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VNIIA neutron generators for thermonuclear research

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Title: VNIIA neutron generators for thermonuclear research


1
The All-Russian Research Institute of Automatics
named after N.L. Dukhov
  • VNIIA neutron generators for thermonuclear
    research
  •  

  Yevgeni P. Bogolubov, Valentin I.
Ryzhkov, Sergey V. Syromukov  
2
2
The All-Russian Research Institute of Automatics
named after N.L. Dukhov
  •  
  • All-Russian Research Institute of Automatics
    named after
  • N.L. Dukhov (VNIIA) is one of the leading
    institutions governed by Federal Agency of Atomic
    Energy.
  • One of the basic activity lines in the institute
    is the development and manufacture of neutron
    generators using sealed accelerating tubes.
  • All produced by VNIIA generators may be divided
    into three types depending upon physical
    principles underlying their operation.
  • 1. Generators using vacuum tubes
  • 2. Generators using gas-filled tubes
  • 3. Generators using "plasma focus" chambers

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3
The All-Russian Research Institute of Automatics
named after N.L. Dukhov
  • Applications.
  • 1. Hazard material control and detection (nuclear
    materials, explosives, toxic agents, drugs)
  • 2. Oilgas field logging
  • 3. Neutron radiography and tomography
  • 4. Scientific research including solar system
    planet study
  • 5. Oncological patient radiotherapy
  • VNIIA is the only firm in the world manufacturing
    such variety of generator types having so wide
    spectrum of specifications and parameters. You
    may familiarize with products of VNIIA on
    website www.vniia.ru .

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The All-Russian Research Institute of Automatics
named after N.L. Dukhov
  • VNIIA serially produces generators having flux
    up to 1010 n/s. Urgent thermonuclear problem,
    radiotherapy, neutron radiography gave impetus
    for the development of neutron generators having
    1010 - 1011 n/s flux.
  • The basic part of generator is sealed
    accelerating tube just the tube defines
    generator parameters. Typical circuit for
    gas-filled neutron tube is shown in Fig.1.

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5
The All-Russian Research Institute of Automatics
named after N.L. Dukhov
Figure 1. Gas-filled neutron tube circuit
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6
The All-Russian Research Institute of Automatics
named after N.L. Dukhov
  • Sealed neutron tube contains ion source,
    accelerating electrode system, and target
    combined in hermetic sealed housing. Tube volume
    includes getter containing bound deuterium and
    tritium. While operation at heating getter
    deuterium and tritium release in tube volume and
    are ionized in ion source. Produced ions are
    formed in beam and accelerated between tube
    electrodes. Accelerated ions bombard target
    saturated with deuterium and tritium, and
    neutrons produce as a result of thermonuclear
    reactions.

7
7
The All-Russian Research Institute of Automatics
named after N.L. Dukhov
  • Gas-filled tubes use self-saturating neutron
    target. Such targets are saturated by deuterium
    and tritium while bombarding by ion beam within
    all tube operation time. This method allows
    appreciable increase of gas-filled tube life time
    in comparison with vacuum tubes. Tube has
    antidynatron electrode (suppressor) providing
    suppression of secondary electron current from
    target.

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8
The All-Russian Research Institute of Automatics
named after N.L. Dukhov
  • Sealed tubes in powerful neutron generators are
    normally counted for 150-250 kV at ion current
    3-5 mA. Such parameters provide neutron flux
    (0,5-1)x1011 n/s.
  • Due to thermonuclear reactions 3H(d,n)4He or
    2H(d,n)3He used in generators for neutron
    production the generators may be successfully
    used for thermonuclear facilities neutron field
    simulation.
  • Portable neutron generators with sealed
    accelerating tubes are the most perspective for
    the purposes. The peculiarity of such generators
    is complete safety when switched off, simple
    operation, small sizes, and operation at any
    position of neutron unit.

9
9
The All-Russian Research Institute of Automatics
named after N.L. Dukhov
  • Simulation of thermonuclear facility neutron
    fields requires minimum distortion of neutron
    spectrum from tube target and distortion in
    neutron emission isotropy. For generator these
    requirements mean decrease of material quantity
    near target. This especially relates to materials
    with high coefficient of fast neutron scattering.
    For solving the task we used powering circuit for
    tube with grounded target in the developed
    generators for thermonuclear research. In such
    generators tube's ion source is under high
    potential inside hermetic housing of neutron unit
    filled with high-voltage dielectric
    neutron-emitting target is grounded and jutted
    out of housing.

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10
The All-Russian Research Institute of Automatics
named after N.L. Dukhov
Figure 2. Neutron unit of generator with
grounded target
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11
The All-Russian Research Institute of Automatics
named after N.L. Dukhov
  • Figure 2 shows neutron unit of generator with
    grounded target. Tube's target juts out neutron
    unit at about 50 mm. Target is heated by ion
    beam. Therefore target is cooled with water.
    Water film thickness near target is about 1 mm.
    High-voltage dielectric thermal compensator is
    positioned by neutron unit side opposite to tube.

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12
The All-Russian Research Institute of Automatics
named after N.L. Dukhov
  • Some thermonuclear research using neutron
    generator should be performed within many tens
    hours. Generator and radiation detectors will be
    placed at rather distance from each other
    materials effectively absorbing neutron emission
    will be placed between them. This stipulates more
    high requirements to neutron output and life time
    of sealed tube. Generator should provide neutron
    flux of about 1011 n/s and life time of sealed
    tube should be at least 100 hours.

13
13
The All-Russian Research Institute of Automatics
named after N.L. Dukhov
  • In some studies neutron unit will be placed
    inside thermonuclear facilities. This requires
    minimizing dimensions of generator's emitting
    module neutron unit. It is necessary to provide
    transportability, possible displacement of
    neutron unit in thermonuclear facility volume.

14
14
The All-Russian Research Institute of Automatics
named after N.L. Dukhov
  • The next requirement is the possibility to
    obtain 2,5 MeV neutrons from the 2H(d,n)3He
    reaction. This requirement is realized by use of
    sealed tube filled with deuterium. D-D neutron
    output is about 100 times less than d-t neutron
    output because of difference in sections.

15
15
The All-Russian Research Institute of Automatics
named after N.L. Dukhov
  • VNIIA is currently developing the ING-14 and
    ING-24 neutron generators intended for simulation
    of thermonuclear facilities neutron field.
  • The ING-14 generator has flux up to 5x1010 n/s.
    Its development is now at final stage. Both
    generators are intended for continuous operation
    within many hours without interruption. They have
    grounded targets, placed beyond neutron units
    that, as shown above, decreases distortion of
    neutron spectrum and radiation isotropy.
    Generators contain neutron unit, power supply
    unit, and cable kit.

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16
The All-Russian Research Institute of Automatics
named after N.L. Dukhov
  • The ING-14 generator uses the GNT5-67 sealed tube
    shown in Fig.3. The tube has ion source with cold
    cathode and permanent magnet. Housing of the tube
    is metal-glass. Tube is mounted on ING-14 neutron
    unit flange so that source and metal-glass
    housing are inside unit and target juts out unit
    at about 5 cm. ING-14 neutron unit photo is
    presented in Fig.4.

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17
The All-Russian Research Institute of Automatics
named after N.L. Dukhov
Figure 3 
  • GNT5-67 sealed neutron tube
  • Neutron energy 14 MeV
  • Neutron flux 5?1010n/s

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18
The All-Russian Research Institute of Automatics
named after N.L. Dukhov
Figure 4.
  • ING-14 neutron generator with GNT5-67 sealed tube
  • Neutron energy 14 MeV
  • Neutron flux
    5?1010n/s

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19
The All-Russian Research Institute of Automatics
named after N.L. Dukhov
  • The ING-24 neutron generator is designed for
    1011 n/s the generator contains metal-ceramic
    tube GNT1-100 photo of this tube is presented in
    Fig.5. This tube is also mounted on ING-24
    neutron unit flange having rather large
    dimensions and appearance analogous to ING-14.
    Target of GNT1-100 tube juts out flange sizes at
    5 cm too.
  • ING-14 and ING-24 specifications are presented
    in the Table 1.

20
20
The All-Russian Research Institute of Automatics
named after N.L. Dukhov
Figure 5. 
  • The GNT1-100 neutron tube
  • Neutron energy 14 MeV
  • Neutron flux 1011n/s

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The All-Russian Research Institute of Automatics
named after N.L. Dukhov
Specifications of VNIIA neutron generators for
thermonuclear research
22
22
The All-Russian Research Institute of Automatics
named after N.L. Dukhov
  •  
  • Thus VNIIA has scientific-technical, design,
    technological and production base for development
    and manufacture of a wide class of neutron
    generators, in that number, generators for
    thermonuclear facilities neutron fields
    simulation.
  • VNIIA is interested in developing
    sciencetechnical co-operation in both delivery
    of generators designed for thermonuclear research
    and joint development of generators and equipment
    on their base.
  •  
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