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GB2270825A - An inspection system - Google Patents

An inspection system Download PDF

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Publication number
GB2270825A
GB2270825A GB9319490A GB9319490A GB2270825A GB 2270825 A GB2270825 A GB 2270825A GB 9319490 A GB9319490 A GB 9319490A GB 9319490 A GB9319490 A GB 9319490A GB 2270825 A GB2270825 A GB 2270825A
Authority
GB
United Kingdom
Prior art keywords
photodiode array
screen
inspection system
optical means
cooling circuit
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB9319490A
Other versions
GB2270825B (en
GB9319490D0 (en
Inventor
Stephen Geoffrey Drake
Kenneth John Wrigglesworth
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sellafield Ltd
Original Assignee
British Nuclear Fuels PLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by British Nuclear Fuels PLC filed Critical British Nuclear Fuels PLC
Publication of GB9319490D0 publication Critical patent/GB9319490D0/en
Publication of GB2270825A publication Critical patent/GB2270825A/en
Application granted granted Critical
Publication of GB2270825B publication Critical patent/GB2270825B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05G—X-RAY TECHNIQUE
    • H05G1/00—X-ray apparatus involving X-ray tubes; Circuits therefor
    • H05G1/08—Electrical details
    • H05G1/64—Circuit arrangements for X-ray apparatus incorporating image intensifiers
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
    • G01N23/02—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material
    • G01N23/04—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material
    • G01N23/043—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material using fluoroscopic examination, with visual observation or video transmission of fluoroscopic images
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/16—Measuring radiation intensity
    • G01T1/20—Measuring radiation intensity with scintillation detectors
    • G01T1/2018—Scintillation-photodiode combinations
    • G01T1/20185—Coupling means between the photodiode and the scintillator, e.g. optical couplings using adhesives with wavelength-shifting fibres
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/16—Measuring radiation intensity
    • G01T1/20—Measuring radiation intensity with scintillation detectors
    • G01T1/2018—Scintillation-photodiode combinations
    • G01T1/20188—Auxiliary details, e.g. casings or cooling
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/16—Measuring radiation intensity
    • G01T1/20—Measuring radiation intensity with scintillation detectors
    • G01T1/2018—Scintillation-photodiode combinations
    • G01T1/20188—Auxiliary details, e.g. casings or cooling
    • G01T1/2019—Shielding against direct hits
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2223/00—Investigating materials by wave or particle radiation
    • G01N2223/40—Imaging
    • G01N2223/407—Imaging stimulable phosphor sheet
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2223/00—Investigating materials by wave or particle radiation
    • G01N2223/40—Imaging
    • G01N2223/413—Imaging sensor array [CCD]
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2223/00—Investigating materials by wave or particle radiation
    • G01N2223/60—Specific applications or type of materials
    • G01N2223/628—Specific applications or type of materials tubes, pipes
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2223/00—Investigating materials by wave or particle radiation
    • G01N2223/60—Specific applications or type of materials
    • G01N2223/631—Specific applications or type of materials large structures, walls
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2223/00—Investigating materials by wave or particle radiation
    • G01N2223/60—Specific applications or type of materials
    • G01N2223/645—Specific applications or type of materials quality control

Landscapes

  • Health & Medical Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Molecular Biology (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Multimedia (AREA)
  • Engineering & Computer Science (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Radiology & Medical Imaging (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)

Abstract

A radioscopic inspection system which comprises an X-ray sensitive phosphorescent screen 12, a photodiode array 22, and optical means for transferring an image from the screen on to the photodiode array 22. The optical means comprises a lens system 18 and a reflector 16 between the screen and the lens system. The inspection system provides X-ray images in near real time of a quality at least equivalent to conventional X-ray film techniques. The photodiode array 22 is shielded from scattered X-rays by a lead-glass element 20 and cooled by a cooling circuit. <IMAGE>

Description

An inspection system This invention relates to an inspection system, and more particularly to a radioscopic inspection system.
In known radioscopic inspection systems the resultant images are usually of low resolution and relatively poor dynamic range with the images degraded by system noise, distortion, and artefacts caused by blur and detector overload.
It is an object of the present invention to provide radioscopic inspection of improved quality in near real time of work pieces.
According to one aspect of the present invention there is provided a radioscopic inspection system, the system comprising an X-ray sensitive phosphorescent screen, a photodiode array, and optical means for transferring an image from the screen on to the photodiode array.
Preferably, the optical means comprises a lens system, and may include a reflector between the screen and the lens system.
The invention will now be further described by way of example only with reference to the single Figure in the accompanying drawing which shows a medial sectional view of a radioscopic inspection system.
Referring to the Figure, an inspection system 10 is shown and comprises a casing 11 containing a phosphorescent screen 12 behind a thin cover plate 14 of a material of low X-ray absorption, such as aluminium, mica, beryllium, etc. A lead-glass front-silvered mirror 16 is positioned at about 450 to the screen 12 so as to reflect images from the screen 12 on to an optical lens system 18. The system 18 is able to provide a very high resolution at a wide numeric aperture, and includes an integral lead-glass element 20 to shield an array of photodiodes 22 from scattered X-rays. A central motorised iris assembly 24 alters the numeric aperture of the optical lens system 18. The array of photodiodes 22 is cooled by a conventional circuit (not shown) to reduce dark current to a minimum, for example by use of a double Peltier cooling stack from which heat is removed by a water cooling circuit.Focusing of the system 10 is achieved by an adjustment screw 28 connected at one end to a plate 30 joined by several rods 32 (only one is shown) to a housing 34 for the photodiodes 22 and the lead glass element 20. The screw 28 extends through an end plate 35 of a sleeve 36 in which the casing 11 extends, the space between the casing 11 and the sleeve 36 being filled with lead shielding 37. A pin 38 at a hollow spigot portion 39 of the housing 34 locates in a slot 40 of a hollow spigot 42 from the lens system 18 and in which the spigot portion 39 slidably locates.
In use of the inspection system 10, a radiographic image of a workpiece (not shown) is formed by X-ray irradiation. The resultant shadowgraph image is detected by the screen 12, reflected by the mirror 16 to the lens system 18, from which the image is transmitted to the photodiodes 22. After a sufficient period of photon counting from the photodiodes 22 has occurred, the X-ray irradiation is stopped, and the photodiodes 22 read sequentially into a frame memory card mounted within a personal computer. Using a slow read out rate, data is digitised to sixteen bits and displayed. Typical dynamic ranges exceed 30,000:1. A resolution of the order of 50 microns has been achieved over a 35mm diagnostic length.
In one application of the invention a 1152 x 770 pixel array of photodiodes 22 has been used, but fewer or larger numbers of photodiodes 22 may also be used.
When the photodiodes 22 are cooled to sub-zero temperatures by the cooling circuit, substantially noise free images are obtained unaffected by photodiode dark current thus enabling photon counting of X-ray scintillations to take place over considerable periods of time.
The inspection system provides X-ray images in near real time of a quality at least equivalent to conventional X-ray film techniques and is capable of detecting defects to nuclear construction acceptance standards. The inspection system may be specifically used for Class I applications where images equal to or better than grain film radiography are required.
In a typical application, using suitable scanning arrangements and fixtures, the inspection system may be used to inspect critical weldments of circumferential and longitudinal geometries and small bore pipework.
Indeed, the inspection system is particularly well suited for the inspection of workpieces such as small bore tubing, ordnance components and aerospace parts.

Claims (7)

Claims
1. A radioscopic inspection system, the system comprising an X-ray sensitive phosphorescent screen, a photodiode array, and optical means for transferring an image from the screen on to the photodiode array.
2. A system as in Claim 1 and wherein the optical means comprises a lens system, and a reflector between the screen and the lens system.
3. A system as in Claim 1 and wherein the photodiode array is shielded from scattered X-rays by a lead-glass element
4. A system as in Claim 1 or Claim 3 and wherein the photodiode array is cooled by a cooling circuit.
5. A system as in Claim 4 and wherein the cooling circuit comprises a double Peltier cooling stack from which heat is removed by a water cooling circuit.
6. A system as in Claim 4 and wherein the photodiode array is cooled to below 0 Centigrade.
7. A system substantially as hereinbefore described with reference to the accompanying drawing.
GB9319490A 1992-09-18 1993-09-17 An inspection system Expired - Fee Related GB2270825B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB929219727A GB9219727D0 (en) 1992-09-18 1992-09-18 An inspection system

Publications (3)

Publication Number Publication Date
GB9319490D0 GB9319490D0 (en) 1993-11-03
GB2270825A true GB2270825A (en) 1994-03-23
GB2270825B GB2270825B (en) 1996-07-03

Family

ID=10722100

Family Applications (2)

Application Number Title Priority Date Filing Date
GB929219727A Pending GB9219727D0 (en) 1992-09-18 1992-09-18 An inspection system
GB9319490A Expired - Fee Related GB2270825B (en) 1992-09-18 1993-09-17 An inspection system

Family Applications Before (1)

Application Number Title Priority Date Filing Date
GB929219727A Pending GB9219727D0 (en) 1992-09-18 1992-09-18 An inspection system

Country Status (1)

Country Link
GB (2) GB9219727D0 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10015264A1 (en) * 2000-03-28 2001-10-11 Siemens Ag X-ray diagnostic device with an X-ray image converter with a combined rear light dose measuring unit
EP1462054A3 (en) * 2003-03-25 2004-10-06 Canon Kabushiki Kaisha Radiographic apparatus
EP1707990A3 (en) * 2005-03-17 2011-03-02 E2V Technologies (UK) Limited X-ray sensor
CN102243433A (en) * 2011-06-28 2011-11-16 中国原子能科学研究院 High-speed neutron camera device

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2167279A (en) * 1984-11-15 1986-05-21 Ian Redmayne Radiation imaging
EP0489906A1 (en) * 1990-07-02 1992-06-17 Varian Associates APPARATUS WITH ELECTRONICALLY IMPROVED X-RAY DETECTION.

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL139433B (en) * 1966-01-25 1973-07-16 Optische Ind De Oude Delft Nv ROENTGENTELEVISION CAMERA.
EP0226661B1 (en) * 1985-12-24 1995-02-22 Loral Vought Systems Corporation Radiographic inspection means and method
SE8404741L (en) * 1984-09-21 1985-05-13 Stig Dahn DEVICE AT AN INSTALLATION FOR LIGHTING OF OBJECTS
GB2196219A (en) * 1986-10-11 1988-04-20 Astromed Ltd Imaging of light-opaque specimens by transmission of radiation therethrough
NL8801946A (en) * 1988-08-04 1990-03-01 Philips Nv ROENTGEN IMAGE SYSTEM.
US5138642A (en) * 1989-03-02 1992-08-11 Innovative Imaging Systems, Inc. Detector imaging arrangement for an industrial CT device

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2167279A (en) * 1984-11-15 1986-05-21 Ian Redmayne Radiation imaging
EP0489906A1 (en) * 1990-07-02 1992-06-17 Varian Associates APPARATUS WITH ELECTRONICALLY IMPROVED X-RAY DETECTION.

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10015264A1 (en) * 2000-03-28 2001-10-11 Siemens Ag X-ray diagnostic device with an X-ray image converter with a combined rear light dose measuring unit
US6359966B2 (en) 2000-03-28 2002-03-19 Siemens Aktiengesellschaft X-ray diagnostic installation having an X-ray image converter with combined back light/dose measuring unit
DE10015264C2 (en) * 2000-03-28 2002-06-13 Siemens Ag X-ray diagnostic device with an X-ray image converter with a combined rear light dose measuring unit
EP1462054A3 (en) * 2003-03-25 2004-10-06 Canon Kabushiki Kaisha Radiographic apparatus
US7053378B2 (en) 2003-03-25 2006-05-30 Canon Kabushiki Kaisha Radiographic apparatus
EP1707990A3 (en) * 2005-03-17 2011-03-02 E2V Technologies (UK) Limited X-ray sensor
CN102243433A (en) * 2011-06-28 2011-11-16 中国原子能科学研究院 High-speed neutron camera device

Also Published As

Publication number Publication date
GB9219727D0 (en) 1992-10-28
GB2270825B (en) 1996-07-03
GB9319490D0 (en) 1993-11-03

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Legal Events

Date Code Title Description
732E Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977)
PCNP Patent ceased through non-payment of renewal fee

Effective date: 20110917