Beta decay is presented in this lecture. The neutrino hypothesis and its relationship with beta decay is discussed. A review of Q value calculations for beta decay is provided. The importance of spin and parity, and how it can be used to assess beta decay, is discussed. Modeling beta decay through the weak force is provided.. The impact of Coulomb interactions on positron and electron spectral shape is presented. The use of Kurie plots in understanding beta decay is introduced. Selection rules in beta decay and beta transitions are explained. Calculating logft and its relation to spin and parity are presented. Double beta decay is discussed.
When looking through the table of nuclides to answer question number 1 on the PDF quiz, I noticed some elements' high-Z isotopes such as 162Eu do not show decay energies even though they are radioactive. Checking the Q-value calculator, however returns Q values for these isotopes. I used these values to find the answer, but why is it that the table of nuclides does not show decay energies for certain isotopes?
ReplyDeleteFor some reason the when taking the quiz and I am not sure if it is the same for everyone but on question 1 if you select an answer in the drop down menu all the drop down menu answers are changed to the last answer you selected. It is the same for question 3 both drop down menus are changed when selecting an answer.
ReplyDeleteI had the same issue. I ended up just sending an email to Dr. Czerwinski with my intended answers and the PDF attached instead of sending the PDF through the embedded app.
DeleteLet me try to fix this
DeletePDF quiz 5 should work well now. Please let me know if you have any issues.
DeleteHow do we calculate logft? I do not even know where to begin.
ReplyDeleteThe expression "Log(ft)" might be confusing, but "f" and "t" are both variables. So you can expand the expression into "Log(f) + Log(t)" using some logarithm rules.
Delete"Log(t)" is easier to calculate as the variable "t" refers to the half life of whichever isotope you're looking at. So for the first problem, look up the half life of 241Pu, convert it to seconds, and just take the base-10 log.
"Log(f)" takes a bit longer, check slide 17 of the lecture to find equations for each type of decay, and select the equation for beta decay. Since we're doing three of these calculations for the Quiz, I would advise just typing out the formula once in Excel and copy and pasting, but you can plug and chug on a calculator if you prefer.
Hope that helps
The logft is also called the comparative half-life. This is discussed on pages 16-18 of the lecture. Examples are provided pages 17 and 18. Please review this section. If you need help please comment on the blog.
DeleteThanks Tyler!
DeleteI completed the lecture. The blog comments were helpful when completing the PDF quiz. I also noticed that the decay energy for 162 Eu wasn't listed in the Chart of the Nuclides and as someone mentioned, I used the Q value obtained from the Q-value calculator.
ReplyDeletethat is the correct approach for solving the question. thanks for your comments.
DeleteExtensive information on Beta decay. The discussion on the neutrino and how it was unaccepted at first sounds quite similar to the current discussion for dark energy/matter.
ReplyDeleteThe log(ft) examples were quite useful.
thanks you for the comments. The neutrino hypothesis is rather a good example of how theory can work.
DeleteI've completed the lecture and submitted the quiz. The examples for calculating the comparative half-life were definitely useful. Thank you!
ReplyDeletethanks for the comments
DeleteI listened to the lecture and submitted the quiz. I had a little problems with saving my answers on the pdf though.
ReplyDeleteI updated the PDF. There we an error in naming the cells that forced them all to be equal. It is now corrected.
DeleteI have completed the lecture and the quiz. It was interesting learning about log(ft).
ReplyDeletethanks for the comment. I like how logft can be used to provide a result for some complicated behavior in the nucleus.
DeleteI have completed the lecture and the quiz earlier and I thought I submitted it but I guess not. I am sorry for the delayed submission. The examples for the calculation of the log(ft) as well as knowledge for the Q value calculation proved to be valuable in helping me solved the problems. I find that calculation by hand helps me understand the material better.
ReplyDeletethanks for you comments.
DeleteTo be honest, I did not enjoy this lecture on beta decay. I will have to review this lecture in order to fill in some of the things I did not understand. I got lost during Fermi and Gamow Teller spins. Are they determined from the parent spin and parity?
ReplyDeletethe spin difference between the parent and daughter state are used to identify Fermi or Gamow-Teller.
DeleteConsider the decay of 3H. This has a spin of 1/2 and decays to 3He, also with a spin of 1/2. This zero net difference means the particles are antiparallel to provide 0 spin change. This is a Fermi.
As system with a spin change of 1, 164Ho to 164Dy. Is an example of Gamow-Teller. The particles are aligned parallel, to provide a spin addition of 1,
Page 339 of Modern Nuclear Chemistry is a good section to read for more on Fermi and Gamow-Teller.
I finished the lecture and quiz a couple of days ago; I just forgot to post about it here. Sorry for the delay!
ReplyDeletethanks for the clarification.
DeleteThank you for further explaining the logft calculation above that really helped me solve those problems. Sorry about such a late post, with being in San Diego with the band for the football game and midterms this was the first chance I go to do this lecture. Very interesting how one can compare half lives in such a way and the extranuclear effects of electron capture. Thank you for the insightful lecture.
ReplyDeletethanks for your comment
DeleteGoing into the details now it helps better in understanding each decay. I got slightly different numbers for the first problem in this quiz but it looks like I am somewhat close to your values. I used the Q value calculator and the Nuclear Wallet Cards chart. Thanks for the lecture. This one was not so complicated.
ReplyDeletethanks for referencing the data. You may find slight differences based on the utilized databases.
DeleteThis is pretty cool. I've always enjoyed the idea of the neutrino, finally learning a little more about them is amazing.
ReplyDeletethanks for the comments. Yes the neutrino is interesting!
Delete