated based on X-rays, and generate voltage amplitude information based on the current signal; a trigger circuit in the acquisition circuit generates 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 outputs the address of the over-threshold channel; a multiplexer in the acquisition circuit selects the voltage amplitude information of the over-threshold channel from the multiple sub-channels according to the channel selection signal provided by the trigger circuit for output; and a control circuit reads the voltage amplitude information output by the multiplexer in the acquisition circuit and the address output by the trigger circuit in response to the global trigger signal from the trigger circuit in the acquisition circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above contents and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0022] FIG1A schematically shows a block diagram of a circuit for reading out energy spectrum data according to an embodiment of the present disclosure;

[0023] FIG1B schematically shows a structural block diagram of an acquisition circuit in an energy spectrum data readout circuit according to an embodiment of the present disclosure;

[0024] FIG1C schematically 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 present disclosure;

[0025] FIG2 schematically shows a structural block diagram of a trigger circuit in an acquisition circuit in an energy spectrum data readout circuit according to an embodiment of the present disclosure;

[0026] FIG3 schematically shows a flow chart of a data readout method executed by an energy spectrum data readout circuit according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0027] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present disclosure. In the detailed description below, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0028] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise," "include," etc. used herein indicate the presence of the features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0029] All terms used herein (including technical and scientific terms) 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.

[0030] When expressions such as "at least one of A, B and C, etc." are used, they should generally be interpreted in accordance with 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.).

[0031] In the technical solutions disclosed herein, the collection, storage, use, processing, transmission, provision, disclosure and application of the data involved (including but not limited to user personal information) comply with the provisions of relevant laws and regulations, take necessary confidentiality measures, and do not violate public order and good morals.

[0032] Embodiments of the present disclosure provide an energy spectrum data readout circuit and a data readout method.

[0033] Figure 1A schematically shows a structural block diagram of an energy spectrum data readout circuit according to an embodiment of the present disclosure. Figure 1B schematically shows a structural block diagram of an acquisition circuit in an energy spectrum data readout circuit according to an embodiment of the present disclosure.

[0034] 1A and 1B , 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 .

[0035] The acquisition circuit 110 includes a plurality of sub-channels 111_0 , 111_1 , . . . , 111_127 , a trigger circuit 112 , and a multiplexer 113 .

[0036] Each of the multiple subchannels 111_0, 111_1, ..., 111_127 (hereinafter collectively referred to as subchannel 111) receives the current pulse signal generated by X-rays entering the semiconductor detector and, based on the current pulse signal, generates a detection signal for determining the type of substance. The detection signal includes voltage amplitude information proportional to the X-ray energy. When X-rays are coherently scattered by a substance, the scattered coherent light interferes within the substance. The angle and wavelength of the emitted diffracted light vary depending on the substance. By measuring the energy spectrum of the emitted light and inverting the crystal structure within the substance using the Bragg formula, the substance's type can be determined.

[0037] In some embodiments, after X-rays pass through the object being inspected, they interact with the pixels of a semiconductor detector (e.g., a cadmium zinc telluride detector) to generate a current signal. This current signal is then extracted through analog front-end electronics (including a charge-sensitive amplifier, filter shaping circuits, and peak sample-and-hold circuits). The voltage amplitude is proportional to the energy of the X-ray photons. Based on this voltage amplitude information, a radiographic image can be generated that reflects the internal structure of the object being inspected.

[0038] 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 .

[0039] The trigger circuit 112 is connected to multiple 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 multiple 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. When the voltage amplitude information exceeds the preset threshold, it indicates that the sub-channel is triggered. In some embodiments, since the present disclosure 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.

[0040] 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 and output it.

[0041] 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 disclosure, the control circuit 120 can be implemented using a field programmable gate array (FPGA).

[0042] The traditional method reads the detection signals of all sub-channels or all triggered sub-channels in the acquisition circuit. This method has a long reading cycle. 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.

[0043] An embodiment of the present disclosure provides an energy spectrum data readout circuit. By setting a trigger circuit and a multiplexer, the detection signal and address of the cross-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 excessively long reading cycles in traditional methods and reducing the waiting time for detection signals.

[0044] In some embodiments, the acquisition circuit 110 can be implemented as an application-specific integrated circuit (ASIC). An ASIC can integrate the functions of several small-scale circuits onto a single chip, thereby meeting the functions required of the acquisition circuit in this disclosure. For example, the acquisition circuit 110 can be implemented as a cadmium zinc telluride (CZN) detector readout chip, which may include 128 subchannels. Each subchannel 111 may include a charge-sensitive amplifier, a filter shaping circuit, and a peak sample-and-hold circuit. The output of each subchannel is connected to a multiplexer 113. When a subchannel is not acquiring a current pulse signal, the output of the multiplexer is in a high-impedance state. When a subchannel in the chip is triggered, the trigger circuit 112 in the acquisition circuit 110 sends a global trigger signal to the control circuit 120. In response to the global trigger signal, the control circuit sends an address readout clock to the acquisition circuit. After receiving the address readout clock, the acquisition circuit's trigger circuit sends the address of the cross-threshold channel to the control circuit. The multiplexer receives the channel selection signal sent by the trigger circuit and acquires and outputs the detection signal of the cross-threshold channel.

[0045] In some embodiments of the present disclosure, 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 configured to receive detection signals of cross-threshold channels sent by the acquisition circuit and convert the voltage amplitude information included in the detection signals from analog signals into digital signals. The analog-to-digital conversion circuit 130 outputs a digital signal, which, along with the address read by the control circuit 120, may be provided to a host computer as readout data. The host computer may then perform subsequent processing based on the readout data, for example, generating a radiographic image of the detected object based on the readout data.

[0046] In some embodiments of the present disclosure, 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, an identification of the acquisition circuit.

[0047] In some embodiments of the present disclosure, the acquisition circuit 110 may further include a bias circuit 115 for providing a bias current or a bias voltage to ensure normal operation of the entire circuit.

[0048] In some embodiments of the present disclosure, the energy spectrum data readout circuit may have a read cycle. During a read cycle, the acquisition circuit, in response to the presence of a cross-threshold channel among the multiple sub-channels, outputs the address and detection signal of the cross-threshold channel, which is then read by the control circuit. When the control circuit completes the read cycle, all circuits are reset and the next read cycle begins.

[0049] The embodiment of the present disclosure only reads the detection signal and address of one cross-threshold channel in one reading cycle. The reading cycle 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 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 a 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 present disclosure is based on the amplitude of the comparison 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 cross-threshold channel and reduces the interference of the digital signal on the analog waveform.

[0050] In some embodiments, the energy spectral data readout circuit 100 may include multiple acquisition circuits, such as the two acquisition circuits 110_1 and 110_2 shown in FIG1A . For example, the energy spectral data readout circuit 100 may include a 256-pixel CdZnTe detector readout module, which includes two CdZnTe detector readout chips with 128 subchannels, serving as acquisition circuits 110_1 and 110_2, respectively. Upon detecting a cross-threshold channel, each acquisition circuit may send a global trigger signal to the control circuit. In response to the global trigger signal, the control circuit may send a chip selection signal and an address readout clock to each acquisition circuit. The selected acquisition circuit outputs the address of the cross-threshold channel based on the address clock and transmits the detection information of the cross-threshold channel to the analog-to-digital conversion circuit. For example, when the nth subchannel in acquisition circuit 110_1 and the mth subchannel in acquisition circuit 110_2 are triggered, both acquisition circuits 110_1 and 110_2 may send a global trigger signal to the control circuit 120. In response to receiving the global trigger signal, the control circuit 120 can select one of the two acquisition circuits 110_1 and 110_2 as the acquisition circuit from which to read data based on a preset priority. For example, if acquisition circuit 110_1 has a higher priority than acquisition circuit 110_2, the control circuit 120 can select acquisition circuit 110_1 as the acquisition circuit from which to read data. In this case, the control circuit 120 can send a chip selection signal to acquisition circuits 110_1 and 110_2 to select acquisition circuit 110_1 to read the detection signal and address of the cross-threshold channel. The control circuit 120 also sends an address read clock to acquisition circuits 110_1 and 110_2. The selected acquisition circuit 110_1 can output the address of the cross-threshold channel to the control circuit 120 based on the address read clock.

[0051] The disclosed embodiments provide a multi-channel energy spectrum data readout circuit for low count rates. The outputs of multiple sub-channels in the acquisition circuit are connected to a multiplexer. In the absence of a current pulse signal, the multiplexer output is in a high-impedance state. This allows the output ports of multiple chips in the acquisition circuit to be spliced ​​together, and a single analog-to-digital conversion circuit processes the detection signal. This single-channel triggering mode reduces readout interfaces and offers strong scalability, meeting the detection needs of low-count-rate scenarios.

[0052] FIG1C schematically 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 present disclosure.

[0053] As shown in FIG1C , each sub-channel 111 in the acquisition circuit includes a charge-sensitive amplifier 1111 , a signal amplitude measurement circuit 1112 , and an over-threshold flag generation circuit 1113 .

[0054] 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.

[0055] 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.

[0056] In some embodiments of the present disclosure, 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 configured 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 configured 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.

[0057] Threshold crossing flag generation circuit 1113 is connected to charge-sensitive amplifier 1111 and is configured to generate a threshold crossing flag based on the relationship between the voltage signal amplitude and a preset threshold. If the voltage signal amplitude exceeds the preset threshold, the subchannel is triggered. If the voltage signal amplitude is less than or equal to the preset threshold, the subchannel is not triggered.

[0058] In some embodiments of the present disclosure, the threshold-crossing flag 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 a preset threshold and generate an threshold-crossing flag based on the comparison result. For example, if the signal amplitude exceeds the preset threshold, the threshold-crossing flag is set to a high level, indicating that the subchannel is a threshold-crossing channel; otherwise, the threshold-crossing flag is set to a low level, indicating that the subchannel is not a threshold-crossing channel. In some embodiments, the shaping time of the second shaping circuit can be shorter than the shaping time of the first shaping circuit. In this way, the first shaping circuit can retain more waveform information of the signal through slower shaping; the second shaping circuit can quickly extract peak information from the signal through faster shaping for subsequent comparison with the threshold.

[0059] During operation, after receiving a current pulse signal, the subchannel processes it through the charge-sensitive amplifier 1111 to obtain a voltage signal. The charge-sensitive amplifier 1111 then sends the voltage signal to the signal amplitude measurement circuit 1112 and the threshold-crossing flag 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. The threshold-crossing flag generation circuit 1113 generates a threshold-crossing flag based on whether the acquired signal amplitude exceeds a preset threshold.

[0060] FIG2 schematically shows a structural block diagram of a trigger circuit in an acquisition circuit in an energy spectrum data readout circuit according to an embodiment of the present disclosure.

[0061] As shown in FIG. 2 , the trigger circuit includes a global trigger signal generating circuit 2121 and an address output circuit 2122 .

[0062] 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.

[0063] In some embodiments of the present disclosure, 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 flag generating circuits of multiple sub-channels to respectively receive the threshold value flag RPB of each sub-channel. <0> , RPB <1> ,...,RPB <127> The output of the OR gate is connected to the control circuit to provide the global trigger signal TOR thereto. The OR gate can generate a global trigger signal based on the threshold crossing flag and send the global trigger signal to the control circuit.

[0064] 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 is <n>The over-threshold indicator received by the input end connected to other sub-channels is at a high level, and the OR gate generates a high-level global trigger signal at the output end after the OR operation and sends it to the control circuit.

[0065] 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 based on 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.

[0066] In some embodiments of the present disclosure, the address output circuit 2122 may include a plurality of flip-flops 21221_0 , 21221_1 , . . . , 21221_n , . . . , 21221_127 (hereinafter collectively referred to as flip-flops 21221 ) and a priority encoder 21222 .

[0067] The input terminals D of the multiple triggers 21221 are connected to the outputs of the threshold value flag generating circuits of the multiple sub-channels to receive the threshold value flag 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.

[0068] For example, when the nth sub-channel 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-crossing flags received by the input terminals of other triggers are low, the trigger flags at the output terminals are low. Based on the trigger flags output by each trigger, it can be determined that the sub-channel corresponding to the trigger 21221_n is the threshold-crossing channel.

[0069] The multiple input terminals of the priority encoder 21222 are connected to the output terminals of the multiple triggers 21221 respectively to receive the trigger flags 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 the 128-bit Switch<127:0>, where 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 one 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 according to the output of multiple triggers. <1> , Trig <2> , ..., Trig <127> , determine the over-threshold channel from 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.

[0070] In some embodiments of the present disclosure, the priority encoder can also select the address of an over-threshold channel from the multiple over-threshold channels according to a preset priority for output when there are multiple over-threshold channels, and output a channel selection signal indicating the selected over-threshold channel.

[0071] Assume that the priority of the 128 sub-channels CH0 to CH127 of the acquisition circuit is CH0>CH1>...>CH127. If sub-channels CH0 and CH1 are both triggered, the trigger flags Trig corresponding to sub-channels CH0 and CH1 are <1> , Trig <2> If the trigger flags of sub-channels CH0 and CH1 are all high and the trigger flags of other sub-channels are all low, the priority encoder can determine that the priority of sub-channel CH0 is higher than that of sub-channel CH1 based on this preset priority, and thus select sub-channel CH0 with a higher priority as the cross-threshold channel between sub-channels CH0 and CH1. The control circuit outputs the channel selection signal Switch<127:0> for selecting sub-channel CH0 at the first output terminal and outputs the address of sub-channel CH0 at the second output terminal ADDR. After completing the reading of the address and detection signal of the cross-threshold channel CH0, the control circuit ends the current read cycle and begins the next read cycle. In the next read cycle, the control circuit can read the address and detection signal of the next priority cross-threshold channel CH1, thereby realizing data reading of all cross-threshold channels.

[0072] In some embodiments of the present disclosure, the address output circuit 2212 may further include a parallel-to-serial conversion circuit 21223. A first input of the parallel-to-serial conversion circuit is connected to the second output of the priority encoder 21222 to receive the address of the cross-threshold channel. The address of the cross-threshold channel is n1-bit parallel data, for example, a 6-bit address ADDR<6:0>. An output of the parallel-to-serial conversion circuit 2212 is connected to the control circuit. The parallel-to-serial conversion circuit 2212 can convert the address of the cross-threshold channel into serial data and provide it to the control circuit.

[0073] In some embodiments, the second input of the parallel-to-serial conversion circuit 21223 can also be connected to a configuration register to receive an acquisition circuit identifier, which is used to select among multiple acquisition circuits when all have over-threshold channels. The acquisition circuit identifier can be n2 rows of parallel data, for example, a 5-bit ID number ADDR<11:7>. In this case, the parallel-to-serial conversion circuit 21223 can convert the n1+n2 bits (e.g., a 7-bit address and a 5-bit acquisition circuit identifier, for a total of 12 bits of data) of parallel data received at the first and second input terminals into serial data and output it at the output terminal of the parallel-to-serial conversion circuit 21223.

[0074] For example, if the nth subchannel in the acquisition circuit is a cross-threshold channel, the first input of the priority encoder is connected to obtain the 7-bit channel address ADDR<6:0> of the cross-threshold channel, and the second input of the configuration register is connected to obtain the 5-bit identifier ADDR<11:7> of the acquisition circuit. In response to receiving a global trigger signal, the control circuit sends an address read clock to the acquisition circuit. The parallel-to-serial conversion circuit uses this address read clock to obtain 12-bit serial address data ADDR<11:0> for subsequent imaging processing.

[0075] FIG3 schematically shows a flow chart of a data readout method executed by an energy spectrum data readout circuit according to an embodiment of the present disclosure.

[0076] 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.

[0077] In step S320 , the trigger circuit in the acquisition circuit generates a global trigger signal and a channel selection signal in response to the presence of an over-threshold channel among the multiple sub-channels, and outputs the address of the over-threshold channel.

[0078] In step S330 , the multiplexer in the acquisition circuit selects a cross-threshold channel from the multiple sub-channels according to the channel selection signal provided by the trigger circuit to output a detection signal.

[0079] In 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.

[0080] Embodiments of the present disclosure also provide an X-ray detector, including the energy spectrum data readout circuit of any embodiment of the present disclosure. 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 (<200 keV) and low count rate (<100 kfps).

[0081] It should also be noted that directional terms such as "up," "down," "front," "back," "left," and "right" mentioned in the embodiments are merely references to the directions in the accompanying drawings and are not intended to limit the scope of protection of this disclosure. Throughout the drawings, identical elements are represented by identical or similar reference numerals. Conventional structures or configurations will be omitted where they may cause confusion in understanding this disclosure.

[0082] Furthermore, the shapes and sizes of the components in the figures do not reflect the actual sizes and proportions, but are merely illustrative of the contents of the embodiments of the present disclosure. In addition, in the claims, any reference signs placed between brackets should not be construed as limiting the claims.

[0083] 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.

[0084] The use of ordinal numbers such as "first," "second," and "third" in the specification and claims to modify corresponding elements does not, in itself, imply any ordinal number for the element, nor does it represent the order of one element relative to another or the order in the manufacturing method. The use of such ordinal numbers is solely to clearly distinguish one element with a certain name from another element with the same name.

[0085] Those skilled in the art will appreciate that the features described in the various embodiments and / or claims of this disclosure may be combined and / or coupled in various ways, even if such combinations and / or couplings are not explicitly described in this disclosure. In particular, the features described in the various embodiments and / or claims of this disclosure may be combined and / or coupled in various ways without departing from the spirit and teachings of this disclosure. All such combinations and / or couplings are intended to fall within the scope of this disclosure.

[0086] The embodiments of the present disclosure are described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present disclosure. Although each embodiment has been described separately above, this does not mean that the measures in each embodiment cannot be used in combination to advantage. The scope of the present disclosure is defined by the appended claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art may make various substitutions and modifications, which should all fall within the scope of the present disclosure.< / n> < / n>

Claims

1. An energy spectrum data readout circuit, comprising: An acquisition circuit, the acquisition circuit comprising: A plurality of sub-channels, each sub-channel being configured to receive a current pulse signal generated based on an X-ray and generate a detection signal based on the current pulse signal; A trigger circuit, connected to the plurality of sub-channels, configured to generate a global trigger signal and a channel gating 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, wherein the over-threshold channel is a sub-channel whose generated detection signal amplitude exceeds a preset threshold; A multiplexer, connected to the plurality of sub-channels and the trigger circuit, configured to select the over-threshold channel from the plurality of sub-channels according to the channel gating signal provided by the trigger circuit to output a detection signal; and A control circuit, connected to the trigger circuit and the multiplexer of the acquisition circuit, configured 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 reading circuit according to claim 1, wherein, Each sub-channel comprises: A charge sensitive amplifier, configured to receive a current pulse signal generated based on an X-ray and convert it into a voltage signal; A signal amplitude measurement circuit, connected to the charge sensitive amplifier, configured to generate a detection signal based on the voltage signal, the detection signal carrying voltage amplitude information proportional to the received X-ray energy; An over-threshold identification generation circuit, connected to the charge sensitive amplifier, configured to generate an over-threshold identification according to the relationship between the amplitude of the voltage signal and the preset threshold.

3. The energy spectrum data reading circuit according to claim 2, wherein, The signal amplitude measurement circuit comprises: A first shaping circuit, connected to the charge sensitive amplifier, configured to amplify and filter and shape the voltage signal output by the charge sensitive amplifier; A peak sampling and holding circuit, connected to the first shaping circuit, configured to perform peak sampling and holding on the signal output by the first shaping circuit after amplification and filtering and shaping to obtain the detection signal.

4. The energy spectrum data reading circuit according to claim 2 or 3, wherein, The over-threshold identification generation circuit comprises: A second shaping circuit, connected to the charge sensitive amplifier, configured to filter and shape the voltage signal output by the charge sensitive amplifier, wherein the shaping time of the second shaping circuit is less than the shaping time of the first shaping circuit; A comparator, connected to the second shaping circuit, configured to compare the signal amplitude output by the second shaping circuit with the preset threshold and generate an over-threshold identification according to the comparison result.

5. The energy spectrum data reading circuit according to any one of claims 2 to 4, wherein, The trigger circuit comprises: A global trigger signal generation circuit, connected to the output ends of the over-threshold identification generation circuits of each sub-channel, configured to determine whether there is an over-threshold channel among the plurality of sub-channels according to the over-threshold identifications output by the over-threshold identification generation circuits, and generate the global trigger signal in the case of the presence of an over-threshold channel; An address output circuit, connected to the over-threshold identification generation circuits of each sub-channel, the global trigger signal generation circuit, and the control end of the multiplexer, configured to select the address of the over-threshold channel from the plurality of sub-channels according to the over-threshold identifications of each sub-channel and the global trigger signal for output, and output a channel gating signal indicating the over-threshold channel to the control end of the multiplexer.

6. The energy spectrum data reading circuit according to claim 5, wherein, The global trigger signal generation circuit includes: an OR gate, multiple input terminals of the OR gate are respectively connected to output terminals of the over-threshold identification generation circuits of the multiple sub-channels, and an output terminal of the OR gate is connected to the control circuit.

7. The energy spectrum data reading circuit according to claim 5 or 6, wherein The address output circuit includes: Multiple flip-flops, input terminals of the multiple flip-flops are respectively connected to output terminals of the over-threshold identification generation circuits of the multiple sub-channels, control terminals of the multiple flip-flops are all connected to an output terminal of the global trigger signal generation circuit, and each flip-flop 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, multiple input terminals of the priority encoder are respectively connected to output terminals of the multiple flip-flops, a first output terminal of the priority encoder is connected to a control terminal of the multiplexer, a 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 the channel trigger signals output by the multiple flip-flops, 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 reading circuit according to claim 7, wherein, The priority encoder is further configured to, in the case of multiple over-threshold channels, select an address of one over-threshold channel from the multiple over-threshold channels according to a preset priority for output, and output a channel selection signal indicating the selected over-threshold channel.

9. The energy spectrum data readout circuit according to claim 7 or 8, wherein, The address output circuit further includes: a parallel-to-serial conversion circuit, a first input terminal of the parallel-to-serial conversion circuit is connected to the second output terminal 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 an output terminal of the parallel-to-serial conversion circuit is connected to the control circuit.

10. The energy spectrum data reading circuit according to claim 9, wherein, The acquisition circuit further includes a configuration register, the configuration register is connected to a second input terminal of the parallel-to-serial conversion circuit in the address output circuit, and is used to provide an identifier of the acquisition circuit to the second input terminal of the parallel-to-serial conversion circuit, and the identifier 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 terminal and the second input terminal into serial data and output the serial data at an 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, wherein The energy spectrum data readout circuit includes multiple acquisition circuits; The control circuit is further configured to, in response to receiving global trigger signals from at least two of the multiple acquisition circuits, select one acquisition circuit from the at least two acquisition circuits according to a preset priority, and read a detection signal and an address output by the selected acquisition circuit.

12. The energy spectrum data reading circuit according to any one of claims 1 to 11, wherein, The acquisition circuit is implemented as an application specific integrated circuit ASIC.

13. The energy spectrum data reading circuit according to any one of claims 1 to 12, wherein, The control circuit is implemented as a field programmable gate array FPGA.

14. An X-ray detector, including the energy spectrum data readout circuit according to any one of claims 1 to 13.

15. A data readout method performed by the energy spectrum data readout circuit according to any one of claims 1 to 13, including: Multiple sub-channels in the acquisition circuit each receive a current pulse signal generated based on X-rays, and generate a detection signal based on the current pulse signal; The trigger circuit in the acquisition circuit responds to the existence of an over-threshold channel among the multiple sub-channels, generates a global trigger signal and a channel gating signal, and outputs the address of the over-threshold channel; The multiplexer in the acquisition circuit selects the over-threshold channel from the multiple sub-channels according to the channel gating signal provided by the trigger circuit to output a detection signal; And 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.

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