PHYSICS 002C Lecture 26 June 1, 2009 Serway and Jewett Chapter 30 – Nuclear Physics Preamble Who cares about nuclear physics? Especially for biologists, for whom it would seem that the relevant size objects are enzymes (10 nm) or a people (1m), learning more about the nucleus (1fm) than its charge Zand atomic mass Ais going too far! Maybe not. For example, except for the actual and perceived biological hazards of radioactive waste, nuclear powerwould be thesolution to the energy problem [foreign oil, depletion of fossil fuels, rising levels of pollution, CO2levels, etc.]. Nuclear magnetic resonance imaging (MRI) is a great way to see the chemical and physical structure of a human body with sub-mm resolution. Subatomic particles are used for killing tumor cells, and muons are proposed by UCR’s Prof. Nagamine as a relatively noninvasive probe of brain function. Neutronsare widely used for measuring properties of biomaterials via neutron scattering. Radio isotopesP32, H3(tritium), and S35are commonly used in bio labs to trace the components of chemical reactions and to separate proteins (Southern blotting) and DNA. Positron emission tomography (PET) uses O15, F18, N13, C11to locate and image hungry tumors in the brain and as an alternative to computed x-ray tomography (CAT) scans for diagnosis of ischemia. Besides all this, it is good to be informed about topics that other people might use to make you do what they want if you are credulous, and to have some inkling of how the world is framed and what are its immutable laws and how amazing it is that there are living creatures courageous enough to subject their sacred hypotheses to the arbiter of truth. Q: What is the arbiter of truth? (a) Mathematical theory; (b) Experiment; (c) Writings in a sacred book; (d) Opinion polls; (e) The US Supreme Court. OUTLINE 1.What is the atomic nucleus made of? 2.How big is it? 3.What holds it together? 4.Does quantum mechanics work for the nucleus? 5.Why does the sun burn? 6.Nuclear Alchemy 7.Radioactivity and biohazards 8.Nuclear fall-out 9.Radioactive decay rates 10.Alpha particle emission 11.Beta decay 1
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