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EP0099300B1 - Ionisationskammer zur Messung von hochenergetischen Gammastrahlungen - Google Patents

Ionisationskammer zur Messung von hochenergetischen Gammastrahlungen Download PDF

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Publication number
EP0099300B1
EP0099300B1 EP83401423A EP83401423A EP0099300B1 EP 0099300 B1 EP0099300 B1 EP 0099300B1 EP 83401423 A EP83401423 A EP 83401423A EP 83401423 A EP83401423 A EP 83401423A EP 0099300 B1 EP0099300 B1 EP 0099300B1
Authority
EP
European Patent Office
Prior art keywords
cylinders
enclosure
ionization chamber
chamber according
perforated
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.)
Expired
Application number
EP83401423A
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English (en)
French (fr)
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EP0099300A1 (de
Inventor
François Cliquet
Pierre Boulay
Jean Duchene
Marc Merelli
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.)
Areva NP SAS
Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Original Assignee
Commissariat a lEnergie Atomique CEA
Framatome SA
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 Commissariat a lEnergie Atomique CEA, Framatome SA filed Critical Commissariat a lEnergie Atomique CEA
Publication of EP0099300A1 publication Critical patent/EP0099300A1/de
Application granted granted Critical
Publication of EP0099300B1 publication Critical patent/EP0099300B1/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 ionization chamber for measuring gamma radiation of high energy. It allows in particular to measure gamma rays whose energy is close to 6 MeV. Such gamma radiation is emitted in particular by the nitrogen 16 induced, by nuclear reactions, in the water of the tank of a pressurized water reactor. The measurement of these gamma rays, and therefore of the quantity of nitrogen 16 formed, is one of the means used to know the power of a reactor and to determine the speed and the flow rate of the fluid circulating in the primary circuit of the reactor. .
  • an ionization chamber comprises a sealed enclosure, filled with an ionizable gas, and one or more electrodes making it possible to create an electric field inside the enclosure.
  • an ionization chamber When nuclear radiation crosses the gas in the chamber, it becomes ionized.
  • the charges produced undergo, in the direction of the field, a drive which is superimposed on their thermal agitation. This entrainment of the charges and in particular of the ions formed makes it possible to induce, through the electrodes, a so-called ionization current which is measured.
  • the object of the present invention is precisely an ionization chamber for the measurement of high energy gamma radiation making it possible to remedy this drawback.
  • the ionization chamber according to the invention has all the other characteristics mentioned above.
  • the invention relates to an ionization chamber for measuring high energy gamma radiation, comprising, as described in document FR-A 2 425 147, a sealed cylindrical enclosure containing an ionizable gas, and two coaxial cylindrical electrodes isolated from each other, located inside the enclosure and brought to different potentials so as to create an electric field in the enclosure, the outermost electrode being formed of a tube with non-perforated wall;
  • this chamber is characterized in that the electrodes each consist of a plurality of coaxial cylinders and in that the non-extreme cylinders are formed from a tube with a perforated wall.
  • the ionization chamber has five cylinders.
  • the cylinders with a perforated wall have a transparency of between 30 and 40%. This transparency makes it possible to optimize the ionization current induced in the chamber.
  • ionization chamber used for the detection of high energy photons, i.e. photons whose energy is greater than 1 MeV
  • most of the nuclear interactions Compton effect, materialization effect of a photon, i.e. production of a pair of electron-positron
  • induced current is produced in the walls of the enclosure and in the electrodes.
  • the thickness of the wall of the enclosure, as well as the material constituting this wall and the electrodes must be chosen as a function of the energy of the gamma rays to be measured.
  • the detection of gamma radiation having an energy close to 6 MeV is carried out using an enclosure whose thickness is between 3 and 4 mm, preferably made of stainless steel.
  • the electrodes can be made of stainless steel, the intermediate cylinders each consisting of perforated steel sheets, rolled and welded together.
  • the induced ionization current depends on the nature and on the pressure of the gas, it is preferable to use a contained gas. 98 to 99% by weight of xenon and having, for example, a pressure between 8.8 and 9.2 bars absolute.
  • the different electrodes have gaps between them such that the electric field is uniform throughout the enclosure. Obtaining in an electric field having the same intensity throughout the enclosure makes it possible to ensure a good collection of the ions formed as well as to optimize the bandwidth of the chamber.
  • one of the ends of the electrodes is fixed and the other end is held in position by first elastic means allowing axial displacement and by second elastic means allowing a radial displacement.
  • the ionization chamber according to the invention may include third elastic means acting axially and only on said other end of the intermediate electrodes.
  • FIG. 1 there is shown the block diagram of the ionization chamber according to the invention.
  • This ionization chamber comprises a sealed cylindrical enclosure 2 having an axis of revolution 3 and consisting of a ferrule 4 closed respectively at the two ends by a lower flange 6 and an upper flange 8. These flanges 6 and 8, being supported on shoulders 9 of the shell 4 are welded to said shell by means of welds such as 10.
  • the sealed enclosure 2 is filled with an ionizable gas which can be introduced into the enclosure by means of a socket 12, sealed after filling of the enclosure.
  • the ionization chamber also comprises cylindrical electrodes 14 arranged coaxially in the enclosure 2 along the axis 3 of said enclosure.
  • the electrodes 14a, 14c and 14e are electrically connected to each other by means of a conductive part 18 connected, by means of a plug 20 passing through the flange 8, to the high voltage (HT).
  • This plug 20 is isolated from the flange 8 by means of an insulator 22 which is not very sensitive to temperature variations such as soapstone.
  • the electrodes 14b and 14d are electrically connected to each other by means of a conductive part 24 and connected, by means of a plug 26 passing through the piece 18 then the flange 8, to the outlet marked S.
  • This plug 26 is isolated from the part 18 and from the flange 8 by means of an insulator 28 which is not very sensitive to temperature variations such as soapstone.
  • the electrodes 14b and 14d are assigned to the collection of ions formed in the enclosure, during the passage of the ionization chamber by gamma radiation.
  • the external electrode 14a is formed from a tube with an unperforated wall
  • the intermediate cylinders 14b, 14c and 14d are formed from a tube comprising perforations 16
  • the central electrode 14e is formed from a full cylinder.
  • the transparency of the intermediate cylinders is between 30 and 40% and for example close to 32%. This transparency has been determined experimentally so as to optimize the ionization current as well as the slope of the current-voltage characteristic.
  • the ionization current depends on the nature of the ionizable gas as well as on its pressure.
  • the ionizable gas contains 98 to 99% by weight of xenon.
  • the gas may for example consist of 98% by weight of xenon and 2% by weight of nitrogen, when it is desired to detect gamma photons having an energy close to 6 MeV, such as those emitted by nitrogen 16 induced in the water of the tank of a pressurized water reactor.
  • the pressure of the gas is preferably chosen between 8.8 and 9.2 bar absolute.
  • the differences between the different electrodes 14 are chosen so as to obtain a uniform electric field throughout the enclosure. Indeed, it can be shown by a simple calculation that the electric field prevailing in a cylindrical volume comprised between two cylindrical electrodes, having a given potential difference, decreases as one approaches the external electrode. By using five cylinders spaced correctly, one can obtain a uniform electric field having an intensity of 2000 V / cm for a bias voltage (HV voltage) of 1100 V. It should be noted that for such a value of the bias voltage, the current-voltage curves in Figure 2 do show a zero slope.
  • HV voltage bias voltage
  • the thickness of the wall of the enclosure as well as the material constituting this wall and the electrodes must be chosen according to the energy of the gamma rays to be measured. .
  • an enclosure 2 made of stainless steel and having a thickness of between 3 and 4 mm and for example close to 3.5 mm. This thickness, determined to obtain a large number of nuclear interactions, is of course also determined to hold the high pressure of the gas filling the enclosure.
  • the electrodes can be made of stainless steel.
  • the intermediate cylinders can be produced in the form of perforated stainless steel sheets, rolled and welded together. It should be noted that intermediate cylinders made up of perforated steel sheets have a mechanical rigidity greater than the electrodes produced in the form of a grid used in certain ionization chambers of the prior art. This makes it possible to contribute to the robustness of the chamber of the invention and to its lifespan.
  • FIG. 3 there is shown an embodiment of the ionization chamber according to the invention.
  • This chamber comprises, as in the schematic diagram of FIG. 1, a cylindrical enclosure 2, containing an ionizable gas, formed of a ferrule 4 and two flanges 6 and 8 welded on the ferrule at its ends, a socket 12 of filling of the gas and five electrodes 14a, 14b, 14c, 14d and 14e corresponding respectively to the external electrode, to the three perforated intermediate electrodes and to the central electrode.
  • the ends of the cylinders 14a, 14c and 14e located near the flange 8 are supported by a cylindrical conductive plate 18a, corresponding to the part 18 of Figure 1, connected to the high voltage (HT ) by means of a form 20; the ends of the electrodes 14a and 14c are fitted into the plate 18a at the shoulder level such that 30 and the end of the electrode 14e is screwed into the plate 18a.
  • the plate 18a, pierced with an opening 34 to allow the passage of the gas inside the enclosure (arrow F), is fixed by means of screws such as 36 on a holding plate 38.
  • the holding plate 38 is fixed to the flange 8 by means of a system with key 42 making it possible to avoid rotation of the assembly and ensuring correct positioning of the connections to the high voltage and to the output S.
  • the ends of the cylinders 14b and 14d located near the flange 8 are integral with metal rings such as 44, mounted on insulating rings 46, themselves fitted into the plate 18a.
  • These insulating rings 46 make it possible to avoid any electrical contact between the electrode 14b, 14d and the electrode 14a, 14c, 14e.
  • the metal rings 44 are connected, by means of plugs 48, passing through the insulating rings 46, to a metal part 24a, corresponding to the part 24 of FIG. 1.
  • This part 24a which is mounted in an insulating block 49 fitted together in the holding plate 38 and the plate 18a, is connected by means of a plug 26 to the output marked S.
  • This block 49 makes it possible to avoid any
  • the ends of the cylinders 14a and 14c located near the flange 6 are fixed, by any known means, to a flange 50, by means of a plate 54, on a cylindrical piece 56 placed in contact with the flange 6.
  • the plate 54 is made integral with the part 56 by means of screws 58, isolated from said part 56 by means of insulating blocks 60.
  • springs such as 66, pressing on the internal surface of the shell 4 of the enclosure, by by means of a ball 68 stresses in compression radially the part 56 and consequently, the flange 50.
  • the ends of the perforated cylinders 14b and 14d located near the flange 6 are fitted into insulating rings 70 fitted into the flange 50.
  • the end of the perforated cylinder 14c located on the side of the flange 6 is fitted into a ring metal 72 mounted on the flange 50.
  • the insulating rings 70 and the metal ring 72 are stressed axially in compression by springs 74 bearing on the plate 54.
  • the good temperature resistance of the chamber is ensured by using as insulating material a material little sensitive to temperature variations such as soapstone.
  • the ionization chamber consists of an enclosure and five electrodes made of stainless steel insulated by statite.
  • the enclosure has an internal diameter of 63 mm, a thickness of 3.5 mm and a length of 300 mm.
  • the external electrode 14a is formed from a tube with a non-perforated wall 57 mm in internal diameter and 1 mm thick.
  • the central electrode 14e is formed from a solid cylinder 8 mm in diameter.
  • the useful volume for the detection of the chamber is 474 cm 3 for a total volume of 592 cm 3
  • the filling gas contains 98% by weight of xenon and 2% by weight of nitrogen.
  • the absolute pressure of the gas is 9 bars.
  • the average operating voltage is 1100V and the maximum operating voltage is 2000 V.
  • the electric field between the electrodes starting from the internal electrode for a bias voltage of 1000V is 2471 V / cm, 2088 V / cm, 1945V / cm and 2210 V / cm. It is therefore approximately uniform.
  • the theoretical sensitivity characterized by the intensity of the current delivered for a gamma photon flux, is 3.2.10- 7 A / Gy / h (3.210- 9 A / rad / h) for a gamma photon flux of 6 MeV , corresponding to a dose rate of 1 Gy / h (100 rad / h).
  • the bandwidth is from 0 to 140 Hz.
  • the characteristics of the ionization chamber are well suited to the detection of gamma photons having an energy of 6 MeV emitted by nitrogen 16, obtained by neutron activation of the oxygen 16 contained in the water. of the primary circuit of a pressurized water reactor.

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  • Measurement Of Radiation (AREA)
  • Electron Tubes For Measurement (AREA)

Claims (11)

1. lonisationskammer zur Messung von hochenergetischer Gammastrahlung mit einer dichten, zylindrischen Kammer (2), die ein ionisierbares Gas enthält, und zwei voneinander isolierten, koaxialen, zylindrischen Elektroden, die sich im Inneren der Kammer (2) befinden und zum Erzeugen eines elektrischen Feldes in der Kammer auf unterschiedliche Potentiale zu bringen sind, wobei die äusserste Elektrode (14a) aus einem Rohr mit einer lochfreien Wand gebildet ist, dadurch gekennzeichnet, dass jede der Elektroden von einer Vielzahl koaxialer Zylinder (14a, 14c, 14e und 14b, 14d) gebildet ist und dass die Zylinder (14b, 14c, 14d) zwischen dem innersten und äussersten Zylinder aus einem Rohr mit einer Öffnungen aufweisenden Wand gebildet sind.
2. lonisationskammer nach Anspruch 1, dadurch gekennzeichnet, dass die durchlöcherten Zylinder (14b, 14c, 14d) eine Durchlässigkeit zwischen 30 und 40% aufweisen.
3. lonisationskammer nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass die verschiedenen Zylinder (14a, 14b, 14c, 14d, 14e) zwischen sich Abstände derart aufweisen, dass das in der Kammer (2) vorliegende elektrische Feld im wesentlichen in der gesamten Kammer gleichförmig ist.
4. lonisationskammer nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, dass die Anzahl der Zylinder (14) fünf beträgt.
5. lonisationskammer nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, dass das ionisierbare Gas ein 98 bis 99 Gew.% Xenon enthaltendes Gas ist.
6. Ionisationskammer nach einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, dass der Gasdruck zwischen 8,8 und 9,2 absoluten Bar liegt.
7. Ionisationskammer nach einem der Ansprüche 1 bis 6, dadurch gekennzeichnet, dass eines der Enden der Zylinder (14a, 14b, 14c, 14d, 14e) fest ist und dass das andere Ende in seiner Lage durch erste, eine axiale Verschiebung erlaubende, elastische Mittel (62) und durch zweite, eine radiale Verschiebung erlaubende, elastische Mittel (66) gehalten ist.
8. Ionisationskammer nach Anspruch 7, dadurch gekennzeichnet, dass sie dritte elastische Mittel (74) umfasst, die axial und ausschliesslich auf das andere Ende der durchlöcherten Zylinder (14b, 14c, 14d) wirken.
9. Ionisationskammer nach einem der Ansprüche 1 bis 8, dadurch gekennzeichnet, dass die durchlöcherten Zylinder (14b, 14c, 14d) jeweils von durchlöcherten, gerollten und verschweissten Metallblechen gebildet sind.
10. lonisationskammer nach einem der Ansprüche 1 bis 9, mit der Gammastrahlung mit einer Energie von ungefähr 6 MeV messbar ist, dadurch gekennzeichnet, dass die Kammer (2) und die Zylinder aus rostfreiem Stahl hergestellt sind.
11. lonisationskammer nach einem der Ansprüche 1 bis 10, mit der Gammastrahlung mit einer Energie von ungefähr 6 MeV messbar ist, dadurch gekennzeichnet, dass die Kammerwand eine Dicke zwischen 3 und 4 mm aufweist.
EP83401423A 1982-07-13 1983-07-08 Ionisationskammer zur Messung von hochenergetischen Gammastrahlungen Expired EP0099300B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8212270A FR2530381A1 (fr) 1982-07-13 1982-07-13 Chambre d'ionisation pour la mesure de rayonnements gamma de haute energie
FR8212270 1982-07-13

Publications (2)

Publication Number Publication Date
EP0099300A1 EP0099300A1 (de) 1984-01-25
EP0099300B1 true EP0099300B1 (de) 1987-01-07

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ID=9275948

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83401423A Expired EP0099300B1 (de) 1982-07-13 1983-07-08 Ionisationskammer zur Messung von hochenergetischen Gammastrahlungen

Country Status (11)

Country Link
US (1) US4583020A (de)
EP (1) EP0099300B1 (de)
JP (1) JPS5929335A (de)
KR (1) KR910010105B1 (de)
BR (1) BR8303699A (de)
CA (1) CA1222836A (de)
DE (1) DE3369029D1 (de)
ES (1) ES8505143A1 (de)
FI (1) FI78363C (de)
FR (1) FR2530381A1 (de)
ZA (1) ZA834825B (de)

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Publication number Priority date Publication date Assignee Title
JP2551128B2 (ja) * 1989-01-07 1996-11-06 三菱電機株式会社 電離箱
US5095217A (en) * 1990-10-17 1992-03-10 Wisconsin Alumni Research Foundation Well-type ionization chamber radiation detector for calibration of radioactive sources
US5120967A (en) * 1991-01-25 1992-06-09 The United States Of America As Represented By The Secretary Of The Air Force Apparatus for direct measurement of dose enhancement
JP2584912B2 (ja) * 1991-06-10 1997-02-26 三菱電機株式会社 ガンマ線補償型中性子電離箱
CN1027021C (zh) * 1993-03-18 1994-12-14 清华大学 气体电离型高能x.γ辐射成象阵列探测装置
FR2703790B1 (fr) * 1993-04-07 1995-05-24 Commissariat Energie Atomique Chambre d'ionisation à haute efficacité de détection de rayonnement.
FR2727525B1 (fr) * 1994-11-25 1997-01-10 Centre Nat Rech Scient Detecteur de rayonnements ionisants a microcompteurs proportionnels
US6046454A (en) * 1995-10-13 2000-04-04 Digirad Corporation Semiconductor radiation detector with enhanced charge collection
CA2450229C (en) * 2001-06-18 2008-09-16 Wisconsin Alumni Research Foundation Radiation detector with converters
AU2002316417A1 (en) * 2001-06-25 2003-01-08 Ionfinity Llc Field ionizing elements and applications thereof
CN100427882C (zh) * 2006-10-13 2008-10-22 清华大学 气体电离型中低能X、γ射线探测器
US20110232936A1 (en) 2010-03-29 2011-09-29 Scott Magner Down-hole Cable having a Fluoropolymer Filler Layer
US9412502B2 (en) 2010-03-29 2016-08-09 Rockbestos Surprenant Cable Corp. Method of making a down-hole cable having a fluoropolymer filler layer
JP2015194453A (ja) * 2013-12-04 2015-11-05 日本電波工業株式会社 ガイガーミュラー計数管及び放射線計測計
WO2017057575A1 (ja) * 2015-09-30 2017-04-06 大日本印刷株式会社 核医学検査装置及び核医学検査方法
RU2630260C2 (ru) * 2015-11-16 2017-09-06 Акционерное общество "Красная Звезда" Высокотемпературная ионизационная камера деления для систем управления и защиты ядерных реакторов
CN115373013A (zh) * 2022-08-12 2022-11-22 陕西卫峰核电子有限公司 一种三轴耐辐照电离室传感器

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US2440167A (en) * 1944-01-20 1948-04-20 Atomic Energy Commission Differential ion chamber
US2499489A (en) * 1944-01-24 1950-03-07 Canadian Radium & Uranium Corp Exploring for radioactive bodies
US2617955A (en) * 1950-08-24 1952-11-11 Nuclear Res Corp Apparatus for detecting atomic and nuclear radiations
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JPS5826142B2 (ja) * 1978-05-04 1983-06-01 日本原子力研究所 放射線電離箱
US4289967A (en) * 1980-05-23 1981-09-15 The United States Of America As Represented By The United States Department Of Energy Multianode cylindrical proportional counter for high count rates

Also Published As

Publication number Publication date
BR8303699A (pt) 1984-02-14
FI832477L (fi) 1984-01-14
FI832477A0 (fi) 1983-07-06
EP0099300A1 (de) 1984-01-25
US4583020A (en) 1986-04-15
CA1222836A (en) 1987-06-09
JPH0255904B2 (de) 1990-11-28
JPS5929335A (ja) 1984-02-16
FR2530381A1 (fr) 1984-01-20
KR840005559A (ko) 1984-11-14
KR910010105B1 (ko) 1991-12-16
ES524054A0 (es) 1985-04-16
FR2530381B1 (de) 1985-02-22
ES8505143A1 (es) 1985-04-16
ZA834825B (en) 1984-04-25
DE3369029D1 (en) 1987-02-12
FI78363C (fi) 1989-07-10
FI78363B (fi) 1989-03-31

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