Thursday, January 26, 2017

Spring 2017 CHEM 312: Lecture 3 Decay Kinetics

This lecture covers the fundamental equations that describe the decay of radionuclides. Basic equations and their utility are presented. Equations for mixtures, equilibrium, and branching of radionuclides are covered. Examples are provided for error evaluation from counts, activity determination, evaluation of half life, and lifetime of isotopes. Discussion of natural radiation and dating are given. Examples are provided for dating from 238U, 14C, and the Oklo reactor. The lecture time for part 1 is 43 minutes. Part 2 is 60 minutes.  The lecture is assigned 26-Jan-17.  The PDF Quiz 3 is due 5-Feb-17.

34 comments:

  1. Good evening, I completed the lecture, and the PDF Quiz is on it's way. Thank you!

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  2. for the question 1: i get λ=ln(87/80.04)/60s=0.0013897; and i put λ into σ equation get the σ=2.5; i am not sure i am right? but what is average value? i have no ideal for this question

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    1. This question is based on lecture 3 part 1 page 9. Based on the total counts the error can be found. Using the error the expected range of values can be determined.

      The decay rate is 87 Bq, so 87 decays/second. In one minute you can determine the total decays, with only 8 % of the decays counted. This provides the total counts. One standard deviation is the square root of the total counts. The counts should be expected to fall within the average +- one standard deviation.

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  3. I finished the lecture and have sent in Quiz 3

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    1. I fixed my answer to question 1. I believe I found my mistake. This time I found the total counts then used its square root to find the standard deviation. Thanks for the help!

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  4. A general comment on question 1 for PDF quiz 3 is provided. What the question is assessing are counts that can occur within one standard deviation of the average. The first thing to do is find the average.

    Decay/second * seconds * detector efficiency

    This is the total counts. The error is the square root of the total counts. The range is then the average +- the square root of the total counts.

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  5. Good afternoon!
    I have finished the lectures and quiz for PDF 3 and sent my quiz to you via email.
    Thanks!
    Halli

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  6. This comment has been removed by the author.

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  7. Good evening, I completed the lecture and submitted quiz 3.

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  8. Hi Sir

    I have sent my pdf_quiz 3
    sorry about the other e-mails, I made a mistake with the half life when calculating decay constant..I forgot to switch the years to seconds. overall
    very interesting lecture.

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    Replies
    1. great to hear you caught the error. Don't worry about other e-mails.

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  9. Hi Ken!

    I sent you an email with Quiz 3 attached!

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  10. Quiz 3 has been sent! Thank you.

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  11. I have submitted quiz 3.

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  12. I completed quiz 3 and sent it. Thank you.

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  13. I have finished lecture 3 and submitted my pdf quiz. Thank you!

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  14. I have submitted quiz 3 via email

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  15. thanks for the comments and the quizzes!

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  16. Just submitted the quiz and finished watching lecture 3 parts 1 and 2.

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  17. Hi! I submitted my quiz! Just wondering if the outline on the radchem website is up-to-date? So the test is scheduled to be assigned this week?

    Thanks,
    Tia

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    Replies
    1. yes, the test will be assigned this week. The test on the site is from last year. I will remove it now to avoid confusion.

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  18. can you please post the answers to quiz 3..its not up yet

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  19. Lecture 3 finished, working on four now. I submitted the quiz last night

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  20. Quiz 3 sumbitted, thanks.

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  21. thanks for the quizzes and comments for Lecture 3.

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