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Radioactivity

Radioactivity. Radioactivity. Radioactivity. Natural decay series. HW 10. Other 2?. Radioactivity. Radioactivity. Radioactivity. Statistical. Compare to human life time!!!. ≡ decay constant. Radioactivity. Show that the mean lifetime . N is difficult to measure.

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Radioactivity

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  1. Radioactivity Nuclear Physics, JU, Second Semester, 2010-2011 (Saed Dababneh).

  2. Radioactivity Nuclear Physics, JU, Second Semester, 2010-2011 (Saed Dababneh).

  3. Radioactivity Natural decay series HW 10 Other 2? Nuclear Physics, JU, Second Semester, 2010-2011 (Saed Dababneh).

  4. Radioactivity Nuclear Physics, JU, Second Semester, 2010-2011 (Saed Dababneh).

  5. Radioactivity Nuclear Physics, JU, Second Semester, 2010-2011 (Saed Dababneh).

  6. Radioactivity Statistical Compare to human life time!!! • ≡ decay constant. Nuclear Physics, JU, Second Semester, 2010-2011 (Saed Dababneh).

  7. Radioactivity • Show that the mean lifetime . • N is difficult to measure. • Instead, measure N ≡ number of decays between t and t+t: • If t <<  (i.e. << t1/2) then show that • and thus defining the activity A(t): Slope=? !!!!!!!!!! Be careful. Nuclear Physics, JU, Second Semester, 2010-2011 (Saed Dababneh).

  8. Radioactivity • Activity measured in units of becquerel (Bq) = 1 decay/s. • 1 curie (Ci) = 3.7 x 1010 Bq. • Activity is not dose!!!!! HW 11 Krane Problem 6.1 Nuclear Physics, JU, Second Semester, 2010-2011 (Saed Dababneh).

  9. Radioactivity Isotope 1 (initial number N0) decays into “stable” isotope 2. Exponential decay of species 1 and exponential growth of species 2. Nuclear Physics, JU, Second Semester, 2010-2011 (Saed Dababneh).

  10. Radioactivity • If parent nucleus decays by two modes: Derive. Nuclear Physics, JU, Second Semester, 2010-2011 (Saed Dababneh).

  11. Radioactivity • If radioactive species 1 is produced in a reactor or accelerator with rate R. Show that HW 12 Production Decay and thus almost linear secular equilibrium Nuclear Physics, JU, Second Semester, 2010-2011 (Saed Dababneh).

  12. Radioactivity • How long should we irradiate? • Activity per cost? Nuclear Physics, JU, Second Semester, 2010-2011 (Saed Dababneh).

  13. Radioactivity • If species 2 is radioactive. • Possible also that species 3 is radioactive. • 1  2  3  4 ….. until we reach a stable isotope. • But for now let us consider species 3 to be stable. • For the parent nucleus assume that N1(t=0)=N0. • For the daughters assume that N2(t=0) = N3(t=0) = 0. • Verify the following: What if 2 = 0? What if 1 is very small? N1(t) = ? Nuclear Physics, JU, Second Semester, 2010-2011 (Saed Dababneh).

  14. Radioactivity • Secular equilibrium • 1 is very small (1 << 2) ► • For large time t, • A2 N01 which is the • limiting value for secular • equilibrium. • Constant activity ► • production = decay. What if t½ for 132Te were 78d? ▼ Nuclear Physics, JU, Second Semester, 2010-2011 (Saed Dababneh).

  15. Radioactivity • Transient equilibrium • If 1 is smaller than 2 (1 < 2), show that Nuclear Physics, JU, Second Semester, 2010-2011 (Saed Dababneh).

  16. Radioactivity • As t increases, • but the activities themselves are not constant. • 230Th decays, in effect, with the decay constant of 234U. Parallel !? Nuclear Physics, JU, Second Semester, 2010-2011 (Saed Dababneh).

  17. Radioactivity • Discuss the case when 1 is larger than 2 (1 > 2). Nuclear Physics, JU, Second Semester, 2010-2011 (Saed Dababneh).

  18. Radioactivity • In general, 1  2  3  4 ….. until we reach a stable isotope. • If N0 of type 1 and N2(t=0) = N3(t=0) = … = 0 ►Bateman equations. Exclude the term (k - k). Nuclear Physics, JU, Second Semester, 2010-2011 (Saed Dababneh).

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