Forest He-3 Tubes: Difference between revisions
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The neutron capture of He-3 may be represented by the reaction below | The neutron capture of He-3 may be represented by the reaction below | ||
<math>n + He^3 \rightarrow p + H^3</math> | <math>n + He^3 \rightarrow p + H^3</math> | ||
About 764 keV of energy is liberated in this nuclear reaction and distributed between the final products according to their masses. Because the proton is | About 764 keV of energy is liberated in this nuclear reaction and distributed between the final products according to their masses. Because the proton is about a factor of 3 lighter than Tritium (H^3) , it will have more kinetic energy by about a factor of 3 (about 573 keV). This liberated proton can ionize other He-3 atoms via the reaction | ||
<math>p+He^3 \rightarrow p + He^3(+) + e^-</math> | <math>p+He^3 \rightarrow p + He^3(+) + e^-</math> | ||
The same proton will ionize several He-3 atoms when dissipating the 573 keV kinetic energy. | |||
The Tritium (H^3) can also ionize the gas but due to its higher mass it does not travel as far (shorter range) as the proton and makes a smaller contribution to the ionization signal. | |||
reference: J. W. Leake, "Nuclear Instruments and Methods", Vol. 63, page 329, 1968). | |||
[[Image:He-3Tube_DetectorDrawing.jpg]] | [[Image:He-3Tube_DetectorDrawing.jpg]] | ||
[[Image:He-3Tube_PPND_Efficiency.jpg | 200 px]] | [[Image:He-3Tube_PPND_Efficiency.jpg | 200 px]] | ||
Revision as of 09:50, 6 June 2008
The neutron capture of He-3 may be represented by the reaction below
[math]\displaystyle{ n + He^3 \rightarrow p + H^3 }[/math]
About 764 keV of energy is liberated in this nuclear reaction and distributed between the final products according to their masses. Because the proton is about a factor of 3 lighter than Tritium (H^3) , it will have more kinetic energy by about a factor of 3 (about 573 keV). This liberated proton can ionize other He-3 atoms via the reaction
[math]\displaystyle{ p+He^3 \rightarrow p + He^3(+) + e^- }[/math]
The same proton will ionize several He-3 atoms when dissipating the 573 keV kinetic energy.
The Tritium (H^3) can also ionize the gas but due to its higher mass it does not travel as far (shorter range) as the proton and makes a smaller contribution to the ionization signal.
reference: J. W. Leake, "Nuclear Instruments and Methods", Vol. 63, page 329, 1968).
File:He-3Tube DetectorDrawing.jpg
