Title: VNIIA neutron generators for thermonuclear research
1The 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
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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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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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The All-Russian Research Institute of Automatics
named after N.L. Dukhov
Figure 1. Gas-filled neutron tube circuit
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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.
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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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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.
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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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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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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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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.
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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. -
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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.
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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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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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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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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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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.
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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
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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. -