EP0357133A1 - Schutzvorrichtung von Neutronenröhren - Google Patents

Schutzvorrichtung von Neutronenröhren Download PDF

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Publication number
EP0357133A1
EP0357133A1 EP89202146A EP89202146A EP0357133A1 EP 0357133 A1 EP0357133 A1 EP 0357133A1 EP 89202146 A EP89202146 A EP 89202146A EP 89202146 A EP89202146 A EP 89202146A EP 0357133 A1 EP0357133 A1 EP 0357133A1
Authority
EP
European Patent Office
Prior art keywords
tube
resistor
elements
voltage
target
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
EP89202146A
Other languages
English (en)
French (fr)
Other versions
EP0357133B1 (de
Inventor
Pierre Société Civile S.P.I.D. Bach
Henri Société Civile S.P.I.D. Bernardet
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.)
SODERN SA
Koninklijke Philips NV
Original Assignee
SODERN SA
Philips Gloeilampenfabrieken NV
Koninklijke Philips Electronics NV
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 SODERN SA, Philips Gloeilampenfabrieken NV, Koninklijke Philips Electronics NV filed Critical SODERN SA
Publication of EP0357133A1 publication Critical patent/EP0357133A1/de
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Publication of EP0357133B1 publication Critical patent/EP0357133B1/de
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Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H3/00—Production or acceleration of neutral particle beams, e.g. molecular or atomic beams
    • H05H3/06—Generating neutron beams

Definitions

  • the invention relates to a device for protecting a neutron tube comprising an ion source whose anode is brought to a positive potential with respect to the cathode by means of a source power supply and whose accelerated ion beam strikes a target disposed on an insulating support and brought to a negative potential supplied by a HV power supply, said protection device being constituted by elements of electrical limitation of the tube current and / or of the target voltage.
  • neutron tubes operate under conditions compatible with the possibilities of heat dissipation, in particular of the target and its support.
  • the ion sources themselves are provided with fairly large extraction orifices in order to allow a high extraction yield to be obtained at a low operating pressure. Furthermore, they can work in an arc-type discharge regime for pressure values which are still compatible with operation of the tube and the very high voltages applicable on these tubes can make it possible to extract large ion currents for short times.
  • the electrical limitations usually mounted on the supply circuits of the anode of the ion source and of the target for the purpose of protecting the supply and the tube can be eliminated and replaced by new elements adapted to a new use.
  • the object of the invention is to provide the manufacturer of the tube with a means of prevention against such changes.
  • the invention is remarkable in that said limitations are made unalterable by including said elements inside the neutron tube so that any attempt to modify the electrical parameters fixing the nominal operating conditions of the tube requires the opening of said tube.
  • Said tube current limiting elements include a resistor connected between the positive terminal of the source power supply and the anode of the ion source, as well as a voltage limiter at a value slightly greater than the specified value, connected between said positive terminal and the negative terminal of the source supply connected to ground.
  • the resistor and the voltage limiter can be placed inside a sealed box supplied by sealed passages or in a sealed glass bulb. They can be produced in screen-printed technology or consist of mixed assemblies of screen-printed elements and discrete components compatible with the quality of vacuum necessary for the neutron tube.
  • the target voltage is limited by a resistor connected between the negative terminal of the HV supply and the target and a voltage limiter connected between said negative terminal and the positive terminal of the HV supply connected to ground.
  • Said resistance can be achieved in one of the following forms: - screen-printed resistance arranged helically on the external face of an insulating cylinder serving as support for the target; - insulated resistive wire (high temperature technology) and wound from turn to turn or into wafer; - high voltage resistive elements in series arranged inside an alumina envelope (or any other insulator compatible with tube technology and THT constraints) which can either be in communication with the tube or under a gas atmosphere according to technology said resistive elements (temperature resistance, degassing), the connection and assembly mode (electric field at the resistors and connection wires) and the maximum level of voltage drop accepted in the resistance by the manufacturer.
  • the neutron tube shown in Figure 1 includes an ion source obtained from a deuterium-tritium mixture contained in the reservoir 1 and in which there is an anode 2, a cathode 3 and a permanent magnet 4 which establishes a field magnetic axial.
  • the ion beam from this source is accelerated by the acceleration electrode 5 and strikes the target 6.
  • the envelope of the tube consists of a conductive part 7 grounded and an insulating part 8 surrounding the support target 9 secured to the acceleration electrode.
  • the ion source is supplied by the DC voltage generator 10 of value V aa , the negative pole of which is connected to the ground of the tube and the positive pole of which is connected to the anode 2 through the resistor 11 of value R a .
  • the discharge current in the neutron tube can be subdivided into two regimes: - a low pressure regime for which the discharge current I d varies as a function of the pressure P DT inside the tube and the anode-cathode voltage V ak according to the relationship: I d ⁇ P ⁇ DT V v ak with ⁇ and v neighbors of 1.
  • This relationship shows that the increase in the discharge current is obtained by an increase in the pressure P DT with an upper limit corresponding to the arc regime or by increase in the anode-cathode voltage V ak ; in the latter case it is necessary increasing the magnetic field B so as to keep a constant V ak / B ratio.
  • V aa R a I d + V ak 0
  • the current I d is then given by:
  • the current I d is limited by the supply voltage V aa and by the resistance R a .
  • the devices which are the subject of the invention will therefore make it possible to act on these two parameters and will include the resistor 11 of value R a compatible with the instantaneous maximum flux provided by the manufacturer and a voltage limiter 12 (spark gap, varistor, gas diode, ...) of impedance Z a , connected to the terminals of the supply 10, limiting the operating voltage to a value slightly higher than the supply voltage desired by the manufacturer and guaranteeing good reliability of the tube.
  • the limiting devices shown diagrammatically in FIG. 1 can be used simultaneously or separately; they are of two types: - limitation of the tube current by limitation of the current of the ion source, - limitation of the target voltage by limitation of the target supply voltage.
  • the instantaneous neutron emission Q n is globally related to the electrical parameters current tube I TU and target voltage V c by a relation of the type Q n ⁇ k I TU V ⁇ vs with 0.3 ⁇ k ⁇ 1 and 3 ⁇ ⁇ 4 for 80 kV ⁇ V c ⁇ 150 kV. This is valid for I TU expressed in amperes, V c in kilovolts, Q n in neutrons / second and for pressures of the hydrogenated gas mixture less than or equal to 10 ⁇ 2 torr.
  • the tube current limiting elements can be mounted so as to form a single limiting assembly 16.
  • FIGS. 2a, 2b and 2c show some examples of assemblies.
  • the resistor 11 and the voltage limiter 12 are arranged in a sealed box BO supplied by sealed passages PAS1 and PAS2.
  • the resistor 11 and the voltage limiter 12 are placed in a sealed tube TU.
  • the resistor 11 and the breakdown voltage limiter 12 are produced in screen-printed technology and must be compatible with the quality of vacuum essential for the neutron tube.
  • the resistor 11 consists of a screen-printed bar B between the feed studs P1 and P2; the spark gap 12 is formed by the groove located between the pad P1 and the pad P3 or between the bar B and the pad.
  • the assembly is placed on the PL insulating plate (alumina, glass) and is compatible with tube technology (high temperature and low degassing rate).
  • FIGS 3 and 4 show two examples of arrangement of the anode current limiter assembly inside the neutron tube itself according to the invention.
  • the anode 2 is mechanically held by the insulating wall 17 on the ion source side.
  • the sealed housing 16 containing the limiting elements 11 and 12 is provided with insulating outputs 18 and 19 serving respectively for its voltage supply and for its connection to the anode; this connection is protected by an insulating sleeve 20.
  • the anode is mounted directly on the sealed housing 16 via the insulating support 21 through which is carried out the connection of the limiting resistor 11 to the anode 2; the spark gap (or varistor) 12 is connected to the voltage supply through the insulated passage 22.
  • the housing 16 is connected to the support of the reservoir 23 and to the frame of the tube 7 by a "three-lip" weld 24.
  • the limitation assembly 16 can be produced using different types of components, by direct mounting of discrete components (resistor, spark gap) assembled in parallel in the base of the tube; the technology of these components must be compatible with ultra-vacuum.
  • discrete components resistor, spark gap
  • Mixed assemblies of screen-printed elements and discrete components can also be assembled according to their compatibility with ultra-vacuum.
  • a resistor 25 is arranged on the outside of the insulating cylinder 9 serving to support the target 6; the end at the base of the cylinder is connected to the negative pole of the high-voltage power supply and the end at the top of the cylinder is connected to the acceleration electrode 5.
  • This resistor 25 may consist for example of screen-printed elements deposited on the outside of the cylinder 9 in the form of a helix or resistive wire insulated according to the high temperature technology and wound from turn to turn or into wafer.
  • the acceleration electrode 5 is held by the insulating support 26.
  • the resistor 25 is formed of resistors in series and deposited inside an alumina envelope 27 serving as a support for the acceleration electrode 5 connected to the upper end of the resistor, the target 6 being supported by the insulating wall of the tube 8.
  • This current limitation by means of the resistor 25 can be supplemented by a voltage limitation by means of a spark gap (or a varistor) 28 disposed inside the alumina envelope and connected between the ground and the "three-lip" weld 29 connected to the negative pole of the target HV supply.
  • a spark gap or a varistor
  • the interior of the alumina casing 27 can be placed either in communication with the tube, or in a gas atmosphere depending on whether the orifice 30 is found open or closed.
  • the solution will depend on the compatibility of the varistors and resistances to ultra-vacuum and the technology of the resistors (temperature resistance, degassing). It is possible, for example, to place the elements for limiting the target voltage under controlled gas of the sulfur hexafluoride type under the pressure of one to a few bars.

Landscapes

  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Particle Accelerators (AREA)
  • Electron Sources, Ion Sources (AREA)
EP89202146A 1988-08-26 1989-08-24 Schutzvorrichtung von Neutronenröhren Expired - Lifetime EP0357133B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8811259A FR2636774A1 (fr) 1988-08-26 1988-08-26 Dispositif de protection des tubes neutroniques
FR8811259 1988-08-26

Publications (2)

Publication Number Publication Date
EP0357133A1 true EP0357133A1 (de) 1990-03-07
EP0357133B1 EP0357133B1 (de) 1994-05-04

Family

ID=9369540

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89202146A Expired - Lifetime EP0357133B1 (de) 1988-08-26 1989-08-24 Schutzvorrichtung von Neutronenröhren

Country Status (5)

Country Link
US (1) US5013969A (de)
EP (1) EP0357133B1 (de)
JP (1) JP2825024B2 (de)
DE (1) DE68915081T2 (de)
FR (1) FR2636774A1 (de)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6441569B1 (en) 1998-12-09 2002-08-27 Edward F. Janzow Particle accelerator for inducing contained particle collisions
CN103068141A (zh) * 2012-12-25 2013-04-24 江苏达胜加速器制造有限公司 一种加速管
JP6257994B2 (ja) * 2013-10-22 2018-01-10 株式会社東芝 中性子発生装置及び医療用加速器システム
JP7126733B2 (ja) * 2018-10-24 2022-08-29 アデルファイ・テクノロジー・インコーポレイテッド 中性子捕捉療法のための中性子源

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE714343C (de) * 1934-01-11 1942-01-05 Mueller C H F Ag Roentgeneinrichtung fuer diagnostische Zwecke mit gemeinsamer Primaerwicklung am Hochspannungs- und Gluehstromtransformator
US2988671A (en) * 1958-06-30 1961-06-13 Schlumberger Well Surv Corp Particle accelerating system
US3364355A (en) * 1965-07-13 1968-01-16 Atomic Energy Commission Usa Neutron generator with occluded gas ion source
DE1589699A1 (de) * 1963-02-18 1970-06-18 Dresser Ind Vorrichtung zur Erzeugung von Korpuskularstrahlimpulsen,insbesondere von Neutronenimpulsen
FR2179527A1 (en) * 1972-04-11 1973-11-23 Texaco Development Corp Electrical connector - for a high voltage radioactivity borehole logging tool

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2951945A (en) * 1954-05-26 1960-09-06 Schlumberger Well Surv Corp Renewable target
US3581093A (en) * 1968-04-23 1971-05-25 Kaman Sciences Corp Dc operated positive ion accelerator and neutron generator having an externally available ground potential target
NL7000938A (de) * 1970-01-23 1971-07-27
US3836785A (en) * 1970-07-15 1974-09-17 Philips Corp Neutron generator having a target on which a beam of hydrogen ions is incident
US4808368A (en) * 1982-09-15 1989-02-28 The United States Of America As Represented By The United States Department Of Energy High voltage supply for neutron tubes in well logging applications

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE714343C (de) * 1934-01-11 1942-01-05 Mueller C H F Ag Roentgeneinrichtung fuer diagnostische Zwecke mit gemeinsamer Primaerwicklung am Hochspannungs- und Gluehstromtransformator
US2988671A (en) * 1958-06-30 1961-06-13 Schlumberger Well Surv Corp Particle accelerating system
DE1589699A1 (de) * 1963-02-18 1970-06-18 Dresser Ind Vorrichtung zur Erzeugung von Korpuskularstrahlimpulsen,insbesondere von Neutronenimpulsen
US3364355A (en) * 1965-07-13 1968-01-16 Atomic Energy Commission Usa Neutron generator with occluded gas ion source
FR2179527A1 (en) * 1972-04-11 1973-11-23 Texaco Development Corp Electrical connector - for a high voltage radioactivity borehole logging tool

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
INTERNATIONAL JOURNAL OF APPLIED RADIATION AND ISOTOPES, vol. 34, no. 1, janvier 1983, pages 269-272, Pergamon Press Ltd, Oxford, GB; L.A. SHOPE et al.: "The operation and life of the zetatron neutron tube in a borehole logging application" *
PROC. SYMP. PULSED NEUTRON RESEARCH, Karlsruhe, 10-15 mai 1965, vol. 2, pages 609-622; C.W. ELENGA et al.: "The generation of neutron pulses and modulated neutron fluxes with sealed-off neutron tubes" *

Also Published As

Publication number Publication date
JP2825024B2 (ja) 1998-11-18
JPH02114498A (ja) 1990-04-26
US5013969A (en) 1991-05-07
FR2636774A1 (fr) 1990-03-23
DE68915081D1 (de) 1994-06-09
DE68915081T2 (de) 1994-10-27
EP0357133B1 (de) 1994-05-04

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