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Nuclear and Radiation Physics, BAU, 1 st Semester, 2006-2007 (Saed Dababneh). 1 The Semi-empirical Mass FormulaVariations……. Additional physics…. Fitting……(Global vs. local)…..

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Nuclear and Radiation Physics, BAU, 1 st Semester, 2006-2007 (Saed Dababneh). 2 Quiz

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Nuclear and Radiation Physics, BAU, 1 st Semester, 2006-2007 (Saed Dababneh). 3 Mass Parabolas and Stability HW 15

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Nuclear and Radiation Physics, BAU, 1 st Semester, 2006-2007 (Saed Dababneh). 4 Mass Parabolas and Stability

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Nuclear and Radiation Physics, BAU, 1 st Semester, 2006-2007 (Saed Dababneh). 5 Mass Parabolas and Stability

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Nuclear and Radiation Physics, BAU, 1 st Semester, 2006-2007 (Saed Dababneh). 6 Mass Parabolas and Stability

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Nuclear and Radiation Physics, BAU, 1 st Semester, 2006-2007 (Saed Dababneh). 7 Mass Parabolas and Stability Odd-Odd Even-Even Vertical spacing between both parabolas ? Determine constants from atomic masses.

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Nuclear and Radiation Physics, BAU, 1 st Semester, 2006-2007 (Saed Dababneh). 8 Mass Parabolas and Stability

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Nuclear and Radiation Physics, BAU, 1 st Semester, 2006-2007 (Saed Dababneh). 9 Nuclear Spin Neutrons and protons have s = ½ (m s = ± ½) so they are fermions and obey the Pauli-Exclusion Principle. The Pauli-Exclusion Principle applies to neutrons and protons separately (distinguishable from each other) (Isospin). Nucleus seen as single entity with intrinsic angular momentum. Associated with each nuclear spin is a nuclear magnetic moment which produces magnetic interactions with its environment. The suggestion that the angular momenta of nucleons tend to form pairs is supported by the fact that all nuclei with even Z and even N have nuclear spin =0. Iron isotopes (even-Z), for even-N (even-A) nuclei =0. Odd-A contribution of odd neutron half-integer spin. Cobalt (odd-Z), for even-N contribution of odd proton half-integer spin. Odd-N two unpaired nucleons large integer spin.

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Nuclear and Radiation Physics, BAU, 1 st Semester, 2006-2007 (Saed Dababneh). 10 Nuclear Spin ZASpin Natural Abundance Half-lifeDecay 265400.059stable... 26553/2...2.7yEC 265600.9172stable... 26571/20.021stable... 265800.0028stable... 26600...1.5My -

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Nuclear and Radiation Physics, BAU, 1 st Semester, 2006-2007 (Saed Dababneh). 11 Nuclear Spin ZASpin Natural Abundance Half-lifeDecay 27564...77.7d + 27577/2...271dEC 27597/21.00stable... 27605...5.272y -

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Nuclear and Radiation Physics, BAU, 1 st Semester, 2006-2007 (Saed Dababneh). 12 Nuclear Magnetic Moment Remember, for electrons Revise: Torque on a current loop. Z component ?? Experiment, applied magnetic field. Gyromagnetic ratio (g-factor)

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Nuclear and Radiation Physics, BAU, 1 st Semester, 2006-2007 (Saed Dababneh). 13 Nuclear Magnetic Moment For Nuclei For free protons and neutrons Proton: g = 5.5856912 ± 0.0000022 3.6 Neutron: g = -3.8260837 ± 0.0000018 3.8 The proton g-factor is far from the g S = 2 for the electron, and even the uncharged neutron has a sizable magnetic moment!!! Internal structure (quarks).

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Nuclear and Radiation Physics, BAU, 1 st Semester, 2006-2007 (Saed Dababneh). 14 Nuclear Magnetic Moment NuclideNuclear spin Magnetic moment (in N ) n1/2-1.9130418 p1/2+2.7928456 2 H (D)1+0.8574376 17 O5/2-1.89279 57 Fe1/2+0.09062293 57 Co7/2+4.733 93 Nb9/2+6.1705

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Nuclear and Radiation Physics, BAU, 1 st Semester, 2006-2007 (Saed Dababneh). 15 Nuclear Parity (r) (-r) Even. (r) - (-r) odd. For a nucleon is either of even ( = +) or odd ( = -) parity. For the nucleus = 1 2 3 … A. Practically not possible. Overall can be determined experimentally. Overall for a nucleus (nuclear state). Transitions and multipolarity of transitions ( - emission).

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