JP3785501B2 - Gas amplification type X-ray imaging detector and gas amplification type X-ray imaging detection method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas amplification X-ray imaging detector and a gas amplification X-ray imaging detection method having a micro gas chamber having a three-dimensional microstructure.
[0002]
[Prior art]
In recent years, there is an increasing demand for measuring X-ray images as two-dimensional images by resolving scattered rays of diffraction / scattering experiments using high-intensity synchrotron radiation. On the other hand, in the synchrotron radiation detector, an X-ray detector for detecting X-rays as a two-dimensional image image has not yet been realized, and research and development are being actively conducted. For example, synchrotron photons have been introduced. Development of micro gas chamber X-ray detectors that cause electrons to be amplified and discharged between the anode and cathode using the electrons generated when colliding with inert gas such as Ar as seeds is being actively conducted. .
[0003]
An example of the micro gas chamber X-ray detector is disclosed in Japanese Patent Laid-Open No. 10-300856. This is an organic thin film that has elasticity as a substrate, and is positioned under the organic thin film, enabling two-dimensional readout using signals induced in the backstrip, large area, and flexible shape. And enables simultaneous measurement of two-dimensional coordinates.
[0004]
[Problems to be solved by the invention]
However, since this discharge is on a flat surface, there is a problem that fluctuation and stability due to charge-up are lacking, and there is no plan for practical use. In addition, there is a problem that the resolution cannot be increased because the pitch is as coarse as 200 μm due to the limitation of the processing technique.
[0005]
An object of the present invention is to provide a gas amplification type X-ray imaging detector and a gas amplification type X-ray imaging detection method that can perform stable gas amplification, have high positional resolution, and are not easily damaged by discharge.
[0006]
[Means for Solving the Problems]
The gas amplification type X-ray imaging detector according to claim 1 of the present invention for solving the above-mentioned problems is an electron between an anode and a cathode, using electrons generated by collision of synchrotron photons and inert gas as seeds. A gas-amplified X-ray imaging detector comprising a micro gas chamber that causes multiplication and discharge, and a detection means that detects electrons amplified by the micro gas chamber,
The micro gas chamber is formed by X-ray lithography, comprising a plurality of through-holes, the substrate conductive material is provided as a A node or cathode, are stacked in an integral structure together the through hole, the Electrons amplified by the micro gas chamber are detected by the detection means ,
The integrated structure is formed by laminating the anode, the first substrate, the cathode, and the second substrate together with the through holes, and is laminated in two or more stages.
The through-holes are formed with a pitch of 200 μm or less, and have a quadrangular or hexagonal shape,
The detection unit is a glass in which an integrated structure in which the through-holes are combined has a fluorescent material and an ITO electrode or a fluorescent material burning protective film, a fluorescent material and an ITO electrode formed on the surface of the second substrate. A portion that is installed on a substrate and emits light when colliding with the fluorescent material is formed so as to be detected as a two-dimensional image by a CCD imaging device .
[0007]
According to the above configuration, since the micro gas chamber is formed by stacking the substrates having a plurality of through holes, the gas amplification factor can be increased. Further, since the micro gas chamber is a fine structure formed by X-ray lithography, it is not easily damaged even when a discharge occurs.
Moreover, according to the said structure, since the pitch of a through-hole is formed with the pitch of 200 micrometers or less, it can be set as high position resolution. In addition, since the gas amplification factor is high, imaging can be performed with high accuracy.
Moreover, according to the said structure, it becomes possible to select a through-hole shape suitably according to the use condition of a micro gas chamber.
Moreover, according to the said structure, the site | part which light-emitted by the X-ray which passed through the through-hole can be directly observed with a CCD image sensor, and two-dimensional imaging can be performed easily.
[0016]
According to a second aspect of the present invention, there is provided a gas amplification type X-ray imaging detection method comprising: a micro that causes electron multiplication and discharge between an anode and a cathode using electrons generated by collision of synchrotron photons and an inert gas as seeds. A gas-amplified X-ray imaging detection method for imaging a gas chamber and electrons detected by the micro gas chamber by a detection means,
The micro gas chamber is formed by X-ray lithography, has a plurality of through holes, and a substrate provided with a conductive material to be an anode or a cathode on both surfaces is laminated with the through holes,
The laminate in which the through holes are combined is formed by laminating the anode, the first substrate, the cathode, and the second substrate by being laminated in two or more stages.
The through-holes are formed with a pitch of 200 μm or less, and have a quadrangular or hexagonal shape,
The laminated body having the through holes is placed on the glass substrate on the surface of the second substrate, on which the fluorescent material and the ITO electrode, or the fluorescent material burning protective film, the fluorescent material and the ITO electrode are formed. And
A portion where electrons amplified by the micro gas chamber emit light when colliding with the fluorescent material is detected as a two-dimensional image on the image display monitor screen of the CCD image sensor .
[0019]
According to the above method, two-dimensional imaging can be easily performed with high position resolution.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a gas amplification X-ray imaging detector according to the present invention will be described below with reference to the drawings.
[0021]
FIG. 1 is a cross-sectional view of a main part of a gas amplification type X-ray imaging detector 1 according to this embodiment. In FIG. 1, a gas amplification type X-ray imaging detector 1 penetrates an electron generated by collision of an emitted gas photon such as an X-ray passing through a conductive X-ray window 10 with an inert gas as a seed. In the hole 5, the micro gas chamber 2 that is multiplied and discharged between the anode 11 and the cathode 12, the glass substrate 17, the ITO electrode 16 provided on the surface thereof, and the surface is applied to the through hole 5. It is comprised with the detection part 3 comprised by the fluorescent material 15 which light-emits by the collision of the electron which has passed through, and the detection means 18 which detects light emission of this fluorescent material 15. A fluorescent material burning protective film 26 is preferably formed on the surface of the fluorescent material 15. At this time, a potential difference of about several tens of kV is applied to the conductive X-ray window 10 and the ITO electrode 16 so that the ITO electrode 16 serves as an anode and the conductive X-ray window 10 serves as a cathode. Electrons amplified by this potential difference collide with the ITO electrode 16 at an accelerated speed to cause the fluorescent material to emit light. The anode 11 and the cathode 12 for electron multiplication create a potential difference locally within the range of the electric field and cause electron buncher (electron avalanche) by gas discharge to multiply electrons. Here, as the potential difference between the electrodes, for example, when the ITO electrode 16 is 0 V, the potential difference with the cathode 12 is 1 kV / cm, the difference between the cathode 12 and the anode 11 is 1 kV / 100 μm, and the anode 11 is electrically conductive. The difference from the X-ray window 10 is preferably 1 kV / cm.
[0022]
In addition, as shown in FIG. 2, it is possible to stack the electrodes 11 and 12 etc. in two stages as needed, so that the electronic amplification can detect the emitted light with the maximum sensitivity and the electron energy of 50 keV. It is. Further, the number of stacked layers can be two or more.
[0023]
Moreover, an example of the shape of the through-hole 5 is shown to Fig.3 (a), (b). 3A shows that the through hole 5 has a hexagonal shape, and FIG. 3B shows that the through hole 5 has a square shape. Thus, in the X-ray imaging detector according to the present invention, the shape of the through hole 5 for gas amplification can be appropriately formed in a predetermined shape. Next, the formation method will be described.
[0024]
The micro gas chamber 2 is formed by X-ray lithography. An example is shown in FIG. In the micro gas chamber 2, first, a Cu film serving as an anode is formed on the Si substrate 20 by vapor deposition or sputtering (FIG. 5A). Next, an electrically insulating material such as an epoxy resin is formed on the surface of the Cu film 11 by spin coating or the like, and a curing process is performed to obtain a substrate 13 (FIG. 5B). An Al film 12 serving as a cathode is formed on the surface of the substrate 13 by vapor deposition or sputtering (FIG. 5C). Then, an electrically insulating material, for example, an epoxy resin or the like is again formed on the surface of the Al film 12 by spin coating or the like, and a curing process is performed to form a substrate 14 (FIG. 5D). Next, an X-ray absorber, such as Au, patterned so that the through holes 5 can be formed at a pitch of 100 μm is formed on the surface of the substrate 14, and X-ray exposure is performed (FIG. 5E). Then, by developing, the portion 21 where the X-ray absorber was not formed is removed (FIG. 5 (f)). Since the Al film 12 transmits X-rays, the lower part 22 of the Al film 12 is also exposed to X-rays. Therefore, the lower portion 22 of the Al film 12 is removed by etching the Al film 12 with H ₂ SO ₄ or the like and developing it again (FIG. 5G). Next, by etching the Cu film 11 with HNO ₃ or the like, a hole to be the through hole 5 can be formed (FIG. 5H). Next, a glass substrate in which an ITO electrode 16 and a fluorescent material 15 are coated on the surface of the substrate 14 and an aluminum thin film serving as a fluorescent material burning protective film 26 having a thickness of 0.1 to 0.5 μm is formed on the surface. 17 are bonded by a known dissimilar material bonding technique such as OH bonding so that the aluminum thin film 26 is on the substrate 14 side (FIG. 5I). Then, after the Si substrate 20 is polished, the Si substrate 20 is removed by etching with KOH.
[0025]
FIG. 4 shows a photograph of an example of the substrates 13 and 14 formed by the aforementioned X-ray lithography. This shows that the shape of the through holes 5 is hexagonal, and these holes can be formed with a pitch of 200 μm or less.
[0026]
Next, returning to FIG. 1, an imaging detection method using a gas amplification X-ray imaging detector according to this embodiment will be described.
[0027]
In FIG. 1, synchrotron photons such as X-rays collide with an inert gas such as Ar gas present in the X-ray / electron conversion unit 4 to generate electrons. When these electrons pass through the plurality of through holes 5 formed in the micro gas chamber 2, the electrons are formed by applying an electric charge between the anode and the cathode formed on both surfaces of the substrate 13 constituting the micro gas chamber 2. Amplified and discharged by the applied electric field.
[0028]
The amplified electrons emit light by colliding with the fluorescent material 15. The light emission of the fluorescent material 15 is directly detected by the CCD image sensor 18 which is a detecting means. At this time, since the through-holes 5 formed in the micro gas chamber 2 are formed with a pitch of 100 μm to 200 μm, it is possible to distinguish a portion emitting light with a very high position resolution, and to easily perform two-dimensional imaging. Is possible. In addition, since the CCD imaging element 18 directly detects the light emitting part, it is not necessary to perform signal conversion or the like, and the apparatus itself can be simplified.
[0029]
Further, the micro gas chamber 2 can be formed with a high aspect ratio by X-ray lithography, and the through hole 5 can be formed in either a square shape or a hexagonal shape. Depending on the intended use of the gas chamber 2, for example, it can be hexagonal when strength is required, or it can be rectangular when positional resolution is required in consideration of compatibility with the CCD image sensor 18.
[0030]
In the above-described embodiment, the case where the CCD image pickup device 18 is used as the detection unit has been described. For example, as shown in FIG. 6, a pixel electrode which is a charge transfer device is provided for each through hole 5. The signal from each pixel electrode can be detected and directly image processed.
[0031]
FIG. 6 is a cross-sectional view of a main part of the gas amplification X-ray imaging detector 1 according to the present embodiment. In FIG. 6, the same members as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.
[0032]
In FIG. 6, the gas amplification type X-ray imaging detector 1 penetrates the electrons using the electrons generated by the collision of the emitted photons such as X-rays that have passed through the conductive X-ray window 10 and the inert gas as seeds. In the hole 5, the micro gas chamber 2 that is multiplied and discharged between the anode 11 and the cathode 12, the pixel electrode 23 that captures the electrons 25 that have passed through the through-hole 5, and the pixel electrode that extracts the captured electrons as current. It is comprised with the detection part 3 comprised by the internal wiring 24. FIG. At this time, a potential difference of about several tens of kV is applied to the conductive X-ray window 10 and the pixel electrode 23 so that the pixel electrode 23 serves as an anode and the conductive X-ray window 10 serves as a cathode. Electrons amplified by this potential difference can be taken out as current by the pixel electrode 23. The anode 11 and the cathode 12 for electron multiplication cause a potential difference locally in the range of the electric field and cause electron buncher (electron avalanche) by gas discharge to multiply electrons. Here, as the potential difference between the electrodes, for example, when the pixel electrode 23 is set to 0 V, the potential difference with the cathode 12 is 1 kV / cm, the difference between the cathode 12 and the anode 11 is 1 kV / 100 μm, and the anode 11 is electrically conductive. The difference from the X-ray window 10 is preferably 1 kV / cm.
[0033]
In the gas amplification type X-ray imaging detector 1 shown in FIG. 6, the amplified electrons collide with the pixel electrode and can be taken out as a current. This current is detected as an image on the image display monitor screen. At this time, since the through-holes 5 formed in the micro gas chamber 2 are formed with a pitch of 100 μm to 200 μm, it is possible to distinguish a portion emitting light with a very high position resolution, and to easily perform two-dimensional imaging. Is possible.
[0034]
If necessary, as shown in FIG. 7, the electronic amplification can be made by stacking the electrodes 11 and 12 etc. in two stages, which enables detection of radiated light with a maximum sensitivity of 50 keV. It is. Further, the number of stacked layers can be two or more.
[0035]
Thus, since the micro gas chamber 2 according to the present invention can be formed with a high aspect ratio by X-ray lithography and it is easy to stack a plurality of substrates, the micro gas chamber 2 is digitized through the micro gas chamber 2. Since gas can be easily amplified and discharged, even when a pixel electrode as a charge transfer element is provided in each through-hole 5, electrons passing through each through-hole 5 can be reliably detected. It is possible to perform two-dimensional imaging from these signals.
[0036]
【The invention's effect】
The gas amplification type X-ray imaging detector according to the present invention enables two-dimensional imaging with high positional resolution, is less damaged by gas amplification and discharge, and is stable over a long period of time. It can be a line imaging detector.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an example of a gas amplification X-ray imaging detector according to the present invention.
FIG. 2 is a diagram showing a cross-sectional view of another example of the gas amplification X-ray imaging detector according to the present invention, and is a diagram showing an example in which electrodes are stacked in two stages.
FIG. 3 is a diagram showing an example in which the through hole of the gas amplification X-ray imaging detector according to the present invention has a hexagonal shape. (A) has a hexagonal through hole, and (b) has a rectangular shape.
FIG. 4 is a view showing a photograph of an example of a substrate constituting a micro gas chamber of a gas amplification type X-ray imaging detector according to the present invention.
FIG. 5 is a diagram for explaining a method of manufacturing a micro gas chamber as an example of a gas amplification X-ray imaging detector according to the present invention.
FIG. 6 is a cross-sectional view of another example of a gas amplification type X-ray imaging detector according to the present invention.
FIG. 7 is a diagram showing a cross-sectional view of another example of a gas amplification type X-ray imaging detector according to the present invention, and is a diagram showing an example in which electrodes are stacked in two stages.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Gas amplification type | mold X-ray imaging detector 2 Micro gas chamber 3 Detection part 4 X-ray | electron conversion part 5 Through-hole 10 Conductive X-ray window 11 Anode (Cu film)
12 Cathode (Al film)
13, 14 Substrate 15 Fluorescent material 16 ITO electrode 17 Glass substrate 18 CCD imaging device 20 Si substrate 23 Pixel electrode 24 Pixel electrode internal wiring 25 Accelerating electron 26 Fluorescent material burning protective film (Al thin film)

Claims (2)

Micro gas chamber that causes electron multiplication and discharge between anode and cathode using electrons generated by collision of synchrotron photon and inert gas as a seed, and detection that detects electrons amplified by the micro gas chamber A gas amplification X-ray imaging detector comprising:
The micro gas chamber is formed by X-ray lithography, comprising a plurality of through-holes, the substrate conductive material is provided as a A node or cathode, are stacked in an integral structure together the through hole, the Electrons amplified by the micro gas chamber are detected by the detection means ,
The integrated structure is formed by laminating the anode, the first substrate, the cathode, and the second substrate together with the through holes, and is laminated in two or more stages.
The through-holes are formed with a pitch of 200 μm or less, and have a quadrangular or hexagonal shape,
The detection unit is a glass in which an integrated structure in which the through-holes are combined has a fluorescent material and an ITO electrode or a fluorescent material burning protective film, a fluorescent material and an ITO electrode formed on the surface of the second substrate. A gas-amplified X-ray imaging detector that is installed on a substrate and is configured to detect a portion that emits light by colliding with the fluorescent material as a two-dimensional image by a CCD imaging device . A micro gas chamber that causes electron multiplication and discharge between the anode and cathode using the electrons generated by the collision of the synchrotron photon and the inert gas as a seed, and the electron amplified by the micro gas chamber by the detection means A gas amplification type X-ray imaging detection method for imaging and detecting,
The micro gas chamber is formed by X-ray lithography, has a plurality of through holes, and a substrate provided with a conductive material to be an anode or a cathode on both surfaces is laminated with the through holes,
The laminate in which the through holes are combined is formed by laminating the anode, the first substrate, the cathode, and the second substrate by being laminated in two or more stages.
The through-holes are formed with a pitch of 200 μm or less, and have a quadrangular or hexagonal shape,
The laminated body having the through holes is placed on the glass substrate on the surface of the second substrate, on which the fluorescent material and the ITO electrode, or the fluorescent material burning protective film, the fluorescent material and the ITO electrode are formed. And
A gas-amplified X-ray imaging detection method for detecting, as a two-dimensional image, on a display screen of an image of the CCD image sensor, a site where electrons amplified by the micro gas chamber emit light when colliding with the fluorescent material .

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