I am almost sure that somebody made a horrible mistake or somebody trolled Wikipedia.
This might be fixed until someone sees my post.
The Neutron Generator page, Neutron generator theory and operation section has the formulae for D-T and D-D fusion. However it seems someone messed it up.
It starts with "2 P + 2 N = 17.7 MeV [19,34 MeV - 1,626 MeV]" which makes no sense whatsoever. I am not sure where they got this. It doesn't even match the He-4 Binding energy. The next line is the simple D-T fusion formula which is D+T = n + He-4, En = 14.1 MeV. Then comes D-D... I have no words for this. "D + D -> p + Positron + 3 x Gamma = 2.5 MeV" Apparently we were not producing any neutrons but rather positrons, protons and gammaes all totaling and 2.5 Mev?! Next line says "high beginning energy: 11,4 MeV : D + D → p + Positron + 2 Gamma + 3He". I mean 11,4 MeV, the OP reaction takes place, not fusion. The deuterons should split up at this energy right? Rest is ridiculous and I'm not even gonna tell anything.
I might be just saying non-sense and all of this rage might be idiotic but excuse me if that is the case.
Cinar Kagan
Neutron Generator Wikipedia Got Messed Up
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Cinar Kagan
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Neutron Generator Wikipedia Got Messed Up
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- D-D = Positron?!?!?!
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Frank Sanns
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Re: Neutron Generator Wikipedia Got Messed Up
It is typical of Wikipedia to give strangely complicated answers on many topics. There are many topics that are unnecessarily complicated and are difficult if even possible to follow by those skilled in the areas. So much for bringing things to a user friendly context.
Here is the reference to that. I can make the changes when I get back to a computer:
==Neutron generator theory and operation==
<!-- Parts of this text, inserted by 119.154.44.9, are based on text from www.thermo.com. It has been edited and referenced here. -->Small neutron generators using the deuterium (D, hydrogen-2, <sup>2</sup>H) tritium (T, hydrogen-3, <sup>3</sup>H) fusion reactions are the most common accelerator based (as opposed to radioactive isotopes) neutron sources. In these systems, neutrons are produced by creating ions of deuterium, tritium, or deuterium and tritium and accelerating these into a hydride target loaded with deuterium, or deuterium and tritium. The DT reaction is used more than the DD reaction because the yield of the DT reaction is 50–100 times higher than that of the DD reaction.
2 P + 2 N = 17.7 MeV [19,34 MeV - 1,626 MeV]
D + T → n + <sup>4</sup>He {{pad|2em}} E<sub>n</sub> = 14.1 MeV
D + D -> p + Positron + 3 x Gamma = 2.5 MeV
high beginning energy: 11,4 MeV : D + D → p + Positron + 2 Gamma + <sup>3</sup>He {{pad|2em}}
E<sub>n</sub> = 13.91 MeV is right. -> sum: ca. 2.5 MeV
Calculation:
6,8 MeV [Proton-> Hypoproton]+ 1,26*1,45 +1,26*0,42 [2,11] MeV [Hyperneutron -> Neutron] + ~ 2x 2.5 [5] MeV [Hyperneutron-> Hyperproton]
2x HN Deuterium + high energie => 3 He + Proton + Positron + 2 x Gamma
Neutrons produced by DD and DT reactions are emitted somewhat [[Anisotropy|anisotropically]] from the target, slightly biased in the forward (in the axis of the ion beam) direction. The anisotropy of the neutron emission from DD and DT reactions arises from the fact the reactions are [[Isotropy|isotropic]] in the [[Center-of-momentum frame|center of momentum coordinate system (COM)]] but this isotropy is lost in the transformation from the COM coordinate system to the [[laboratory frame of reference]]. In both frames of reference, the He nuclei recoil in the opposite direction to the emitted neutron consistent with the law of [[Momentum#Conservation|conservation of momentum]].
The gas pressure in the ion source region of the neutron tubes generally ranges between 0.1 and 0.01 [[torr|mm Hg]]. The [[mean free path]] of electrons must be shorter than the discharge space to achieve ionization (lower limit for pressure) while the pressure must be kept low enough to avoid formation of discharges at the high extraction voltages applied between the electrodes. The pressure in the accelerating region, however, has to be much lower, as the mean free path of electrons must be longer to prevent formation of a discharge between the high voltage electrodes.<ref name="ch8">{{ cite book |author1=van der Horst |author2=H. L. | year = 1964 | title = Gas-Discharge Tubes | chapter = VIIIc Neutron Generators | pages = 281–295 | publisher = Philips Technical Library | location = Eindhoven, Netherlands | series = Philips Technical Library | volume = 16 | oclc = 10391645 | id = UDC No. 621.387
| chapter-url = http://www.coultersmithing.com/OldStuff ... pdf}}</ref>
The ion accelerator usually consists of several electrodes with cylindrical symmetry, acting as an [[einzel lens]]. The ion beam can thus be focused to a small point at the target. The accelerators typically require power supplies of 100–500 kV. They usually have several stages, with voltage between the stages not exceeding 200 kV to prevent [[field emission]].<ref name="ch8"/>
In comparison with radionuclide neutron sources, neutron tubes can produce much higher [[neutron flux]]es and consistent (monochromatic) neutron energy spectra can be obtained. The neutron production rate can also be controlled.<ref name="ch8"/>
Here is the reference to that. I can make the changes when I get back to a computer:
==Neutron generator theory and operation==
<!-- Parts of this text, inserted by 119.154.44.9, are based on text from www.thermo.com. It has been edited and referenced here. -->Small neutron generators using the deuterium (D, hydrogen-2, <sup>2</sup>H) tritium (T, hydrogen-3, <sup>3</sup>H) fusion reactions are the most common accelerator based (as opposed to radioactive isotopes) neutron sources. In these systems, neutrons are produced by creating ions of deuterium, tritium, or deuterium and tritium and accelerating these into a hydride target loaded with deuterium, or deuterium and tritium. The DT reaction is used more than the DD reaction because the yield of the DT reaction is 50–100 times higher than that of the DD reaction.
2 P + 2 N = 17.7 MeV [19,34 MeV - 1,626 MeV]
D + T → n + <sup>4</sup>He {{pad|2em}} E<sub>n</sub> = 14.1 MeV
D + D -> p + Positron + 3 x Gamma = 2.5 MeV
high beginning energy: 11,4 MeV : D + D → p + Positron + 2 Gamma + <sup>3</sup>He {{pad|2em}}
E<sub>n</sub> = 13.91 MeV is right. -> sum: ca. 2.5 MeV
Calculation:
6,8 MeV [Proton-> Hypoproton]+ 1,26*1,45 +1,26*0,42 [2,11] MeV [Hyperneutron -> Neutron] + ~ 2x 2.5 [5] MeV [Hyperneutron-> Hyperproton]
2x HN Deuterium + high energie => 3 He + Proton + Positron + 2 x Gamma
Neutrons produced by DD and DT reactions are emitted somewhat [[Anisotropy|anisotropically]] from the target, slightly biased in the forward (in the axis of the ion beam) direction. The anisotropy of the neutron emission from DD and DT reactions arises from the fact the reactions are [[Isotropy|isotropic]] in the [[Center-of-momentum frame|center of momentum coordinate system (COM)]] but this isotropy is lost in the transformation from the COM coordinate system to the [[laboratory frame of reference]]. In both frames of reference, the He nuclei recoil in the opposite direction to the emitted neutron consistent with the law of [[Momentum#Conservation|conservation of momentum]].
The gas pressure in the ion source region of the neutron tubes generally ranges between 0.1 and 0.01 [[torr|mm Hg]]. The [[mean free path]] of electrons must be shorter than the discharge space to achieve ionization (lower limit for pressure) while the pressure must be kept low enough to avoid formation of discharges at the high extraction voltages applied between the electrodes. The pressure in the accelerating region, however, has to be much lower, as the mean free path of electrons must be longer to prevent formation of a discharge between the high voltage electrodes.<ref name="ch8">{{ cite book |author1=van der Horst |author2=H. L. | year = 1964 | title = Gas-Discharge Tubes | chapter = VIIIc Neutron Generators | pages = 281–295 | publisher = Philips Technical Library | location = Eindhoven, Netherlands | series = Philips Technical Library | volume = 16 | oclc = 10391645 | id = UDC No. 621.387
| chapter-url = http://www.coultersmithing.com/OldStuff ... pdf}}</ref>
The ion accelerator usually consists of several electrodes with cylindrical symmetry, acting as an [[einzel lens]]. The ion beam can thus be focused to a small point at the target. The accelerators typically require power supplies of 100–500 kV. They usually have several stages, with voltage between the stages not exceeding 200 kV to prevent [[field emission]].<ref name="ch8"/>
In comparison with radionuclide neutron sources, neutron tubes can produce much higher [[neutron flux]]es and consistent (monochromatic) neutron energy spectra can be obtained. The neutron production rate can also be controlled.<ref name="ch8"/>
Achiever's madness; when enough is still not enough. ---FS
We have to stop looking at the world through our physical eyes. The universe is NOT what we see. It is the quantum world that is real. The rest is just an electron illusion. ---FS
We have to stop looking at the world through our physical eyes. The universe is NOT what we see. It is the quantum world that is real. The rest is just an electron illusion. ---FS