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InterviewSolution
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Detemine how many times the intensity of a narrow beam of thermal neutrons will decrease after passing through the heavy water layer of thickness `d=5.0 cm`. The effective cross-section are of neutrons quitting the beam due to scattering if the thickness of the plate is `d= 0.50 cm`. The effective cross-section of interaction of deuterium and oxygen nuclei with thermal neutrons are equal to `sigma_(1_= 7.0 b ` and `sigma_(s)= 11 b` respectivley. |
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Answer» Here `(1)/(eta)=e^(-n_(2)sigma_(2)+n_(1)sigma_(1)d)` where `1` refers to `O^(1)` and 2 o r `D` nuclei Using `n_(2)=2n,n_(1)=n=` concentration of `O` nuclei in heavy water we get `(1)/(eta)= e^(-2sigma_(2)+sigma_(1)nd)` Now using the data for heavy water `n=(1.1xx6.023xx10^(23))/(20)= 3.313xx10^(22)per c c` Thus substituting the values `eta= 20.4=(I_(0))/(I)` |
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