A radiation detection circuit and a radiation detection method

Abstract

The present application discloses a radiation detection circuit and method. The radiation detection circuit includes: a detector, a charge sensitive amplifier, and a low-pass filter connected in sequence; the detector is configured to generate charges based on detected rays; the charge sensitive amplifier is configured to amplify the charges by a specific multiple to obtain a first voltage signal; the low-pass filter is configured to perform amplification and filtering processing on the first voltage signal to obtain a target voltage signal; which can reduce the complexity of the circuit structure, lower the design difficulty and cost.

Description

Technical Field

[0001] This application belongs to the field of integrated circuit technology, and particularly relates to a radiation detection circuit and a radiation detection method. Background Art

[0002] In the related art, a radiation detection analog channel includes a radiation source, a detector, a charge sensitive amplifier (CSA), a pole-zero cancellation circuit, and a first-order semi-Gaussian shaper connected in sequence; rays are emitted by the radiation source and reach the detector, the detector generates charges after detecting the rays, then a pole-zero cancellation circuit and a CSA are used to obtain an amplified voltage signal, and finally a detection signal is obtained through the first-order semi-Gaussian shaper.

[0003] The circuit structure of this radiation detection analog channel is complex, the design difficulty is relatively high, and the cost is also relatively high. Summary of the Invention

[0004] The purpose of the embodiments of this application is to provide a radiation detection circuit and method, which can reduce the complexity of the circuit structure, and lower the design difficulty and cost.

[0005] In a first aspect, the embodiments of this application provide a radiation detection circuit, including: a detector, a charge sensitive amplifier, and a low-pass filter connected in sequence;

[0006] The detector is configured to generate charges based on the detected rays;

[0007] The charge sensitive amplifier is configured to amplify the charges by a specific multiple to obtain a first voltage signal;

[0008] The low-pass filter is configured to perform amplification and filtering processing on the first voltage signal to obtain a target voltage signal.

[0009] In some embodiments, the radiation detection circuit further includes: a coupling circuit; the output end of the detector is connected to the input end of the coupling circuit; the output end of the coupling circuit is connected to the first input end of the charge sensitive amplifier; the second input end of the charge sensitive amplifier is connected to a first reference voltage; the output end of the charge sensitive amplifier is connected to the input end of the low-pass filter;

[0010] The coupling circuit is configured to couple the charges into the first input end of the charge sensitive amplifier;

[0011] The charge sensitive amplifier is configured to amplify the charges by the specific multiple based on the first reference voltage and the coupled charges to obtain the first voltage signal.

[0012] In some embodiments, the coupling circuit includes a first resistor and a first capacitor; one end of the first resistor is connected to a first power supply; the other end of the first resistor is connected to the output end of the detector; the ground end of the detector is grounded; the output end of the detector is connected to one end of the first capacitor; the other end of the first capacitor is connected to the first input end of the charge sensitive amplifier;

[0013] The first resistor is configured to provide a first direct current path to the output end of the detector to discharge the direct current leaked by the detector;

[0014] The first capacitor is configured to couple the charge into the first input end of the charge sensitive amplifier.

[0015] In some embodiments, the charge sensitive amplifier includes a first operational amplifier and a feedback circuit; the output end of the coupling circuit is connected to the first input end of the first operational amplifier; the second input end of the first operational amplifier is connected to the first reference voltage; the output end of the first operational amplifier is connected to the input end of the low-pass filter; the feedback circuit is connected across the first input end and the output end of the first operational amplifier;

[0016] The first operational amplifier is configured to amplify the charge based on the first reference voltage and the coupled charge and output the first voltage signal;

[0017] The feedback circuit is configured to control the amplification factor of the charge to be the specific amplification factor.

[0018] In some embodiments, the feedback circuit includes a second resistor and a second capacitor; the second resistor and the second capacitor are connected in parallel to form a first parallel branch; the first parallel branch is connected across the first input end and the output end of the first operational amplifier; the first parallel branch is configured to control the amplification factor of the charge to be the specific amplification factor based on the impedance value of the second resistor and the capacitive reactance value of the second capacitor.

[0019] In some embodiments, the first operational amplifier includes a first to tenth transistor and a control circuit;

[0020] The drain, gate, and source of the first transistor are respectively connected to a second power supply, the first output terminal of the control circuit, and a first common connection point; the first common connection point is formed by connecting the drain of the second transistor and the drain of the third transistor; the gate of the second transistor is connected to the gate of the eighth transistor to form a first common node; the source of the second transistor is connected to the drain of the fourth transistor; the source of the fourth transistor is connected to the drain of the sixth transistor; the source of the sixth transistor is connected to the drain of the eighth transistor; the source of the eighth transistor is connected to the source of the ninth transistor; the gate of the third transistor is connected to the gate of the ninth transistor to form a second common node; the source of the third transistor is connected to the drain of the fifth transistor; the source of the fifth transistor is connected to the drain of the seventh transistor to form a third common node; the source of the seventh transistor is connected to the drain of the ninth transistor; the gate of the tenth transistor is connected to the common connection point of the fourth transistor and the sixth transistor; the drain of the tenth transistor is connected to the common connection point of the eighth transistor and the ninth transistor; the source of the tenth transistor is grounded; the gates of the fourth transistor and the fifth transistor are both connected to the second output terminal of the control circuit; the gates of the sixth transistor and the seventh transistor are both connected to the third output terminal of the control circuit;

[0021] The first common node is connected to the output terminal of the coupling circuit; the second common node is connected to the first reference voltage; the third common node is connected to the input terminal of the low-pass filter.

[0022] In some embodiments, the first to fifth transistors are all P-type metal-oxide-semiconductor field-effect transistors; the sixth to tenth transistors are all N-type metal-oxide-semiconductor field-effect transistors.

[0023] In some embodiments, the low-pass filter includes a third resistor, a fourth resistor, a third capacitor, and a second operational amplifier; one end of the third resistor is connected to the output terminal of the charge-sensitive amplifier; the second end of the third resistor is connected to the first input terminal of the second operational amplifier; the second input terminal of the second operational amplifier is connected to a second reference voltage; a second parallel branch formed by the parallel connection of the fourth resistor and the third capacitor is connected across the first input terminal and the output terminal of the second operational amplifier.

[0024] In some embodiments, the product of the fourth resistor and the third capacitor is equal to the product of the second resistor and the second capacitor.

[0025] In a second aspect, an embodiment of the present application provides a radiation detection method, and the method includes:

[0026] The detector generates charges based on the detected rays;

[0027] The charge-sensitive amplifier amplifies the charge by a specific multiple to obtain a first voltage signal;

[0028] The low-pass filter amplifies and filters the first voltage signal to obtain a target voltage signal.

[0029] In the embodiment of the present application, the detector in the radiation detection circuit generates charge based on the detected rays, and then, the CSA in the radiation detection circuit amplifies the charge by a specific multiple to obtain a first voltage signal; finally, the low-pass filter of the radiation detection circuit amplifies and filters the first voltage signal to obtain a target voltage signal. Since both the CSA and the low-pass filter include an operational amplifier and a feedback circuit connected between the input terminal and the output terminal of the operational amplifier, and the feedback circuit includes a capacitor and a resistor, by selecting appropriate resistance impedance values and capacitor reactance values, only one pole can exist in the transfer function of the radiation detection circuit, thereby improving the counting rate of the radiation detection circuit. That is, only the detector, CSA, and low-pass filter in the radiation detection circuit can meet the high counting rate requirements of radiation detection, and a pole-zero cancellation circuit is not required, and the circuit of the low-pass filter is much simpler than that of the first-order semi-Gaussian shaper. Therefore, the radiation detection circuit of the present application reduces the complexity of the circuit structure, reduces the design difficulty and cost while ensuring the high counting rate requirements. Description of the Drawings

[0030] Figure 1 It is a schematic diagram of the composition architecture of a radiation detection channel in some embodiments;

[0031] Figure 2 It is a schematic diagram of the composition circuit of a first-order semi-Gaussian shaper in some embodiments;

[0032] Figure 3 It is a schematic diagram of the composition structure of a radiation detection circuit provided by an embodiment of the present application;

[0033] Figure 4 It is a schematic diagram of the composition structure of another radiation detection circuit provided by an embodiment of the present application;

[0034] Figure 5 It is a schematic diagram of the composition structure of yet another radiation detection circuit provided by an embodiment of the present application;

[0035] Figure 6 It is a schematic diagram of the composition structure of still another radiation detection circuit provided by an embodiment of the present application;

[0036] Figure 7 It is a schematic diagram of the composition structure of yet another radiation detection circuit provided by an embodiment of the present application;

[0037] Figure 8Schematic diagram of the composition structure of a first operational amplifier provided by an embodiment of the present application;

[0038] Figure 9 Schematic diagram of the composition structure of a low - pass filter provided by an embodiment of the present application;

[0039] Figure 10 Specific circuit diagram of the composition structure of a CSA structure provided by an embodiment of the present application;

[0040] Figure 11 Schematic diagram of the composition structure of the overall architecture of a radiation detection channel provided by an embodiment of the present application;

[0041] Figure 12 Schematic diagram of the implementation process of a radiation detection method provided by an embodiment of the present application. Detailed implementation manners

[0042] Next, the technical solutions in the embodiments of the present application will be clearly described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art belong to the scope of protection of the present application.

[0043] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, rather than to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. generally belong to the same category, and the number of objects is not limited. For example, the first object can be one or at least two. In addition, "and / or" in the specification and claims means at least one of the connected objects, and the character " / " generally represents an "or" relationship between the associated objects before and after.

[0044] Next, the image processing method provided by the embodiments of the present application will be described in detail in conjunction with the accompanying drawings, through specific embodiments and their application scenarios.

[0045] In traditional radiation detection analog channels, a radiation source emits rays, which reach a detector. After the detector detects the rays, it provides charges. Then, a CSA is cascaded with a first - order semi - Gaussian shaper, and a pole - zero cancellation circuit is used at the same time as the main channel of radiation detection, and the operational amplifier of the CSA is a traditional Miller operational amplifier.

[0046] The advantage of this is that it can eliminate the overshoot of the circuit and improve the counting rate at the same time.

[0047] Figure 1Schematic diagram of the composition architecture of a radiation detection channel in some embodiments, as shown in Figure 1 As shown, the radiation detection channel 10 includes a radiation source 101, a detector 102, a CSA 103, a pole-zero cancellation circuit 104, and a first-order semi-Gaussian shaper 105;

[0048] Among them, the radiation source 101 emits rays to reach the detector 102. The detector 102 generates charges based on the detected rays. These charges are successively amplified by using the pole-zero cancellation circuit 104 and the CSA 103 to obtain an amplified voltage signal. Finally, the voltage signal is filtered by the first-order semi-Gaussian shaper 105 to obtain a detection signal.

[0049] Figure 2 Schematic diagram of the composition circuit of a first-order semi-Gaussian shaper in some embodiments, as shown in Figure 2 As shown, the first-order semi-Gaussian shaper includes a resistor Rpz, two resistors Rsh’, Rsh”, three capacitors Csh’, Csh”, Cdif, a resistor Rsh1, and two operational amplifiers OA1 and OA2. Among them, the amplification factors of OA1 and OA2 are both -A; the impedance value of Rsh1 is the quotient of Rsh and A; Rpz is a pole-zero cancellation resistor used to eliminate overshoot; Cdif is a coupling capacitor that couples the output (Vcsa) of the CSA to the first-order semi-Gaussian shaper. It can be understood that Vcsa is the input of the first-order semi-Gaussian shaper (the output of the CSA); Vshaper is the output of the first-order semi-Gaussian shaper.

[0050] Here, the first RC parallel branch formed by the parallel connection of Rpz and Cdif is connected between Vcsa and the input terminal of OA1; the second RC parallel branch formed by the parallel connection of Rsh’ and Csh’ is connected across the input terminal and the output terminal of OA1; Rsh1 is connected between the output terminal of OA1 and the input terminal of OA2; the third RC parallel branch formed by the parallel connection of Rsh” and Csh” is connected across the input terminal and the output terminal of OA2; the output terminal of OA2 outputs Vshaper.

[0051] In this embodiment, the transfer function of the first-order semi-Gaussian shaper can be seen in formula (1);

[0052]

[0053] It can be seen that the transfer function of the first-order semi-Gaussian shaper is relatively complex. Combining Figure 1 , in order to improve the technical rate of the radiation detection channel including the first-order semi-Gaussian shaper, it is necessary to use a pole-zero cancellation circuit in cooperation with the use of the first-order semi-Gaussian shaper. In this way, the circuit structure of the radiation detection channel is complex, the design difficulty is relatively high, and the cost is also relatively high.

[0054] Based on the above technical problems, an embodiment of the present application provides a radiation detection circuit, as Figure 3 shown. The radiation detection circuit 30 includes: a detector 301, a CSA 302, and a low-pass filter 303 connected in sequence;

[0055] The detector 301 is configured to generate charges based on the detected rays;

[0056] The CSA 302 is configured to amplify the charges by a specific multiple to obtain a first voltage signal;

[0057] The low-pass filter 303 is configured to amplify and filter the first voltage signal to obtain a target voltage signal.

[0058] Here, no specific limitation is imposed on the specific multiple, and the specific multiple can be one thousand times or ten thousand times.

[0059] In the embodiment of the present application, the detector in the radiation detection circuit generates charges based on the detected rays, and then the CSA in the radiation detection circuit amplifies the charges by a specific multiple to obtain a first voltage signal; finally, the low-pass filter of the radiation detection circuit amplifies and filters the first voltage signal to obtain a target voltage signal. Since both the CSA and the low-pass filter include an operational amplifier and a feedback circuit connected between the input terminal and the output terminal of the operational amplifier, and the feedback circuit includes a capacitor and a resistor, by selecting appropriate resistance impedance values and capacitance reactance values, only one pole can exist in the transfer function of the radiation detection circuit, thereby improving the counting rate of the radiation detection circuit. That is, only the detector, CSA, and low-pass filter in the radiation detection circuit can meet the high counting rate requirements of radiation detection, without the need for a pole-zero cancellation circuit, and the circuit of the low-pass filter is much simpler than that of the first-order semi-Gaussian shaper. Therefore, the radiation detection circuit of the present application reduces the complexity of the circuit structure, the design difficulty, and the cost while ensuring the counting rate requirements.

[0060] Figure 4 is a schematic diagram of the composition structure of another radiation detection circuit according to an embodiment of the present application, as Figure 4 shown. The radiation detection circuit 40 includes: a detector 401, a coupling circuit 402, a CSA 403, and a low-pass filter 404 connected in sequence; the output terminal of the detector 401 is connected to the input terminal of the coupling circuit 402; the output terminal of the coupling circuit 402 is connected to the first input terminal of the CSA 403; the second input terminal of the CSA 403 is connected to the first reference voltage Vref1; the output terminal of the CSA 403 is connected to the input terminal of the low-pass filter 404;

[0061] The detector 401 is configured to generate charges based on detected rays;

[0062] The coupling circuit 402 is configured to couple the charges into the first input terminal of the CSA;

[0063] The CSA 403 is configured to amplify the charges by the specific multiple based on the first reference voltage Vref1 and the coupled charges, to obtain the first voltage signal;

[0064] The low-pass filter 404 is configured to perform amplification and filtering processing on the first voltage signal, to obtain the target voltage signal.

[0065] Here, Vref1 may be 0.9V (volt).

[0066] In the embodiment of the present application, charges are coupled into the first input terminal of the CSA through a coupling circuit, and an operational amplifier circuit amplifies the charges by the specific multiple based on the first reference voltage and the coupled charges, and outputs the first voltage signal, so as to obtain a target voltage signal after amplification and filtering processing of the first voltage signal.

[0067] Figure 5 It is a schematic structural diagram of the composition of another radiation detection circuit provided by the embodiment of the present application. As Figure 5 shown, the radiation detection circuit 50 includes: a detector 501, a first resistor 502, a first capacitor 503, a CSA 504, and a low-pass filter 505; the output terminal of the detector 501 and one end of the first capacitor 503 are both connected to one end of the first resistor 502; the other end of the first resistor 502 is connected to the first power supply VDD1; the grounding terminal of the detector 501 is grounded to GND; the other end of the first capacitor 503 is connected to the first input terminal of the CSA 504; the second input terminal of the CSA 504 is connected to the first reference voltage Vref1; the output terminal of the CSA 504 is connected to the input terminal of the low-pass filter 505;

[0068] The detector 501 is configured to generate charges based on detected rays;

[0069] The first resistor 502 is configured to provide a first direct current path to the output terminal of the detector 501, to discharge the direct current leaked by the detector 501;

[0070] The first capacitor 503 is configured to couple the charges into the first input terminal of the CSA 504;

[0071] The CSA 504 is configured to amplify the charge by a specific multiple based on the first reference voltage Vref and the coupled charge, and output the first voltage signal.

[0072] The low-pass filter 505 is configured to perform amplification and filtering on the first voltage signal to obtain a target voltage signal.

[0073] It can be understood that the voltage of the first power supply VDD1 can be 1.8V; the charge coupling method is AC coupling.

[0074] In the embodiment of the present application, a first DC path is provided to the output end of the detector through a first resistor, which can discharge the leaked DC current in the case of the leaked DC current of the detector; the charge can be AC-coupled into the first input end of the charge-sensitive amplifier through a first capacitor, so that the operational amplifier circuit can amplify the charge.

[0075] Figure 6 FIG. is a schematic structural diagram of another radiation detection circuit provided by the embodiment of the present application. As Figure 6 shown, the radiation detection circuit 60 includes: a detector 601, a coupling circuit 602, a CSA 603, and a low-pass filter 604 connected in sequence; the CSA 603 includes a first operational amplifier 6031 and a feedback circuit 6032; the output end of the detector 601 is connected to the input end of the coupling circuit 602; the output end of the coupling circuit 602 is connected to the first input end of the first operational amplifier 6031; the second input end of the first operational amplifier 6031 is connected to the first reference voltage Vref1; the output end of the first operational amplifier 6031 is connected to the input end of the low-pass filter 604; the feedback circuit 6032 is connected across the first input end and the output end of the first operational amplifier 6031.

[0076] The detector 601 is configured to generate charges based on the detected rays.

[0077] The coupling circuit 602 is configured to couple the charge into the first input end of the charge-sensitive amplifier.

[0078] The first operational amplifier 6031 is configured to amplify the charge based on the first reference voltage and the coupled charge, and output the first voltage signal.

[0079] The feedback circuit 6032 is configured to control the amplification multiple of the charge to be the specific amplification multiple.

[0080] The low-pass filter 604 is configured to perform amplification and filtering on the first voltage signal to obtain a target voltage signal.

[0081] It can be understood that the feedback circuit 6032 is not only used to control the amplification factor of the charge to the specific amplification factor, but also affects the time constant of the CSA 603 at the same time.

[0082] Here, the first operational amplifier 6031 may be an amplification structure of a cascode structure.

[0083] In the embodiment of the present application, the amplification factor of the charge is controlled to the specific amplification factor through the feedback circuit, and the charge is amplified by the first operational amplifier based on the first reference voltage and the coupled charge, so that a first voltage signal can be obtained.

[0084] Figure 7 It is a schematic diagram of the composition structure of another radiation detection circuit provided by the embodiment of the present application. As Figure 7 shown, the radiation detection circuit 70 includes: a detector 701, a coupling circuit 702, a CSA 703, and a low-pass filter 704 connected in sequence; the CSA 703 includes a first operational amplifier 7031 and a first parallel branch 7032; the output end of the detector 701 is connected to the input end of the coupling circuit 702; the output end of the coupling circuit 702 is connected to the first input end of the first operational amplifier 7031; the second input end of the first operational amplifier 7031 is connected to the first reference voltage Vref1; the output end of the first operational amplifier 7031 is connected to the input end of the low-pass filter 704; the parallel branch 7032 is connected across the first input end and the output end of the first operational amplifier 7031; the first parallel branch 7032 is formed by the parallel connection of a second resistor and the second capacitor;

[0085] The detector 701 is configured to generate charges based on the detected rays;

[0086] The coupling circuit 702 is configured to couple the charges into the first input end of the charge sensitive amplifier;

[0087] The first operational amplifier 7031 is configured to amplify the charge based on the first reference voltage and the coupled charge, and output the first voltage signal;

[0088] The first parallel branch 7032 is configured to control the amplification factor of the charge to the specific amplification factor based on the impedance value of the second resistor and the capacitive reactance value of the second capacitor;

[0089] The low-pass filter 704 is configured to perform amplification and filtering processing on the first voltage signal to obtain a target voltage signal.

[0090] Here, the second resistor can be a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET); the equivalent resistance of the MOSFET can be adjusted by adjusting the time constant of the MOSFET.

[0091] It can be understood that a current path can be formed through the second resistor for discharging the AC leakage current; the input charge can be accumulated through the second capacitor.

[0092] In the embodiment of the present application, the amplification factor of the charge is controlled to be the specific amplification factor through the first parallel branch based on the impedance value of the second resistor and the capacitive reactance value of the second capacitor. At the same time, the time constant of the first operational amplifier can be adjusted based on the impedance value of the second resistor and the capacitive reactance value of the second capacitor.

[0093] Figure 8 It is a schematic diagram of the composition structure of a first operational amplifier provided by an embodiment of the present application, as Figure 8 shown, the first operational amplifier includes a first transistor T1 to a tenth transistor T10;

[0094] The drain, gate, and source of the first transistor T1 are respectively connected to the second power supply VDD2, the first output terminal of the control circuit, and a first common connection point; the first common connection point is formed by connecting the drains of the second transistor T2 and the third transistor T3; the gate of the second transistor T2 is connected to the gate of the eighth transistor T8 to form a first common node; the source of the second transistor T2 is connected to the drain of the fourth transistor T4; the source of the fourth transistor T4 is connected to the drain of the sixth transistor T6; the source of the sixth transistor T6 is connected to the drain of the eighth transistor T8; the source of the eighth transistor T8 is connected to the source of the ninth transistor T9; the gate of the third transistor T3 is connected to the gate of the ninth transistor T9 to form a second common node; the source of the third transistor T3 is connected to the drain of the fifth transistor T5; the source of the fifth transistor T5 is connected to the drain of the seventh transistor T7 to form a third common node; the source of the seventh transistor T7 is connected to the drain of the ninth transistor T9; the gate of the tenth transistor T10 is connected to the common connection point of the fourth transistor T4 and the sixth transistor T6; the drain of the tenth transistor T10 is connected to the common connection point of the eighth transistor T8 and the ninth transistor T9; the source of the tenth transistor T10 is grounded; the gates of the fourth transistor T4 and the fifth transistor T5 are both connected to the second output terminal of the control circuit; the gates of the sixth transistor T6 and the seventh transistor T7 are both connected to the third output terminal of the control circuit;

[0095] Here, the voltage value of the second power supply VDD2 can be equal to the voltage value of the first power supply VDD1. For example, VDD2 can also be 1.8V. The first common node is connected Figure 7 to the output terminal of the coupling circuit 702 shown; the second common node is connected to the first reference voltage Vref1; the third common node is connected Figure 7 to the input terminal of the low-pass filter 704 shown.

[0096] Meanwhile, the connection point Vin of the gates of the second transistor T2 and the eighth transistor T8 is the first input terminal of the first operational amplifier; Vip is the second input terminal of the first operational amplifier; Vcsa’ is the output terminal of the first operational amplifier.

[0097] In the embodiments of the present application, the control circuit can generate first to third bias voltage signals; control the gate voltage of the first transistor T1 through the first bias voltage; control the gate voltages of the fourth transistor T4 and the fifth transistor T5 through the second bias voltage; control the gate voltages of the sixth transistor T6 and the seventh transistor T7 through the third bias voltage.

[0098] It can be understood that since the control circuit is outside the radiation detection circuit, it is not shown in this Figure 8 application.

[0099] In the embodiments of the present application, T1 to T10 all operate in the saturation region, that is, operate in the amplification state. Among them, T1 and T10 are transistors that provide current to the CSA; the current output by VDD2 is led out by T1 to T2 and T3; the current is led back to the ground terminal by T10.

[0100] In the embodiments of the present application, T1 to T5 are P-type metal oxide semiconductor field effect transistors (Positive channel Metal Oxide Semiconductor, PMOS) tubes; T6 to T10 are N-type metal oxide semiconductor field effect transistors (Negative channel Metal Oxide Semiconductor, NMOS) NMOS tubes.

[0101] It can be understood that the first operational amplifier in the embodiments of the present application corresponds to Figure 6 the first operational amplifier in

[0102] Figure 9 is a schematic diagram of the composition structure of a low-pass filter provided by the embodiments of the present application, as shown in Figure 9As shown, the low-pass filter includes: a third resistor R3, a fourth resistor R4, a third capacitor C3, and a second operational amplifier OA3; one end of the third resistor R3 is connected to the output end of the CSA; the second end of the third resistor R3 is connected to the first input end of the second operational amplifier OA3; the second input end of the second operational amplifier OA3 is connected to a second reference voltage Vref2; a second parallel branch formed by the parallel connection of the fourth resistor R4 and the third capacitor C3 is connected across the first input end and the output end of the second operational amplifier OA3.

[0103] Here, the low-pass filter can correspond to Figure 3 the low-pass filter 303 in Figure 4 the low-pass filter 404 in Figure 5 the low-pass filter 506 in Figure 6 the low-pass filter 604 in Figure 7 or the low-pass filter 704 in

[0104] Vcsa1 output from the CSA output end is the input of the low-pass filter; the output of the low-pass filter is Vshaper1; the amplification factor of OA3 is -A.

[0105] It can be understood that the impedance value of R4 and the capacitive reactance value of C3 in the second parallel branch connected across the first input end and the output end of the second operational amplifier will affect the bandwidth of the low-pass filter.

[0106] The transfer function of this low-pass filter is shown in Formula (2);

[0107]

[0108] By comparing Formula (2) and Formula (1), it can be seen that the low-pass filter proposed in this application has a simpler transfer function.

[0109] At the same time, by comparing Figure 9 and Figure 2 it can be seen that the low-pass filter provided in the embodiment of this application, compared with the traditional filter, reduces at least one circuit structure as shown in Figure 9 , greatly reduces the circuit complexity, and at the same time can ensure the counting rate of the radiation detection circuit; rather than simply improving the counting rate by selecting appropriate component parameters or adjusting the circuit structure.

[0110] Figure 10 is the specific circuit diagram of the composition of a CSA structure provided in the embodiment of this application, as shown in Figure 10As shown in the figure, the CSA structure includes: a first resistor R1, a first capacitor C1, a first operational amplifier OA4, a second resistor R2, a second capacitor C2, a first power supply VDD1, a first reference voltage Vref1, and a ground terminal GND. One end of the detector D1 is connected to one end of R1; the other end of R1 is connected to VDD1; the ground terminal of D1 is connected to GND; the output terminal of D1 is connected to one end of C1; the other end of C1 is connected to the first input terminal of OA4; the R2C2 parallel branch formed by the parallel connection of R2 and C2 is connected across the first input terminal and the output terminal of OA4; the second input terminal of OA4 is connected to Vref1.

[0111] Here, the CSA structure corresponds to Figure 3 CSA 302 in; the input Vin' of the CSA structure is the output of the detector; the output of the CSA structure is Vcsa1; and the amplification factor of OA4 is not limited.

[0112] The transfer function of this CSA structure is shown in Formula (3):

[0113]

[0114] Where, Vin is Figure 10 the voltage of the input Vin' in (the output of the detector).

[0115] In the embodiment of the present application, since the radiation detection channel mainly includes a CSA structure and a CSA structure in a low-pass filter except for the detector, and the CSA structure is connected to the low-pass filter at the back, according to Formula (2) and Formula (3), the transfer function of the entire radiation detection channel can be obtained as shown in Formula (4):

[0116]

[0117] It can be seen that when designing the circuit, let R4C3 = R2C2; thus, Formula (4) is transformed into Formula (5);

[0118]

[0119] It can be seen that there is only one pole in Formula (5); since there is only one pole in the transfer function of the entire radiation detection channel, overshoot can be avoided.

[0120] To understand the overshoot phenomenon, an example is given as follows: It is stipulated that after a voltage pulse comes, the voltage needs to return to 0.9V within a certain time (preset); in the case of overshoot, the voltage will return to a voltage lower than 0.9V and then return to 0.9V.

[0121] Thus, in the embodiments of the present application, by taking different component parameters in the radiation detection channel (the impedance value of R4, the capacitive reactance value of C3, or the impedance value of R2, the capacitive reactance value of C2), two poles can be converted into one pole, thereby avoiding overshoot phenomena.

[0122] It can be understood that the overall structure of the radiation detection channel proposed in the embodiments of the present application is simpler, but it can still achieve the effect of improving the counting rate. The feedback resistor in the CSA is implemented by a MOS transistor; the operational amplifier in the CSA uses an active load cascode operational amplifier; the filter uses a low-pass filter instead of a first-order semi-Gaussian shaper. Compared with the traditional structure, the novelty of this structure is that it has lower power consumption, smaller noise, smaller layout area, simpler structure and transfer function.

[0123] In some embodiments, a digital processor is further included in the overall architecture of the radiation detection channel; as Figure 11 shown, the radiation detection circuit 110 includes a detector 1101, a CSA 1102, a filter 1103 and a digital processor 1104; wherein, the charge generated by the detector 1101 is input to the CSA 1102; the CSA 1102 amplifies the input charge to obtain a voltage signal Vcsa2; the filter 1103 amplifies and filters the voltage signal Vcsa2 to obtain an amplified and filtered voltage signal Vshaper2; the digital processor 1104 performs analog-to-digital conversion on Vshaper2 to obtain a digital signal Dout.

[0124] In summary, the overall architecture of the radiation detection channel in the embodiments of the present application has a simpler structure and a simpler transfer function, with lower design difficulty compared to traditional design schemes; it has a smaller chip area, saving design costs; it has lower power consumption, saving power costs; it reduces the noise of the overall circuit and improves the accuracy of the CSA.

[0125] Based on the above embodiments, the embodiments of the present application provide a radiation detection method, as Figure 12 shown, the method includes:

[0126] Step S1201: The detector generates charge based on the detected rays;

[0127] Step S1202: The CSA amplifies the charge by a specific multiple to obtain a first voltage signal;

[0128] Step S1203: The low-pass filter amplifies and filters the first voltage signal to obtain a target voltage signal.

[0129] The embodiments of the present application provide another radiation detection method, and the method includes the following steps:

[0130] Step 1301: The detector generates charges based on the detected rays;

[0131] Step 1302: The coupling circuit couples the charges into the first input terminal of the CSA;

[0132] Step 1303: The CSA amplifies the charges by the specific multiple based on the first reference voltage and the coupled charges, and outputs the first voltage signal;

[0133] Step 1304: The low-pass filter amplifies and filters the first voltage signal to obtain the target voltage signal.

[0134] It should be noted that in this article, the terms "including", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that the circuit or method including not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such a circuit or method. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of additional identical elements in the circuit or method including the element.

[0135] In addition, it should be pointed out that the scope of the circuit and method in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in the reverse order according to the functions involved. For example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0136] The embodiments of the present application have been described above in conjunction with the accompanying drawings. However, the present application is not limited to the above specific embodiments. The above specific embodiments are merely illustrative and not restrictive. Under the inspiration of the present application, those of ordinary skill in the art can also make many forms without departing from the purpose of the present application and the scope protected by the claims, and all of them belong to the protection scope of the present application.

Claims

1. A radiation detection circuit, characterized in that, Including: A detector, a charge sensitive amplifier, and a low-pass filter connected in sequence; The detector is configured to generate charges based on the detected rays; The charge sensitive amplifier is configured to amplify the charges by a specific multiple to obtain a first voltage signal; wherein, the charge sensitive amplifier includes a first operational amplifier and a feedback circuit, the feedback circuit includes a second resistor and a second capacitor, and the second resistor and the second capacitor are connected in parallel to form a first parallel branch; the first parallel branch is connected across the first input terminal and the output terminal of the first operational amplifier; The low-pass filter is configured to amplify and filter the first voltage signal to obtain a target voltage signal; wherein, the low-pass filter includes a third resistor, a fourth resistor, a third capacitor, and a second operational amplifier; one end of the third resistor is connected to the output terminal of the charge sensitive amplifier; the second end of the third resistor is connected to the first input terminal of the second operational amplifier; the second input terminal of the second operational amplifier is connected to a second reference voltage; a second parallel branch formed by the parallel connection of the fourth resistor and the third capacitor is connected across the first input terminal and the output terminal of the second operational amplifier, and the product of the fourth resistor and the third capacitor is equal to the product of the second resistor and the second capacitor.

2. The circuit according to claim 1, wherein Further including: A coupling circuit; the output terminal of the detector is connected to the input terminal of the coupling circuit; the output terminal of the coupling circuit is connected to the first input terminal of the charge sensitive amplifier; The second input terminal of the charge sensitive amplifier is connected to a first reference voltage; the output terminal of the charge sensitive amplifier is connected to the input terminal of the low-pass filter; The coupling circuit is configured to couple the charges into the first input terminal of the charge sensitive amplifier; The charge sensitive amplifier is configured to amplify the charges by the specific multiple based on the first reference voltage and the coupled charges to obtain the first voltage signal.

3. The circuit according to claim 2, wherein The coupling circuit includes a first resistor and a first capacitor; one end of the first resistor is connected to a first power supply; the other end of the first resistor is connected to the output terminal of the detector; the grounding terminal of the detector is grounded; the output terminal of the detector is connected to one end of the first capacitor; the other end of the first capacitor is connected to the first input terminal of the charge sensitive amplifier; The first resistor is configured to provide a first direct current path to the output terminal of the detector to discharge the direct current leaked by the detector; The first capacitor is configured to couple the charges into the first input terminal of the charge sensitive amplifier.

4. The circuit according to claim 2, wherein The output terminal of the coupling circuit is connected to the first input terminal of the first operational amplifier; the second input terminal of the first operational amplifier is connected to the first reference voltage; the output terminal of the first operational amplifier is connected to the input terminal of the low-pass filter; the feedback circuit is connected across the first input terminal and the output terminal of the first operational amplifier; The first operational amplifier is configured to amplify the charges based on the first reference voltage and the coupled charges and output the first voltage signal; The feedback circuit is used to control the amplification factor of the charge to be the specific factor.

5. The circuit according to claim 4, wherein, The first parallel branch is used to control the amplification factor of the charge to be the specific factor based on the impedance value of the second resistor and the capacitive reactance value of the second capacitor.

6. The circuit according to claim 4, characterized in that, The first operational amplifier includes the first to tenth transistors and a control circuit; The drain, gate, and source of the first transistor are respectively connected to a second power supply, the first output terminal of the control circuit, and a first common connection point; the first common connection point is formed by connecting the drains of the second transistor and the third transistor; the gate of the second transistor is connected to the gate of the eighth transistor to form a first common node; the source of the second transistor is connected to the drain of the fourth transistor; the source of the fourth transistor is connected to the drain of the sixth transistor; the source of the sixth transistor is connected to the drain of the eighth transistor; the source of the eighth transistor is connected to the source of the ninth transistor; the gate of the third transistor is connected to the gate of the ninth transistor to form a second common node; the source of the third transistor is connected to the drain of the fifth transistor; the source of the fifth transistor is connected to the drain of the seventh transistor to form a third common node; the source of the seventh transistor is connected to the drain of the ninth transistor; the gate of the tenth transistor is connected to the common connection point of the fourth transistor and the sixth transistor; the drain of the tenth transistor is connected to the common connection point of the eighth transistor and the ninth transistor; the source of the tenth transistor is grounded; the gates of the fourth transistor and the fifth transistor are both connected to the second output terminal of the control circuit; the gates of the sixth transistor and the seventh transistor are both connected to the third output terminal of the control circuit; The first common node is connected to the output terminal of the coupling circuit; the second common node is connected to the first reference voltage; the third common node is connected to the input terminal of the low-pass filter.

7. The circuit according to claim 6, wherein The first to fifth transistors are all P-type metal-oxide-semiconductor field-effect transistors; the sixth to tenth transistors are all N-type metal-oxide-semiconductor field-effect transistors.

8. A radiation detection method, characterized in that, Applied to the circuit according to any one of claims 1-7, the method includes: The detector generates charges based on the detected rays; The charge-sensitive amplifier amplifies the charges by a specific factor to obtain a first voltage signal; The low-pass filter amplifies and filters the first voltage signal to obtain a target voltage signal.

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