Luminescent glass-ceramics for use in flat panel x-ray detectors, flat panel x-ray detectors, and imaging systems - Patents.com

Abstract

Luminescent glass ceramics are disclosed. The luminescent glass ceramics may be used as X-ray conversion layers (screens) for flat panel imagers (FPDs) and as part of imaging systems. FPDs may have single screens and dual screens. The luminescent glass ceramics may be used in either the front screen or the rear screen. The luminescent glass ceramics may be used in high-energy X-ray applications, including energies from about 0.3 to about 20 MeV. A laminate may be attached to the luminescent glass ceramic in high-energy applications. The luminescent glass ceramic may include a glass matrix hosting luminescent centers and light-scattering centers. The materials used for the luminescent centers and light-scattering centers may be the same or different. The luminescent glass ceramic may be coated on a glass substrate.

Description

[Technical field]

[0001] STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT This invention was made with government support under grants C140151 awarded by the National Institutes of Health and DMR1600783 awarded by the National Science Foundation. The Government has certain rights in this invention.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 62 / 965,460, filed Jan. 24, 2020, and U.S. Provisional Patent Application No. 62 / 965,471, which are incorporated herein by reference.

[0003] This application relates generally to structures and materials for radiation detectors, radiation detection, and digital radiography. [Background technology]

[0004] Flat panel detectors (FPDs) have been used in digital X-ray imaging devices. For example, "indirect" FPDs form X-ray images by detecting the incident spatial distribution of X-rays using a scintillating screen, i.e., an X-ray conversion layer, combined with a 2D photosensor array. Known FPDs may use a single screen in either a front-illuminated (FI) mode, where the incident X-rays first pass through the scintillating screen, or a back-illuminated (BI) mode, where the X-rays first pass through the photosensor array. However, most of the incident X-ray beam passes through the screen undetected. Increasing the thickness of the single scintillating layer is not a viable solution, as image quality is then adversely affected by excessive spatial blurring.

[0005] International Patent Application Publication No. WO2019 / 226859 describes a dual-screen sandwich configuration in which the rear screen is a scintillating glass that serves a dual purpose, acting as a substrate for a 2D photosensor array and as an X-ray conversion layer for X-rays that pass through the front screen undetected. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Patent Application Publication No. WO2019 / 226859 Summary of the Invention [Means for solving the problem]

[0007] A structure is disclosed that includes a photosensor array and a screen that includes a scintillating glass ceramic. The scintillating glass ceramic includes a glass matrix that hosts luminescent centers and light scattering centers. The scintillating glass ceramic is configured to convert incident X-ray radiation into light quanta. A surface of the scintillating glass ceramic faces the photosensor array. The photosensor array is operable to capture at least a portion of the light quanta from the screen and convert the captured light quanta into an electrical signal.

[0008] In one aspect of the disclosure, the luminescent glass-ceramic can be a substrate for a photosensor array.

[0009] In one embodiment of the disclosure, the luminescent glass ceramic may be configured to convert incident x-ray radiation incident on a surface of the luminescent glass ceramic facing the photosensor array and / or a surface of the luminescent glass ceramic opposite the surface facing the photosensor array such that the structure can operate in front-illuminated (FI) mode and / or back-illuminated (BI) mode.

[0010] In one aspect of the disclosure, the light scattering centers may include a combination of crystals having the same composition or different compositions. In one aspect of the disclosure, the light emitting centers may include a combination of crystals having the same composition or different compositions.

[0011] In one aspect of the disclosure, the luminescent center crystal may be doped with an activator.

[0012] In one aspect of the disclosure, the crystal may be a halide crystal.

[0013] Additionally or alternatively, the luminescent centers are selected from transition metals, rare earth metals, actinides and ns 2 The material may include one or more materials selected from the group consisting of ions from the first and second series of type activators.

[0014] In one embodiment of the disclosure, the luminescence center is Tb 3+ and the luminescent glass-ceramic may comprise Tb2O3. The percentage of Tb2O3 may vary as needed for the application and may be, for example, about 6%.

[0015] In one embodiment of the disclosure, the luminescent glass-ceramic may further comprise a sensitizer. The sensitizer may be an ns 2 In one embodiment of the disclosure, the sensitizer may be one or more materials selected from the group consisting of Gd 3+ and / or Ce 3+ may be also possible.

[0016] In one aspect of the disclosure, the glass matrix may be an oxyhalide matrix.

[0017] In one embodiment of the disclosure, the structure may further comprise a stack positioned on a surface of the luminescent glass-ceramic opposite the surface facing the photosensor array. The stack may comprise a material selected from the group consisting of copper, brass, lead, and leaded glass. In one embodiment of the disclosure, the incident x-ray radiation may have an energy of about 0.3 to about 20 MeV.

[0018] Also disclosed is a structure having two screens. The structure comprises a first luminescent screen, a photosensor array, and a second luminescent screen comprising a luminescent glass ceramic. The first luminescent screen converts an absorbed portion of incident radiation directed to the structure into photons. The photosensor array is between the first luminescent screen and the second luminescent screen. The luminescent glass ceramic comprises a glass matrix hosting light emitting centers and light scattering centers. The luminescent glass ceramic is configured to convert at least a portion of the incident radiation transmitted through the first luminescent screen and the photosensor array into photons. The photosensor array is operable to capture at least a portion of the photons from the first luminescent screen and the second luminescent screen and convert the captured photons into an electrical signal.

[0019] In one embodiment of the disclosure, the second luminescent screen may further comprise a backing in contact with another surface of the luminescent glass-ceramic, the surface in contact with the backing being the surface opposite the surface facing the photosensor array, and the backing may have optical properties including being absorptive or reflective to photons.

[0020] In one embodiment of the disclosure, the luminescent glass-ceramic of the second luminescent screen may be a substrate for a photosensor array.

[0021] In one embodiment of the disclosure, the luminescent glass-ceramic of the second luminescent screen may have different thicknesses depending on the application and whether it is used as a substrate. In one embodiment of the disclosure, the luminescent glass-ceramic may have a thickness greater than about 0.5 mm.

[0022] In one embodiment of the disclosure, the light scattering centers in the luminescent glass ceramic of the second luminescent screen may include crystals of the same composition or a combination of crystals having different compositions. In one embodiment of the disclosure, the luminescent centers in the luminescent glass ceramic of the second luminescent screen may include crystals of the same composition or a combination of crystals having different compositions. In one embodiment of the disclosure, the crystals of the luminescent centers in the luminescent glass ceramic of the second luminescent screen may be doped with an activator. In one embodiment of the disclosure, the crystals may be halide crystals.

[0023] Additionally or alternatively, the luminescent centers in the luminescent glass-ceramic of the second luminescent screen are selected from transition metals, rare earth metals, actinides and ns 2 In one embodiment of the disclosure, the luminescent center may include one or more materials selected from the group consisting of ions from the first and second rows of type activators. 3+ and the luminescent glass-ceramic may comprise Tb2O3. The percentage of Tb2O3 may vary as needed for the application and may be, for example, about 6%.

[0024] In one embodiment of the disclosure, the luminescent glass-ceramic of the second luminescent screen may further comprise a sensitizer. The sensitizer may be a ns 2 In one embodiment of the disclosure, the sensitizer may be one or more materials selected from the group consisting of Gd 3+ and / or Ce 3+ may be also possible.

[0025] In one embodiment of the disclosure, the glass matrix of the second luminescent screen may be an oxyhalide matrix.

[0026] Also disclosed is a luminescent glass-ceramic for X-ray conversion comprising a glass matrix hosting light emitting centers, light scattering centers, and one or more high-Z elements. The luminescent glass-ceramic may be used in many different configurations and other imaging applications, such as MeV imaging.

[0027] In one disclosed embodiment, the light scattering centers may have a size greater than about 10 nm. In one disclosed embodiment, the concentration of light scattering centers within the glass matrix may be such that the scattering length is greater than about 1 μm.

[0028] In one embodiment of the disclosure, the luminescent glass-ceramic weighs about 3.0 g. . cm -3 It may have a greater density.

[0029] In one embodiment of the disclosure, the photon emission may be in the wavelength range of about 375 nm to about 650 nm. In one embodiment of the disclosure, the wavelength of the photon emission may be based on the application and the photosensor array used.

[0030] In one embodiment of the disclosure, the one or more high-Z elements may be a sensitizer. Alternatively or in addition, the luminescent glass-ceramic may further comprise a further sensitizer, the sensitizer being a ns 2 The metal may be one or more materials selected from the group consisting of lanthanide ions and lanthanide types.

[0031] In one aspect of the disclosure, the light scattering centers may comprise crystals of the same composition or a combination of crystals having different compositions.

[0032] In one aspect of the disclosure, the ceramic glass matrix may be an oxyhalide matrix.

[0033] Also disclosed is another structure having two screens. The structure includes a first luminescent screen, a photosensor array, and a second luminescent screen comprising a luminescent glass ceramic and a glass substrate. The luminescent glass ceramic may be a coating on the glass substrate. The photosensor array is between the first luminescent screen and the second luminescent screen. The luminescent glass ceramic comprises a glass matrix hosting luminescent centers and light scattering centers. The luminescent glass ceramic is configured to convert at least a portion of incident radiation transmitted through the first luminescent screen and the photosensor array into photons. The photosensor array is operable to capture at least a portion of the photons from the first luminescent screen and the second luminescent screen and convert the captured photons into an electrical signal.

[0034] In one aspect of the disclosure, the structure may further comprise a glass film coated on the luminescent glass-ceramic. The glass film may be a substrate for a photosensor array.

[0035] In one aspect of the disclosure, the light-emitting and light-scattering centers may comprise crystals. The crystals may be selected from the group consisting of halide crystals, silicate crystals, sulfide crystals, or other crystals. In one aspect of the disclosure, the crystals may be doped.

[0036] Also disclosed is an imaging system comprising a processor configured to communicate with the structure as described above, the photosensor array configured to generate an image having a plurality of pixels, in this aspect the processor may be configured to receive electrical signals from the structure and use the electrical signals to generate an image having a plurality of pixels. [Brief description of the drawings]

[0037] [Figure 1] Figure 1a is a diagram of one example of a luminescent glass-ceramic according to an embodiment of the disclosure, and Figures 1b-1d are diagrams of another example of a luminescent glass-ceramic according to an embodiment of the disclosure. [Figure 2a] 1A-1D illustrate the progression of a luminescent event in a non-scattering scintillating medium and show incident radiation that triggers a luminescent event. [Figure 2b] 1A-1C illustrate the progression of a luminescent event in a non-scattering luminescent medium and show the resulting emission being omnidirectional. [Figure 2c] FIG. 1 illustrates the progression of a luminescence event within a non-scattering luminescent medium, showing photons arriving at the interface between the non-scattering luminescent medium and an external medium at angles smaller than the critical angle can occur. [Figure 2d] FIG. 1 illustrates the progression of a light emission event within a non-scattering luminescent medium, showing photons arriving at the interface at angles greater than the critical angle that are internally reflected, "trapped," and exit at the side of the non-scattering luminescent medium. [Diagram 3] Figure 3a shows a comparison between luminescent media, illustrating a scattering medium, and Figure 3b shows a comparison between luminescent media, illustrating a transparent medium without scattering. [Figure 4] Figure 4a illustrates a single screen structure having a luminescent glass-ceramic used as an X-ray conversion layer in an indirect flat panel X-ray detector according to disclosed embodiments in front-illuminated (FI) mode and Figure 4b illustrates a single screen structure having a luminescent glass-ceramic used as an X-ray conversion layer in an indirect flat panel X-ray detector according to disclosed embodiments in back-illuminated (BI) mode. [Diagram 5] 1 is a schematic cross-sectional view of a dual screen structure having a luminescent glass-ceramic conversion layer for use in a dual screen sandwich detector configuration, according to an embodiment of the disclosure. [Figure 6] 1 is a schematic diagram illustrating a photosensor array and certain control components according to an embodiment of the disclosure. [Figure 7] FIG. 2 is a schematic cross-sectional view of another single screen structure having a luminescent glass-ceramic conversion layer for use in a detector for high-energy photons, according to an embodiment of the disclosure. [Figure 8] 1 is a graph of test results for a luminescent glass-ceramic according to an embodiment of the disclosure. [Figure 9]1 is a graph of test results for a luminescent glass-ceramic according to an embodiment of the disclosure. [Figure 10] 1 is a graph of test results for a luminescent glass-ceramic according to an embodiment of the disclosure. [Figure 11] 1 is a graph of test results for a luminescent glass-ceramic according to an embodiment of the disclosure. [Figure 12] 1 is a graph of test results for a luminescent glass-ceramic according to an embodiment of the disclosure. [Figure 13] 1 is a graph of test results for a luminescent glass-ceramic according to an embodiment of the disclosure. [Figure 14] 1 is a graph of test results for a luminescent glass-ceramic according to an embodiment of the disclosure. [Figure 15] 1 is a graph of test results for a luminescent glass-ceramic according to an embodiment of the disclosure. [Figure 16] FIG. 1 shows the quantum efficiency of two known photodiodes. [Figure 17] 1 is a flow chart for forming a scintillating thin film on a glass substrate according to an embodiment of the disclosure. [Figure 18] 1 is a schematic cross-sectional view of a structure having a scintillating conversion layer for use in a dual screen sandwich detector configuration, in which the scintillating conversion layer is coated on a glass substrate, according to an embodiment of the disclosure. [Figure 19] 19a and 19b are SEM cross-sectional images and cross-sectional views of an example scintillator thin film. [Figure 20] FIG. 1 shows an example of a light emitting thin film coated on a thin glass substrate in visible light and exposure to 45 keV x-rays according to disclosed embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] According to the disclosed embodiment, the luminescent glass ceramic 1A may be comprised of a glass matrix 5 that includes both luminescent centers 10 and light scattering centers 15. The term glass ceramic as used herein refers to a composite material that includes at least one amorphous phase and one crystalline phase. The glass matrix 5 hosts both the luminescent centers 10 and the light scattering centers 15. The glass matrix 5 is stable without experiencing undesirable devitrification while hosting both the luminescent centers 10 and the light scattering centers 15. The glass matrix 5 is stable under expected operating conditions, including but not limited to use in flat panel imaging systems. The glass matrix may also have a composition that includes desired precursor crystalline elements that are thermally stable enough to precipitate crystallites. In the figures (e.g., FIG. 1a), the luminescent centers 10 are shown as green circles and the scattering centers 15 are shown as blue hexagons. However, the shapes and colors of the figures are for illustrative purposes only, and the shapes of the elements may vary within the glass matrix 5. Also, the sizes of the luminescent centers 10 and the light scattering centers 15 shown in the figures are merely illustrative. Additionally, the size and color (light blue) of the glass matrix 5 are for illustrative purposes only.

[0039] According to the disclosed embodiment, the glass matrix 5 has a high degree of transparency at the emitted wavelength to prevent self-absorption. A low phonon energy matrix is ​​preferred to increase the scintillation efficiency by reducing non-radiative return via multi-phonon energy transfer. In some disclosed embodiments, the luminescent glass-ceramic 1A may also serve as a substrate for FPD electronics such as the photosensor array 600. According to the present embodiment, the luminescent glass-ceramic 1A may have the required thermal and mechanical properties such as, but not limited to, glass transition temperature, crystallization temperature, melting point, elastic modulus, strength, hardness, and impact resistance. The glass matrix 5 may be based on systems such as halides, oxides, oxyhalides, borates, tellurides, chalcogenides, phosphates, germanates, silicates, fluorosilicates, aluminosilicates, β-quartz, β-spodumene phosphate, cordierite, and others.

[0040] The term luminescent center as used herein refers to an intentional imperfection in a material, added in a controlled manner, that produces light emission when excited by appropriate radiation. Luminescent centers can also be referred to herein as activators (intentionally added to a glass matrix or crystal). Luminescent centers 10 may be elements, ions, or compounds that convert incident radiation into light (UV, visible, and / or infrared) that can be easily detected by an FPD. In some embodiments of the disclosure, the emission spectrum of the luminescent center 10 may match the quantum efficiency curve of the photosensitive array 600 for greater efficiency. FIG. 16 shows the quantum efficiency curve of a photo sensor array 600.

[0041] Transition metals (Z=22-30, and 40-48), rare earth metals (Z=21, 39, and 57-71), actinides (Z=89-103), or ns 2 There are many items or combinations of items that can also serve as luminescent centers, including ions from the first and second rows of type activators (Z=31, 32, 49-51, 79, and 81-83). Crystalline materials may also serve as emission sources (luminescent centers). Crystals may be either intrinsic or non-intrinsic scintillators. Combinations of scintillating crystals and other materials may also be used for improved light output.

[0042] As described above, the glass matrix 5 includes light scattering centers 15 in addition to the light emitting centers 10. The term light scattering centers as used herein refers to intentional imperfections in a transparent material that are added in a controlled manner that lead to elastic scattering of light. The inventors have found that the use of both the light emitting centers 10 and the light scattering centers 15 improves detection efficiency and performance for imaging systems in both single and dual screen configurations.

[0043] The inventors have found that the light scattering centers 15 in the glass matrix 5 are important to prevent "light trapping" of the emission in the imaging system. During a luminescence event triggered by a source (Figure 2a), the emitted light is omnidirectional (Figure 2b). Thus, most of the light is incident at the interface between the luminescent medium and the external medium at angles greater than the critical angle that leads to total internal reflection (TIR), i.e. light trapping. The "trapped" light either exits the side of the luminescent medium or is self-absorbed without being detected, greatly reducing the efficiency of the scintillator / detector system. The critical angle is defined by the following equation:

[0044]

number

[0045] where n1 is the refractive index of the scintillator medium and n2 is the refractive index of the external medium.

[0046] However, according to the disclosed embodiment, the presence of light scattering centers 15 in the glass matrix 5 leads to a decrease in this "trapping" effect to a large extent. The light scattering centers 15 in the glass matrix 5 redirect the emission until it can escape the scintillator glass-ceramic 1A and be detected by the photosensor array 600, or be absorbed internally or by the backing layer, some photons may be self-absorbed in the glass matrix 5, which is why a transparent matrix is ​​desirable. Crystals may also be light scattering centers 15.

[0047] Some examples of crystals that may be precipitated in an oxyhalide matrix, or other glass systems, include the following: PbWO4, Yb2TeO6, PbTeO4, TeO2, CdF3, PbF2, BaF2, BaCl2, BaI2, BaBr2, CaF2, SrCl2, LaF3, Na, YF4, YLiF4, GdF3, and TbF3. However, additional oxides, halides, or other types of crystals may be used in the glass matrix 5 (or combinations of different types of crystals may be used). The chemicals required for synthesis, either in chemical composition or amount, should not be detrimental to the formation of the precursor glass, i.e., they must enable glass formation and not facilitate undesired crystallization. Oxyhalide glass ceramics can also have high transparency due to the crystallite size, which can be controlled via thermal temperature parameters. In the disclosed embodiment, the crystals should be large enough in size to allow light scattering at the scintillation emission wavelength, but not so concentrated that it reduces the scattering length to a level that reduces the number of photons that escape due to self-absorption. In some disclosed embodiments, the crystals may be larger than about 10 nm. In some disclosed embodiments, the size of the crystals may be a function of the scintillation emission wavelength. In some disclosed embodiments, the level may be larger than about 1 μm.

[0048] Figures 3a and 3b show the difference in the amount of light reaching the detector (photosensor array 600) in a scattering material versus a transparent material. Figure 3a shows the light path in a scattering luminescent medium and Figure 3b shows a transparent non-scattering scintillator. A large percentage of the emission is coupled to the detector in the scattering scintillator. In the figure, the light path is shown by the arrows. The incident radiation is shown by the longer arrow. The detector (photosensor array 600) is on the opposite side of the incident radiation.

[0049] In another embodiment of the disclosure, the luminescent glass ceramic 1B may also comprise a sensitizer 20, as shown in FIG. 1b. The term sensitizer as used herein refers to an ion capable of transferring its excitation energy to an adjacent activator inducing an excited state leading to luminescence. The presence of the sensitizer may significantly improve the scintillation efficiency. The sensitizer 20 is shown in FIG. 1b as a red star. However, the illustration is merely illustrative and the shape and color of the sensitizer 20 may vary. In addition, the size of the sensitizer 20 in FIG. 1b is for illustrative purposes only. The sensitizer 20 increases the scintillation efficiency via energy transfer to the luminescent center 10. The energy transfer is indicated by the dotted arrow (red) in FIG. 1b. In one embodiment of the disclosure, the sensitizer 20 is Sb 3+ and Bi 3+ ns etc. 2 Ion, Ce 3+ ,Pr 3+ ,EU 2+ , Gd 3+ , Tm 3+ , and Yb 3+ The sensitizer may be a lanthanide such as lanthanides, or other ions capable of transferring energy from an excited state to the activator. In addition, careful selection of the sensitizer may increase the X-ray absorption of the material through high density and high average atomic number for high scintillation efficiency.

[0050] A combination of different sensitizing items may be used. The form of ions added to the composition should not be detrimental to the formation of the precursor glass, i.e., they should enable glass formation and should not facilitate undesirable crystallization that may undesirably alter the transparency of the scintillator and / or adversely affect the efficiency of the luminescent centers.

[0051] In another embodiment of the disclosure, the same component may act as both the luminescent center 10 and the light scattering center 15 in the luminescent glass-ceramic 1C, as shown in FIG. 1c. The crystals may be either intrinsic or non-intrinsic scintillator materials. For example, halide crystals may be used as both the luminescent center 10 and the light scattering center 15 in ceramics used in X-ray conversion. There is a strong affinity of rare earth ions for halide anions, so they may be easily incorporated as activator materials. The low phonon energy of the halide crystals creates an efficient host for improved scintillation efficiency.

[0052] The emitting / scattering center 15A is shown in FIG. 1c as a purple octagon. However, the illustration is merely exemplary and the shape and color of the emitting / scattering center 15A may vary. Additionally, the size of the emitting / scattering center 15A in FIG. 1c is for illustrative purposes only. Emission is indicated by the green arrows and scattered light is indicated by the blue dashed arrows. For example, Eu 2+ Certain crystals, such as the halide crystals described above, which may or may not be doped with an activator such as BaCl2:Eu, may act as both scattering and emitting centers, for example. 2+ and BaCl2, Y3Al5O 12 Other non-halide crystals such as Zn2SiO4, PbWO4, etc. may also act as both emitting and scattering centers.

[0053] The sensitizer 20 may also be used in luminescent / scattering centers within a luminescent glass-ceramic 1D, as shown in FIG. 1d.

[0054] In one embodiment of the disclosure, the luminescent glass ceramic 1 has a thickness of about 3.0 g to allow efficient absorption of incident radiation. . cm -3The composition of the luminescent glass-ceramic 1 may be tailored to a particular type of incident radiation. In another embodiment of the disclosure, the glass matrix 5 also has high-Z elements. As used herein, high-Z elements refer to any element with an atomic number greater than or equal to 64.

[0055] 4a shows an example (example structure) of a flat panel detector (FPD) 400 having any of the luminescent glass ceramics (collectively referred to herein using the number "1") as a conversion layer (luminescent glass ceramic conversion layer referred to herein using the number "405"). A photosensor array 600 including photodiodes 608 (also referred to herein as photosensitive storage elements) and TFTs 606 (also referred to herein as switching elements) is on the opposite side of the source of X-rays 420 (not shown). The FPD 400 in FIG. 4a is in front illumination (FI) mode.

[0056] The photosensitive storage elements 608 produce an electrical signal (charge) in response to photons. The photosensor array 600 may be placed in close contact with a luminescent glass-ceramic conversion layer 405 that absorbs the x-rays 420 and produces light.

[0057] The electrical signal is proportional to all the photons (reaching from the luminescent glass-ceramic conversion layer 405 to the respective photosensitive storage element and being absorbed by the photosensitive element). The photosensitive storage elements 608 may be a-Si:H photodiodes, MIS type sensors, or other sensor types known in the art. The switching elements 106 may be a-Si:H type, metal oxide thin film transistor (MOTFT) type, or other types of thin film transistor (TFT) elements known in the art. Each switching element 606 corresponds to a photosensitive storage element 608. Each switching element 606 is used to read out an electrical signal from the corresponding storage element 608.

[0058] Photosensor array 600 may also include additional layers (not shown in the drawings), such as, but not limited to, opposing bias metal layers and metal layers, and other layers of photodiodes (and other dielectric materials or layers).

[0059] An example of a photosensor array 600 and surrounding electronics (shown in FIG. 6 without the various layers) is shown in FIG. 6. The example in FIG. 6 shows a 3×3 array. Thus, in the example, there are nine pixels 614. However, the number of pixels in FIG. 6 is shown as an example only for descriptive purposes, and any number of rows and columns of pixels may be used. The number of pixels may be based on the particular application of use in the FPD 400. As shown in FIGS. 4 and 6, the pixel includes a photosensitive storage element 608 and a switching element 606. In the example, the switching element 606 is shown at a corner of the pixel 614. In other aspects of the disclosure, the switching element 606 may be in other locations.

[0060] FIG. 6 illustrates certain components of an imaging system for scanning a structure and subsequently creating an image. The image has a plurality of pixels 614. As shown, a scan control unit 605 is coupled to each row of pixels via gate lines 622. A bias voltage is applied to the photosensitive storage elements 608. A transparent metal bias layer is an example of a component used for the bias voltage. The switching elements 606 are controlled via respective gate lines 622. When the switching elements 606 are powered, they pass charge to respective data lines 626. Each data line is connected to a plurality of charge amplifiers 608.

[0061] The multiple charge amplifiers 608 are coupled to a multiplexer 610. The multiplexer 610 is then coupled to an A / D 615 (converter) that provides an input to a processor 660. The processor 660 controls the scan control unit 605 to power on / off the switching elements 606. The processor 660 may store the electrical signals from the storage elements / switches in a memory (not shown in FIG. 6). Images may be created using the digital values ​​stored in the memory. The charge amplifiers 608 are typically implemented in a custom ASIC chip. The scan control unit 605 is typically implemented with a gate control chip available in the display industry. The multiplexer 610 is used to reduce the number of connections from the amplifiers and reduce the number of ADC channels. To quickly process the large amount of data sampled from the photosensor array 600, a memory is typically included in the processor 660. In one aspect of the disclosure, a host computer 650 (e.g., another processor) is coupled to the processor 660 via an interface. The host computer 650 can receive the digital pixel information from the memory buffer and create a visual representation of the image on a display (not shown).

[0062] The scan control unit 605 may sequentially power the switching elements 606 on and off, one row at a time. The other elements of the imaging system are well known to those skilled in the art.

[0063] The processor 660 is typically physically integrated with the flat panel detector and may be electronically integrated with the gate control chip, amplifier chip, buffer memory, and interface to the host computer 650. The chips are then typically implemented as application specific integrated circuits (ASICs), each of which may process hundreds of data channels.

[0064] The host computer 650 may be a microcontroller or microprocessor, or any other processing hardware, such as a CPU or GPU. Memory (not shown) may be separate from (or integrated with) the processor. For example, the microcontroller or microprocessor includes at least one storage device, such as, but not limited to, a RAM, a ROM, and a persistent storage device. In one aspect of the disclosure, the processor may be configured to execute one or more programs stored in a computer-readable storage device.

[0065] In the disclosed embodiment, the photosensor array 600 may then be deposited directly on the surface of the luminescent glass-ceramic conversion layer 405, which replaces the normal glass substrate layer. This then enables the use of BI (back-illuminated) X-ray imaging, where the X-rays are incident from the bottom as shown in FIG. 4b. This leads to a sharper image at the same radiation dose as in prior art FI (front-illuminated) systems, or a lower radiation dose image with the same clarity.

[0066] FIG. 5 shows an example of a flat panel imager (FPD) 500 (another example of a structure) having one of the luminescent glass ceramics 1 as the conversion layer 405 in a dual screen configuration. Advantageously, the luminescent glass ceramic conversion layer 405 is used as both the photodetector and the substrate for the photosensor array 600. This eliminates the need for a separate (non-luminescent) glass substrate layer, as in known FPDs (eliminating loss of definition due to light spreading in the substrate between the screen and the photosensor array, and other sources of detrimental light piping effects). Furthermore, such an arrangement improves spatial resolution over a single screen of the same total thickness, since the two screens sandwich the photosensor array, reducing the average distance from an absorption event to the array, thus minimizing the effects of light scattering. The combined thickness of the two screens may also be made thicker than a single screen while maintaining spatial resolution, leading to a detector requiring less radiation dose. In addition, more photons from the luminescent glass ceramic 1 reach the photosensor array 600 due to the elimination of any absorption in the separate substrate layer.

[0067] The FPD 500 may be used in an imaging system in a similar manner as described above (FIG. 6). The FPD 500 may include two screens 550, 560 (front screen 550 and rear screen 560). In FI mode, the front screen 550 may be closest to the radiation source of the two screens. The photosensor array 600 may be disposed between the front screen 550 and the rear screen 560. The front screen 550 has a surface B facing the photosensor array 600. The rear screen 560 has a surface C facing the photosensor array 600.

[0068] The front screen 550 may comprise a scintillating phosphor layer 580 or material. For example, the front screen 550 may include fluorescent crystals that may capture the incident X-rays 420 and convert the captured X-rays into photons 525 (only one representative example is shown in FIG. 5 to simplify the illustration). In some examples, the screen 550 may be of a powder or granular type (e.g., GdO2S2:Tb, CaWO4, BaFCl:Eu). In other examples, the screen 550 may be comprised of nanometer-sized particles such as quantum dots, rather than the micron-sized particles typical of "standard" screens such as GdO2S2:Tb. In yet other examples, the luminescent material may be of a perovskite type. The front screen 550 may emit photons (e.g., photon bursts) in the visible light range.

[0069] In other embodiments of the disclosure, the front screen 550 may comprise a structured light-emitting layer. For example, the front screen 550 may include light-emitting fluorescent needle structures that may capture incident X-rays 420 and convert the captured X-rays into light quanta 525. In some examples, the front screen 550 may be a vacuum-deposited needle structure made of CsI:Tl. If CsI:Tl is used, the front screen 550 may emit light in the approximately 550 nm region. In other embodiments of the disclosure, liquid light-emitting materials may be used. In some examples, different types and combinations of light-emitting materials may be used.

[0070] The screens 550, 560 may have different thicknesses. As shown in FIG. 5, the rear screen 560 is thicker than the front screen 550. This allows the thinner front screen to capture finer details in the incident spatial pattern of x-rays, while the thicker rear screen compensates for the fact that some of the incident x-ray flux is not subsequently captured by the front screen 550. The thicker the front screen 550, the fewer incident x-rays 420 reach the rear screen 560. Thus, the thickness of each screen may be determined based on the particular performance demands, including signal-to-noise ratio, and may be based on the particular application in which the FPD 500 is used.

[0071] The surface C of the luminescent glass-ceramic conversion layer 405 is smooth. The surface C has a smoothness that meets the standards required for a substrate for electronic components. For example, the smoothness may be about 1 nm RMS. In other embodiments of the disclosure, the smoothness may be about 1 to about 5 nm RMS. In yet other embodiments of the disclosure, the smoothness may be about 5 nm to about 20 nm RMS. One or both screens 550, 560 may include an optional backing layer 510 (backing layer not shown in front screen). However, the backing layer 510 may provide support for the scintillation portion of the front screen 550. In addition, the backing layer 510 may have optical characteristics at the wavelengths of the photons produced in the screen that improve imaging performance for a particular application (absorbent or reflective). For example, the optical reflectivity of the backing may be very high to maximize imaging signal-to-noise ratio or low to maximize imaging spatial resolution. For example, in one disclosed embodiment, the diffuse optical reflectance of the backing 510 may be very high (above about 90%) to maximize the imaging signal-to-noise ratio, or may be low (below about 10%) if the goal is to maximize the imaging spatial resolution.

[0072] In some embodiments, the backing layer 510 may be omitted from the rear screen 560. The front screen 550 may also optionally include a protective layer 505. For example, the protective layer 505 may be a plastic film.

[0073] The incident X-rays 420 may not be completely captured by the front screen 550 (light-emitting front screen) because the material may not be thick enough to absorb all of the incident X-rays. The uncaptured (and unconverted) X-rays may pass through the front screen 550 and the photosensor array 600 and reach the light-emitting glass-ceramic conversion layer 405. Thus, according to disclosed embodiments, the light-emitting glass-ceramic conversion layer 405 facilitates the photosensor array 600 to utilize the extra photons induced from the X-rays that are not or cannot be converted by the front screen 550. In a dual screen configuration, the photosensor array 600 is configured to convert the photons from both screens 550, 560 into electrical signals. The vertical lines extending from each switching element 606 indicate the boundaries of the pixels.

[0074] 7 shows an example of a flat panel imager (FPD) 700 (another example structure) having one of the luminescent glass ceramics 1 as a conversion layer 405 to high energy photons. In this embodiment of the disclosure, the FPD 700 also has a stack 705. The photosensor array 600 is disposed on a surface of the luminescent glass ceramic conversion layer 405 opposite the incident x-rays or gamma rays 420A. The stack 705 is disposed on a surface of the luminescent glass ceramic conversion layer 405 near the incident x-rays or gamma rays 420A.

[0075] The stack 705 may increase sensitivity by providing forward scattered photons and electrons 710 upon interaction with the high energy beam (only one representative example of electrons is shown to simplify the diagram). The scattered photons and electrons 710 enter the luminescent glass-ceramic conversion layer 405 and deposit energy to create light as an image signal. In some embodiments, the stack 705 may be, but is not limited to, copper, brass, lead, or leaded glass.

[0076] Here, the incident X-rays 420A may have energies in the range of 0.3 to 20 MeV, characteristic of portal imaging in radiation oncology practice. Advantageously, the photosensor array 600 may be deposited directly on the surface of the luminescent glass-ceramic conversion layer 405.

[0077] In some disclosed embodiments, the luminescent glass-ceramic 1 may be incorporated into the screen of an FPD for applications requiring high energy x-ray beams, such as cone beam computed tomography, where existing detectors have relatively poor performance. In other embodiments, the luminescent glass-ceramic 1 may be used in other clinical applications, including image-guided surgery and general radiology.

[0078] inspection The luminescent glass ceramic is produced by mixing an oxyhalide matrix, Tb 3+ Luminescent center, BaCl2 light scattering center, and sensitizer Gd 3+ The inventors have found that oxyhalide glass systems have many favorable properties, including low photon energy for large scintillation efficiency, and the ability to host a large proportion of rare earth elements. Trivalent terbium is a bright scintillator with a favorable emission spectrum that is well suited for the light-sensitive memory elements in FPDs. Although primarily used as a light scattering center, BaCl2 is also a scintillator, adding to the brightness of the material. Gadolinium is a sensitizer, increasing the X-ray absorption of the glass-ceramic through its higher atomic number (high Z) and greater density.

[0079] The luminescent glass ceramic has the structure (52-x)B2O3-5SiO2-10BaCl2-10GdF3-xTb2O3-23Li2O. Mole Percentage The composition is achieved by mixing the powders to achieve the compositions, where x is 0, 2, 4, 6, and 8. ... 3+ but with TbF3, Tb4O7, TbO2, and / or Tb6O instead of Tb2O3. 11 There are also different compositions that achieve this, such as by substituting

[0080] The powder is heated to a temperature of 1000°C, creating molten glass. The temperature of the molten glass is reduced to 975°C before being poured into a brass mould at 400°C; the reduction in temperature to 975°C is a refinement step to reduce bubbles within the material and may not be necessary depending on the composition and other factors.

[0081] As the material cools to room temperature at a rate of about 1.5°C per minute, BaCl2 crystals spontaneously precipitate within the glass matrix to form the glass-ceramic material. Although the entire process occurs in an argon environment, certain compositions, such as those with all-oxide starting materials, may not require an inert environment. For other compositions, a separate thermal step, also known as ceramming, may be necessary to precipitate the crystals.

[0082] The powder is dried prior to the melting process, although depending on the hygroscopicity of the powder, the drying step may not be necessary. As the luminescent glass-ceramic is slowly cooled to room temperature, it is annealed to reduce internal stresses, which may also occur as a separate step.

[0083] The luminescent glass-ceramic is formed in a brass mold, and the final shape and surface finish are determined by parting and polishing the material. There are other methods of forming the luminescent glass-ceramic, such as rolling and press forming. Annealing may also occur after these forming processes to relieve internal stresses.

[0084] There are alternative methods for producing luminescent glass-ceramics, such as powder processing, in which glass frits are sintered and then partially crystallized. In addition, other ceramic processing techniques can be utilized in their manufacture, including, but not limited to, jetting, tape and slip casting, isostatic pressing, or extrusion. In other aspects, glass-ceramics can also be obtained through a sol-gel route.

[0085] X-ray diffraction measurements of the as-built glasses and heat-treated samples (glass-ceramics) were carried out on a Philips X'Pert MRD X-ray diffractometer (PANalytical Inc., Westborough, MA, USA) in the 2θ range from 20° to 80° (2θ) on the x-axis. The scan speed step size was 0.05° and the time step was either 10 or 30 s.

[0086] X-ray diffraction (XRD) experiments confirmed the presence of BaCl2 crystallites within the luminescent glass-ceramic, as shown in Figure 8. Figure 8 shows the diffraction patterns (intensity) for the luminescent glass-ceramic made as described above with five different percentages of Tb2O3: (a) 0% Tb2O3, (b) 2% Tb2O3, (c) 4% Tb2O3, (d) 6% Tb2O3, and (e) 8% Tb2O3. The pattern for orthorhombic BaCl2 (PDF#00-024-0094) is shown in control (f). Powder diffraction files are available from the Clearinghouse for Diffraction Data. As shown in Figure 8, the diffraction peaks associated with the orthorhombic BaCl2 pattern (f) are clearly visible in the diffraction patterns (a)-(e). There is reasonable agreement with the more prominent peaks, such as 22.0°, 23.9°, 31.0°, and 34.2°.

[0087] Differential scanning calorimetry (DSC) (Netzsch DSC 200 F3) scans were performed on each as-built sample from 300° C. to 590° C. at a rate of 10 K per minute. As shown in FIG. 9, the scans confirmed that the samples, e.g., luminescent glass-ceramics, contained an amorphous (glassy) phase. This is indicated by the presence of a glass transition temperature (the temperature at which the scan curves or decreases) between 430 and 455° C. for all samples. FIG. 9 shows scans for luminescent glass-ceramics made as described above with five different percentages of Tb2O3: (a) 0% Tb2O3, (b) 2% Tb2O3, (c) 4% Tb2O3, (d) 6% Tb2O3, and (e) 8% Tb2O3.

[0088] The DSC results also indicate the necessary thermal stability of the material, as no thermal events occur until the glass transition temperature is reached, and the maximum processing temperature for the a-Si:H TFT arrays can be as low as 300° C. The scan is relatively flat up to the glass transition temperature.

[0089] Figure 10 shows the density of luminescent glass-ceramics with five different percentages of Tb2O3, e.g., density as a function of Tb2O3 content. The density is calculated from the measured mass and volume. The density differences are small and within the experimental uncertainty, and the density measurements range from 3.2 to 3.5 g cm for all samples. -3 These densities (as shown in FIG. 10) combined with the X-ray attenuation properties of the constituent elements give the material an appropriate X-ray mass attenuation coefficient (as shown in FIG. 11) by which a functional scintillator can be produced at practical dimensions. FIG. 11 shows the calculated X-ray mass attenuation coefficient for each sample, e.g., luminescent glass-ceramic, as a function of Tb2O3 content at 60 keV energy. The bars indicate the experimental uncertainty in the density determination.

[0090] The attenuation of X-rays by a sample for a given energy is determined by its density and the X-ray mass attenuation coefficient. The transmission of X-rays through a material may be described by the exponential attenuation principle.

[0091]

number

[0092] In the formula, I o is the incident intensity of the beam of monoenergetic photons, I is the transmitted intensity, μ / ρ is the X-ray mass attenuation coefficient, and x is the mass thickness, which is defined as mass per unit area: x=ρt (3)

[0093] where ρ is the density of the material and t is its thickness. Larger values ​​of density and mass attenuation coefficient lead to greater X-ray attenuation.

[0094] Figure 12 shows the 3.3 g cm- 3 and the calculated attenuation for each nominal formula versus thickness based on the assumed density of 60 keV X-rays, (a) 0% Tb2O3, (b) 2% Tb2O3, (c) 4% Tb2O3, (d) 6% Tb2O3, and (e) 8% Tb2O3. At thicknesses of about 5 mm and above, the total attenuation approaches 100% for all samples at 60 keV X-ray radiation, as shown in Figure 12.

[0095] At a thickness of about 2 mm, the total attenuation is close to or above 90%. FIG. 12 shows that ceramics may be used for the FPD in different thicknesses while still achieving high total attenuation. The thickness may be such that the FPD is compact and at the same time thick enough to meet the mechanical requirements of being a substrate for the photosensor array 600. For example, the ceramic may be at least about 5 mm. In other embodiments, the ceramic may be at least about 7 mm. The thickness may be such that the signal to noise ratio is maximized.

[0096] X-ray scintillation output is measured with a specially modified X-ray flat panel detector, where the housing of a commercial indirect FPD (AXS-2430FDi, Analogic Canada Corporation) is modified so that the luminescent glass ceramic can be pressed into direct contact with the light-sensitive array (TFT and photodiode array layers). Additionally, the modified X-ray flat panel detector can be rotated so that the incident X-ray beam enters first through the luminescent glass ceramic (front-illuminated) or first through the TFT / photodiode readout (back-illuminated).

[0097] Samples (luminescent glass-ceramics) with the composition 50B2O3-5SiO2-10BaCl2-10GdF3-2Tb2O3-23Li2O are split and then polished to several different thicknesses using sandpaper. Samples in this series are polished to 5.00, 2.50, 1.25, and 0.63±0.10 mm. The samples are shown to have the necessary properties to withstand the forces required to shape and polish them, and can exist as free-standing structures with a thickness of 0.63±0.10 mm. The samples maintain their integrity while being characterized, indicating their mechanical durability and chemical stability. Figure 13 shows the intensity, e.g., X-ray scintillation power, for luminescent glass-ceramics of various thicknesses in (a) front- and (b) back-illuminated configurations. Each sample (luminescent glass-ceramic) contains 2% Tb2O3. Circles are front-illuminated, squares are back-illuminated. FIG. 13 also shows that the luminescent glass-ceramics have the ability to be formed into various shapes and the necessary mechanical durability. Intensity is in arbitrary units. The bars indicate the experimental uncertainty in the intensity determination. The output signal initially rises with thickness due to the increase in X-ray absorption, and then (especially for FI) levels off or actually decreases. The decrease indicates a decrease in the light escape efficiency with depth within the material due to light absorption.

[0098] Luminescent glass-ceramics have tunable properties that are composition-dependent. As shown in FIG. 14, a dopant, Tb, added to the composition (e.g., in the form of Tb2O3) 3+ The amount of Tb2O3 can have a large effect on the scintillation performance of the material. Dopants may also be added in other ways. Figure 14 shows the X-ray scintillation output for luminescent glass-ceramics with various amounts of Tb2O3. The thickness of each sample is 5.0 mm. The measurements are taken in a back-illuminated configuration. As can be seen, the luminescent glass-ceramic with 6% Tb2O3 has the highest output of the five different samples. Intensity is in arbitrary units. The bars indicate the experimental uncertainty in the intensity determination.

[0099] X-ray excitation emission spectra were measured with a custom setup where the sample was placed at the input port of a 76.2 mm integrating sphere (Labsphere, Inc.) and irradiated using a tungsten anode X-ray tube producing standard RQA9 beam quality (120 kVp tube voltage, 40 mm Al filtration). The resulting x-ray luminescent light was directed into a CCD-type optical spectrometer (Spectral Products SM242, Putnam, CT). The integration time was 35 ms.

[0100] Figure 15 shows the X-ray excited emission spectrum of a sample of luminescent glass-ceramic containing 2% Tb2O3 emission. 3+ The emission from the ion beam dominates the spectrum, with a peak at about 490 ( 5 D4 → 7 F6), 545( 5 D4 → 7 F5), and 590 nm ( 5 D4 → 7 F4) and other Tb 3+ A peak due to Tb can be seen. 3+ The green emission of is an excellent fit to the quantum efficiency curve of known amorphous silicon detectors. The emission from BaCl2, centered at about 402 nm, is quite small in comparison, but does contribute to the overall signal.

[0101] Thin Film (Coating) In other disclosed embodiments, a luminescent (or scintillator) thin film may be coated or deposited on a glass substrate. In some disclosed embodiments, the luminescent thin film may be composed of the same components described above, including luminescent and scattering centers, and a glass matrix as a luminescent glass-ceramic. The film may also be composed of one or more sensitizers.

[0102] Thin films can be synthesized via a variety of thin film deposition methods including, but not limited to, chemical vapor deposition, physical vapor deposition, conversion coating, ion beam deposition, spraying, or physical coating processes (spin and dip coating).

[0103] FIG. 17 shows an example of a method for producing a thin film according to an embodiment of the disclosure. In S1700, a deposition target is formed. The target includes materials necessary to deposit a film consisting of luminescent centers, light scattering centers, and a glass matrix. The target may also include materials to allow for the deposition of a sensitizer. The luminescent center may be an element, an ion, or a compound. In some embodiments, the luminescent center may be a crystal, such as a halide (cesium iodide and barium chloride), a silicate (gadolinium orthosilicate and lutetium yttrium oxyorthosilicate), or a sulfide (gadolinium oxysulfide), or other crystalline materials may be used. These luminescent centers may further include one or more of europium, cesium, terbium, thallium, or other dopants to increase scintillation performance (their ions). The crystalline material may also act as a light scattering center. In other embodiments, additional materials may also act as light scattering centers.

[0104] In one embodiment of the disclosure, the luminescent (or scintillator) thin film 1805 is thermally stable in the areas required for TFT deposition and can be synthesized as a planar continuous layer.

[0105] In S1705, the materials required for depositing the light emitting centers, the light scattering centers, and the glass matrix are mounted on a rotating object holder. The rotating object holder is placed in a deposition chamber with a deposition substrate, e.g., a glass substrate. The deposition chamber is rotated for about 10 -5Torr. However, the pressure may be changed for different compositions. In S1710, the laser is pulsed onto the material used for the glass matrix. The energy of the laser may depend on the material used for the glass matrix. The laser is pulsed a first number of times. The first number of times may depend on the thickness of the film and the target material used. In S1715, the laser is pulsed onto the material for the light emitting centers and the light scattering centers (and sensitizer, if included). The energy of the laser may be the same. In other embodiments, the energy may vary depending on the material used. The laser is pulsed a second number of times. The second number of times may depend on the thickness of the film and the material used. S1710 and S1715 are repeated a third number of times. The third number of times may also depend on the thickness of the layer and the material used.

[0106] According to the disclosed embodiments, the use of luminescent (or scintillator) thin films (as coatings) offers the opportunity to utilize certain luminescent materials that may not be applicable in bulk glass-ceramics synthesized via traditional methods such as melt quenching or powder processing. Bulk synthesis methods must use materials that are compatible with the glass matrix and can severely limit the scintillator to glass ratio. However, the luminescent (or scintillator) thin films (as coatings) shown in Figures 19a, 19b and 20 demonstrate the ability to synthesize glass-ceramic films with high scintillator to glass ratios using luminescent and light scattering center materials formed within the ablated target. Pulsed laser deposition (PLD) ablates the target material and directs it to the substrate. The luminescent centers, light scattering centers and glass matrix materials are ablated and directed to the substrate, leading to a physically combined glass-ceramic.

[0107] The thin film described above may be incorporated into the screen of FPD. When incorporated into FPD to detect X-rays, coating thickness (film thickness) can be increased for large X-ray absorption and improved scintillation yield. Luminescent center to glass matrix ratio can also be increased to improve scintillation yield. In some embodiments, FPD may have one screen or dual screens.

[0108] FIG. 18 shows an example of a dual screen FPD 1800 (another example of a structure), where the rear screen 560A includes a luminescent glass ceramic conversion layer (scintillator film) 1805 coated on a glass substrate 1810. The scintillator film 1805 may be coated on the glass substrate 1810 in the manner described in FIG. 17. However, other methods of coating the scintillator film may be used. FIG. 18 also shows an optional glass film 1815, which serves as a substrate for the photosensor array 600. This has the advantage that a thin glass substrate layer may be selected to have the physical properties that need to be compatible with existing electronic manufacturing equipment for the photosensor array 600. The optional glass film 1815 may be fabricated using pulses of a laser on a material deposited as glass. The optional glass film 1815 may be thin to reduce light spreading in, increasing spatial resolution. The number of pulses and the energy of the laser may depend on the material and thickness. Any thin glass film 1815 is thermally stable in the area required for TFT deposition and can be synthesized as a planar continuous layer.

[0109] In some embodiments of the disclosure, the scintillator thin film 1805 may be incorporated into the screen of an FPD for applications requiring high energy x-ray beams, such as cone beam computed tomography, where existing detectors have relatively poor performance. In other embodiments, the scintillator thin film 1805 may be used in other clinical applications, including image guided surgery and general radiology.

[0110] Exemplary Manufacturing BaCl2:Eu acts as both a light-emitting and light-scattering center 2+ A prototype was developed consisting of an amorphous Si matrix deposited on a SiO2 glass substrate via pulsed laser deposition, and an excimer laser was applied to a pressed BaCl2:Eu substrate to create the emission and scattering centers. 2+ It is used to ablate a powder target and a Si target to create a glass matrix. The target materials are fixed in a target holder and the laser alternates between firing pulses on each material to synthesize a glass-ceramic film. The matrix is ​​first ablated on a Si target using 1000 laser pulses, then on a BaCl2:Eu target using 5000 laser pulses. 2+ This sequence is repeated for a total of 500 cycles. The glass-ceramic thin film is then capped with an optional glass protective layer by 1000 laser pulses on a Si target.

[0111] FIG. 19a shows a BaCl:Eu in an amorphous Si matrix as prepared according to the above description. 2+ Figure 19b shows a SEM cross-sectional image of the membrane, with a higher magnification of the membrane inset, and Figure 19c shows different parts of the membrane within the SEM image.

[0112] FIG. 20 shows the BaCl2:Eu crystal in an amorphous borosilicate matrix exposed to visible light and 45 keV X-rays. 2+ The film is shown. As can be seen, when exposed to X-rays the film emits light creating a measurable signal detectable by the TFT / photodiode array and may therefore be used for imaging. The two semicircular shapes are the uncoated portions of the glass substrate created by masking the substrate during the deposition process.

[0113] In the description, the term "about" indicates that the recited value may be varied somewhat as long as such variation does not result in non-compliance of the process or structure to the illustrated disclosure. For example, the term "about" for some elements may refer to a variation of ±0.1%, while the term "about" for other elements may refer to a variation of ±1%, ±10%, or ±20%, or any point therein.

[0114] The terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the invention. As used herein, the singular forms "a," "an," and "the" are intended to include the plural unless the content clearly indicates otherwise. Furthermore, it is to be understood that the terms "comprising" and / or "comprising" as used herein specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or the addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0115] Corresponding structures, materials, acts, and equivalents of all means or step-plus-function elements in the following claims, if any, are intended to include any structure, material, or act for performing a function in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or to limit the invention to the disclosed form. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the invention. The embodiments have been selected and described in order to best explain the principles and practical application of the invention, and to enable those skilled in the art to understand the invention in various embodiments together with various modifications as suitable for the particular use contemplated. [Explanation of symbols]

[0116] 1A Luminescent Glass Ceramic 1B Luminescent Glass-Ceramic 1C Luminescent Glass Ceramic 1D Luminescent Glass-Ceramic 5. Glass matrix 10 Luminous Center 15 Light scattering center 15A Emission / Scattering Center 20 Sensitizers 106 Switching element 400 Flat Panel Detector 405 Luminescent glass ceramic conversion layer 420 X-ray 500 Flat panel imaging device 505 Protective layer 510 Backing layer 525 Photon 550 Front Screen 560 Rear Screen 580 Light-emitting fluorescent layer 600 Photosensor Array 605 Scan Control Unit 606 Switching element 608 Photodiodes, photosensitive memory elements, charge amplifiers 610 Multiplexer 614 pixels 615 A / D 622 Gate Line 626 Data Line 650 host computer 660 Processor 700 Flat Panel Imaging Device 705 Lamination 710 electronic 1800 Flat panel imaging device 1805 Luminescent (or scintillator) thin film 1810 Glass substrate 1815 Glass thin film

Claims

1. A photosensor array; a screen comprising a luminescent glass ceramic, the luminescent glass ceramic comprising a glass matrix hosting luminescent centers and light scattering centers, the luminescent glass ceramic configured to convert incident X-ray radiation into photons, a surface of the luminescent glass ceramic facing the photosensor array, the photosensor array operable to capture at least a portion of the photons from the screen and convert the captured photons into electrical signals; A structure equipped with.

2. 2. The structure of claim 1, wherein the luminescent glass ceramic is configured to convert incident X-ray radiation incident on the surface of the luminescent glass ceramic facing the photosensor array and / or a surface of the luminescent glass ceramic opposite the surface facing the photosensor array.

3. 3. The structure of claim 1 or 2, further comprising a stack positioned on a surface of the luminescent glass-ceramic opposite the surface facing the photosensor array, the stack may comprise a material selected from the group consisting of copper, brass, lead, and leaded glass.

4. 4. The structure of claim 1, wherein the incident X-ray radiation has an energy of about 0.3 to about 20 MeV.

5. A structure comprising: a first luminescent screen for converting an absorbed portion of incident radiation directed at said structure into photons; A photosensor array; a second luminescent screen comprising a luminescent glass ceramic, the photosensor array being between the first luminescent screen and the second luminescent screen; Equipped with the luminescent glass ceramic comprises a glass matrix hosting light emitting centers and light scattering centers, the luminescent glass ceramic being configured to convert at least a portion of the incident radiation transmitted through the first luminescent screen and the photosensor array into photons; The photosensor array is operable to capture at least a portion of the light quanta from the first light emitting screen and the second light emitting screen and convert the captured light quanta into an electrical signal.

6. 6. The structure of claim 5, wherein the second luminescent screen further comprises a backing in contact with another surface of the luminescent glass-ceramic, the other surface facing the photosensor array, the backing being absorptive or reflective to the photons.

7. The structure of claim 1 , wherein the luminescent glass-ceramic is a substrate for the photosensor array.

8. The structure of claim 1 , wherein the light scattering centers comprise crystals of the same composition or a combination of crystals having different compositions.

9. 9. The structure of claim 1, wherein the luminescent centers comprise crystals of the same composition or a combination of crystals having different compositions, and the crystals of the luminescent centers and / or light scattering centers can be halide crystals.

10. The structure of claim 9, wherein the crystal of the luminescent center is doped with an activator.

11. The luminescence center is a transition metal, a rare earth metal, an actinide, or an ns ２ The luminescent center comprises one or more materials selected from the group consisting of ions from the first and second rows of type activators, and the luminescent center is Tb ３＋ and the luminescent glass ceramic is Tb ２ O ３ and Tb ２ O ３ The structure of any one of claims 1 to 10, wherein the mole percentage of can be about 6%.

12. the luminescent glass-ceramic further comprises a sensitizer configured to absorb incident X-ray radiation and transfer energy to an activator; The sensitizer is ns ２ The lanthanide ion may be one or more materials selected from the group consisting of Gd ３＋ and / or Ce ３＋ The structure of any one of claims 1 to 11,

13. 13. The structure of any one of claims 1 to 12, wherein the glass matrix is ​​an oxyhalide matrix.

14. 14. The structure of any one of claims 1 to 13, wherein the luminescent glass-ceramic is greater than about 0.5 mm thick.

15. A luminescent glass-ceramic for X-ray conversion comprising a glass matrix hosting light-emitting centers, light-scattering centers, and one or more high-Z elements.

16. 16. The luminescent glass-ceramic for X-ray conversion according to claim 15, wherein the light scattering centers have a size greater than about 10 nm.

17. 17. A luminescent glass-ceramic for X-ray conversion according to claim 15 or claim 16, wherein the concentration of light scattering centres in the glass matrix is ​​such that the scattering length is greater than about 1 μm.

18. The luminescent glass-ceramic has a viscosity of about 3.0 g cm －３ 18. A luminescent glass-ceramic for X-ray conversion according to claim 15, having a higher density.

19. 19. A luminescent glass-ceramic for X-ray conversion according to any one of claims 15 to 18, wherein the photon emission is in the wavelength range from about 375 nm to about 650 nm.

20. The present invention further comprises a sensitizer configured to absorb incident radiation and transfer energy to an activator, wherein the one or more high-Z elements can be a sensitizer, and the sensitizer is an ns ２ 20. A luminescent glass-ceramic for X-ray conversion according to claim 15, wherein the glass-ceramic is one or more materials selected from the group consisting of lanthanide ions and lanthanide ions.

21. 21. A luminescent glass-ceramic for X-ray conversion according to claim 15, wherein the light scattering centres comprise crystallites of the same composition or a combination of crystallites having different compositions.

22. 22. A luminescent glass-ceramic for X-ray conversion according to claim 15, wherein the glass matrix is ​​an oxyhalide matrix.

23. A structure comprising: a first luminescent screen for converting an absorbed portion of incident radiation directed at said structure into photons; A photosensor array; a second luminescent screen comprising a luminescent glass ceramic and a glass substrate, the luminescent glass ceramic being a coating on the glass substrate, the photosensor array being between the first luminescent screen and the second luminescent screen; Equipped with the luminescent glass ceramic comprises a glass matrix hosting light emitting centers and light scattering centers, the luminescent glass ceramic being configured to convert at least a portion of the incident radiation transmitted through the first luminescent screen and the photosensor array into photons; The photosensor array is operable to capture at least a portion of the light quanta from the first light emitting screen and the second light emitting screen and convert the captured light quanta into an electrical signal.

24. 24. The structure of claim 23, further comprising a glass film coated on the luminescent glass ceramic, the glass film being capable of being a substrate for the photosensor array.

25. 25. The structure of claim 23 or 24, wherein the light-emitting centers and the light-scattering centers comprise crystals, the crystals can be selected from the group consisting of halide crystals, silicate crystals, and sulfide crystals, and the crystals can be doped.

26. An imaging system comprising a processor configured to communicate with a structure according to any one of claims 1 to 14 or claims 23 to 25, or a luminescent glass-ceramic according to any one of claims 15 to 22, wherein a photosensor array is configured to produce an image having a plurality of pixels, The processor is configured to receive electrical signals from the structure and use the electrical signals to create the image having the plurality of pixels.

27. The structure of any one of claims 1 to 13, wherein the light scattering centers are BaCl 2 and the mole percentage of BaCl 2 is about 10%.

Images