The lecture on nuclear reactions is presented in two parts. Nuclear reaction notation is introduced. The role of energetics in nuclear reactions is discussed and evaluated, including Q value, reaction barriers, and threshold energy. Center of mass and laboratory frames are discussed. The different processes involved in the formation of isotopes is provided including photonuclear processes. Reaction energetics, mechanisms and types are described. Nuclear reaction cross sections are described, with a presentation on values and limits given. This includes role of angular momentum in cross section values. The stellar production of elements is presented in terms of nuclear reactions. These provide the basis for understanding the formation of isotopes in stars. Part one is 27 minutes, part 2 is 36 minutes.
The lecture is assigned on Tuesday 30 January 2018 and due Sunday 4 February 2018. The answers to the Lecture 9 PDF quiz will be posted Sunday 5 February 2017.
lecture 9 reviewed and quiz 9 emailed
ReplyDeleteLecture 9 reviewed and the pdf quiz has been submitted. I was a bit confused on question 2, aren't both 208Pb(12C,23F)197Au and 206Pb(6Li,15C)197Au correct nuclear reactions?
ReplyDeleteBut I don't think 15C is an isotope that you can use since it has a really short half life.
DeleteThe 15C is a reaction product, so I can occur as part of the reaction. It would be difficult, but not impossible, to use it as a projectile. You can review radioactive beams. (https://scholars.opb.msu.edu/en/publications/a-gas-jet-target-for-radioactive-ion-beam-experiments-4)
Deleteboth the reactions listed above are correct.
DeleteI have submitted the quiz via email and watched the lecture.
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ReplyDeleteLecture 9 viewed and submitted. But I had a few questions about the lecture.
In lecture 9 part 1 you say "reaction energies so large a change in mass is observable." I don't really understand what this means? As in there is a mass difference between 17-O+p and 15-N + 2-He? Does Energy "have mass" or can it just be "converted to mass"? If there is somewhere to read about this that I missed I'd be grateful to be pointed in the right direction!
As always, thank you for your time;
-Sarah
The relationship between mass and energy is E=mc^2. In nuclear reactions the amount of energy released is so large that mass changes can be observed. The best example is the annihilation that occurs from a electron-positron interaction. All the mass of the particles is converted to energy.
DeleteFrom the equation E=mc^2, energy can be a manifestation of mass.
Lecture 9 reviewed and quiz submitted on canvas.
ReplyDeleteI have reviewed lecture 9 and submitted quiz 9 by email.
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ReplyDeleteLecture done and quiz completed. I was unsure about where in the videos you talked about the things that were asked of in question 3. There are also a few dead links that you posted for the lecture as well.
ReplyDeleteI will fix the dead links, sorry about that.
DeleteAnswers to question 3 are in a number of parts of the lecture. The figure is described on slides 23 and 24. The compound nucleus reactions are given on slide 23. Measurement of radii are from scattering reactions, which are introduced in lecture 2 page 19. I understand this is not directly from the current lecture. The highest energy would be related to the highest Coulomb interaction, which is discussed in barriers for charged particles, page 12 of lecture 9.
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ReplyDeleteSorry for posting late.
ReplyDeleteQuiz was submitted on time. Ryan Cheung
many thanks for the comments and pdf quizzes!
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