X-ray imaging device and X-ray radiographic apparatus
An X-ray imaging device includes an X-ray detection section, a cold electron source, and a light-shielding coating layer. The X-ray detection section includes an X-ray conversion layer made of an X-ray converter material which generates electric charges upon incidence of an X-ray, a first charge injection blocking layer formed on an incidence surface of the X-ray conversion layer, and a second charge injection blocking layer formed on a rear surface of the X-ray conversion layer. The cold electron source has a plurality of electron emission sections arranged in a matrix form, each of the electronic emission sections being capable of emitting electrons toward the second charge injection blocking layer of the X-ray detection section. The light-shielding coating layer blocks incidence of the visible light into the X-ray detection section.
1. An X-ray imaging device, comprising:
an X-ray detection section including (i) an X-ray conversion layer having a first surface into which an X-ray enters and a second surface opposite to the first surface and made of an X-ray converter material for generating electric charges upon an incidence of the X-ray, (ii) a first charge injection blocking layer formed on the first surface of the X-ray conversion layer, and (iii) a second charge injection blocking layer formed on the second surface of the X-ray conversion layer;
a cold electron source having a plurality of electron emission sections arranged in a matrix form, each of the electronic emission sections being capable of emitting electrons toward the second charge injection blocking layer of the X-ray detection section;
a light-shielding section for shielding visible light from entering into the X-ray detection section;
a voltage application section for applying a voltage to the X-ray conversion layer of the X-ray detection section to generate an electric field which induces avalanche multiplication;
an electron source drive section for driving the plurality of electron emission sections of the cold electron source in sequence so that the electrons are emitted; and
a read section for electronically detecting the electric charges generated by the incidence of the X-ray into the X-ray conversion layer and then neutralized by the electrons emitted from the plurality of electron emission sections,
wherein the voltage application section generates an average electric field of between 0.1×10 8 V/m and 0.6×10 8 V/m in the X-ray conversion layer of the X-ray detection section.
2. The X-ray imaging device according to claim 1 , wherein the X-ray converter material includes amorphous selenium.
3. The X-ray imaging device according to claim 1 , wherein the cold electron source is a ballistic electron surface-emitting device.
4. The X-ray imaging device according to claim 1 , wherein the cold electron source is a Spindt-type electron source.
5. The X-ray imaging device according to claim 1 , wherein the light-shielding section is a light-shielding coating layer made of a light-shielding resin material, the light-shielding coating layer being formed so as to cover at least the first surface of the X-ray conversion layer of the X-ray detection section into which the X-ray enters.
6. The X-ray imaging device according to claim 1 , wherein the light-shielding section is a light-shielding casing made of a light-shielding material for housing at least the X-ray detection section and the cold electron source therein.
7. An X-ray radiographic apparatus, comprising:
an X-ray imaging device;
a moving section for spatially moving the X-ray imaging device; and
an X-ray irradiation section placed on an opposite side of the X-ray imaging device with respect to a photographing target for irradiating the photographing target with a transmitted X-ray and making the transmitted X-ray enter into the X-ray imaging device,
wherein the X-ray imaging device comprises:
an X-ray detection section including (i) an X-ray conversion layer having a first surface into which the X-ray enters and a second surface opposite to the first surface and made of an X-ray converter material for generating electric charges upon an incidence of the X-ray, (ii) a first charge injection blocking layer formed on the first surface of the X-ray conversion layer, and (iii) a second charge injection blocking layer formed on the second surface of the X-ray conversion layer;
a cold electron source having a plurality of electron emission sections arranged in a matrix form, each of the electronic emission sections being capable of emitting electrons toward the second charge injection blocking layer of the X-ray detection section;
a light-shielding section for shielding visible light from entering into the X-ray detection section;
a voltage application section for applying a voltage to the X-ray conversion layer of the X-ray detection section to generate an electric field which induces avalanche multiplication;
an electron source drive section for driving the plurality of electron emission sections of the cold electron source in sequence so that the electrons are emitted; and
a read section for electronically detecting the electric charges generated by the incidence of the X-ray into the X-ray conversion layer and then neutralized by the electrons emitted from the plurality electron emission sections, and
wherein the voltage application section generates an average electric field of between 0.1×10 8 V/m and 0.6×10 8 V/m in the X-ray conversion layer of the X-ray detection section.
8. The X-ray radiographic apparatus according to claim 7 , wherein the cold electron source is a ballistic electron surface-emitting device.
9. The X-ray radiographic apparatus according to claim 7 , wherein the cold electron source is a Spindt-type electron source.
10. The X-ray radiographic apparatus according to claim 7 , wherein the light-shielding section is a light-shielding coating layer made of a light-shielding resin material, the light-shielding coating layer being formed so as to cover at least the first surface of the X-ray conversion layer of the X-ray detection section into which the X-ray enters.
11. The X-ray radiographic apparatus according to claim 7 , wherein the light-shielding section is a light-shielding casing made of a light-shielding material for housing at least the X-ray detection section and the cold electron source therein.