Photon counting detector in time delay summation mode

Abstract

The radiation detector (100) comprises a first sensing element (150.1) and a second sensing element (150.2). The radiation detector (100) is configured to (A) determine a first count (N1) of radiation particles incident on the first sensing element (150.1) during a first exposure (E1), and (B) sum the first count (N1) with a first remainder (C1), thereby obtaining a second remainder (C2), the first remainder (C1) is related to a count (N0) of radiation particles incident on a sensing element (150.0) different from the first and second sensing elements (150.1, 150.2). The radiation detector (100) is configured to (A) determine a second count (N2) of radiation particles incident on the second sensing element (150.2) during a second exposure (E2) following the first exposure (E1), and (B) sum the second count (N2) with the second remainder (C2), thereby obtaining a third remainder (C3).

Description

Background Art

[0001] The imaging system may include a radiation source and a radiation detector. The radiation source may send a radiation beam toward an object located between the radiation source and the radiation detector; and the radiation detector may capture an image of the object based on the interaction between the radiation beam and the object. The imaging system may operate in a time delay integration (TDI) mode to generate an image of the object with an improved signal-to-noise ratio and reduced motion blur. Summary of the invention

[0002] Disclosed herein is a radiation detector comprising a first sensing element and a second sensing element. The radiation detector is configured to (A) determine a first count of radiation particles incident on the first sensing element during a first exposure, and (B) sum the first count with a first carry forward number to obtain a second carry forward number, wherein the first carry forward number is related to a count of radiation particles incident on a sensing element different from the first and second sensing elements. The radiation detector is configured to (A) determine a second count of radiation particles incident on the second sensing element during a second exposure subsequent to the first exposure, and (B) sum the second count with the second carry forward number to obtain a third carry forward number.

[0003] In one aspect, the radiation detector further comprises a third sensing element. The radiation detector is configured to (A) determine a third count of radiation particles incident on the third sensing element during a third exposure after the second exposure, and (B) sum the third count with the third remainder number to obtain a fourth remainder number.

[0004] In one aspect, the radiation detector includes a first counter configured to (A) determine a first count and (B) sum the first count with a first balance number. The radiation detector includes a second counter configured to (A) determine a second count and (B) sum the second count with a second balance number.

[0005] In one aspect, the radiation detector is configured to transfer the second balance number from the first counter to the second counter.

[0006] In one aspect, the radiation detector includes a first counter and a first register. The first counter is configured to determine a first count. The first register is configured to sum the first count with a first balance number. The radiation detector includes a second counter and a second register. The second counter is configured to determine a second count. The second register is configured to sum the second count with a second balance number.

[0007] In one aspect, the radiation detector is configured to transfer the second balance number from the first register to the second register.

[0008] In one aspect, a radiation detector includes a digital processor including a computer memory. A first register and a second register are implemented in the computer memory.

[0009] In one aspect, the radiation detector is configured to capture an image of the object. A value of a picture element of the image is equal to the third remainder number.

[0010] In one aspect, the radiation particles are X-rays.

[0011] In one aspect, a radiation detector includes: a radiation absorbing layer including an electrode; a first voltage comparator configured to compare a voltage of the electrode with a first threshold; a second voltage comparator configured to compare the voltage with a second threshold; a counter configured to record the number of photons absorbed by the radiation absorbing layer; and a controller. The controller is configured to start a time delay from the time when the absolute value of the voltage is determined by the first voltage comparator to be equal to or exceed the absolute value of the first threshold. The controller is configured to enable the second voltage comparator during the time delay. The controller is configured to increase the number recorded by the counter by one if the absolute value of the voltage is determined by the second voltage comparator to be equal to or exceed the absolute value of the second threshold.

[0012] The system may include the above-mentioned radiation detector, a radiation source and a frame. The radiation source is configured to send a radiation beam toward an object. The frame is configured to rotate around an axis. The radiation detector is fixed to the frame. The radiation detector is configured to capture an image of the object based on the interaction between the radiation beam and the object. In one aspect, the system may also include a radiation source target, which is fixed to the frame and configured to receive an electron beam, thereby emitting a radiation beam.

[0013] A method of using the system includes: taking a first image of an object with a radiation detector, wherein (A) a frame rotates around the object and around an axis, and (B) a radiation source remains stationary at a first source position relative to the object. Taking the first image includes (A) sending a radiation particle pulse toward the object with the radiation source during an exposure, (B) determining a count of radiation particles incident on a first sensing element during the exposure with the radiation detector, (C) summing the count with a remainder number with the radiation detector to obtain another remainder number, (D) sending another radiation particle pulse toward the object during another exposure after the exposure, (E) determining another count of radiation particles incident on a second sensing element during the another exposure with the radiation detector, and (F) summing the another count with another remainder number with the radiation detector; and, after taking the first image, taking a second image of the object with the radiation detector, wherein (A) the frame rotates around the object and around the axis, and (B) the radiation source remains stationary at the second source position relative to the object. Taking a second image includes (A) sending a radiation particle pulse toward the object during the exposure using a radiation source, (B) determining a count of radiation particles incident on the first sensing element during the exposure using a radiation detector, (C) summing the count with a remainder number using the radiation detector to obtain another remainder number, (D) sending another radiation particle pulse toward the object during another exposure after the exposure using the radiation source, (E) determining another count of radiation particles incident on the second sensing element during the another exposure using the radiation detector, and (F) summing the another count with another remainder number using the radiation detector. The first source position is different from the second source position. The method may also include reconstructing a three-dimensional image of the object based on at least the first image and the second image.

[0014] In one aspect, the radiation source (A) varies from point X to point Y through a series of intermediate points during capture of a first image, (B) varies from point Y back to point X after the first image is captured and before the second image is captured, and (C) varies from point X to point Y through a series of intermediate points during capture of the second image. Points X and Y are both relative to the frame.

[0015] In one aspect, the radiation source sending the radiation beam is accomplished by directing an electron beam to a target point on a radiation source target, thereby generating the radiation beam from the target point. Varying the radiation source includes moving the target point.

[0016] The system may include the above-mentioned radiation detector and a radiation source, the radiation source being configured to send a radiation beam toward the film. The radiation detector is configured to take an image of the film based on the interaction between the radiation beam and the film. In one aspect, the system may also include a radiation source target, the radiation source target being configured to receive the electron beam, thereby emitting the radiation beam.

[0017] A method of using the above system includes capturing an image of a film using a radiation detector, wherein a radiation source and the film (A) are both linearly translated relative to the radiation detector and (B) remain stationary relative to each other. Capturing the image includes (A) sending a first pulse of radiation particles toward the film during a first exposure using the radiation source, (B) determining a first count of radiation particles incident on a first sensing element during the first exposure using the radiation detector, (C) summing the first count with a first remainder number using the radiation detector to obtain a second remainder number, (D) sending a second pulse of radiation particles toward the film during a second exposure after the first exposure using the radiation source, (E) determining a second count of radiation particles incident on a second sensing element during the second exposure using the radiation detector, and (F) summing the second count with the second remainder number using the radiation detector.

[0018] The membrane may include an anode layer, an electrolyte layer, and a cathode layer, wherein the electrolyte layer is sandwiched between the anode layer and the cathode layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1A A semiconductor radiation detector according to an embodiment is schematically shown.

[0020] Figure 1B A semiconductor radiation detector 100 according to an alternative embodiment is shown.

[0021] Figure 2 According to an embodiment Figure 1A An exemplary top view of a portion of a detector in FIG.

[0022] Figure 3A and 3B According to an embodiment, Figure 1A or a component diagram of the electronic system of the detector in 1B.

[0023] Figure 4 Schematically illustrates the temporal variation of a current flowing through an electrode of a diode or an electrical contact of a resistor exposed to radiation by a radiation absorbing layer (upper curve) and the corresponding temporal variation of a voltage of the electrode (lower curve) according to an embodiment, wherein the current is caused by carriers generated by radiation particles incident on the radiation absorbing layer.

[0024] Figure 5 Schematically illustrating a method according to an embodiment of the present invention Figure 4 The temporal variation of the current flowing through an electrode (upper curve) and the corresponding temporal variation of the voltage of the electrode (lower curve) caused by noise (eg, dark current) in an electronic system operating in the manner shown.

[0025] Figure 6Schematically illustrates the temporal variation of a current flowing through an electrode of a radiation absorbing layer exposed to radiation (upper curve) and the corresponding temporal variation of a voltage of the electrode (lower curve) when an electronic system operates at a higher rate to detect incident radiation particles according to one embodiment, wherein the current is caused by carriers generated by radiation particles incident on the radiation absorbing layer.

[0026] Figure 7 Schematically illustrating a method according to an embodiment of the present invention Figure 6 The temporal variation of the current flowing through an electrode (upper curve) and the corresponding temporal variation of the voltage of the electrode (lower curve) caused by noise (eg, dark current) in an electronic system operating in the manner shown.

[0027] Figure 8 Schematically illustrating a method according to an embodiment of the present invention Figure 6 The temporal variation of the current flowing through the electrode (upper curve) and the corresponding temporal variation of the voltage of the electrode caused by carriers generated by a series of radiation particles incident on the radiation absorbing layer in an electronic system operating in the manner shown, wherein RST terminates before te.

[0028] Fig. 9 According to one embodiment, a suitable method for utilizing Figure 4 A flow chart of a method of operating an electronic system or the like to detect radiation is shown.

[0029] Fig.10 According to one embodiment, a suitable method for utilizing Figure 6 A flow chart of a method of operating an electronic system or the like to detect radiation is shown.

[0030] Figure 11A-11E An imaging system in operation is schematically shown according to an embodiment.

[0031] Fig.12 A flow chart outlining the operation of an imaging system according to an embodiment is shown.

[0032] Fig.13A and Fig. 13B Counters and registers of an imaging system according to various embodiments are shown.

[0033] Figures 14A-14D An imaging system is schematically shown in operation according to an alternative embodiment.

[0034] Fig.15 A summary according to an embodiment is shown Figures 14A-14D Flowchart of the operation of the imaging system. DETAILED DESCRIPTION

[0035] Radiation Detectors

[0036] Figure 1A A semiconductor radiation detector 100 according to an embodiment is schematically shown. The semiconductor radiation detector 100 may include a radiation absorption layer 110 and an electronic layer 120 (e.g., an application-specific integrated circuit or ASIC) for processing or analyzing an electrical signal generated in the radiation absorption layer 110 by incident radiation. In an embodiment, the semiconductor radiation detector 100 does not include a scintillator. The radiation absorption layer 110 may include a semiconductor material, such as silicon, germanium, GaAs, CdTe, CdZnTe, or a combination thereof. The semiconductor may have a high mass attenuation coefficient for the radiation energy of interest. The radiation absorption layer 110 may include one or more diodes (e.g., pin or pn) formed by one or more discrete regions 114 of a first doping region 111 and a second doping region 113. The second doping region 113 may be separated from the first doping region 111 by an optional intrinsic region 112. The discrete portions 114 are separated from each other by the first doping region 111 or the intrinsic region 112. The first doping region 111 and the second doping region 113 have opposite doping types (for example, the first doping region 111 is p-type and the second doping region 113 is n-type, or the first doping region 111 is n-type and the second doping region 113 is p-type). Figure 1A In the example of , each discrete region 114 of the second doped region 113 forms a diode together with the first doped region 111 and the optional intrinsic region 112. That is, in Figure 1A In the example of FIG. 1 , the radiation absorbing layer 110 has a plurality of diodes having a first doped region 111 as a common electrode. The first doped region 111 may also have a plurality of discrete portions.

[0037] Figure 1B A semiconductor radiation detector 100 according to an alternative embodiment is shown. The semiconductor radiation detector 100 may include a radiation absorbing layer 110 and an electronic layer 120 (e.g., an ASIC) for processing or analyzing an electrical signal generated in the radiation absorbing layer 110 by incident radiation. In an embodiment, the semiconductor radiation detector 100 does not include a scintillator. The radiation absorbing layer 110 may include a semiconductor material, such as silicon, germanium, GaAs, CdTe, CdZnTe, or a combination thereof. The semiconductor may have a high mass attenuation coefficient for the radiation energy of interest. The radiation absorbing layer 110 may not include a diode, but include a resistor.

[0038] When a radiation particle strikes the radiation absorption layer 110 including the diode, it can be absorbed and generate one or more carriers through a variety of mechanisms. The radiation particle can generate 10 to 100,000 carriers. The carriers can drift to the electrode of one of the diodes under the action of an electric field. The electric field can be an external electric field. The electrical contact (or electrode) 119B may include a plurality of discrete portions, each of which is in electrical contact with the discrete region 114. In one embodiment, the carriers can drift in multiple directions, and the carriers generated by a single radiation particle are substantially not shared by two different discrete regions 114 (here, "substantially not shared by..." means that the discrete region 114 to which less than 5%, less than 2%, or less than 1% of these carriers flow is different from the discrete region 114 to which the remaining carriers flow). In one embodiment, the carriers generated by a single radiation particle can be shared by two different discrete regions 114.

[0039] Figure 2 An exemplary top view of a portion of a semiconductor radiation detector 100 is shown, which has a 4×4 array of discrete regions 114. The carriers generated by radiation particles incident on one of the discrete regions 114 around the footprint are substantially not shared by another of the discrete regions 114. The area around the discrete region 114 is referred to as a pixel (also referred to as a sensing element) associated with the discrete region 114, in which substantially all (more than 95%, more than 98%, or more than 99%) of the carriers generated by radiation particles incident on the region flow to the discrete region 114. That is, less than 5%, less than 2%, or less than 1% of the carriers flow out of the pixel. By measuring the drift current flowing into each discrete region 114 or the rate of change of the voltage of each discrete region 114, the number of radiation particles absorbed in the pixel associated with the discrete region 114 (which is related to the intensity of the incident radiation) and / or the energy of the radiation particles can be determined. Thus, the spatial distribution (e.g., image) of the incident radiation intensity can be determined by individually measuring the drift current flowing into each discrete region in the array of discrete regions 114 or measuring the rate of change of the voltage of each discrete region in the array of discrete regions 114. The pixels can be organized into any suitable array, such as a square array, a triangular array, and a honeycomb array. The pixels can have any suitable shape, such as a circle, a triangle, a square, a rectangle, and a hexagon. The pixels can be individually addressable.

[0040] When a radiation particle strikes the radiation absorption layer 110, which includes a resistor but not a diode, it can be absorbed and generate one or more carriers through a variety of mechanisms. The radiation particle can generate 10 to 100,000 carriers. The carriers can drift to the electrical contacts 119A and 119B under the action of an electric field. The electric field can be an external electric field. The electrical contact 119B includes a plurality of discrete portions. In one embodiment, the carriers can drift in multiple directions, and the carriers generated by a single radiation particle are substantially not shared by two different discrete portions of the electrical contact 119B (here, "substantially not shared by..." means that the discrete portion to which less than 5%, less than 2%, or less than 1% of these carriers flow is different from the discrete portion to which the remaining carriers flow). In one embodiment, the carriers generated by a single radiation particle can be shared by two different discrete portions of the electrical contact 119B. The carriers generated by radiation particles incident on the occupied space around one of the discrete portions of the electrical contact 119B are substantially not shared by another of the discrete portions of the electrical contact 119B. The area around the discrete portion of the electrical contact 119B is referred to as a pixel associated with the discrete portion of the electrical contact 119B, in which substantially all (more than 95%, more than 98%, or more than 99%) of the carriers generated by radiation particles incident on the area flow to the discrete portion of the electrical contact 119B. That is, less than 5%, less than 2%, or less than 1% of these carriers flow out of the pixel associated with the discrete portion of the electrical contact 119B. By measuring the drift current flowing into each discrete portion of the electrical contact 119B or the rate of change of the voltage of each discrete portion of the electrical contact 119B, the number of radiation particles absorbed in the pixel associated with the discrete portion of the electrical contact 119B (which is related to the intensity of the incident radiation) and / or the energy of the radiation particles can be determined. Thus, the spatial distribution (e.g., image) of incident radiation intensity can be determined by individually measuring the drift current flowing into each discrete portion of the array of discrete portions of electrical contacts 119B or measuring the rate of change of the voltage of each discrete portion of the array of discrete portions of electrical contacts 119B. The pixels can be organized into any suitable array, such as a square array, a triangular array, and a honeycomb array. The pixels can have any suitable shape, such as a circle, a triangle, a square, a rectangle, and a hexagon. The pixels can be individually addressable.

[0041] The electronic layer 120 may include an electronic system 121 for each pixel, and the electronic system 121 is suitable for processing or interpreting the signals generated by the radiation particles incident on each pixel of the radiation absorption layer 110. The electronic system 121 may include analog circuits such as filter networks, amplifiers, integrators, and comparators, or digital circuits such as microprocessors and memories. The electronic system 121 may include components shared by multiple pixels or components dedicated to a single pixel. For example, the electronic system 121 may include an amplifier dedicated to each pixel and a microprocessor shared by all pixels. The electronic system 121 may be electrically connected to the pixel through a through-hole interconnect (via) 131. The space between the through-hole interconnects may be filled with a filling material 130, thereby increasing the mechanical stability of the connection between the electronic layer 120 and the radiation absorption layer 110. Other bonding techniques can connect the electronic system 121 to the pixel without using a through-hole interconnect.

[0042] Electronic Systems

[0043] Figure 3A and Figure 3B Each of the diagrams shows a component of the electronic system 121 according to an embodiment. The electronic system 121 may include a first voltage comparator 301 , a second voltage comparator 302 , a counter 320 , a switch 305 , a voltmeter 306 , and a controller 310 .

[0044] The first voltage comparator 301 is configured to connect an electrode (eg, Figure 1A or Figure 1B119B) is compared with a first threshold value. The diode can be a diode formed by a first doped region 111, a discrete region 114 of a plurality of discrete regions 114 of a second doped region 113, and an optional intrinsic region 112. Alternatively, the first voltage comparator 301 is configured to compare the voltage of an electrical contact (e.g., a discrete portion of the electrical contact 119B) with a first threshold value. The first voltage comparator 301 can be configured to monitor the voltage directly, or to calculate the voltage by integrating the current flowing through the diode or the electrical contact over a period of time. The controller 310 can controllably enable or disable the first voltage comparator 301. The first voltage comparator 301 can be a continuous comparator. That is, the first voltage comparator 301 can be configured to be enabled continuously and to monitor the voltage continuously. The first voltage comparator 301 configured as a continuous comparator reduces the probability that the system 121 misses a signal generated by an incident radiation particle. The first voltage comparator 301 configured as a continuous comparator is particularly applicable when the incident radiation intensity is relatively high. The first voltage comparator 301 may be a clocked comparator, which has the advantage of low power consumption. The first voltage comparator 301 configured as a clocked comparator may cause the system 121 to miss signals generated by some incident radiation particles. When the incident radiation intensity is low, the probability of missing the incident radiation particles is low because the time interval between two consecutive photons is relatively long. Therefore, the first voltage comparator 301 configured as a clocked comparator is particularly applicable when the incident radiation intensity is relatively low. The first threshold value may be 5-10%, 10%-20%, 20-30%, 30-40% or 40-50% of the maximum voltage that an incident radiation particle can generate in a diode or a resistor. The maximum voltage may depend on the energy of the incident radiation particle (i.e., the wavelength of the incident radiation particle), the material of the radiation absorption layer 110, or other factors. For example, the first threshold value may be 50mV, 100mV, 150mV or 200mV.

[0045] The second voltage comparator 302 is configured to compare the voltage with the second threshold value. The second voltage comparator 302 can be configured to monitor the voltage directly, or to calculate the voltage by integrating the current flowing through the diode or the electrical contact in a time period. The second voltage comparator 302 can be a continuous comparator. The controller 310 can controllably enable or disable the second voltage comparator 302. When the second voltage comparator 302 is disabled, the power consumption of the second voltage comparator 302 can be 1%, 5%, 10% or 20% less than the power consumption when the second voltage comparator 302 is enabled. The absolute value of the second threshold value is greater than the absolute value of the first threshold value. As used herein, the "absolute value" or "modulus" |x| of the term real number x is a non-negative value of x regardless of its sign. That is, if x>=0, then |x|=x, and if x<0, then |x|=-x.

[0046] The second threshold value can be 200%-300% of the first threshold value. The second threshold value can be at least 50% of the maximum voltage that an incident radiation particle can generate in a diode or a resistor. For example, the second threshold value can be 100mV, 150mV, 200mV, 250mV or 300mV. The second voltage comparator 302 and the first voltage comparator 301 can be the same component. In other words, the system 121 can have a voltage comparator that can compare the voltage with two different threshold values ​​at different times.

[0047] The first voltage comparator 301 or the second voltage comparator 302 may include one or more operational amplifiers or any other suitable circuits. The first voltage comparator 301 or the second voltage comparator 302 may have a high speed to allow the system 121 to operate under high incident radiation flux. However, high speed often comes at the expense of power consumption.

[0048] The counter 320 is configured to record the number of radiation particles reaching the diode or resistor. The counter 320 can be a software component (eg, a number stored in a computer memory) or a hardware component (eg, 4017 IC and 7490 IC).

[0049] The controller 310 may be a hardware component, such as a microcontroller and a microprocessor. The controller 310 is configured to start the time delay from the time when the first voltage comparator 301 determines that the absolute value of the voltage is equal to or exceeds the absolute value of the first threshold (e.g., the absolute value of the voltage increases from an absolute value below the first threshold to a value equal to or higher than the absolute value of the first threshold). Absolute values ​​are used herein because the voltage can be negative or positive, depending on whether the voltage of the cathode or anode of the diode is used or which electrical contact is used. The controller 310 may be configured to keep the second voltage comparator 302, the counter 320, and any other circuits not required for the operation of the first voltage comparator 301 disabled before the first voltage comparator 301 determines that the absolute value of the voltage is equal to or exceeds the absolute value of the first threshold. The time delay may terminate before or after the voltage becomes stable (i.e., the rate of change of the voltage is substantially zero). The term "the rate of change of the voltage is substantially zero" means that the time variation of the voltage is less than 0.1% / ns. The term "the rate of change of the voltage is substantially non-zero" means that the time variation of the voltage is at least 0.1% / ns.

[0050] The controller 310 may be configured to enable the second voltage comparator during the time delay (including the start and end). In one embodiment, the controller 310 is configured to enable the second voltage comparator at the start of the time delay. The term "enable" means that the component enters an operating state (e.g., by sending a signal such as a voltage pulse or a logic level, by providing power, etc.). The term "disable" means that the component enters a non-operating state (e.g., by sending a signal such as a voltage pulse or a logic level, by cutting off power, etc.). The operating state may have a higher power consumption (e.g., 10 times higher, 100 times higher, 1000 times higher) than the non-operating state. When the absolute value of the voltage is equal to or exceeds the absolute value of the first threshold value, the controller 310 itself may be disabled until the output of the first voltage comparator 301 enables the controller 310.

[0051] The controller 310 may be configured to increase the number recorded by the counter 320 by one if the second voltage comparator 302 determines that the absolute value of the voltage is equal to or exceeds the absolute value of the second threshold during the time delay.

[0052] The controller 310 can be configured to cause the voltmeter 306 to measure the voltage when the time delay expires. The controller 310 can be configured to connect the electrode to electrical ground to reset the voltage and release any carriers accumulated on the electrode. In one embodiment, the electrode is connected to electrical ground after the time delay expires. In one embodiment, the electrode is connected to electrical ground for a limited reset time period. The controller 310 can connect the electrode to electrical ground by controlling the switch 305. The switch can be a transistor, such as a field effect transistor (FET).

[0053] In one embodiment, the system 121 has no analog filtering networks (eg, RC networks). In one embodiment, the system 121 has no analog circuits.

[0054] The voltmeter 306 may feed its measured voltage to the controller 310 as an analog signal or a digital signal.

[0055] The system 121 may include a capacitance module 309 electrically connected to an electrode or electrical contact of the diode 300, wherein the capacitance module is configured to collect carriers from the electrode. The capacitance module may include a capacitor located in a feedback path of the amplifier. An amplifier configured in this way is called a capacitive transimpedance amplifier (CTIA). A capacitive transimpedance amplifier has a high dynamic range by preventing the amplifier from saturating and improves the signal-to-noise ratio by limiting the bandwidth in the signal path. The carriers from the electrode are collected over a period of time ("integration period", e.g., Figure 4 As shown, at t 0 to 1 Between, or t 1 -t 2 After the integration period ends, the voltage of the capacitor is sampled and then reset by a reset switch. The capacitance module may include a capacitor directly connected to the electrode.

[0056] Electrode current and voltage

[0057] Figure 4 Schematically shows the time variation of the current flowing through the electrode caused by the carriers generated by the radiation particles incident on the diode or resistor (upper curve) and the corresponding time variation of the voltage of the electrode (lower curve). The voltage can be the integral of the current with respect to time. At time t 0 , the radiation particles hit the diode or resistor, carriers begin to be generated in the diode or resistor, current begins to flow through the electrode of the diode or resistor, and the absolute value of the voltage of the electrode or electrical contact begins to increase. 1 , the first voltage comparator 301 determines that the absolute value of the voltage is equal to or exceeds the absolute value of the first threshold value V1, and the controller 310 starts the time delay TD1, and the controller 310 can deactivate the first voltage comparator 301 at the beginning of TD1. 1 If it was previously disabled, then at t 1 The controller 310 is enabled. During TD1, the controller 310 enables the second voltage comparator 302. The term "period" of the time delay as used herein means the beginning and the end (i.e., the end) and any time therebetween. For example, the controller 310 may enable the second voltage comparator 302 at the end of TD1. If during TD1, the second voltage comparator 302 is enabled at time t 2If the absolute value of the voltage is determined to be equal to or greater than the absolute value of the second threshold value V2, the controller 310 increases the number recorded by the counter 320 by one. e , all carriers generated by the radiation particles drift out of the radiation absorption layer 110. At time t s , time delay TD1 is terminated. Figure 4 In the example, time t s At time t e That is, TD1 ends after all carriers generated by the radiation particles drift out of the radiation absorption layer 110. Therefore, the rate of change of the voltage is t s is substantially zero. The controller 310 can be configured to terminate TD1 or 2 , or disable the second voltage comparator 302 at any time in between.

[0058] The controller 310 may be configured to cause the voltmeter 306 to measure the voltage when the time delay TD1 expires. In one embodiment, the controller 310 causes the voltmeter 306 to measure the voltage after the rate of change of the voltage becomes substantially zero after the time delay TD1 expires. The voltage at this time is proportional to the amount of carriers generated by the radiation particles related to the energy of the radiation particles. The controller 310 may be configured to determine the energy of the radiation particles based on the voltage measured by the voltmeter 306. One way to determine the energy is to bin the voltage. The counter 320 may have a sub-counter for each bin. When the controller 310 determines that the energy of the radiation particle falls in a bin, the controller 310 may increase the number recorded in the sub-counter for the bin by one. Therefore, the system 121 is capable of detecting radiation images and is capable of resolving the radiation energy of each radiation particle.

[0059] After TD1 terminates, the controller 310 connects the electrode to electrical ground during a reset period RST to allow carriers accumulated at the electrode to flow to ground and reset the voltage. After RST, the system 121 is ready to detect another incident radiation particle. Implicitly, Figure 4 In the example of , the rate of incident radiation particles that the system 121 can handle is limited to 1 / (TD1+RST). If the first voltage comparator 301 has been disabled, the controller 310 can enable it at any time before the RST terminates. If the controller 310 has been disabled, it can be enabled before the RST terminates.

[0060] Figure 5 Schematically showing the Figure 4In the system 121 operating in the manner shown, the temporal variation of the current flowing through the electrode (upper curve) and the corresponding temporal variation of the voltage of the electrode (lower curve) caused by noise (e.g., dark current, background radiation, scattered X-rays, fluorescent X-rays, shared charges from adjacent pixels) are shown. 0 , the noise starts. If the noise is not large enough to cause the absolute value of the voltage to exceed the absolute value of V1, the controller 310 does not enable the second voltage comparator 302. If the first voltage comparator 301 determines that the noise is large enough to cause the absolute value of the voltage to exceed the absolute value of V1 at time t 1 If the absolute value of V2 exceeds the absolute value of V1, the controller 310 starts the time delay TD1, and the controller 310 may disable the first voltage comparator 301 at the beginning of TD1. During TD1 (e.g., at the end of TD1), the controller 310 enables the second voltage comparator 302. The noise is unlikely to be large enough to cause the absolute value of the voltage to exceed the absolute value of V2 during TD1. Therefore, the controller 310 does not increase the number recorded by the counter 320. At time t e , the noise ends. At time t s , time delay TD1 terminates. The controller 310 can be configured to deactivate the second voltage comparator 302 when TD1 terminates. The controller 310 can be configured not to cause the voltmeter 306 to measure the voltage if the absolute value of the voltage does not exceed the absolute value of V2 during TD1. After TD1 terminates, the controller 310 connects the electrode to electrical ground during the reset period RST to allow carriers accumulated at the electrode due to noise to flow to the ground and reset the voltage. Therefore, the system 121 can be very effective in noise suppression.

[0061] Figure 6 Schematically illustrates the time variation of the current flowing through the electrode (upper curve) and the corresponding time variation of the voltage of the electrode (lower curve) caused by the carriers generated by the radiation particles incident on the diode or resistor when the system 121 is operated to detect incident radiation particles at a rate higher than 1 / (TD1+RST). The voltage can be the integral of the current with respect to time. At time t 0 , the radiation particles hit the diode or resistor, carriers begin to be generated in the diode or resistor, current begins to flow through the electrodes of the diode or the electrical contacts of the resistor, and the absolute value of the voltage at the electrodes or electrical contacts begins to increase. At time t 1 , the first voltage comparator 301 determines that the absolute value of the voltage is equal to or exceeds the absolute value of the first threshold value V1, the controller 310 starts a time delay TD2 shorter than TD1, and the controller 310 can deactivate the first voltage comparator 301 at the beginning of TD2. 1 If it was previously disabled, then at t 1The controller 310 is enabled. During TD2 (eg, at the end of TD2), the controller 310 enables the second voltage comparator 302. If during TD2, the second voltage comparator 302 determines that the absolute value of the voltage is greater than or equal to 0 at time t 2 If the absolute value of the second threshold value V2 is equal to or exceeds the absolute value of the second threshold value V2, the controller 310 increases the number recorded by the counter 320 by one. e , all carriers generated by the radiation particles drift out of the radiation absorption layer 110. At time t h , time delay TD2 is terminated. Figure 6 In the example, time t h At time t e That is, TD2 ends before all carriers generated by the radiation particles drift out of the radiation absorption layer 110. Therefore, the rate of change of voltage is t h is substantially non-zero. The controller 310 may be configured to terminate TD2, or at t 2 , or disable the second voltage comparator 302 at any time in between.

[0062] The controller 310 may be configured to infer t from the voltage as a function of time during TD2. e The voltage at which a particle is emitted is determined using the inferred voltage.

[0063] After TD2 ends, the controller 310 connects the electrode to electrical ground during a reset period RST to allow carriers accumulated at the electrode to flow to the ground and reset the voltage. e The rate of change of the voltage after RST may be substantially non-zero because when RST is terminated before te, all carriers generated by the radiation particles have not yet drifted out of the radiation absorbing layer 110. The rate of change of the voltage at t e After that, it becomes essentially zero, and the voltage at t e Then it stabilizes to the residual voltage VR. In one embodiment, RST is e Time or t e After t is terminated, and the rate of change of the voltage after RST can be substantially zero, because at t e All carriers generated by the radiation particle drift out of the radiation absorbing layer 110. After the RST, the system 121 is ready to detect another incident radiation particle. If the first voltage comparator 301 has been disabled, the controller 310 can enable it at any time before the RST is terminated. If the controller 310 has been disabled, it can be enabled before the RST is terminated.

[0064] Figure 7 Schematically showing the Figure 6In the system 121 operating in the manner shown, the temporal variation of the current flowing through the electrode (upper curve) and the corresponding temporal variation of the voltage of the electrode (lower curve) caused by noise (e.g., dark current, background radiation, scattered radiation, fluorescent X-rays, shared charge from adjacent pixels) are shown. 0 , the noise starts. If the noise is not large enough to cause the absolute value of the voltage to exceed the absolute value of V1, the controller 310 does not enable the second voltage comparator 302. If the first voltage comparator 301 determines that the noise is large enough to cause the absolute value of the voltage to exceed the absolute value of V1 at time t 1 If the absolute value of the voltage exceeds the absolute value of V1, the controller 310 starts the time delay TD2, and the controller 310 may disable the first voltage comparator 301 at the beginning of TD2. During TD2 (e.g., at the end of TD2), the controller 310 enables the second voltage comparator 302. The noise is unlikely to be large enough to cause the absolute value of the voltage to exceed the absolute value of V2 during TD2. Therefore, the controller 310 does not increase the number recorded by the counter 320. At time t e , the noise ends. At time t h , time delay TD2 terminates. The controller 310 can be configured to deactivate the second voltage comparator 302 when TD2 terminates. After TD2 terminates, the controller 310 connects the electrode to electrical ground during a reset period RST to allow carriers accumulated at the electrode due to noise to flow to the ground and reset the voltage. Therefore, the system 121 can be very effective in noise suppression.

[0065] Figure 8 Schematically showing the Figure 6 The time variation of the current flowing through the electrode (upper curve) and the corresponding time variation of the voltage of the electrode (lower curve) caused by the carriers generated by a series of radiation particles incident on the diode or resistor in the system 121 operating in the manner shown, where RST is at t e The voltage curve caused by the carriers generated by each incident radiation particle is offset by the residual voltage before this photon. The absolute value of the residual voltage increases continuously with each incident photon. When the absolute value of the residual voltage exceeds V1 (see Figure 8 ), the controller starts the time delay TD2, and the controller 310 can disable the first voltage comparator 301 at the beginning of TD2. If no other radiation particles are incident on the diode or resistor during TD2, the controller connects the electrode to the electrical ground during the reset period RST when TD2 ends, thereby resetting the residual voltage. Therefore, the residual voltage does not increase the number recorded by the counter 320.

[0066] Run the flow chart

[0067] Fig. 9 Shows suitable for use such as Figure 4 1. A flow chart of a method for detecting radiation using a system such as the system 121 operating as shown in FIG. 1. In step 901, the voltage of an electrode of a diode or an electrical contact of a resistor exposed to radiation is compared to a first threshold value, for example using a first voltage comparator 301. In step 902, it is determined whether the absolute value of the voltage is equal to or exceeds the absolute value of the first threshold value V1, for example using a controller 310. If the absolute value of the voltage does not equal or exceed the absolute value of the first threshold value, the method returns to step 901. If the absolute value of the voltage is equal to or exceeds the absolute value of the first threshold value, then continue to step 903. In step 903, for example using the controller 310, a time delay TD1 is started. In step 904, for example using the controller 310, a circuit (e.g., a second voltage comparator 302 or a counter 320) is enabled during the time delay TD1 (e.g., when TD1 expires). In step 905, for example using the second voltage comparator 302, the voltage is compared to a second threshold value V2. In step 906, it is determined, for example using the controller 310, whether the absolute value of the voltage is equal to or exceeds the absolute value of the second threshold value V2. If the absolute value of the voltage does not equal or exceed the absolute value of the second threshold value, the method proceeds to step 910. If the absolute value of the voltage equals or exceeds the absolute value of the second threshold value, then continue to step 907. In step 907, for example using the controller 310, the number recorded in the counter 320 is increased by one. In optional step 908, for example using the voltmeter 306, the voltage at the end of the time delay TD1 is measured. In optional step 909, for example using the controller 310, the radiation particle energy is determined based on the voltage measured in step 908. There may be a counter for each energy bin. After measuring the radiation particle energy, the counter for the bin to which the photon energy belongs may be increased by one. The method proceeds to step 910 after step 909. In step 910, the voltage is reset to electrical ground, for example by connecting an electrode of a diode or an electrical contact of a resistor to electrical ground. For example, when neighboring pixels share a large portion (eg, >30%) of carriers generated from a single photon, steps 908 and 909 may be omitted.

[0068] Fig.10 Shows suitable for use such as Figure 61. Flowchart of a method for detecting radiation using a system such as the system 121 operating as shown in FIG. 1. In step 1001, the voltage of an electrode of a diode or an electrical contact of a resistor exposed to radiation is compared with a first threshold value, for example, using a first voltage comparator 301. In step 1002, it is determined whether the absolute value of the voltage is equal to or exceeds the absolute value of the first threshold value V1, for example, using a controller 310. If the absolute value of the voltage does not equal or exceed the absolute value of the first threshold value, the method returns to step 1001. If the absolute value of the voltage is equal to or exceeds the absolute value of the first threshold value, then continue to step 1003. In step 1003, for example, using the controller 310, a time delay TD2 is started. In step 1004, for example, using the controller 310, a circuit (e.g., a second voltage comparator 302 or a counter 320) is enabled during the time delay TD2 (e.g., when TD2 expires). In step 1005, for example, using the second voltage comparator 302, the voltage is compared with a second threshold value. In step 1006, it is determined whether the absolute value of the voltage is equal to or exceeds the absolute value of the second threshold value V2, for example, using the controller 310. If the absolute value of the voltage does not equal or exceed the absolute value of the second threshold value, the method proceeds to step 1010. If the absolute value of the voltage is equal to or exceeds the absolute value of the second threshold value, then continue to step 1007. In step 1007, the number recorded in the counter 320 is increased by one, for example, using the controller 310. The method proceeds to step 1010 after step 1007. In step 1010, the voltage is reset to electrical ground, for example, by connecting an electrode of a diode or an electrical contact of a resistor to electrical ground.

[0069] The semiconductor radiation detector 100 can be used for phase contrast X-ray imaging (PCI) (also known as phase sensitive X-ray imaging). Phase contrast X-ray imaging includes techniques that use at least in part the phase shift of an X-ray beam caused by an object (including the spatial distribution of the phase shift) to form an image of the object. One method of obtaining the phase shift is to convert the phase into an intensity change.

[0070] Phase contrast X-ray imaging can be combined with tomography to obtain a 3D distribution of the real part of the refractive index of an object. Phase contrast X-ray imaging is more sensitive to density variations in an object than conventional intensity-based X-ray imaging (e.g. radiography). Phase contrast X-ray imaging is particularly suitable for imaging soft tissues.

[0071] Imaging System

[0072] Fig.11A An imaging system 1100 according to an embodiment is schematically shown. In an embodiment, the imaging system 1100 may include a radiation source 1122, a radiation detector 1100, and a frame 1140.

[0073] In one embodiment, the radiation detector 100 may be fixed to a frame 1140 .

[0074] In one embodiment, the radiation source 1122 may transmit a radiation beam 1124 (eg, X-rays) toward an object 1190 located between the radiation source 1122 and the radiation detector 100 .

[0075] In one embodiment, the radiation detector 100 may capture an image of the object 1190 in a single exposure based on the interaction between the radiation beam 1124 and the object 1190 .

[0076] The interaction between the radiation beam 1124 and the object 1190 may include the following situations: (A) some radiation particles in the radiation beam 1124 incident on the object 1190 are blocked by the object 1190; and (B) some radiation particles in the radiation beam 1124 incident on the object 1190 pass through the object 1190 without changing their directions.

[0077] In one embodiment, the imaging system 1100 may include a radiation source target 1120. In one embodiment, the radiation source 1122 may be implemented by directing an electron beam (not shown) to a target point 1122ts on the radiation source target 1120, thereby generating a radiation beam 1124 (as shown) from the target point 1122ts.

[0078] In one embodiment, radiation source target 1120 may be secured to frame 1140 .

[0079] Imaging system operation in time-delay-sum mode

[0080] In one embodiment, as described below, the imaging system 1100 can capture a first image of the object 1190 in a time delay summation mode. For illustration, the radiation detector 100 can include four sensing elements 150.0, 150.1, 150.2, and 150.3 arranged in a row (as shown).

[0081] In one embodiment, when the radiation detector 100 captures the first image of the object 1190 in the time delay and sum mode, the frame 1140 can rotate counterclockwise around the object 1190 and around an axis (not shown). In one embodiment, the axis can be perpendicular to the page. In one embodiment, the axis can intersect the object 1190.

[0082] In one embodiment, the radiation detector 100 may capture a first image of the object 1190 through multiple exposures in a time delay and sum mode. In one embodiment, the radiation beam 1124 may be a pulse of radiation particles directed toward the object 1190 during each exposure.

[0083] Exposure to obtain data for generating the first image

[0084] refer to Fig.11A , assume that during exposure E0, radiation ray 1126 travels from point 1192 of object 1190 to sensing element 150.0 (as shown) due to radiation beam 1124 from radiation source 1122. Therefore, counter 320 ( Figure 3A and Figure 3B ) counts and records the number N0 of radiation particles incident on the sensing element 150.0 during exposure E0. Note that the counter 320 counts and records the number of radiation particles (eg, the number of photons), not the amount of charge.

[0085] In one embodiment, the count N0 may be considered as the balance number C1.

[0086] In one embodiment, reference Fig. 11B During exposure E1 following exposure E0, radiation ray 1126 travels from point 1192 of object 1190 to sensing element 150.1 (as shown) due to radiation beam 1124 from radiation source 1122. Thus, counter 320 ( Figure 3A and Figure 3B ) counts and records the number N1 of radiation particles incident on the sensor element 150.1 during exposure E1.

[0087] In one embodiment, the radiation detector 100 may sum the count N1 and the remainder C1 to obtain a remainder C2.

[0088] In one embodiment, reference Fig. 11C During exposure E2 following exposure E1, radiation ray 1126 travels from point 1192 of object 1190 to sensing element 150.2 (as shown) due to radiation beam 1124 from radiation source 1122. Thus, counter 320 ( Figure 3A and Figure 3B ) counts and records the number N2 of radiation particles incident on the sensor element 150.2 during exposure E2.

[0089] In one embodiment, the radiation detector 100 may sum the count N2 and the remainder C2 to obtain a remainder C3.

[0090] In one embodiment, reference Fig.11DDuring exposure E3 following exposure E2, radiation ray 1126 travels from point 1192 of object 1190 to sensing element 150.3 (as shown) due to radiation beam 1124 from radiation source 1122. Thus, counter 320 ( Figure 3A and Figure 3B ) counts and records the number N3 of radiation particles incident on the sensor element 150.3 during exposure E3.

[0091] In one embodiment, the radiation detector 100 may sum the count N3 and the remainder C3 to obtain a remainder C4.

[0092] In one embodiment, the entire exposure (ie, the total exposure time) when the radiation detector 100 captures (ie, obtains photon counts and generates) the first image of the object 1190 in the time delay and sum mode. FIG. 11A to FIG. 11D During exposures (E0-E3), the radiation source 1122 can remain stationary relative to the object 1190 at a first source position.

[0093] Generation of the first image

[0094] In one embodiment, the first image of the object 1190 may be generated as follows: for a point 1192 of the object 1190, the remainder number C4 may be used as the value of the primitive of the first image corresponding to the point 1192. In one embodiment, for other points of the object 1190, the values ​​of the primitives of the first image corresponding to these points may be determined in a manner similar to the manner in which the values ​​of the primitives of the first image corresponding to the point 1192 are generated.

[0095] In an embodiment, imaging system 1100 may capture a second image of object 1190 in time delay and sum mode in a manner similar to the manner in which imaging system 1100 captured the first image in time delay and sum mode as described above.

[0096] In one embodiment, the radiation source 1122 may remain stationary relative to the object 1190 at a second source position (e.g., 100 Å) throughout the exposure when the radiation detector 100 captures (i.e., obtains photon counts and generates) a second image of the object 1190 in the time delay and sum mode. Fig.11E shown).

[0097] In one embodiment, the first source position of the radiation source 1122 (eg FIG. 11A to FIG. 11D ) may be different from the second source position of the radiation source 1122 (eg Fig.11E As shown), the first image and the second image of the object 1190 are actually taken from two different angles relative to the object 1190.

[0098] The radiation source changes relative to the frame

[0099] In one embodiment, reference Fig.11A IE, during the capture of the first image in the time delay and sum mode, the radiation source 1122 may be moved back and forth relative to the frame 1140 (although the radiation source 1122 remains stationary relative to the object 1190).

[0100] Specifically, in one embodiment, the radiation source 1122 can be positioned at a point X ( Fig.11A ) through a series of points in the middle ( Fig. 11B and Fig. 11C ) to point Y relative to frame 1140 ( Fig.11D ). Note that “X” and “Y” are used for ease of reference and are Figure 11A-11E They are not shown in FIG.

[0101] Then, in one embodiment, after taking the first image and before taking the second image, the radiation source 1122 may be moved from point Y back to point X ( Fig.11E ).

[0102] Then, in one embodiment, during the capture of the second image in the time delay sum mode, the radiation source 1122 may again pass from point X through a series of intermediate points (respectively Fig. 11B and Fig. 11C 2 points in ) to point Y.

[0103] In one embodiment, reference Fig.11A , the radiation source 1122 that transmits the radiation beam 1124 can be implemented by directing the electron beam to the target point 1122ts on the radiation source target 1120, thereby generating the radiation beam 1124 from the target point 1122ts. Therefore, referring to Figure 11A-11E In one embodiment, the radiation source 1122 may be varied as described above by moving the target point 1122ts (ie, by directing the electron beam to a different location of the target point 1122ts on the radiation source target 1420).

[0104] Flowchart of the operation of the imaging system

[0105] Fig.12 A flow chart 1200 outlining the operation of the imaging system 1100 is shown according to one embodiment.

[0106] In step 1210, the operation may include capturing a first image of the object using a radiation detector, wherein (A) the frame rotates around the object and around an axis, and (B) the radiation source remains stationary at a first source position relative to the object, wherein capturing the first image includes: (A) during an exposure, sending a radiation particle pulse toward the object using the radiation source, (B) determining, using the radiation detector, a count of radiation particles incident on a first sensing element during the exposure, (C) summing, using the radiation detector, the count with a remainder number to obtain another remainder number, (D) during another exposure after the exposure, sending another radiation particle pulse toward the object using the radiation source, (E) determining, using the radiation detector, another count of radiation particles incident on a second sensing element during the another exposure, and (F) summing, using the radiation detector, the another count with another remainder number. For example, in the above embodiment, reference is made to Figures 11A-11D , the radiation detector 100 captures a first image of the object 1190 in a time delay and sum mode, wherein (A) the frame 1140 rotates around the object 1190 and about an axis, and (B) the radiation source 1122 remains stationary at a first source position relative to the object 1190.

[0107] In step 1220, after the first image is captured, a second image of the object is captured using a radiation detector, wherein (A) the frame rotates around the object and around the axis, and (B) the radiation source remains stationary at a second source position relative to the object, wherein the capturing of the second image includes: (A) during exposure, using the radiation source to send a radiation particle pulse toward the object, (B) using the radiation detector to determine the count of radiation particles incident on the first sensing element during the exposure, (C) using the radiation detector to sum the count with the remainder number to obtain another remainder number, (D) during another exposure after the exposure, using the radiation source to send another radiation particle pulse toward the object, (E) using the radiation detector to determine another count of radiation particles incident on the second sensing element during the another exposure, and (F) using the radiation detector to sum the other count with another remainder number, wherein the first source position is different from the second source position. For example, in the above embodiment, reference Fig.11E , the radiation detector 100 captures a second image of the object 1190 in a time delay and summation mode, wherein (A) the frame 1140 rotates around the object 1190 and about the axis, and (B) the radiation source 1122 remains stationary at a second source position relative to the object 1190, and wherein the first source position is different from the second source position.

[0108] Other embodiments

[0109] Computed tomography

[0110] In one embodiment, a three-dimensional image of the object 1190 may be reconstructed based on at least the first image and the second image of the object 1190 .

[0111] The counter counts and sums simultaneously

[0112] In one embodiment, reference Figure 11A-11E and Fig.13A , the counter 320 for each of the four sensing elements 150.0-150.3 can (A) determine the count of radiation particles incident on each of the sensing elements, and (B) sum the count with the balance number from the previous counter 320.

[0113] For example, counter 320.2 for sensing element 150.2 may (A) determine count N2 of radiation particles incident on sensing element 150.2 during exposure E2, and (B) sum count N2 with balance C2 from counter 320.1 to obtain balance C3. Similarly, counter 320.3 for sensing element 150.3 may (A) determine count N3 of radiation particles incident on sensing element 150.3 during exposure E3, and (B) sum count N3 with balance C3 from counter 320.2 to obtain balance C4.

[0114] In one embodiment, reference Figure 11A-11E and Fig.13A , the radiation detector 100 may transfer the remaining number from the counter 320 for the sensing element 150 to the counter 320 for the next sensing element 150. For example, the radiation detector 100 may transfer the remaining number C2 from the counter 320.1 to the counter 320.2. Similarly, the radiation detector 100 may transfer the remaining number C3 from the counter 320.2 to the counter 320.3.

[0115] Counter counts and register sums

[0116] In an alternative embodiment, reference Figure 11A-11E and Fig. 13B , the radiation detector 100 may include a register 325 for each sensing element 150 .

[0117] In one embodiment, the counter 320 for each of the four sensor elements 150.0-150.3 can determine the count of radiation particles incident on each sensor element 150, and the register 325 for each sensor element 150 can sum the count with the remainder number from the register 325 for the previous sensor element 150.

[0118] For example, counter 320.2 for sensing element 150.2 may determine count N2 of radiation particles incident on sensing element 150.2 during exposure E2, and register 325.2 sums count N2 with remainder C2 from register 325.1 to obtain remainder C3. Similarly, counter 320.3 for sensing element 150.3 may determine count N3 of radiation particles incident on sensing element 150.3 during exposure E3, and register 325.3 sums count N3 with remainder C3 from register 325.2 to obtain remainder C4.

[0119] In one embodiment, reference Figure 11A-11E and Fig. 13B , the radiation detector 100 may transfer the balance number from the register 325 for the sensing element 150 to the register 325 for the next sensing element 150. For example, the radiation detector 100 may transfer the balance number C2 from the register 325.1 to the register 325.2. Similarly, the radiation detector 100 may transfer the balance number C3 from the register 325.2 to the register 325.3.

[0120] In an embodiment, radiation detector 100 may include a digital processor (not shown), which may include computer memory (not shown), and registers 325.0-325.3 may be implemented in the computer memory.

[0121] Alternative Embodiments

[0122] The radiation detector moves linearly

[0123] FIG14 schematically illustrates an imaging system 1400 according to an embodiment. In an embodiment, the imaging system 1400 may include a radiation source 1422 and a radiation detector 100.

[0124] In an embodiment, the radiation source 1422 may send a radiation beam 1424 toward a membrane 1490 located between the radiation source 1422 and the radiation detector 100 .

[0125] In one embodiment, imaging system 1400 may be configured to capture the first image of object 1190 in the same manner as imaging system 1100 in the time delay and sum mode ( Figures 11A-11D ) An image of membrane 1490 is taken in a similar manner in time delay and summation mode.

[0126] In one embodiment, the difference between (A) the manner in which the imaging system 1400 captures an image of the membrane 1490 in the time delay summation mode and (B) the manner in which the imaging system 1100 captures a first image of the object 1190 in the time delay summation mode can be that in the imaging system 1400, when the radiation detector 100 captures (i.e., obtains photon counts and then generates) an image of the membrane 1490 in the time delay summation mode, the radiation detector 100 can move linearly relative to the membrane 1490.

[0127] Specifically, refer to Figures 14A-14D In one embodiment, when the radiation detector 100 captures an image of the membrane 1490 in a time-delay-sum mode, the radiation source 1422 and the membrane 1490 can (A) translate linearly (move without rotation) relative to the radiation detector 100 and (B) remain stationary relative to each other.

[0128] For illustration, refer to Figures 14A-14D , the radiation detector 100 of the imaging system 1400 may have 27 sensing elements 150 arranged in 3 rows and 9 columns. For simplicity, Figures 14A-14D Only the first column of 3 sensor elements 150 are shown. The remaining 8 columns of sensor elements 150 are located behind the first column and are therefore hidden from view.

[0129] In one embodiment, the membrane 1490 may include an anode layer, an electrolyte layer, and a cathode layer, wherein the electrolyte layer is sandwiched between the anode layer and the cathode layer. In other words, the membrane 1490 may be a battery membrane.

[0130] In one embodiment, reference Fig.14A , the imaging system 1400 may include a radiation source target 1420. In one embodiment, the radiation source 1422 that sends the radiation beam 1424 may be implemented by directing an electron beam (not shown) to a target point 1422ts on the radiation source target 1420, thereby generating the radiation beam 1424 from the target point 1422ts (as shown). Therefore, referring to Figures 14A-14D , the radiation source 1422 can be moved by moving the target point 1422ts (ie, by directing the electron beam to a different point on the radiation source target 1420).

[0131] In one embodiment, radiation source target 1420 may remain stationary relative to radiation detector 100 while radiation source 1422 and film 1490 are linearly translated relative to radiation detector 100 so that radiation detector 100 captures an image of film 1490 in a time delay and sum mode.

[0132] Operational Flowchart of Imaging System 1400

[0133] Fig.15A flow chart 1500 outlining the operation of the imaging system 1400 of FIG. 14 is shown according to one embodiment.

[0134] In step 1410, the operation may include capturing an image of the film using a radiation detector, wherein the radiation source and the film (A) are both linearly translated relative to the radiation detector and (B) remain stationary relative to each other, wherein capturing the image includes: (A) during a first exposure, sending a first radiation particle pulse toward the object using the radiation source, (B) determining a first count of radiation particles incident on a first sensing element during the first exposure using the radiation detector, (C) summing the first count with a first remainder number using the radiation detector to obtain a second remainder number, (D) during a second exposure after the first exposure, sending a second radiation particle pulse toward the object using the radiation source, (E) determining a second count of radiation particles incident on a second sensing element during the second exposure using the radiation detector, and (F) summing the second count with the second remainder number using the radiation detector. For example, in the above embodiment, reference is made to Figures 14A-14D , the radiation detector 100 captures an image of the film 1490 in a time-delay-sum mode, wherein the radiation source 1422 and the film 1490 (A) are linearly translated relative to the radiation detector 100 and (B) remain stationary relative to each other.

[0135] Although various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for illustrative purposes only and are not intended to be limiting, with the true scope and spirit being indicated by the appended claims.

Claims

1. A radiation detector comprising a first sensor element and a second sensor element, in, The radiation detector is configured to (A) determine a first count of radiation particles incident on the first sensing element during a first exposure, and (B) sum the first count with a first remainder number to obtain a second remainder number, wherein the first remainder number is related to the count of radiation particles incident on a sensing element different from the first sensing element and the second sensing element, and Wherein the radiation detector is configured to (A) determine a second count of radiation particles incident on the second sensing element during a second exposure after the first exposure, and (B) sum the second count with the second remainder number to obtain a third remainder number.

2. The radiation detector according to claim 1, further comprising a third sensing element, in, The radiation detector is configured to (A) determine a third count of radiation particles incident on the third sensing element during a third exposure subsequent to the second exposure, and (B) sum the third count with the third remainder number to obtain a fourth remainder number.

3. A system comprising a radiation detector, a radiation source and a frame according to claim 1, in, The radiation source is configured to send a radiation beam toward an object, wherein the frame is configured to rotate about an axis, wherein the radiation detector is fixed to the frame, and Wherein the radiation detector is configured to capture an image of the object based on an interaction between the radiation beam and the object. 4 . The system of claim 3 , further comprising a radiation source target fixed to the frame and configured to receive the electron beam to emit the radiation beam.

5. A system comprising a radiation detector according to claim 1 and a radiation source configured to send a radiation beam towards a film, in, The radiation detector is configured to capture an image of the film based on an interaction between the radiation beam and the film. 6 . The system of claim 5 , further comprising a radiation source target configured to receive the electron beam to thereby emit the radiation beam.

7. The radiation detector according to claim 1, in, The radiation detector includes a first counter configured to (A) determine the first count, and (B) sum the first count with the first balance number, and Wherein, the radiation detector includes a second counter configured to (A) determine the second count and (B) sum the second count with the second balance number.

8. The radiation detector according to claim 7, in, The radiation detector is configured to transfer the second balance number from the first counter to the second counter.

9. The radiation detector according to claim 1, in, The radiation detector includes a first counter and a first register, wherein the first counter is configured to determine the first count, wherein the first register is configured to sum the first count and the first balance number, Wherein, the radiation detector comprises a second counter and a second register, wherein the second counter is configured to determine the second count, and The second register is configured to sum the second count and the second balance.

10. The radiation detector according to claim 9, in, The radiation detector is configured to transfer the second balance number from the first register to the second register.

11. The radiation detector according to claim 9, in, The radiation detector includes a digital processor including computer memory, and The first register and the second register are implemented in the computer memory.

12. The radiation detector according to claim 1, in, The radiation detector is configured to capture an image of the object, and The value of the image element of the image is equal to the third remainder number.

13. The radiation detector according to claim 1, in, The radiation particles are X-rays.

14. The radiation detector according to claim 1, in, The radiation detector comprises: a radiation absorbing layer, including electrodes; a first voltage comparator configured to compare the voltage of the electrode with a first threshold; a second voltage comparator configured to compare the voltage with a second threshold; a counter configured to record the number of photons absorbed by the radiation absorbing layer; and Controller, wherein the controller is configured to start the time delay from the time when the first voltage comparator determines that the absolute value of the voltage is equal to or exceeds the absolute value of the first threshold value, wherein the controller is configured to enable the second voltage comparator during the time delay, and The controller is configured to increase the number recorded by the counter by one if the second voltage comparator determines that the absolute value of the voltage is equal to or exceeds the absolute value of the second threshold.

15. A method of using the system according to any one of claims 3-4, the method include: capturing a first image of the object using the radiation detector, wherein (A) the frame rotates around the object and around the axis, and (B) the radiation source remains stationary at a first source position relative to the object, wherein capturing the first image comprises: (A) sending a radiation particle pulse toward the object using the radiation source during an exposure, (B) determining a count of radiation particles incident on the first sensing element during the exposure using the radiation detector, (C) summing the count with a remainder number using the radiation detector to obtain another remainder number, (D) sending another radiation particle pulse toward the object during another exposure after the exposure using the radiation source, (E) determining another count of radiation particles incident on the second sensing element during the another exposure using the radiation detector, and (F) summing the another count with the another remainder number using the radiation detector; and After taking the first image, taking a second image of the object using the radiation detector, wherein (A) the frame rotates around the object and around the axis, and (B) the radiation source remains stationary at a second source position relative to the object, wherein taking the second image includes: (A) sending a radiation particle pulse toward the object using the radiation source during an exposure, (B) determining a count of radiation particles incident on the first sensing element during the exposure using the radiation detector, (C) summing the count with a remainder number using the radiation detector to obtain another remainder number, (D) sending another radiation particle pulse toward the object during another exposure after the exposure, (E) determining another count of radiation particles incident on the second sensing element during the another exposure using the radiation detector, and (F) summing the another count with the another remainder number using the radiation detector, Wherein, the first source position is different from the second source position.

16. The method of claim 15, further comprising reconstructing a three-dimensional image of the object based at least on the first image and the second image.

17. The method according to claim 15, in, The radiation source (A) during said capturing of said first image, from point X to point Y via a series of intermediate points, (B) after taking the first image and before taking the second image, moving back from point Y to point X, and (C) during said capturing of said second image, moving from point X to point Y via a series of intermediate points, Wherein, point X and point Y are relative to the frame.

18. The method according to claim 17, in, said radiation source transmitting a radiation beam is implemented by directing an electron beam to a target point on a radiation source target, thereby generating said radiation beam from said target point, and Wherein, changing the radiation source includes moving the target point.

19. A method of using the system according to any one of claims 5-6, the method comprising taking an image of the film with the radiation detector, in, The radiation source and the film (A) both translate linearly relative to the radiation detector and (B) remain stationary relative to each other, wherein capturing the image includes: (A) during the first exposure, using the radiation source to send a first radiation particle pulse toward the film, (B) using the radiation detector to determine the first count of radiation particles incident on the first sensing element during the first exposure, (C) using the radiation detector to sum the first count with the first remainder number to obtain the second remainder number, (D) during the second exposure after the first exposure, using the radiation source to send a second radiation particle pulse toward the film, (E) using the radiation detector to determine the second count of radiation particles incident on the second sensing element during the second exposure, and (F) using the radiation detector to sum the second count with the second remainder number.

20. The method according to claim 19, in, The membrane includes an anode layer, an electrolyte layer, and a cathode layer, wherein the electrolyte layer is sandwiched between the anode layer and the cathode layer.

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