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.
I thought the lecture was good but I had some trouble with the q calculator for question 1.1. I just did the calculation by hand though so it wasn't a big deal.
ReplyDeleteI was able to get the q value with http://www.nndc.bnl.gov/qcalc/
ReplyDeleteTarget 248Cm, projectile 18O, ejectile 266Rf. Q value -43.466 MeV, Threshold 46.620 MeV.
Using the site http://nrv.jinr.ru/nrv/webnrv/qcalc/ one finds Q value of -43.4664 MeV.
Sorry to hear you had issues. ken
The trouble I ran into was for question 1.1, the 248Cm(18O,5n)261Rf reaction if my notation is correct. When I tried to put in into the Q value calculator I get the message, "Reaction Q-values for 248Cm + 18O: No Q-value information could be obtained"
Deletedid you try 5n as the ejectile? If you do it works. You need to play around with the databases at times.
DeleteMy pleasure to be part of the education process.
DeleteSo for compound nuclear reactions, a projectile and a target collide at a specific interaction parameter to form a single, short-lived nucleus?
ReplyDeletethat is correct.
DeleteFor PDF quiz 9 question 1.1.5 please let page 2 of the first lecture. Your notation should be the short hand notation as listed on page 111 of Nuclear and Radiochemistry.
ReplyDeleteWhy are compound nuclear reactions energetically so unfavorable?
ReplyDeleteThese have the highest coulomb barriers.
DeleteAnswers to PDF quiz posted.
ReplyDeleteIn the second part of the lecture it says that the simplest consequence of a nuclear collision is not a "reaction" can you expand on that?
ReplyDeleteSorry if this got posted twice my internet was being funky.
The simplest interaction is scattering. The Coulomb charges causes the particle to change path. No nucleons are exchanged by the particle is impacted. Generally has the highest cross section; scattering cross section.
DeleteOh okay thank you just I was trying to think about that in depth and wanted to know for my own curiosity.
DeleteThat is terrific. Happy to answer
DeleteI found the information relating the nuclear reactions to the big bang to be very enlightening. :)
ReplyDeleteI like to think about all the elements coming from stars.
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