GB2167279A - Radiation imaging - Google Patents

Radiation imaging Download PDF

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Publication number
GB2167279A
GB2167279A GB08428842A GB8428842A GB2167279A GB 2167279 A GB2167279 A GB 2167279A GB 08428842 A GB08428842 A GB 08428842A GB 8428842 A GB8428842 A GB 8428842A GB 2167279 A GB2167279 A GB 2167279A
Authority
GB
United Kingdom
Prior art keywords
detector
radiation
array
scintillation elements
sheet
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.)
Withdrawn
Application number
GB08428842A
Other versions
GB8428842D0 (en
Inventor
Ian Redmayne
Original Assignee
Ian Redmayne
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 Ian Redmayne filed Critical Ian Redmayne
Priority to GB08428842A priority Critical patent/GB2167279A/en
Publication of GB8428842D0 publication Critical patent/GB8428842D0/en
Publication of GB2167279A publication Critical patent/GB2167279A/en
Application status is Withdrawn legal-status Critical

Links

Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01TMEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/16Measuring radiation intensity
    • G01T1/20Measuring radiation intensity with scintillation detectors
    • G01T1/2018Scintillation-photodiode combination
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01TMEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/16Measuring radiation intensity
    • G01T1/20Measuring radiation intensity with scintillation detectors
    • G01T1/202Measuring radiation intensity with scintillation detectors the detector being a crystal
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01TMEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/29Measurement performed on radiation beams, e.g. position or section of the beam; Measurement of spatial distribution of radiation
    • G01T1/2914Measurement of spatial distribution of radiation
    • G01T1/2921Static instruments for imaging the distribution of radioactivity in one or two dimensions; Radio-isotope cameras

Abstract

A detector 1 for the detection of radiation such as X-ray radiation comprises an array of scintillation elements 4 embedded in a sheet 2 of radiation absorbing material. The scintillation elements 4 are monitored individually, for example by a corresponding array of photodiodes, to build up a picture of the incident radiation. The front face of the sheet and the inner walls of the bores 3 may be coated with a reflective material. The detector finds particular application in weld radiography. The detector may be stepped relative to the radiation source, the signals produced by the rows of the detector as they pass a predetermined point being summed. <IMAGE>

Description

SPECIFICATION Radiation imaging This invention relates to radiation imaging systems, in particular X-ray radiation, and aims to provide an improved detector for the detection of X-rays. The invention finds particular application in the detection of X-rays transmitted through pipe walls or the like when inspecting welds, allowing for real-time radiography of the welds.

GB-A-1570310 discloses a system in which an X-ray source is positioned inside a pipe to be tested and X-rays transmitted through the pipe wall are detected on a fluorescent screen which is scanned by a video camera to produce a real time display. The display may be stored, and still pictures may also be taken of the fluorescent screen. This system has a number of drawbacks in that it does not lend itself readily to image enhancement techniques or storage of the screen display for analysis, and sympathetic fluorescence in the screen itself limits resolution.

The present invention provides a detector for the detection of radiation such as X-ray radiation comprising an array of scintillation elements. It will be appreciated that the invention is applicable to the detection of any type of radiation utilising a scintillator.

The scintillation elements may be monitored by respective photodiodes. The output frequency of the elements is preferably matched to the peak response of the diodes.

The scintillation elements may be embedded in a sheet of radiation-absorbent material isolating the elements and forming a screen. The front surface of the screen is preferably covered by a thin opaque film of reflective material.

Each element in the screen may be optically coupled to its respective photodiode directly, by a lens or mirror system or by fibre optics etc. As an alternative to a photodiode array the light emitted by the elements may be recorded with a T.V. or film camera etc.

Particularly where a photodiode array is used the output may be digitised to enable immediate storage, retrieval and manipulation using digital image display and processing techniques.

A one or two dimensional array may be used. Where a two dimensional array is used, the array may be stepped through the radiation beam, the response of each row or group of rows elements as they pass a particular point in the subject being summed to produce a time averaged image which will have a reduced noise component and reduced systematic errors arising from differences in the response of the different elements.

A square array may be used. However a hexagonal array will allow for closer packing and in effect overlapping of the elements where the array is stepped through a beam, the alternate rows in the array being summed.

The invention will be further described by way of example with reference to the accompanying drawings, in which, Figure 1 is a perspective view, partly cut away, of a detector according to one form of the invention; and Figure 2 is a plan view of the detector of Fig. 1.

A detector 1 comprises a thin sheet 2 of radiation absorbent material such as gold or lead.

The sheet 2 is perforated with a regular array of discrete through holes 3 which are each filled with a scintillation material such as Cadmium Sulphide (Silver doped) or Sodium lodide, forming a scintillation element 4. The type of material used may be varied according to the manner of detecting the light output from the array, for example to produce an output wavelength matched to the peak response of a particular photodiode, T.V. or other system (not shown).

The thickness of the material and the size and spacing of the holes may be chosen to suit a particular application, depending in particular on the resolution required.

The aspect ratio of the scintillators: diameter (d)/thickness (t) is chosen to optimise the response to direct, image forming radiation, and to minimise the effects of scattered radiation.

The front surface of the screen, facing the incident radiation, is coated with a thin opaque film of reflective material and the inside wall of each hole 3 is also made highly reflective.

Typical dimensions for the scintillation elements and the screen are as follows: Screen Element Width Length Diameter Depth Grid Size Application /mm /mm /#m /Am Ijim 1 10 40 500 50 Small Bore Pipework 4 40 160 1000 200 Large Bore Pipework 200 300 400 500 500 Medical, Large Castings The grid size is the centre to centre spacing of adjacent elements on a square array. As mentioned other arrays may be used, for example a hexagonal array. It can be seen that the resolution of the detector will depend on the size and spacing of the elements. The typical overall dimensions may of course be varied, but will be limited in part by the control system required to monitor a large number elements.

The array is preferably monitored by an assembly of photodiodes, each optically coupled to a respective element. This assembly may be self scanning, feeding its output directly or via a channel plate amplifier to a short term integrating store and then into a digital frame store or via an analogue to digital converter so that the frame store has a digital record of the image intensity, the Z dimension in the X-Y position in the element array. Standard digital image processing and display techniques may then be used on the stored data.

By carefully choosing the aspect ratio (d/t) and orientation of the elements the screen may be made preferentially responsive to direct image forming radiation. Discrimination of the diode output voltage may also be used to enhance the direct/scattered radiation response.

The screens 2, containing the elements 4, may be formed as replaceable units in a detector, to allow changing of screens to suit different radiation patterns and geometries.

Advantages may be gained by reducing the spread of the radiation beam to match the size of the detector, reducing the amount of scatter. The detector and radiation source may be moved or stepped around the subject to build up a complete image.

Arrays may be coupled side by side to cover larger areas.

The detector may be formed by cutting or slicing a crystal of Sodium lodide into thin sheets of thickness equal to the required element diameter or width and then forming a laminate with an absorbent material such as Gold. The Laminate is then sliced, transverse to the laminated sheets, and the slices reformed into a laminate with further sheets of absorbent material to form a grid as shown, but with square cross section scintillation elements.

Claims (9)

1. A detector for the detection of X-ray radiation, comprising an array of discrete scintillation elements.
2. A detector as claimed in claim 1, comprising a two dimensional array of scintillation elements.
3. A detector as claimed in claim 1 or 2, wherein the scintillation elements are monitored by a corresponding array of photodiodes.
4. A detector as claimed in claim 1, 2 or 3 wherein the scintillation elements are embedded in a sheet of radiation absorbing material.
5. A detector as claimed in claim 4, wherein a front surface of the sheet of material has an X-ray transparent, reflective coating.
6. A detector for the detector of X-ray radiation, substantially as hereinbefore described with reference to the accompanying drawings.
7. Apparatus for weld radiography, including a detector as claimed in claim 1.
8. A method of radiation imaging, comprising illuminating an object to be imaged with radiation and detecting the transmitted radiation with a detector as defined in claim 1.
9. A method as claimed in claim 8, wherein the detector is stepped relative to the incident radiation and signals generated by each row of the array as they pass a predetermined point are summed.
GB08428842A 1984-11-15 1984-11-15 Radiation imaging Withdrawn GB2167279A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08428842A GB2167279A (en) 1984-11-15 1984-11-15 Radiation imaging

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB08428842A GB2167279A (en) 1984-11-15 1984-11-15 Radiation imaging

Publications (2)

Publication Number Publication Date
GB8428842D0 GB8428842D0 (en) 1984-12-27
GB2167279A true GB2167279A (en) 1986-05-21

Family

ID=10569752

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08428842A Withdrawn GB2167279A (en) 1984-11-15 1984-11-15 Radiation imaging

Country Status (1)

Country Link
GB (1) GB2167279A (en)

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2204769A (en) * 1987-05-14 1988-11-16 Hamamatsu Photonics Kk Position-sensitive radiation detector
WO1989012838A1 (en) * 1988-06-17 1989-12-28 Wallac Oy Sample plate liquid scintillation counter
WO1990002960A1 (en) * 1988-09-06 1990-03-22 Wallac Oy An apparatus for monitoring the radioactivity of a plurality of liquid scintillation samples deposited on multi-well sample plates
WO1990006526A1 (en) * 1988-12-02 1990-06-14 Wallac Oy Method for the correction of an error caused by variations in the sample volume in a liquid scintillation counter
EP0397600A1 (en) * 1989-05-11 1990-11-14 Ciba-Geigy Ag Method and apparatus for measuring the radioactivity of samples
US4982095A (en) * 1987-09-04 1991-01-01 Hitachi, Ltd. Multi-element type radiation detector
US4991969A (en) * 1988-04-26 1991-02-12 Mitsubishi Denki Kabushiki Kaisha Method for measuring film thickness
EP0423030A1 (en) * 1989-10-12 1991-04-17 Commissariat A L'energie Atomique Radioluminescent screen with improved quality factor and spatial resolution for imaging X- or gamma-photons
US5030828A (en) * 1990-06-25 1991-07-09 Grumman Aerospace Corporation Recessed element photosensitive detector array with optical isolation
GB2270825A (en) * 1992-09-18 1994-03-23 British Nuclear Fuels Plc An inspection system
EP0589691A2 (en) * 1992-09-23 1994-03-30 Wallac Oy Preventing optical crosstalk between liquid scintillation samples in translucent sample plates
US5382798A (en) * 1991-02-11 1995-01-17 Mouyen; Francis Ionizing radiation sensor used in a system of radiographic imaging
NL1007593C2 (en) * 1996-11-21 1998-10-20 Mitsubishi Electric Corp An apparatus for measuring a radiation dose, and deep corpuscular beam detector.
WO1999028764A1 (en) * 1997-11-28 1999-06-10 Nanocrystal Imaging Corporation Composite nanophosphor screen for detecting radiation
US5952665A (en) * 1997-11-28 1999-09-14 Nanocrystals Technology L.P. Composite nanophosphor screen for detecting radiation
WO2000025151A1 (en) * 1998-10-28 2000-05-04 Koninklijke Philips Electronics N.V. Method of manufacturing a layered scintillation detector
EP1037010A2 (en) * 1999-03-11 2000-09-20 Wallac Oy Method and arrangement for processing measurement data
WO2002033723A2 (en) * 2000-10-16 2002-04-25 Nanocrystal Imaging Corporation High resolution high output microchannel based radiation sensor
US6784432B2 (en) * 2000-11-27 2004-08-31 Koninklijke Philips Electronics N.V. X-ray detector module
EP2549298A2 (en) 2007-10-10 2013-01-23 Commissariat A L'energie Atomique Et Aux Energies Alternatives Large-format scintillator for an imaging device, scintillator module and method for manufacturing a scintillator

Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1120393A (en) * 1965-05-06 1968-07-17 Cole E K Ltd Improvements in or relating to radiation detectors
GB1380162A (en) * 1971-01-10 1975-01-08 Baird Atomic Europ Nv Radiation detection arrangements
GB1406685A (en) * 1972-12-13 1975-09-17 Baird Atomic Inc Sensing matrices for radioactivity-distribution detectors
GB1476450A (en) * 1973-10-30 1977-06-16 Thomson Csf Radiography apparatus
US4059765A (en) * 1975-04-24 1977-11-22 Japan Atomic Energy Research Institute Gamma-ray scintillation detector
GB1564385A (en) * 1977-03-24 1980-04-10 Emi Ltd Arrangements for detecting ionising radiation
GB2034148A (en) * 1978-08-30 1980-05-29 Gen Electric Multi element, high resolution scintillator structure
GB1585364A (en) * 1976-05-19 1981-03-04 Philips Nv Device for measuring the absorption of radiation in a body section
GB2061055A (en) * 1979-10-09 1981-05-07 Emi Ltd Imaging system
GB2072452A (en) * 1979-09-29 1981-09-30 Hitachi Medical Corp Apparatus for detecting locating of incident radiation
GB1603714A (en) * 1978-04-26 1981-11-25 Galileo Electro Optics Corp Devices for obtaining information about radiation sources
EP0089148A1 (en) * 1982-03-15 1983-09-21 The Board Of Trustees Of The Leland Stanford Junior University Multiple line detector for use in radiography
WO1983003683A1 (en) * 1982-04-18 1983-10-27 Koslow Techn Corp Large arrays of discrete ionizing radiation detectors multiplexed using fluorescent optical converters

Patent Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1120393A (en) * 1965-05-06 1968-07-17 Cole E K Ltd Improvements in or relating to radiation detectors
GB1380162A (en) * 1971-01-10 1975-01-08 Baird Atomic Europ Nv Radiation detection arrangements
GB1406685A (en) * 1972-12-13 1975-09-17 Baird Atomic Inc Sensing matrices for radioactivity-distribution detectors
GB1476450A (en) * 1973-10-30 1977-06-16 Thomson Csf Radiography apparatus
US4059765A (en) * 1975-04-24 1977-11-22 Japan Atomic Energy Research Institute Gamma-ray scintillation detector
GB1585364A (en) * 1976-05-19 1981-03-04 Philips Nv Device for measuring the absorption of radiation in a body section
GB1564385A (en) * 1977-03-24 1980-04-10 Emi Ltd Arrangements for detecting ionising radiation
GB1603714A (en) * 1978-04-26 1981-11-25 Galileo Electro Optics Corp Devices for obtaining information about radiation sources
GB2034148A (en) * 1978-08-30 1980-05-29 Gen Electric Multi element, high resolution scintillator structure
GB2072452A (en) * 1979-09-29 1981-09-30 Hitachi Medical Corp Apparatus for detecting locating of incident radiation
GB2061055A (en) * 1979-10-09 1981-05-07 Emi Ltd Imaging system
EP0089148A1 (en) * 1982-03-15 1983-09-21 The Board Of Trustees Of The Leland Stanford Junior University Multiple line detector for use in radiography
WO1983003683A1 (en) * 1982-04-18 1983-10-27 Koslow Techn Corp Large arrays of discrete ionizing radiation detectors multiplexed using fluorescent optical converters

Cited By (35)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4831263A (en) * 1987-05-14 1989-05-16 Hamamatsu Photonics Kabushiki Kaisha Position-sensitive radiation detector
GB2204769A (en) * 1987-05-14 1988-11-16 Hamamatsu Photonics Kk Position-sensitive radiation detector
GB2204769B (en) * 1987-05-14 1991-02-06 Hamamatsu Photonics Kk Position-sensitive radiation detector
US4982095A (en) * 1987-09-04 1991-01-01 Hitachi, Ltd. Multi-element type radiation detector
US4991969A (en) * 1988-04-26 1991-02-12 Mitsubishi Denki Kabushiki Kaisha Method for measuring film thickness
WO1989012838A1 (en) * 1988-06-17 1989-12-28 Wallac Oy Sample plate liquid scintillation counter
US5061853A (en) * 1988-06-17 1991-10-29 Wallac Oy Sample plate liquid scintillation counter
US5039860A (en) * 1988-09-06 1991-08-13 Wallac Oy Apparatus for monitoring the radioactivity of a plurality of liquid scintillation samples deposited on multi-well sample plates
WO1990002960A1 (en) * 1988-09-06 1990-03-22 Wallac Oy An apparatus for monitoring the radioactivity of a plurality of liquid scintillation samples deposited on multi-well sample plates
WO1990006526A1 (en) * 1988-12-02 1990-06-14 Wallac Oy Method for the correction of an error caused by variations in the sample volume in a liquid scintillation counter
EP0397600A1 (en) * 1989-05-11 1990-11-14 Ciba-Geigy Ag Method and apparatus for measuring the radioactivity of samples
US5043581A (en) * 1989-05-11 1991-08-27 Ciba-Geigy Corporation Method for measuring the radioactivity of samples and an apparatus for carrying out the method
FR2653262A1 (en) * 1989-10-12 1991-04-19 Commissariat Energie Atomique radioluminescent screen a quality factor and IMPROVED spatial resolution for imaging in x or gamma photons.
US5047642A (en) * 1989-10-12 1991-09-10 Commissariat A L'energie Atomique Radioluminescent screen with an improved quality factor and spatial resolution for X or gamma photon imaging
EP0423030A1 (en) * 1989-10-12 1991-04-17 Commissariat A L'energie Atomique Radioluminescent screen with improved quality factor and spatial resolution for imaging X- or gamma-photons
US5030828A (en) * 1990-06-25 1991-07-09 Grumman Aerospace Corporation Recessed element photosensitive detector array with optical isolation
US5382798A (en) * 1991-02-11 1995-01-17 Mouyen; Francis Ionizing radiation sensor used in a system of radiographic imaging
GB2270825B (en) * 1992-09-18 1996-07-03 British Nuclear Fuels Plc An inspection system
GB2270825A (en) * 1992-09-18 1994-03-23 British Nuclear Fuels Plc An inspection system
EP0589691A3 (en) * 1992-09-23 1995-12-06 Wallac Oy Preventing optical crosstalk between liquid scintillation samples in translucent sample plates
EP0589691A2 (en) * 1992-09-23 1994-03-30 Wallac Oy Preventing optical crosstalk between liquid scintillation samples in translucent sample plates
NL1007593C2 (en) * 1996-11-21 1998-10-20 Mitsubishi Electric Corp An apparatus for measuring a radiation dose, and deep corpuscular beam detector.
US6452184B1 (en) * 1997-11-28 2002-09-17 Nanocrystal Imaging Corp. Microchannel high resolution x-ray sensor having an integrated photomultiplier
US5952665A (en) * 1997-11-28 1999-09-14 Nanocrystals Technology L.P. Composite nanophosphor screen for detecting radiation
US6300640B1 (en) * 1997-11-28 2001-10-09 Nanocrystal Imaging Corporation Composite nanophosphor screen for detecting radiation having optically reflective coatings
WO1999028764A1 (en) * 1997-11-28 1999-06-10 Nanocrystal Imaging Corporation Composite nanophosphor screen for detecting radiation
US6534772B1 (en) * 1997-11-28 2003-03-18 Nanocrystal Imaging Corp. High resolution high output microchannel based radiation sensor
WO2000025151A1 (en) * 1998-10-28 2000-05-04 Koninklijke Philips Electronics N.V. Method of manufacturing a layered scintillation detector
EP1037010A2 (en) * 1999-03-11 2000-09-20 Wallac Oy Method and arrangement for processing measurement data
EP1037010A3 (en) * 1999-03-11 2001-11-07 Wallac Oy Method and arrangement for processing measurement data
WO2002033723A2 (en) * 2000-10-16 2002-04-25 Nanocrystal Imaging Corporation High resolution high output microchannel based radiation sensor
WO2002033723A3 (en) * 2000-10-16 2002-08-29 Nanocrystal Imaging Corp High resolution high output microchannel based radiation sensor
US6784432B2 (en) * 2000-11-27 2004-08-31 Koninklijke Philips Electronics N.V. X-ray detector module
EP2549298A2 (en) 2007-10-10 2013-01-23 Commissariat A L'energie Atomique Et Aux Energies Alternatives Large-format scintillator for an imaging device, scintillator module and method for manufacturing a scintillator
US8368026B2 (en) 2007-10-10 2013-02-05 Commissariat A L'energie Atomique Et Aux Energies Alternatives Scintillator for an imaging device, scintillator module, imaging device with such a scintillator and method of manufacturing a scintillator

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Publication number Publication date
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732 Registration of transactions, instruments or events in the register (sect. 32/1977)
WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)