Difference between revisions of "Fast neutron damage to HPGe Detector"

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A decrease in the energy resolution of a large HPGe was first seen after the irradiation of <math>5\times 10^7 n/cm^2 </math><ref>P. H. Stelson, J. K. Dickens, S. Raman, and R. C. Trammell, “Deterioration of Large Ge(Li) Diodes Caused by Fast Neutrons,” Nuclear Instruments and Methods 98,481 (1972).</ref>, so <math>5\times 10^6 n/cm^2 </math> is a safe number to stay under.  
 
A decrease in the energy resolution of a large HPGe was first seen after the irradiation of <math>5\times 10^7 n/cm^2 </math><ref>P. H. Stelson, J. K. Dickens, S. Raman, and R. C. Trammell, “Deterioration of Large Ge(Li) Diodes Caused by Fast Neutrons,” Nuclear Instruments and Methods 98,481 (1972).</ref>, so <math>5\times 10^6 n/cm^2 </math> is a safe number to stay under.  
  
The maximum flux occurs right at the center of the detector, where the expression for flux simplifies to <math>n_{rate}\frac{1}{4\pi d^2}</math>
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The maximum flux occurs right at the center of the detector, where the expression for flux simplifies to <math>n_{rate}\frac{1}{4\pi d^2}</math>.  The number of hours taken to reach an integral flux of <math>5\times 10^6 n/cm^2 </math>, as a function of the CF-252 source distance HPGe face, is shown below. This graph assumes the current activity of the Cf252 source on 01/2017.
  
  

Revision as of 06:11, 29 December 2016

A decrease in the energy resolution of a large HPGe was first seen after the irradiation of [math]5\times 10^7 n/cm^2 [/math]<ref>P. H. Stelson, J. K. Dickens, S. Raman, and R. C. Trammell, “Deterioration of Large Ge(Li) Diodes Caused by Fast Neutrons,” Nuclear Instruments and Methods 98,481 (1972).</ref>, so [math]5\times 10^6 n/cm^2 [/math] is a safe number to stay under.

The maximum flux occurs right at the center of the detector, where the expression for flux simplifies to [math]n_{rate}\frac{1}{4\pi d^2}[/math]. The number of hours taken to reach an integral flux of [math]5\times 10^6 n/cm^2 [/math], as a function of the CF-252 source distance HPGe face, is shown below. This graph assumes the current activity of the Cf252 source on 01/2017.


References

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