EP0063083A1 - Röntgenstrahlungsdetektor - Google Patents

Röntgenstrahlungsdetektor Download PDF

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Publication number
EP0063083A1
EP0063083A1 EP82400629A EP82400629A EP0063083A1 EP 0063083 A1 EP0063083 A1 EP 0063083A1 EP 82400629 A EP82400629 A EP 82400629A EP 82400629 A EP82400629 A EP 82400629A EP 0063083 A1 EP0063083 A1 EP 0063083A1
Authority
EP
European Patent Office
Prior art keywords
electrodes
chamber
ionization
rays
plate
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
EP82400629A
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English (en)
French (fr)
Other versions
EP0063083B1 (de
Inventor
Robert Allemand
Jean-Jacques Gagelin
Edmond Tournier
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.)
Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Original Assignee
Commissariat a lEnergie Atomique CEA
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Publication date
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Publication of EP0063083A1 publication Critical patent/EP0063083A1/de
Application granted granted Critical
Publication of EP0063083B1 publication Critical patent/EP0063083B1/de
Expired legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J47/00—Tubes for determining the presence, intensity, density or energy of radiation or particles
    • H01J47/02—Ionisation chambers

Definitions

  • the present invention relates to an X-ray detector and in particular to X-rays which have passed through an object and / or an organ which are supplied by a source emitting towards the object or the organ, a plane beam of incident X-rays. with a wide angular opening and a small thickness.
  • This invention applies more particularly to the tomography of organs, but also to industrial control, such as baggage control for example.
  • X-ray detectors make it possible to measure the absorption of an X-ray beam passing through an object or an organ, this absorption being linked to the density of the tissues of the organ examined or the density of the materials constituting the object studied. .
  • this type of detector has significant drawbacks: it is possible to reduce the thickness of the plates in order to increase the quantity of X-rays detected, but to the detriment of collimation due to the small thickness of the plates; this small thickness of the plates also caused a very significant microphony.
  • detectors of this type have a great complexity of construction which leads to a high manufacturing cost and they require mounting in a dust-free room, because any dust on one of the plates, can cause an initiation or a deterioration of the leakage current. between two consecutive plates. It is added to these drawbacks that the numerous plates used require very numerous electrical connections, inside the sealed chamber, which poses difficult problems of reliability of the welds of the connections on the plates.
  • This other type of detector comprises a sealed chamber containing a gas ionizable by rays from the organ or object and, in this chamber, a plate for collecting the electrons resulting from the ionization of the gas; this plate is parallel the plane of the beam of incident rays and it is brought to a positive high voltage.
  • a series of electrodes for collecting the ions resulting from the ionization of the gas by the X-rays coming from the object is arranged in parallel and facing the preceding plate; these ion collection electrodes are brought to a potential close to 0 and are directed towards the source which emits the X-rays, in the direction of the object.
  • ion collection electrode defines an elementary cell of the detector. These electrodes are located in a plane parallel to the plane of the beam of the incident rays and respectively provide a current which is the sum, on the one hand of a measurement current proportional to the quantity of ions obtained by the ionization of the gas in sight of each electrode, under the effect of the rays coming from the object or the organ, in a direction corresponding to that of the incident rays and, on the other hand, of a diffusion current coming from the rays diffused by l 'object or by the organ, or in general by all the obstacles encountered by the incident rays, in directions other than that of the incident rays.
  • This type of detector has certain advantages: there are no longer, as in the detector mentioned above, separation plates; this eliminates any annoying phenomenon of microphony. Due to the removal of these separation plates, the quantity of X-rays detected is maximum; the realization of this type of detector is very simple and it is very little sensitive to dust.
  • This type of detector has however a serious drawback which results from the fact that the current collected on each of the electrodes brought to a potential close to O, comprises a parasitic current, which falsifies the measurements; this current is a diffusion current coming from the rays diffused in other very directions than that of the incident rays.
  • the charge collection electrodes of the main ionization chamber are carried by one of the faces of an electrically insulating plate, the charge collection plate of said chamber.
  • main ionization being brought to a second determined potential
  • the secondary ionization chamber containing the same ionizable gas as the main ionization chamber and comprising a series of charge collection electrodes carried by the other face of the electrically insulating plate , these electrodes being respectively connected to the electrodes of the main ionization chamber and being brought to the same second potential close to zero
  • the secondary ionization chamber further comprising a charge collection plate parallel to the electrically insulating plate, located at look at the electron collection electrodes and brought to a third potential of sign opposite to the first potential, the ionization of the g az in this secondary ionization chamber being produced by the X-rays scattered by the object.
  • the charge collection electrodes of the main chamber are respectively located opposite the charge collection electrodes of the secondary chamber.
  • the first and third potentials have the same absolute value.
  • the ionizable gas is xenon.
  • the electrodes for collecting ions and electrons from the main and secondary chambers consist of a deposit of copper on an insulating support.
  • Figure 1 shows schematically and in perspective, a known type of detector comprising a plate 1 brought to a positive high voltage + HT and, opposite, a series of electrodes 2 brought to a potential close to 0 volts.
  • This plate and these electrodes are located in a sealed main chamber 3, shown diagrammatically and which contains at least one ionizable gas, such as xenon for example.
  • This detector makes it possible to detect the X-rays which have passed through an object or an organ 0, these rays being supplied by a point source S which emits towards the object or the organ, a plane beam F of incident X-rays; this beam has a wide angular opening and a small thickness.
  • FIG. 3 shows schematically and in perspective, a detector according to the invention.
  • This detector comprises a sealed chamber 6 containing at least one ionizable gas such as xenon for example; this chamber is subdivided into two ionization chambers: a main ionization chamber 3 and a secondary ionization chamber 7.
  • the main ionization chamber 3 contains, like the detector of the type known in FIG.
  • the electrodes 2 of the main ionization chamber 3 respectively provide a current which is the sum on the one hand, of a measurement current proportional to the quantity of ions obtained by the ionization of the gas opposite each electrode of the main ionization chamber, under the effect of the rays coming from the object, in directions corresponding to that of the incident rays 9, and of a diffusion current resulting from the ionization of the gas by the rays scattered 8 by the object, in other directions than that of the incident rays.
  • the secondary ionization chamber 7 contains, like the main ionization chamber, a plate 10 parallel to the plane of the incident X-ray beam, which is brought to a negative high voltage -HT, as well as a series of electrodes 11 planes, parallel to the plane of the incident X-ray beam, located on another face of the insulating plate 4 which carries the electrodes 2 of the main ionization chamber 3.
  • These electrodes 11 are worn, like the. electrodes 2 of the main ionization chamber, at a potential close to O. They are respectively connected by connections 12, to the corresponding electrodes of the main ionization chamber 3.
  • the electrodes 11 of the secondary ionization chamber and the electrodes 2 of the main ionization chamber are preferably identical and located opposite one another.
  • the secondary ionization chamber 7 makes it possible, as will be seen in detail below, to compensate, for the subsequent treatment of the currents originating from the amplifiers 5, the parasitic currents which circulate in each electrode of the main ionization chamber and which originate X-rays scattered by the object, or the organ O.
  • the electrodes 11 of the secondary ionization chamber 7 are electrodes for collecting electrons e-, while plate 10 is a plate for collecting Xe + ions from of the xenon ionization contained in the secondary chamber 7, by the X-rays scattered by the object or the organ O.
  • the electrodes of the secondary ionization chamber are located opposite the electrodes of the chamber main ionization and positive and negative high voltages have the same absolute value.
  • FIG. 4 schematically represents a side view of the detector of the invention.
  • this view there is a point source S, the object or the organ O, one of the rays 9 emitted by the source S and, at the output of the object O, the direct ray 13 coming from the object 0, in the same direction as the incident ray 9; one also distinguishes in this figure one of the scattered rays 8, coming from the object 0, in a direction different from the direction of the incident ray 9.
  • This ionization is represented schematically in the figure, by Xe + ions which are attracted by the electrodes 2, and by e- electrons which are attracted by the positive plate 1.
  • An ionization thus occurs opposite each of the electrodes of the chamber main ionization thanks to X-rays from the object, in the direction of the incident rays.
  • the ionization chamber 7 makes it possible to compensate for this "diffusion current", thanks to to the ionization produced in this chamber, the scattered X-rays 8; this ionization causes the circulation, in the electrodes 11 of the secondary chamber, of a current 1 D which is cut off, thanks to the connection 12, from the parasitic "diffusion current” taken into account by the electrodes of the main ionization.
  • the amplifiers 5 connected to each of the electrodes of the main and secondary ionization chambers receive a current I M which is effectively the measurement current corresponding to the ionization of the gas, caused opposite each of the electrodes of the chamber d main ionization by the rays 13 coming from the object or the organ in the directions which correspond to those of the incident rays 9.
  • the plates and electrodes of the main and secondary ionization chambers are preferably produced in the form of a copper deposit on an insulating support.

Landscapes

  • Measurement Of Radiation (AREA)
  • Electron Tubes For Measurement (AREA)
  • Apparatus For Radiation Diagnosis (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)
EP82400629A 1981-04-15 1982-04-06 Röntgenstrahlungsdetektor Expired EP0063083B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8107568A FR2504278B1 (fr) 1981-04-15 1981-04-15 Detecteur de rayons x
FR8107568 1981-04-15

Publications (2)

Publication Number Publication Date
EP0063083A1 true EP0063083A1 (de) 1982-10-20
EP0063083B1 EP0063083B1 (de) 1985-08-28

Family

ID=9257430

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82400629A Expired EP0063083B1 (de) 1981-04-15 1982-04-06 Röntgenstrahlungsdetektor

Country Status (5)

Country Link
US (1) US4469947A (de)
EP (1) EP0063083B1 (de)
JP (1) JPS57179776A (de)
DE (1) DE3265745D1 (de)
FR (1) FR2504278B1 (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2570908A1 (fr) * 1984-09-24 1986-03-28 Commissariat Energie Atomique Systeme de traitement des signaux electriques issus d'un detecteur de rayons x
EP0334750A1 (de) * 1988-03-23 1989-09-27 Commissariat A L'energie Atomique Detektoranordnung für die Tomographie mittels ionisierender Strahlungen
DE3901837A1 (de) * 1989-01-23 1990-07-26 H J Dr Besch Bildgebender strahlendetektor mit pulsintegration

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5072123A (en) * 1990-05-03 1991-12-10 Varian Associates, Inc. Method of measuring total ionization current in a segmented ionization chamber
SE513161C2 (sv) * 1997-11-03 2000-07-17 Digiray Ab En metod och en anordning för radiografi med plant strålknippe och en strålningsdetektor
SE514460C2 (sv) * 1999-04-14 2001-02-26 Xcounter Ab Förfarande för detektering av joniserande strålning, strålningsdetektor och anordning för användning vid radiografi med plant strålknippe
SE514475C2 (sv) * 1999-04-14 2001-02-26 Xcounter Ab Strålningsdetektor, en anordning för användning vid radiografi med plant strålknippe och ett förfarande för detektering av joniserande strålning
SE514443C2 (sv) * 1999-04-14 2001-02-26 Xcounter Ab Strålningsdetektor och en anordning för användning vid radiografi med plant strålknippe
SE514472C2 (sv) * 1999-04-14 2001-02-26 Xcounter Ab Strålningsdetektor och en anordning för användning vid radiografi
SE0000793L (sv) * 2000-03-07 2001-09-08 Xcounter Ab Tomografianordning och -förfarande
WO2012000847A2 (fr) * 2010-07-01 2012-01-05 Thomson Licensing Procede d'estimation de diffusion de la lumiere

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4047041A (en) * 1976-04-19 1977-09-06 General Electric Company X-ray detector array
GB1598962A (en) * 1978-03-21 1981-09-30 Siemens Ag Arrangement for detecting radiation

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3812362A (en) * 1973-07-02 1974-05-21 Honeywell Inc Smoke detector circuit
FR2249517B1 (de) * 1973-10-30 1976-10-01 Thomson Csf
US4031396A (en) * 1975-02-28 1977-06-21 General Electric Company X-ray detector
FR2314699A1 (fr) * 1975-06-19 1977-01-14 Commissariat Energie Atomique Dispositif d'analyse pour tomographie a rayons x par transmission
DE2642846A1 (de) * 1976-09-23 1978-03-30 Siemens Ag Roentgenschichtgeraet zur herstellung von transversalschichtbildern
DE2707409C2 (de) * 1977-02-21 1985-02-21 Hartwig Dipl.-Ing. 2409 Scharbeutz Beyersdorf Ionisationsbrandmelder
JPS54131881U (de) * 1978-03-06 1979-09-12
FR2469797A1 (fr) * 1979-11-14 1981-05-22 Radiologie Cie Gle Detecteur a ionisation gazeuse et tomodensitometre utilisant un tel detecteur

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4047041A (en) * 1976-04-19 1977-09-06 General Electric Company X-ray detector array
GB1598962A (en) * 1978-03-21 1981-09-30 Siemens Ag Arrangement for detecting radiation

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2570908A1 (fr) * 1984-09-24 1986-03-28 Commissariat Energie Atomique Systeme de traitement des signaux electriques issus d'un detecteur de rayons x
EP0334750A1 (de) * 1988-03-23 1989-09-27 Commissariat A L'energie Atomique Detektoranordnung für die Tomographie mittels ionisierender Strahlungen
FR2629215A1 (fr) * 1988-03-23 1989-09-29 Commissariat Energie Atomique Ensemble de detection pour tomographie a rayonnements ionisants
US5018175A (en) * 1988-03-23 1991-05-21 Commissariat A L'energie Atomique Detection array for ionizing radiation tomography
DE3901837A1 (de) * 1989-01-23 1990-07-26 H J Dr Besch Bildgebender strahlendetektor mit pulsintegration

Also Published As

Publication number Publication date
JPS57179776A (en) 1982-11-05
US4469947A (en) 1984-09-04
EP0063083B1 (de) 1985-08-28
FR2504278B1 (fr) 1985-11-08
DE3265745D1 (en) 1985-10-03
JPH0335634B2 (de) 1991-05-28
FR2504278A1 (fr) 1982-10-22

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