Internal electrostatic confinement fusion (??????????????)

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Internal electrostatic confinement
fusion(??????????????)

• ????
• by ?????

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Paper
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Institute

• Institute of Advanced Energy, Kyoto University
  Prof. Kiyoshi Yoshikawa's  Research Group
• ??????????????? ??????????? ??????????? ?? ?
  ???
• http//www.iae.kyoto-u.ac.jp/beam/index_j.html

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Brief introduction of Internal electrostatic
confinement fusion IECF

• IECF is the scheme of injecting the ions and
  electrons towards the spherical center, trapping
  both species in the electrostatic self-field and
  giving rise to fusion in the dense core.
• (Fusion mechanism is not completely understood.)
• For effective production of neutron, multi-well
  potential is needed.
• Energy of neutron
• dd?3Hen 2.5 MeV
• dt?4Hen 14.1 MeV
• (d3He?4Hep 14.7 MeV)

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Background

• The concept of IECF is conceived in 1950s.
• The first purpose is to investigate the room
  temperature fusion system (for power source ?).
• ?Not realistic
• ?Latest type, input 100W ?Output by fusion 1µW
• But
• IECF is a good neutron source.
• ? Investigation is continued.

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The Machine
Intensity of neutron dd?3Hen 2.5 MeV ? 5106
n/s (High voltage and ion current are unknown)
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Advantage of IECF compared with neutron source
(example 252Cf)

• Mono-energetic spectrum
• No decreasing by particle decay
• Easy to operate
• Able to use proton source
• (d3He?4Hep 14.7 MeV)
• Good application ?

Energy spectrum of neutron from 252Cf O.I.
Batenkov et al., INDC(NDS)-146,(1983)
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Purpose of this paper

• To measure ion current dependency of neutron
  yield (N?I2) for investigating IEFC mechanism
• To explain mechanism by theoretical calculation
  for offering the technical advantages
• ?
• The structure of internal potential is unknown. ?
  fusion mechanism
• Information for developing the technical progress
  To optimize high voltage, current and to
  develop cooling system ?Technical advantages

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Ion current dependency of neutron yield

• Calculation by multi-well potential N?I2 (Iion
  current)
• ?Experimental result scales linearly I
• Limitation of high voltage and current are 70kV
  and 15 mA, respectively.
• Not to exceed the threshold for multi-well
  potential
• Perveance I(mA)/V1.5(kV) gt 2.2
• Re-experiment by sufficient condition by using
  pulse current
• I2 dependency over the threshold was confirmed.

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Result of theoretical calculation

• To construct the program by multi-well potential
  and to simulate the dependency of ion current
• N?I3 dependency exists in the high current
  region.
• ?Increased ion current make multi-well potential
  unstable and this unstably increase the density
  of central region.
• ?The experiment to confirm this dependency in the
  high current region should be performed.

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Result of theoretical calculation

• To construct the program by multi-well potential
  and to simulate the dependency of ion current
• N?I3 dependency exists in the high current
  region.
• ?Increased ion current make multi-well potential
  unstable and this unstably increase the density
  of central region.
• ?The experiment to confirm this dependency in the
  high current region should be performed.

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Conclusion

• The dependency of ion current (N?I2) by
  multi-well potential is confirmed.
• There may be the dependency N?I3 in the high ion
  current region.
• ? The experiment should be performed.

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Progress after this experiment

• Multi-well potential was first measured by the
  laser-induced fluorescence method.
• To increase the nuetron intensity of D-D reaction
  
• ? 2108 n/s

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Future plan

• Improvement of ion source
• Glow discharge Magnetron ion source
• Intensity of neutron will be increased by
  one-order (108?109 n/s).

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Application
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Examples
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Mine sweeper ?

• Development with 7 organizations
• They plan to operate this machine in Afghanistan.

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Why neutron source ?

• It is very difficult to distinguish mine from
  other metals by metal detector.
• ? mine/metals 1/1000 under the ground
• ?The plastic and ceramic mine cannot be detected.
• The composition of TNT is known.
• ?By measuring ? ray from TNT reacted with neutron
  and back scattered neutron by proton in TNT, we
  will be able to distinguish mine from other
  metals.

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What detect ?

• ? ray from neutron capture 1H(n,?), 14N(n,?)
• Energy
• 1H(n,?) 2.22 MeV
• 14N(n,?) 10.8 MeV
• CsI, NaI, BGO for detection
• 10.8 MeV ? Detected by BGO multi compton gamma
  camera

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BGO gamma compton camera

• Expected performance
• (1m1m field, 20cm depth, 30 g mine)
• 106 n/cm2/s
• Efficiency 99.9
• Miss identify 40 _at_ 10 min

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Other method
????????????????? ???????????
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Summary

• Present performance of IECF 2108 n/s.
• IECF will be able to be used for several
  applications by adjusting neutron intensity.
• Mine sweeper with IECF is planned.