WO2022172480A1 - X線管 - Google Patents
X線管 Download PDFInfo
- Publication number
- WO2022172480A1 WO2022172480A1 PCT/JP2021/026831 JP2021026831W WO2022172480A1 WO 2022172480 A1 WO2022172480 A1 WO 2022172480A1 JP 2021026831 W JP2021026831 W JP 2021026831W WO 2022172480 A1 WO2022172480 A1 WO 2022172480A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- vacuum envelope
- window
- ray tube
- envelope
- vacuum
- Prior art date
Links
- 238000010894 electron beam technology Methods 0.000 claims abstract description 12
- 239000000463 material Substances 0.000 claims abstract description 11
- 230000002093 peripheral effect Effects 0.000 claims abstract description 8
- 238000004846 x-ray emission Methods 0.000 claims description 9
- 230000005855 radiation Effects 0.000 abstract description 10
- 230000005684 electric field Effects 0.000 description 3
- 230000005856 abnormality Effects 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 229910052790 beryllium Inorganic materials 0.000 description 1
- ATBAMAFKBVZNFJ-UHFFFAOYSA-N beryllium atom Chemical compound [Be] ATBAMAFKBVZNFJ-UHFFFAOYSA-N 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J35/00—X-ray tubes
- H01J35/02—Details
- H01J35/16—Vessels; Containers; Shields associated therewith
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J35/00—X-ray tubes
- H01J35/02—Details
- H01J35/16—Vessels; Containers; Shields associated therewith
- H01J35/18—Windows
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J35/00—X-ray tubes
- H01J35/02—Details
- H01J35/16—Vessels; Containers; Shields associated therewith
- H01J35/165—Vessels; Containers; Shields associated therewith joining connectors to the tube
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J2235/00—X-ray tubes
- H01J2235/16—Vessels
- H01J2235/165—Shielding arrangements
- H01J2235/168—Shielding arrangements against charged particles
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J2235/00—X-ray tubes
- H01J2235/18—Windows, e.g. for X-ray transmission
Definitions
- An embodiment of the present invention relates to an X-ray tube.
- an X-ray tube consists of a vacuum envelope that keeps the inside in a vacuum, a cathode that is provided in the vacuum envelope and emits an electron beam, and an electron beam that is provided inside the vacuum envelope and emitted from the cathode. It has an anode target that emits X-rays incident on the focal plane, and an X-ray emission window that transmits X-rays emitted from the focal plane of the anode target.
- recoil electrons are generated when the electron beam emitted from the cathode collides with the focal plane of the anode target. Recoil electrons fly out in all directions, and fly in the direction of lower potential due to the electric field.
- Some recoil electrons emit secondary electrons when they collide with the vacuum envelope. Due to these recoil electrons and secondary electrons, a charging phenomenon occurs on the inner surface of the vacuum envelope 3, and the potential gradient between the vacuum envelope 3 and the X-ray radiation window increases, making it easier for discharge to occur. , X-rays obtained through the X-ray radiation window may cause problems such as an abnormal X-ray image and apparatus stoppage. In order to deal with such problems, a technique has been proposed in which a hood or the like is provided to cover the anode target to prevent recoil electrons and secondary electrons from going toward the inner surface of the vacuum envelope.
- the present embodiment has been made in view of the above points, and its purpose is to provide an X-ray tube that can prevent problems such as X-ray image abnormalities and device stoppages with a simple configuration.
- one embodiment includes a vacuum envelope that maintains the interior in a vacuum, a cathode that is provided in the vacuum envelope and emits an electron beam, and a cathode that is provided in the vacuum envelope and An X-ray tube comprising: an anode target for emitting X-rays when the electron beam emitted from the cathode is incident on a focal plane; and an X-ray emission window for transmitting the X-rays emitted from the focal plane of the anode target.
- the X-ray radiation window includes a window material and a support for the window material
- the vacuum envelope has a joint portion that is joined to the support and faces the outside of the vacuum envelope.
- the support is an X-ray tube provided with a cover that covers the inner peripheral surface of the joint.
- FIG. 1 is a vertical cross-sectional view showing a schematic configuration of an X-ray tube according to an embodiment.
- FIG. 2 is a vertical cross-sectional view showing a schematic configuration of an X-ray tube according to a comparative example.
- the X-ray tube 1 is a fixed anode X-ray tube, and includes a vacuum envelope 3 that maintains a vacuum inside, a cathode 5 provided in the vacuum envelope 3, and an anode 7. , with an X-ray emission window 9 .
- the vacuum envelope 3 is made of an insulator such as glass or ceramics.
- the cathode 5 is arranged on one side within the vacuum envelope 3 and is provided with a filament 11 .
- the cathode 5 emits an electron beam 13 from the filament 11 in the X direction in FIG.
- the anode 7 is arranged on the other side in the vacuum envelope 3 , facing the cathode 5 , and is provided with an anode target 15 .
- the anode target 15 emits X-rays 8 in the Z direction in FIG. 1 when the electron beam 13 emitted from the filament 11 of the cathode 5 collides with the focal plane.
- the X-ray radiation window 9 is composed of a window material 17 and a support 19 that supports the window material 17 .
- the window material 17 is made of a material that attenuates the X-rays 8 less, such as Be (beryllium), and is formed as thin as several tens of micrometers to several hundred micrometers.
- the window material 17 allows the X-rays 8 to pass therethrough while keeping the inside of the vacuum envelope 3 airtight.
- the support 19 is insulated from the anode 7 and the cathode 5 and is designed with sufficient withstand voltage for high voltages.
- the support 19 includes a window holding portion 21, a support-side joint portion 23 joined to an envelope-side joint portion (joint portion) 3a formed in the vacuum envelope 3, and a cover portion 25. ing.
- the envelope-side joint portion 3a is formed so as to protrude outward from the vacuum envelope 3 continuously from the envelope main body 3b.
- the cover portion 25 has a cylindrical shape, is arranged from the support side joint portion 23 to the inner peripheral side of the envelope side joint portion 3a, and is provided along the inner peripheral surface of the envelope side joint portion 3a. and covers the entire inner peripheral surface of the envelope-side joint portion 3a. Furthermore, in the present embodiment, the cover portion 25 is arranged inside the vacuum envelope 3 relative to the window member holding portion 21, which is the position at which the window member 17 is attached, so that the envelope side joint portion 3a is raised. It extends to the starting position K.
- the direction of the recoil electrons a and the field-emitted electrons b change depending on the design of the X-ray tube 1 and the electric field. Further, secondary electrons are generated when the recoil electrons a collide with the vacuum envelope 3 . Then, when the recoil electrons a heading for the X-ray emission window 9 collide with the enclosure-side joint portion 3a of the vacuum envelope 3, the electrical charge causes a potential difference and discharge occurs at this portion, causing the X-ray emission window 9 to collapse. It will adversely affect the X-rays 8 that pass through.
- the cover portion 25 of the support 19 covers the inner peripheral surface of the envelope-side joint portion 3a of the vacuum envelope 3. Therefore, the recoil electrons a heading for the X-ray radiation window 9 can be prevented from colliding with the envelope-side junction 3a of the vacuum envelope 3.
- FIG. 1 As a result, the enclosure-side joint portion 3a is prevented from being positively or negatively charged.
- the support 19 of the X-ray radiation window 9 is simply provided with the covering portion 25 that covers the inner peripheral surface of the envelope-side joint portion 3a, so the configuration is simple.
- the covering portion 25 is arranged inside the vacuum envelope 3 relative to the mounting position of the window member 17, so that the X-rays 8 passing through the window member 17 are located on the envelope side. It is possible to effectively prevent problems due to electrification of the joint portion 3a.
- cover portion 25 is formed integrally with the support 19 , it may be formed separately and fixed to the window member holding portion 21 .
- the cover portion 25 is not limited to being formed in a cylindrical shape, and may be formed in a tubular shape of a truncated cone, the diameter of which narrows toward the inner side of the vacuum envelope 3 .
Landscapes
- X-Ray Techniques (AREA)
Abstract
Description
係るX線管では、陰極から放出された電子ビームは陽極ターゲットの焦点面に衝突した際に反跳電子が発生することが知られている。反跳電子はあらゆる方向に飛び出し、電界によってポテンシャルの低い方向に飛んでいく。一部の反跳電子は真空外囲器に衝突した際に二次電子を放出する。
これらの反跳電子や二次電子により、真空外囲器3の内面で帯電現象が発生し、真空外囲器3とX線放射窓の間で電位勾配が大きくなり放電が発生しやすくなるため、X線放射窓を通過して得たX線のX線画像異常や装置停止等の不具合が生じる場合がある。
このような不具合に対して、陽極ターゲットを覆うフード等を設けて、反跳電子や二次電子が真空外囲器の内面に向かうのを防止する技術が提案されている。
図1に示すように、X線管1は、固定陽極X線管であり、内部を真空に保持する真空外囲器3と、真空外囲器3内に設けた陰極5と、陽極7と、X線放射窓9を備えている。
真空外囲器3は、ガラスやセラミックスなどの絶縁物で形成されている。
陽極7は、陰極5に対向して、真空外囲器3内の他方側に配置されており、陽極ターゲット15が設けられている。陽極ターゲット15は、陰極5のフィラメント11から放出された電子ビーム13が焦点面に衝突して、図1のZ方向に向けてX線8を放出する。
窓材17は、X線8の減衰が少ない材料、たとえばBe(ベリリウム)で形成され、また、厚さは数10μm~数100μmと薄く成形されている。窓材17は、真空外囲器3の内部の気密状態を保持しつつX線8を透過させる。
支持体19は、陽極7及び陰極5と絶縁されており、高電圧に対して十分な耐電圧に合わせて設計されている。
この支持体19は、窓材保持部21と、真空外囲器3に形成された外囲器側接合部(接合部)3aに接合される支持体側接合部23と、覆い部25とを備えている。
覆い部25は、円筒形状を成し、支持体側接合部23から、外囲器側接合部3aの内周側に配置されており、外囲器側接合部3aの内周面に沿って設けてあり、外囲器側接合部3aの内周面全面を覆っている。
更に、本実施形態では、覆い部25は、窓材17の取り付け位置である窓材保持部21よりも真空外囲器3の内側に配置されており、外囲器側接合部3aの立ち上げ開始位置Kまで延出されている。
まず、比較例の図2を参照して、覆い部25が無い場合につて、説明する。尚、図2では、上述した実施形態に係るX線管1と同一の作用効果を奏する部分には、同一の符号を付しており、上述した実施形態とは、支持体19に覆い部25が形成されていないことのみが異なっている。
そして、X線放射窓9に向かう反跳電子aが、真空外囲器3の外囲器側接合部3aに衝突すると、帯電により電位差が生じこの部分で放電が生じ、X線放射窓9を通過するX線8に悪影響を与えることになる。
しかも、本実施形態では、X線放射窓9の支持体19に、外囲器側接合部3aの内周面を覆う覆い部25を形成するだけであるから、構成が簡易である。
例えば、覆い部25は支持体19に一体に形成したが、別体にして窓材保持部21に固定しても良い。
また、覆い部25は、円筒形状に形成することに限らず、真空外囲器3の内側ほど径を狭める円錐台の筒形状であっても良い。
Claims (2)
- 内部を真空に保持する真空外囲器と、前記真空外囲器内に設けて電子ビームを放出する陰極と、前記真空外囲器内に設けて前記陰極から放出する前記電子ビームが焦点面に入射してX線を放出する陽極ターゲットと、前記陽極ターゲトの前記焦点面から放出する前記X線を透過させるX線放射窓とを備えるX線管であって、
前記X線放射窓は、窓材と、前記窓材の支持体とを備え、
前記真空外囲器には前記支持体に接合する接合部が前記真空外囲器の外側に向けて突設して形成されており、
前記支持体は、前記接合部の内周面を覆う覆い部を備えているX線管。 - 前記覆い部は、前記窓材の取り付け位置よりも真空外囲器の内側に配置されている請求項1に記載のX線管。
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN202180093491.7A CN116868299A (zh) | 2021-02-12 | 2021-07-16 | X射线管 |
EP21925728.4A EP4293698A1 (en) | 2021-02-12 | 2021-07-16 | X-ray tube |
US18/446,616 US20240021401A1 (en) | 2021-02-12 | 2023-08-09 | X-ray tube |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2021020784A JP2022123457A (ja) | 2021-02-12 | 2021-02-12 | X線管 |
JP2021-020784 | 2021-02-12 |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US18/446,616 Continuation US20240021401A1 (en) | 2021-02-12 | 2023-08-09 | X-ray tube |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2022172480A1 true WO2022172480A1 (ja) | 2022-08-18 |
Family
ID=82837669
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2021/026831 WO2022172480A1 (ja) | 2021-02-12 | 2021-07-16 | X線管 |
Country Status (5)
Country | Link |
---|---|
US (1) | US20240021401A1 (ja) |
EP (1) | EP4293698A1 (ja) |
JP (1) | JP2022123457A (ja) |
CN (1) | CN116868299A (ja) |
WO (1) | WO2022172480A1 (ja) |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS62121773U (ja) * | 1986-12-17 | 1987-08-01 | ||
JPH03110753U (ja) | 1990-02-28 | 1991-11-13 | ||
US20070291901A1 (en) * | 2006-06-15 | 2007-12-20 | Varian Medical Systems Technologies, Inc. | X-ray tube window bonding with smooth bonding surface |
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2021
- 2021-02-12 JP JP2021020784A patent/JP2022123457A/ja active Pending
- 2021-07-16 WO PCT/JP2021/026831 patent/WO2022172480A1/ja active Application Filing
- 2021-07-16 CN CN202180093491.7A patent/CN116868299A/zh active Pending
- 2021-07-16 EP EP21925728.4A patent/EP4293698A1/en active Pending
-
2023
- 2023-08-09 US US18/446,616 patent/US20240021401A1/en active Pending
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS62121773U (ja) * | 1986-12-17 | 1987-08-01 | ||
JPH03110753U (ja) | 1990-02-28 | 1991-11-13 | ||
US20070291901A1 (en) * | 2006-06-15 | 2007-12-20 | Varian Medical Systems Technologies, Inc. | X-ray tube window bonding with smooth bonding surface |
Also Published As
Publication number | Publication date |
---|---|
CN116868299A (zh) | 2023-10-10 |
EP4293698A1 (en) | 2023-12-20 |
JP2022123457A (ja) | 2022-08-24 |
US20240021401A1 (en) | 2024-01-18 |
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