TW202307463A - Method of determination of photon origination points using radiation detectors and radiation sensing system - Google Patents

Abstract

Disclosed herein is a method, comprising: receiving, with a first radiation sensor, a first photon from an object, the first radiation sensor comprising M sensing element groups, wherein each sensing element group of the M sensing element groups comprises multiple sensing elements, and wherein M is an integer greater than 1; determining a first subset of the M sensing element groups based on electrical signals in the M sensing element groups of the first radiation sensor; and determining a first estimated path of the first photon based on positions of the sensing element groups in the first subset.

Description

Method and radiation sensing system for determining point of origin of photons using radiation detector

The invention relates to a method and a radiation sensing system for determining the point of origin of a photon using a radiation detector.

A radiation detector is a device that measures the properties of radiation. Examples of properties may include the spatial distribution of the intensity, phase and polarization of the radiation. The radiation measured by the radiation detector may be radiation that has been transmitted through the object. The radiation measured by the radiation detector may be electromagnetic radiation, such as infrared light, visible light, ultraviolet light, X-rays or gamma rays. Radiation can also be of other types, such as alpha and beta rays. An imaging system may include one or more image sensors, each of which may have one or more radiation detectors.

A method is disclosed herein, the method comprising: using a first radiation sensor to receive a first photon from an object, the first radiation sensor comprising M sensing element groups, wherein the M sensing element groups Each sensing element group in the element group includes a plurality of sensing elements, and wherein M is an integer greater than 1; the determination of the A first subset of M sensing element groups; and determining a first estimated path of the first photon based on the positions of the sensing element groups in the first subset.

In an aspect, said determining said first subset includes identifying a set of sensing elements of said sets of M sensing elements having a photon presence signal.

In an aspect, said identifying comprises: determining a voltage of a dedicated electrode of each sensing element of said first radiation sensor; and combining said The voltage of the dedicated electrode of a plurality of sensing elements, thereby obtaining the group voltage of each sensing element group, wherein the photon presence signal in the sensing element group is that the group voltage of the sensing element group exceeds a predetermined threshold voltage events.

In one aspect, the dedicated electrodes of the plurality of sensing elements of each sensing element group in the M sensing element groups are electrically connected to the group node using metal wires, and wherein all the sensing element groups in the sensing element group The photon presence signal is an event that a voltage of a group node of the sensing element group exceeds a predetermined threshold voltage.

In an aspect, said determining said first subset further comprises excluding a set of sensing elements from said first subset based on a temporal relationship between photon presence signals in sets of sensing elements in said first subset .

In an aspect, the temporal relationship is a temporal order of the photon presence signals in the sets of sensing elements in the first subset.

In one aspect, the first photons are scattered within the first radiation sensor.

In an aspect, the first estimated path of the first photon includes a portion external to the first radiation sensor.

In one aspect, the sensing elements of the M sensing element groups are located in a plurality of radiation absorbing layers of the radiation sensor.

In one aspect, the first photon-opaque layer separates any two adjacent radiation absorbing layers of the plurality of radiation absorbing layers.

In one aspect, the first photon is a gamma ray photon or an X-ray photon.

In one aspect, all of the M sensing element groups have the same number of sensing elements.

In one aspect, the method includes receiving second photons from an object using a second radiation sensor, the second radiation sensor comprising N sets of sensing elements, wherein the N sets of sensing elements Each sensing element group in includes a plurality of sensing elements, and wherein, N is an integer greater than 1; the N sensing elements are determined based on electrical signals in the sensing element groups of the second radiation sensor a second subset of sets of elements; and determining a second estimated path of the second photon based on the positions of the sets of sensing elements in the second subset.

In an aspect, the method further includes determining a location of a photon origin point of the first photon and the second photon based on the first estimated path and the second estimated path.

In one aspect, the method further includes rotating the first radiation sensor and the second radiation sensor around the object while maintaining the first radiation sensor and the second radiation sensor The detectors remain stationary relative to each other.

In an aspect, the method further includes: receiving second photons from the object using the first radiation sensor; determining the A second subset of M sets of sensing elements; and, based on a position of the set of sensing elements in the second subset, determining a second estimated path of the second photon.

In an aspect, the method further includes determining a location of a photon origin point of the first photon and the second photon based on the first estimated path and the second estimated path.

In one aspect, the determining the first estimated path of the first photon comprises: determining a best-fit straight line passing through the sensing element groups in the first subset, so as to obtain the first estimated path.

In one aspect, the first radiation sensor comprises a stack of P signal processing dies and 2P radiation absorbing layers, P being an integer greater than 1, wherein each of the P signal processing dies is dedicated to processing electrical signals in two adjacent radiation absorbing layers of the 2P radiation absorbing layers, and wherein at least one of the P signal processing wafers is sandwiched between two radiation absorbing layers of the 2P radiation absorbing layers between.

In an aspect, the two radiation absorbing layers are separated by another radiation absorbing layer of the 2P radiation absorbing layers.

In an aspect, the separation layer is sandwiched between any two adjacent radiation absorbing layers of the 2P radiation absorbing layers, and wherein the separation layer is configured to block gamma rays and X-rays.

In one aspect, the first radiation sensor comprises (A) a stack of Q radiation absorbing layers, and (B) a multi-signal processing die for each of the Q radiation absorbing layers, wherein for all The multi-signal processing chip of each radiation absorbing layer of the Q radiation absorbing layers and the dedicated electrodes of all sensing elements of each radiation absorbing layer are located on the same side surface of each radiation absorbing layer, and Wherein, there is no straight line (A) perpendicular to the same side surface of each radiation absorbing layer and (B) intersecting the signal processing wafer for each radiation absorbing layer and each radiation absorbing layer Any dedicated electrode of any sensing element of the layer intersects.

In an aspect, a plurality of signal processing dies of the multiple signal processing dies for one of the Q radiation absorbing layers are physically attached to a support substrate, and wherein the plurality of signal processing dies are physically attached to a support substrate, and wherein the plurality of signal processing dies A handle wafer is sandwiched between the support substrate and the radiation absorbing layer.

In an aspect, the multi-signal processing wafer for one of the Q radiation absorbing layers is located in the recess of an adjacent one of the Q radiation absorbing layers.

In an aspect, the multi-signal processing wafer for a radiation absorbing layer of the Q radiation absorbing layers is located in a recess of a separation layer, and wherein the separation layer is configured to block gamma rays and X-rays .

Disclosed herein is a system comprising a first radiation sensor configured to receive a first photon from an object, wherein the first radiation sensor comprises M sensor sensing element groups, wherein each sensing element group in the M sensing element groups includes a plurality of sensing elements, wherein M is an integer greater than 1, wherein the system is configured based on the Electrical signals in M sets of sensing elements of a radiation sensor determine a first subset of the M sets of sensing elements, and wherein the system is configured to sense The position of the set of elements determines a first estimated path of the first photon.

In one aspect, the system further includes a second radiation sensor configured to receive second photons from the object, wherein the second radiation sensor includes N Sensing element groups, wherein each of the N sensing element groups includes a plurality of sensing elements, wherein N is an integer greater than 1, wherein the system is configured based on the The electrical signals in the sensing element sets of the second radiation sensor determine a second subset of the N sensing element sets, and wherein based on the system being configured to sense The position of the set of elements determines a second estimated path of the second photon.

In an aspect, the system is configured to determine a location of a photon origin point of the first photon and the second photon based on the first estimated path and the second estimated path.

In one aspect, the first radiation sensor comprises a stack of P signal processing dies and 2P radiation absorbing layers, P being an integer greater than 1, wherein each of the P signal processing dies is dedicated to processing electrical signals in two adjacent radiation absorbing layers of the 2P radiation absorbing layers, and wherein at least one of the P signal processing wafers is sandwiched between two radiation absorbing layers of the 2P radiation absorbing layers between.

In an aspect, the two radiation absorbing layers are separated by another radiation absorbing layer of the 2P radiation absorbing layers.

In an aspect, the separation layer is sandwiched between any two adjacent radiation absorbing layers of the 2P radiation absorbing layers, and wherein the separation layer is configured to block gamma rays and X-rays.

In one aspect, the first radiation sensor comprises (A) a stack of Q radiation absorbing layers, and (B) a multi-signal processing die for each of the Q radiation absorbing layers, wherein for all The multi-signal processing chip of each radiation absorbing layer of the Q radiation absorbing layers and the dedicated electrodes of all sensing elements of each radiation absorbing layer are located on the same side surface of each radiation absorbing layer, and Wherein, there is no straight line (A) perpendicular to the same side surface of each radiation absorbing layer and (B) intersecting the signal processing wafer for each radiation absorbing layer and each radiation absorbing layer Any dedicated electrode of any sensing element of the layer intersects.

In an aspect, a plurality of signal processing dies of the multiple signal processing dies for one of the Q radiation absorbing layers are physically attached to a support substrate, and wherein the plurality of signal processing dies are physically attached to a support substrate, and wherein the plurality of signal processing dies A handle wafer is sandwiched between the support substrate and the radiation absorbing layer.

In an aspect, the multi-signal processing wafer for one of the Q radiation absorbing layers is located in the recess of an adjacent one of the Q radiation absorbing layers.

In an aspect, the multi-signal processing wafer for a radiation absorbing layer of the Q radiation absorbing layers is located in a recess of a separation layer, and wherein the separation layer is configured to block gamma rays and X-rays .

radiation detector

As an example, FIG. 1 schematically shows a radiation detector 100 . Radiation detector 100 may include an array of picture elements 150 (also referred to as sensing elements 150 ). The array may be a rectangular array (as shown in Figure 1), a honeycomb array, a hexagonal array, or any other suitable array. The array of primitives 150 in the example of FIG. 1 has 4 columns and 7 rows; however, in general, the array of primitives 150 can have any number of rows and any number of columns.

Each primitive 150 may be configured to detect radiation incident thereon from a radiation source (not shown), and may be configured to measure properties of the radiation (eg, energy, wavelength, and frequency of particles). Radiation can include particles such as photons and subatomic particles. Each primitive 150 may be configured to count, over a period of time, the number of radiation particles incident thereon whose energies fall within a plurality of energy intervals. All primitives 150 may be configured to count the number of radiation particles incident thereon in multiple energy intervals over the same period of time. When the incident radiation particles have similar energies, the primitive 150 may simply be configured to count the number of radiation particles incident thereon over a period of time without measuring the energy of the individual radiation particles.

Each primitive 150 may have its own analog-to-digital converter (ADC) configured to digitize an analog signal representing the energy of an incident radiation particle into a digital signal, or convert an analog signal representing the total energy of a plurality of incident radiation particles to a digital signal. Analog signals are digitized into digital signals. Primitives 150 may be configured to work in parallel. For example, while one primitive 150 is measuring incident radiation particles, another primitive 150 may be waiting for the radiation particles to arrive. Primitives 150 may not necessarily be individually addressable.

The radiation detector 100 described herein can be used in, for example, X-ray telescopes, X-ray mammography, industrial X-ray defect detection, X-ray microscopy or microradiography, X-ray casting inspection, X-ray non-destructive testing, X-ray weld inspection, X-ray digital subtraction angiography, etc. It may also be appropriate to use the radiation detector 100 in place of a photographic plate, photographic film, PSP plate, X-ray image intensifier, scintillator, or other semiconductor X-ray detector.

Figure 2 schematically illustrates a simplified cross-sectional view of the radiation detector 100 of Figure 1 along line 2-2, according to an embodiment. Specifically, the radiation detector 100 may include a radiation absorbing layer 110 and an electronics layer 120 (which may include one or more ASICs (Application Specific Integrated Circuits)) for processing or analyzing electrical signals generated in the radiation absorbing layer 110 by incident radiation. or programmable logic device). The radiation detector 100 may or may not include a scintillator (not shown). The radiation absorbing layer 110 may include semiconductor materials such as silicon, germanium, GaAs, CdTe, CdZnTe or combinations thereof. The semiconductor material may have a high mass attenuation coefficient for the radiation of interest.

As an example, FIG. 3 schematically shows a detailed cross-sectional view of the radiation detector 100 of FIG. 1 along line 2-2. Specifically, the radiation absorbing layer 110 may include one or more diodes (eg, p-i-n or p-n) formed by the first doped region 111 , one or more discrete regions 114 of the second doped region 113 . The second doped region 113 may be separated from the first doped region 111 by an optional intrinsic region 112 . The discrete regions 114 may be separated from each other by the first doped region 111 or the intrinsic region 112 . The first doped region 111 and the second doped region 113 may have opposite types of doping (eg, region 111 is p-type and region 113 is n-type, or region 111 is n-type and region 113 is p-type). In the example of FIG. 3 , each discrete region 114 of the second doped region 113 forms a diode with the first doped region 111 and optionally the intrinsic region 112 . That is, in the example of FIG. 3, the radiation absorbing layer 110 has a plurality of diodes (more specifically, 7 diodes correspond to 7 primitives 150 in a column in the array of FIG. 3, only two of them are marked 150). A plurality of diodes may have an electrode 119A as a common (common) electrode. The first doped region 111 may also have discrete portions.

The electronics layer 120 may include an electronic system 121 suitable for processing or interpreting signals generated by radiation incident on the radiation absorbing layer 110 . Electronic system 121 may include analog circuits such as filter networks, amplifiers, integrators, and comparators, or digital circuits such as microprocessors and memory. Electronic system 121 may include one or more ADCs (analog-to-digital converters). Electronic system 121 may include elements shared by primitives 150 or elements specific to a single primitive 150 . For example, electronic system 121 may include an amplifier dedicated to each picture element 150 and a microprocessor shared among all picture elements 150 . Electronic system 121 may be electrically connected to graphics element 150 through via 131 . The spaces between the via holes may be filled with a filling material 130 , which may increase the mechanical stability of the connection of the electronic device layer 120 to the radiation absorbing layer 110 . Other bonding techniques may connect electronics 121 to primitive 150 without using vias 131 .

When radiation from a radiation source (not shown) strikes the radiation absorbing layer 110 comprising diodes, radiation particles may be absorbed and generate one or more charge carriers (eg, electrons, holes) through a variety of mechanisms. Charge carriers can drift to the electrodes of one of the diodes under the electric field. The electric field may be an external electric field. Electrode 119B may include discrete portions, each discrete portion being in electrical contact with discrete region 114 . The term "electrical contact" may be used interchangeably with the word "electrode". Electrode 119B may also be referred to as dedicated electrode 119B because it is dedicated to picture element 150 . In an embodiment, the charge carriers may drift in all directions such that charge carriers generated by a single radiation particle are not substantially shared by two distinct discrete regions 114 (herein "substantially not shared by...  ..shared means that less than 2%, less than 0.5%, less than 0.1%, or less than 0.01% of these charge carriers flow to a different discrete region 114 compared to the rest of the charge carriers ). Charge carriers generated by radiation particles incident around the footprint of one of the discrete regions 114 are substantially not shared with the other of the discrete regions 114 . The primitives 150 associated with the discrete region 114 may be the area surrounding the discrete region 114 in which substantially all (greater than 98%, greater than 99.5%, greater than 99.9%, or greater than 99.99%) of the The charge carriers flow to the discrete regions 114 . That is, less than 2%, less than 1%, less than 0.1%, or less than 0.01% of these charge carriers flow through the primitive 150 .

Figure 4 schematically illustrates a detailed cross-sectional view of the radiation detector 100 of Figure 1 along line 2-2, according to an alternative embodiment. More specifically, the radiation absorbing layer 110 may include resistors of semiconductor materials such as silicon, germanium, GaAs, CdTe, CdZnTe, or combinations thereof, but not diodes. The semiconductor material may have a high mass attenuation coefficient for the radiation of interest. In an embodiment, the electronics layer 120 of FIG. 4 is similar in structure and function to the electronics layer 120 of FIG. 3 .

When radiation strikes the radiation absorbing layer 110, which includes a resistor and does not include a diode, it can be absorbed and generate one or more charge carriers through a variety of mechanisms. Radiation particles can generate 10 to 100,000 charge carriers. Charge carriers can drift to electrodes 119A and 119B under the electric field. The electric field may be an external electric field. Electrode 119B may include discrete portions. In an embodiment, the charge carriers may drift in all directions such that the charge carriers generated by a single radiation particle are not substantially shared by two distinct discrete portions of the electrode 119B (herein "substantially not shared by .. ...shared"means that less than 2%, less than 0.5%, less than 0.1%, or less than 0.01% of these charge carriers flow to a different discrete part). Charge carriers generated by radiation particles incident around the footprint of one of the discrete portions of electrode 119B are not substantially shared with the other of the discrete portions of electrode 119B. A primitive 150 associated with a discrete portion of electrode 119B may be an area around the discrete portion in which substantially all (greater than 98%, greater than 99.5%, greater than 99.9%, or greater than 99.99%) of the ) charge carriers flow to discrete portions of electrode 119B. That is, less than 2%, less than 0.5%, less than 0.1%, or less than 0.01% of the charge carriers flow through the picture element associated with a discrete portion of electrode 119B.

Radiation Sensing Systems and Radiation Sensors

Fig. 5 schematically shows a perspective view of a radiation sensing system 500 according to an embodiment. In an embodiment, the radiation sensing system 500 may include a radiation sensor 510 . In an embodiment, radiation sensor 510 may include a stack of 12 radiation absorbing layers 110 and 6 signal processing dies 122 as shown.

In an embodiment, each signal processing die 122 may be similar in function and structure to the electronics layer 120 of FIGS. 2-4 . For example, each signal processing die 122 may be an ASIC die or a programmable logic device for processing and analyzing electrical signals generated by incident radiation in sensing elements 150 of the radiation absorbing layer 110 served by the signal processing die 122 .

In an embodiment, the 12 radiation absorbing layers 110 may be divided into 6 pairs, each pair having two adjacent radiation absorbing layers 110 . In an embodiment, each pair of two adjacent radiation absorbing layers 110 may share a signal processing chip 122 . In other words, the shared signal processing chip 122 is dedicated to processing and analyzing electrical signals generated in the sensing elements 150 of two adjacent radiation absorbing layers 110 .

For example, the signal processing chip 122.1 is dedicated to processing and analyzing electrical signals generated in two adjacent radiation absorbing layers 110.1a and 110.1b. In other words, the signal processing die 122.1 is used for both radiation absorbing layers 110.1a and 110.1b. As another example, a signal processing die 122.6 is used for two adjacent radiation absorbing layers 110.6a and 110.6b.

In an embodiment, most of the signal processing die 122 may be sandwiched between two radiation absorbing layers 110 . For example, signal processing die 122.6 is sandwiched between radiation absorbing layers 110.5b and 110.6b. Note that the two radiation absorbing layers 110.5b and 110.6b are separated by the radiation absorbing layer 110.6a.

In an embodiment, for each of the 12 radiation absorbing layers 110, its dedicated electrode 119B is located on its right side surface, and its common electrode 119A is located on its left side surface. For example, the radiation absorbing layer 110.1a has 4×6=24 sensing elements 150, and the 24 dedicated electrodes 119B of the 24 sensing elements 150 of the radiation absorbing layer 110.1a are all located on the right side surface 110s of the radiation absorbing layer 110.1a. The common electrode 119A of the 24 sensing elements 150 of the radiation absorbing layer 110.1a is located on the left side surface of the radiation absorbing layer 110.1a, but is not shown for simplicity.

In an embodiment, transmission lines (not shown) electrically connecting the sensing elements 150 of both radiation absorbing layers 110.1a and 110.1b to the associated signal processing die 122.1 run on the right side surface of the radiation absorbing layer 110.1b. In embodiments, the arrangement of the transmission lines and their associated signal processing dies 122 in the other pairs of radiation absorbing layers 110 may be similar.

In an embodiment, the sensing elements 150 of the radiation sensor 510 may be divided into sensing element groups 152 , and each sensing element group may have a plurality of sensing elements 150 . In an embodiment, all sensing element groups 152 of the radiation sensor 510 may have the same number of sensing elements 150 . For example, all sensing element groups 152 of radiation sensor 510 may have two sensing elements 150 . As a result, the 24 sensing elements 150 of the radiation absorbing layer 110.1a are divided into 12 sensing element groups 152 as shown.

object to be analyzed

In an embodiment, object 520 may be positioned such that photons originating from object 520 and traveling toward radiation sensor 510 will be incident (ie, hit) the radiation sensor on the side of radiation sensor 510 that does not have electrodes 119A or 119B. detector 510 (as shown).

For example, a photon 521 originating from object 520 and traveling along path 521 p towards radiation sensor 510 strikes the side of radiation sensor 510 . In an embodiment, this side of the radiation sensor 510 does not have any electrodes 119A or 119B.

Photon Presence Signal - Group Voltage

In an embodiment, the photons 521 may be scattered inside the radiation sensor 510 after being incident on the radiation sensor 510 (eg, Compton scattering). As a result, photons 521 may generate electrical signals in some sensing elements 150 of radiation sensor 510 . As a result, the voltage of the dedicated electrodes 119B of some sensing elements 150 in the radiation sensor 510 may rise.

In an embodiment, if the combined voltage (eg, the sum) of the voltages of the two dedicated electrodes 119B of the two sensing elements 150 of the sensing element group 152 (referred to simply as the group voltage) exceeds a predetermined threshold voltage, it can be considered Photons 521 are present in sensing element group 152 of radiation sensor 510 .

The event that the group voltage of the sensing element group 152 exceeds a predetermined threshold voltage may be referred to as a photon presence signal in the sensing element group 152 .

For example, if the signal processing chip 122.1 determines the voltages of the two dedicated electrodes 119B of the two sensing elements 150 of the sensing element group 152(4,1), then it is determined that the group voltage of the sensing element group 152(4,1) exceeds the predetermined , then it can be considered that the photon 521 exists in the sensing element group 152(4,1).

System Operation - Determine Photon Estimation Path

As an example, assume that photon presence signals are present in sensing element groups 152(2,3), 152(3,2), and 152(4,1). These three sensing element groups are shown in gray in Figure 5 for ease of viewing. As a result, photons 521 may be considered to be present in these three sensing element groups 152 in an embodiment. These three sensing element groups constitute a subset of all sensing element groups 152 of radiation sensor 510 . Note that, in essence, the three sensing element groups 152(2,3), 152(3,2) and 152 of the subset are identified based on the electrical signals in the sensing element group 152 of the radiation sensor 510 (4,1). Specifically, three sensing element groups 152(2,3), 152(3,2), and 152(4,1) of the subset are identified because they have photon presence signals.

In an embodiment, the estimated path 521p' of the photon 521 may be based on the position of the sensing element group 152 in the subset comprising the sensing element groups 152(2,3), 152(3,2), and 152(4,1) to make sure.

In an embodiment, the estimated path 521p' may be a best-fit straight line through the three sensing element groups 152(2,3), 152(3,2), and 152(4,1) of the subset.

In an embodiment, the radiation sensing system 500 may further include a computer 530 electrically connected to all six signal processing chips 122 of the radiation sensor 510 . In an embodiment, computer 530 may determine a best-fit straight line through all three sensing element groups 152(2,3), 152(3,2), and 152(4,1).

In an embodiment, the estimation path 521p' extends to infinity in two opposite directions outside the radiation sensor 510 . As a result, the estimated path 521 p ′ includes a portion outside the radiation sensor 510 .

In the above example, for simplicity of illustration, all sensing element groups 152 (i.e., three sensing element groups 152(2,3), 152(3,2) and 152(4,1) with photon presence signals ) are all located in the same radiation absorbing layer 110 (ie, radiation absorbing layer 110.1a). In general, sensing element groups 152 having photon presence signals may be in the plurality of radiation absorbing layers 110 .

Flow chart outlining system operation

FIG. 6 shows a flowchart outlining the operation of radiation sensing system 500 according to an embodiment. In step 610, the radiation sensor receives photons from the object, the radiation sensor includes M sensing element groups, where M is an integer greater than 1. For example, in the above embodiments, radiation sensor 510 receives photons 521 from object 520 . The radiation sensor 510 includes a plurality of sensing element groups 152 . If the other radiation absorbing layer 110 is similar to the radiation absorbing layer 110.1a, then M=12 layers×12 groups/layer=144 sensing element groups 152 .

Additionally, in step 610, each sensing element group in the M sensing element groups includes a plurality of sensing elements. For example, in the above embodiment, each of the 144 sensing element groups 152 of the radiation sensor 510 includes two sensing elements 150 .

In step 620, a subset of M sensing element groups is determined based on electrical signals in the sensing element groups of the radiation sensor. For example, in the above-described embodiment, it is determined based on the electrical signal in the sensing element group 152 of the radiation sensor 510 that the three sensing element groups 152(2,3), 152(3,2) and 152(4 , a subset of 1).

In step 630, an estimated path of the photon is determined based on the locations of the sets of sensing elements in the subset. For example, in the embodiments described above, the estimated path 521p' of the photon 521 is determined based on the positions of the three sensing element groups 152(2,3), 152(3,2) and 152(4,1) in the subset.

Additional embodiments

Time relationship of photon presence signal

In an embodiment, with respect to step 620 of FIG. 6 , determining a subset may further include excluding a sensing element set from the subset based on a temporal relationship between photon presence signals in the sensing element set in the subset.

In the above example, the determination of the subsets may also include based on the temporal relationship between the photon presence signals in the sensing element groups 152(2,3), 152(3,2) and 152(4,1), from which Sensing element group 152 is excluded from the subset.

For example, assume that a photon presence signal occurs in sensing element group 152(2,3), then in sensing element group 152(4,1), then in sensing element group 152(3,2). Since photons 521 may travel deeper into radiation sensor 510 over time, the photon presence signal in sensing element set 152(3,2) is likely not caused by photons 521 . Thus, in an embodiment, sense element group 152(3,2) may be excluded from the subset. The determination of the estimated path 521p' of the photon 521 may then be based on the remaining sensing element sets in the subset (ie, based on sensing element sets 152(2,3) and 152(4,1)).

In other words, the determination of the subset also includes based on the temporal order of the photon presence signals in the sensing element groups 152(2,3), 152(3,2) and 152(4,1) of the subset, from the subset Sensing element group 152 is excluded.

Separation layer between radiation absorbing layers

In an embodiment, referring to FIG. 5, the radiation sensor 510 may further include 11 separation layers (not shown) between the 12 radiation absorbing layers 110, so that the separation layer is sandwiched between any two adjacent radiation layers 110. between and thus separate the absorbent layers 110 . For example, referring to Figure 11, a separation layer 117 is sandwiched between and thus separates two adjacent radiation absorbing layers 110.1a and 110.1b.

In an embodiment, the 11 separate layers may be opaque to photons 521 . In other words, if a photon 521 strikes any one of the 11 separation layers, the photon 521 is blocked and absorbed by the separation layer.

In an embodiment, photons 521 may be gamma ray photons or X-ray photons. In an embodiment, the 11 separation layers may include tungsten that blocks and absorbs gamma-ray photons and X-ray photons.

Estimated path of the second photon

Referring to FIG. 7 , assume that a second photon 522 originating from an object 520 and traveling toward the radiation sensor 510 along a path 522p hits one side of the radiation sensor 510 . Note that this side of radiation sensor 510 does not have any electrodes 119A or 119B.

In an embodiment, computer 530 may determine estimated path 522p′ of second photon 522 . In an embodiment, the determination of the estimated path 522p' of the second photon 522 may be similar to the determination of the estimated path 521p' of the first photon 521 described above.

photon origin

In an embodiment, the computer 530 may analyze whether the estimated path 521p' and the estimated path 522p' intersect each other. Assume that computer 530 determines that estimated path 521 p ′ and estimated path 522 p ′ intersect each other at intersection point 525 . As a result, this intersection point 525 can be considered a photon origin point for both the first photon 521 and the second photon 522 . It can be said that the determination of the photon origin point 525 of the first photon 521 and the second photon 522 is based on the first estimated path 521p′ of the first photon 521 and the second estimated path 522p′ of the second photon 522 .

Radiotracers as sources of gamma-ray photons

In an embodiment, object 520 may contain a positron-emitting radiotracer. Each emitted positron may collide with and combine with nearby electrons, resulting in one or more gamma-ray photons. In an embodiment, these gamma ray photons may include photons 521 and 522 described above.

Alternative embodiment

a second radiation sensor receiving the second photon

In the embodiments described above, referring to FIG. 7 , radiation sensor 510 receives both photons 521 and 522 . In an alternative embodiment, referring to FIG. 8, as shown in the figure, the radiation sensing system 500 may further include another radiation sensor 512 receiving the second photon 522, while the first radiation sensor 510 receives the first photon 521.

In an embodiment, radiation sensor 512 may be similar to radiation sensor 510 in structure and function. Radiation sensors 510 and 512 do not have to have the same number of radiation absorbing layers 110 or the same number of sensing elements 150 or the same number of sensing element groups 152 .

In an embodiment, the signal processing chip 122 (not shown) of the radiation sensor 512 may be electrically connected to the computer 530 .

In an embodiment, using two radiation sensors 510 and 512 to determine the photon point of origin 525 ( FIG. 8 ) of photons 521 and 522 may be similar to determining the photon origin of photons 521 and 522 using only radiation sensor 510 as described above. Point 525 (Fig. 7).

Rotation of radiation sensor

In an embodiment, referring to FIG. 8 , the radiation sensors 510 and 512 may rotate around the object 520 while the radiation sensors 510 and 512 scan the entire object 520 from different angles. In an embodiment, radiation sensors 510 and 512 may be stationary relative to each other as radiation sensors 510 and 512 rotate around object 520 .

Dedicated electrode 119B side

In the above embodiment, referring to FIG. 5, in a pair of radiation absorbing layers 110.1a and 110.1b, the dedicated electrode 119B of the radiation absorbing layer 110.1b is located on the right side surface of the radiation absorbing layer 110.1b, and the common electrode 119B of the radiation absorbing layer 110.1b Electrode 119A is located on the left side surface of radiation absorbing layer 110.1b; and dedicated electrode 119B of radiation absorbing layer 110.1a is located on the right side surface of radiation absorbing layer 110.1a, and common electrode 119A of radiation absorbing layer 110.1a is located on the right side surface of radiation absorbing layer 110.1a. on the left surface.

In an alternative embodiment, in the first pair of radiation absorbing layers 110.1a and 110.1b, the dedicated electrode 119B of the radiation absorbing layer 110.1b is still located on the right side surface of the radiation absorbing layer 110.1b, and the common electrode of the radiation absorbing layer 110.1b 119A is still located on the left side surface of the radiation absorbing layer 110.1b; however, the dedicated electrode 119B of the radiation absorbing layer 110.1a is located on the left side surface of the radiation absorbing layer 110.1a, and the common electrode 119A of the radiation absorbing layer 110.1a is located on the radiation absorbing layer 110.1a on the right side of the surface.

Photon Presence Signal - Voltage at Group Node

In the above embodiment, referring to FIG. 5 , the photon presence signal is defined as being present in the sensing element group 152 if the group voltage of the sensing element group 152 exceeds a predetermined threshold voltage.

In an alternative embodiment, the dedicated electrodes 119B of the sensing elements 150 of each sensing element group 152 of the radiation sensor 510 may be electrically connected to the group nodes using metal wires. For example, referring to sensing element group 152 ( 4 , 2 ), the 2 dedicated electrodes 119B of sensing element group 152 ( 4 , 2 ) are electrically connected to group node 154 using metal lines 156 . Other sensing element groups 152 of radiation sensor 510 may have similar connections.

In this alternative embodiment, the photon presence signal may be defined such that the photon presence signal is present in the sensing element group 152 if the voltage at the group node 154 of the sensing element group 152 exceeds a predetermined threshold voltage.

Signal processing die and dedicated electrodes are located on the same side surface of the radiation absorbing layer

In the above embodiment, referring to FIG. 5, the signal processing chip 122.1 for the radiation absorbing layer 100.1a and the dedicated electrode 119B of the radiation absorbing layer 100.1a are not on the same side surface 110s of the radiation absorbing layer 110.1a.

In an alternative embodiment, referring to FIG. 9, as shown, the multiple (eg, 4) signal processing wafers 122 for the radiation absorbing layer 100.1a and the 24 dedicated electrodes 119B of the radiation absorbing layer 100.1a may not be in the On the same side surface 110s of the radiation absorbing layer 110.1a.

In an embodiment, the footprint of the signal processing die 122 for the radiation absorbing layer 100.1a does not overlap the dedicated electrode 119B of the radiation absorbing layer 100.1a. In other words, there is no line (A) perpendicular to the side surface 110s of the radiation absorbing layer 110.1a and (B) intersecting the signal processing wafer 122 for the radiation absorbing layer 110.1a and any dedicated electrode of the radiation absorbing layer 110.1a 119B intersects.

In an embodiment, the features described above with respect to the radiation absorbing layer 110.1a and its four associated signal processing dies 122 also apply to the other eleven radiation absorbing layers 110 of the radiation sensor 510 and their associated signal processing dies 122 .

Signal processing wafer in recess adjacent to radiation absorbing layer

FIG. 10 shows a cross-sectional view of the radiation sensor 510 of FIG. 9 along plane 10 . In an embodiment, referring to FIG. 10 , as shown, a multiple signal processing die 122 for a radiation absorbing layer 110.1 b may be located in the recess 116 of an adjacent radiation absorbing layer 110.1 a.

Signal processing wafer in recess of separation layer

FIG. 11 shows a cross-sectional view of the radiation sensor 510 of FIG. 9 along plane 10 with a separation layer 117 sandwiched between any two adjacent absorbing layers 110 of the radiation sensor 510 . In an embodiment, referring to FIG. 11 , a multi-signal processing die 122 for the radiation absorbing layer 110.1b may be located in the recess 118 of the separation layer 117 as shown.

In an embodiment, the separation layer 117 of the radiation sensor 510 may be configured to block gamma rays and X-rays.

Support substrates for signal processing chips

In an embodiment, referring to FIG. 9, the two left signal processing dies 122 for the radiation absorbing layer 110.1a may be physically attached to the first support substrate 122s such that the two left signal processing dies 122 are sandwiched between the first Between the supporting substrate 122s and the radiation absorbing layer 110.1a.

Similarly, in an embodiment, the two right side signal processing dies 122 for the radiation absorbing layer 110.1a may be physically attached to a second support substrate (not shown for simplicity) such that the two right side signal processing The wafer 122 is sandwiched between the second support substrate and the radiation absorbing layer 110.1a.

In an embodiment, the signal processing die 122 for the other 11 radiation absorbing layers 110 of the radiation sensor 510 may have similar features (ie, the supporting substrate for the signal processing die 122 ).

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 purposes of illustration and not limitation, with the true scope and spirit being indicated by the appended claims.

10: Plane 100: radiation detector 110, 110.1a, 110.1b, 110.5b, 110.6a, 110.6b: radiation absorbing layer 110s: side surface 111: the first doped region 112: Intrinsic area 113: area 114: discrete area 116, 118: concave part 117: separation layer 119A, 119B: electrodes 120: Electronic device layer 121: Electronic system 122, 122.1, 122.6: signal processing chips 122s: the first supporting substrate 130: filling material 131: Through hole 150: primitive 152(2,3), 152(3,2), 154(4,1), 152(4,2): sensing element group 154: group node 156: metal wire 500: Radiation Sensing System 510, 512: radiation sensor 520: object 521, 522: photons 521p, 521p', 522p, 522p': path 525: Intersection point 530: computer 610, 620, 630: steps

Fig. 1 schematically shows a radiation detector according to an embodiment. Fig. 2 schematically shows a simplified cross-sectional view of a radiation detector according to an embodiment. Fig. 3 schematically shows a detailed cross-sectional view of a radiation detector according to an embodiment. Figure 4 schematically shows a detailed cross-sectional view of a radiation detector according to an alternative embodiment. Fig. 5 schematically shows a perspective view of a radiation sensor of a radiation sensing system in operation according to an embodiment. Figure 6 shows a flowchart outlining the operation of the radiation sensing system. Fig. 7 schematically shows the radiation sensing system in further operation according to an embodiment. Fig. 8 schematically shows a radiation sensing system according to an alternative embodiment. Fig. 9 schematically shows a perspective view of a radiation sensor according to an alternative embodiment. 10 to 11 schematically illustrate cross-sectional views of the radiation sensor of FIG. 9 according to an embodiment.

610, 620, 630: steps

Claims (35)

A method of determining a point of origin of a photon using a radiation detector, comprising: receiving a first photon from an object using a first radiation sensor, the first radiation sensor comprising M sensing element groups, Wherein, each sensing element group in the M sensing element groups includes a plurality of sensing elements, and Wherein, M is an integer greater than 1; determining a first subset of the M sets of sensing elements based on electrical signals in the M sets of sensing elements of the first radiation sensor; and A first estimated path of the first photon is determined based on a position of a set of sensing elements in the first subset. The method of using a radiation detector to determine a point of origin of a photon as claimed in claim 1, wherein said determining said first subset comprises identifying a sensing element group having a photon presence signal among said M sensing element groups . The method of using a radiation detector to determine the point of origin of a photon as claimed in claim 2, wherein the identification includes: determining a voltage at a dedicated electrode of each sensing element of said first radiation sensor; and Combining the voltages of the dedicated electrodes of the plurality of sensing elements in each sensing element group of the M sensing element groups, thereby obtaining the group voltage of each sensing element group, Wherein said photon presence signal in a set of sensing elements is an event that a set voltage of said set of sensing elements exceeds a predetermined threshold voltage. The method for determining the point of origin of a photon using a radiation detector as described in claim 2, Wherein, the dedicated electrodes of the multiple sensing elements of each sensing element group in the M sensing element groups are electrically connected to the group nodes using metal wires, and Wherein said photon presence signal in a sensing element group is an event that a voltage of a group node of said sensing element group exceeds a predetermined threshold voltage. The method of using a radiation detector to determine the point of origin of a photon as claimed in claim 2, wherein said determining said first subset further comprises based on the photon existence signals in the sensing element groups in said first subset , excluding groups of sensing elements from the first subset. The method for determining a point of origin of a photon using a radiation detector as claimed in claim 5, wherein the time relationship is a time sequence of photon presence signals in the sensing element groups in the first subset. The method for determining the point of origin of photons by using a radiation detector as claimed in claim 1, wherein the first photons are scattered inside the first radiation sensor. The method of determining a point of origin of a photon using a radiation detector as claimed in claim 1, wherein the first estimated path of the first photon includes a portion outside the first radiation sensor. The method for determining the origin point of photons by using a radiation detector as claimed in claim 1, wherein the sensing elements of the M sensing element groups are located in multiple radiation absorbing layers of the first radiation sensor. The method of determining a point of origin of a photon using a radiation detector as recited in claim 9, wherein a layer opaque to the first photon separates any two adjacent radiation absorbing layers of the plurality of radiation absorbing layers. The method for determining the point of origin of a photon using a radiation detector as claimed in claim 1, wherein the first photon is a gamma ray photon or an X-ray photon. The method for determining the point of origin of a photon using a radiation detector as claimed in claim 1, wherein all the M sensing element groups have the same number of sensing elements. The method of using a radiation detector to determine the point of origin of a photon as described in Claim 1, further comprising: receiving second photons from the object using a second radiation sensor, the second radiation sensor comprising N sensing element groups, Wherein, each sensing element group in the N sensing element groups includes a plurality of sensing elements, and Wherein, N is an integer greater than 1; determining a second subset of the N sets of sensing elements based on electrical signals in sets of sensing elements of the second radiation sensor; and A second estimated path of the second photon is determined based on the locations of the sensing element sets in the second subset. The method of using a radiation detector to determine a photon origin point as claimed in claim 13, further comprising determining the photon origin point of the first photon and the second photon based on the first estimated path and the second estimated path s position. The method of determining a point of origin of a photon using a radiation detector as recited in claim 13, further comprising rotating the first radiation sensor and the second radiation sensor around the object while maintaining the first The radiation sensor and the second radiation sensor are stationary relative to each other. The method of using a radiation detector to determine the point of origin of a photon as described in Claim 1, further comprising: receiving second photons from the object using the first radiation sensor; determining a second subset of the M sets of sensing elements based on electrical signals in sets of sensing elements of the first radiation sensor; and A second estimated path of the second photon is determined based on the locations of the sensing element sets in the second subset. The method for determining a photon origin point using a radiation detector as claimed in claim 16, further comprising determining the position of the photon origin point of the first photon and the second photon based on the first estimated path and the second estimated path . The method of using a radiation detector to determine the point of origin of a photon as claimed in claim 1, wherein said determining the first estimated path of the first photon comprises: Determining a best-fit straight line through the set of sensing elements in the first subset, thereby obtaining the first estimated path. The method of determining the point of origin of a photon using a radiation detector as described in claim 1, Wherein, the first radiation sensor includes stacks of P signal processing chips and 2P radiation absorbing layers, where P is an integer greater than 1, Wherein, each of the P signal processing chips is dedicated to processing electrical signals in two adjacent radiation absorbing layers of the 2P radiation absorbing layers, and Wherein, at least one of the P signal processing chips is sandwiched between two radiation absorbing layers of the 2P radiation absorbing layers. The method of determining a point of origin of a photon using a radiation detector as recited in claim 19, wherein said two radiation absorbing layers are separated by another one of said 2P radiation absorbing layers. The method of using a radiation detector to determine the point of origin of a photon as claimed in claim 19, wherein the separation layer is sandwiched between any two adjacent radiation absorbing layers of the 2P radiation absorbing layers, and Wherein, the separation layer is configured to block gamma rays and X-rays. The method of determining the point of origin of a photon using a radiation detector as described in claim 1, wherein said first radiation sensor comprises (A) a stack of Q radiation absorbing layers, and (B) a multi-signal processing wafer for each of said Q radiation absorbing layers, Wherein, the multi-signal processing chip for each radiation absorbing layer of the Q radiation absorbing layers and the dedicated electrodes of all sensing elements of each radiation absorbing layer are located on the same surface of each radiation absorbing layer. on the side surface, and Wherein, there is no straight line (A) perpendicular to the same side surface of each radiation absorbing layer and (B) intersecting the signal processing wafer for each radiation absorbing layer and each radiation absorbing layer Any dedicated electrode of any sensing element of the layer intersects. The method of determining the point of origin of a photon using a radiation detector as claimed in claim 22, wherein a plurality of signal processing dies of said multiple signal processing dies for a radiation absorbing layer of said Q radiation absorbing layers are physically attached to a support substrate, and Wherein, the plurality of signal processing chips are sandwiched between the supporting substrate and the radiation absorbing layer. The method for determining the point of origin of a photon using a radiation detector as claimed in claim 22, wherein the multi-signal processing wafer for one of the Q radiation absorbing layers is located in the Q radiation absorbing layers In the recess of the adjacent radiation absorbing layer. The method of determining the point of origin of a photon using a radiation detector as claimed in claim 22, wherein the multi-signal processing wafer for the radiation absorbing layer of the Q radiation absorbing layers is located in the recess of the separation layer, and Wherein, the separation layer is configured to block gamma rays and X-rays. A radiation sensing system comprising a first radiation sensor configured to receive first photons from an object, Wherein, the first radiation sensor includes M sensing element groups, Wherein, each sensing element group in the M sensing element groups includes a plurality of sensing elements, Wherein, M is an integer greater than 1, Wherein, the radiation sensing system is configured to determine a first subset of the M sensing element groups based on electrical signals in the M sensing element groups of the first radiation sensor, and Wherein the radiation sensing system is configured to determine a first estimated path of the first photon based on the positions of the sensing element sets in the first subset. The radiation sensing system of claim 26, further comprising a second radiation sensor configured to receive second photons from the object, Wherein, the second radiation sensor includes N sensing element groups, Wherein, each sensing element group in the N sensing element groups includes a plurality of sensing elements, Wherein, N is an integer greater than 1; wherein the radiation sensing system is configured to determine a second subset of the N sensing element groups based on electrical signals in the sensing element groups of the second radiation sensor, and Wherein the radiation sensing system is configured to determine a second estimated path of the second photon based on the positions of the sets of sensing elements in the second subset. The radiation sensing system of claim 27, wherein the radiation sensing system is configured to determine the distance of the first photon and the second photon based on the first estimated path and the second estimated path The location of the point of origin of the photon. The radiation sensing system of claim 26, Wherein, the first radiation sensor includes stacks of P signal processing chips and 2P radiation absorbing layers, where P is an integer greater than 1, Wherein, each of the P signal processing chips is dedicated to processing electrical signals in two adjacent radiation absorbing layers of the 2P radiation absorbing layers, and Wherein, at least one of the P signal processing chips is sandwiched between two radiation absorbing layers of the 2P radiation absorbing layers. The radiation sensing system of claim 29, wherein the two radiation absorbing layers are separated by another one of the 2P radiation absorbing layers. The radiation sensing system of claim 29, wherein the separation layer is sandwiched between any two adjacent radiation absorbing layers of the 2P radiation absorbing layers, and Wherein, the separation layer is configured to block gamma rays and X-rays. The radiation sensing system of claim 26, wherein said first radiation sensor comprises (A) a stack of Q radiation absorbing layers, and (B) a multi-signal processing die for each of said Q radiation absorbing layers, Wherein, the multi-signal processing chip for each radiation absorbing layer of the Q radiation absorbing layers and the dedicated electrodes of all sensing elements of each radiation absorbing layer are located on the same surface of each radiation absorbing layer. on the side surface, and Wherein, there is no straight line (A) perpendicular to the same side surface of each radiation absorbing layer and (B) intersecting the signal processing wafer for each radiation absorbing layer and each radiation absorbing layer Any dedicated electrode of any sensing element of the layer intersects. The radiation sensing system of claim 32, wherein a plurality of signal processing dies of said multiple signal processing dies for a radiation absorbing layer of said Q radiation absorbing layers are physically attached to a support substrate, and Wherein, the plurality of signal processing chips are sandwiched between the supporting substrate and the radiation absorbing layer. The radiation sensing system of claim 32, wherein the multi-signal processing wafer for one of the Q radiation absorbing layers is located adjacent to one of the Q radiation absorbing layers in the recess. The radiation sensing system of claim 32, wherein the multi-signal processing wafer for the radiation absorbing layer of the Q radiation absorbing layers is located in the recess of the separation layer, and Wherein, the separation layer is configured to block gamma rays and X-rays.

Images