ProblemSet-6-2005 - NE-524 Interaction of radiation with...

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Unformatted text preview: NE-524 Interaction of radiation with Matter Problem Set #6 (Complete by 11/20/2005) 1) Aluminum bronze, an alloy containing 90% Cu and 10% Al by weight has a density of 7.6 g/cc. What are the linear and mass attenuation coefficients? ( Cu = 9.91 and Al = 4.45 barns) 2) Compute the thickness of Al and Pb to transmit 10% of a narrow beam of 0.1 MeV photons. 3) 4) What fraction of their energies do 1 MeV and 0.1 MeV photons lose if they are scattered through an angle of 90o? In an experiment, it was found that a 1 cm thick lead absorber attenuated a 10 MeV neutron flux to 84.5% of its initial value. What is the total cross section? (Pb atomic weight = 207.21, = 11.3 g/cc) A sample containing an unknown quantity of chromium is irradiated for one week in a thermal neutron flux of 10E11 n/cm2.sec. The resulting Cr-51 gamma rays produce a net counting rate of 600 counts per minutes in a scintillation counter with an efficiency of 10%. How many grams of chromium were in the original sample? - 5) - thermal neutron activation = 13.5 barns reaction: Cr-50 + n ----> Cr-51 + Cr-51 half life = 27.8 days Cr-50 forms 4.31% by number of the naturally occurring chromium Cr atomic weight = 52.01 Cr-51 branching ratio = 9.8% Answers: 1) 2) 3) 4) 5) 0.718 cm-1, 0.0944 cm2/g Al: 4.98 and Pb: 0.038 cm 1 MeV: 0.338 and 0.1 MeV: 0.836 5.12 barns 9.47E-6 grams ...
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This note was uploaded on 04/11/2008 for the course CHNE 524 taught by Professor Mohagheghi during the Fall '08 term at New Mexico.

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