Difference between revisions of "Forest He-3 Tubes"

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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 abotu a factor of 3 lighter that T
+
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
ritium (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]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]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

He-3Tube PPND Efficiency.jpg