Nuclear Physics PHY 361 2008-04-21

Outline history structure of the nucleus binding energy radioactivity nuclear binding force liquid drop model shell model – magic numbers binding energy chart of nuclides line of stability, drip line, island of stability radioactivity ,, decay fission, fusion I will start with a brief reminder of where we were last, and explain the different options available for polarizing the beam. Then I will go on and show the progress we have made towards a feasible design of the novel splitter polarizer geometry. We have also done new detailed simulations of the different designs and recalculated the costing of each for comparison. Based on this new information, we have arrived at a choice for the baseline design.

History Becquerel – discovered radioactivity (1896) Rutherford – nuclear model classified ,, radiation,  particle = 4He nucleus used  scattering to discover the nuclear model postulated ‘neutrons’ A=Z+N (1920); bound p+ e- state? Mosley – studied nucleus via X-ray spectra correlated (Z = charge of nucleus) with periodic table extra particles in nucleus: A = Z + ? Chadwick – discovered neutron (1932) Pauli – postulated neutral particle from -decay (1930) Fermi – theory or weak decay (1933) ‘neutrino’ Fission – Hahn, Strassmann, (&Meitner!) (1938) first reactor (chain reaction), Fermi (1942) Bohr, Wheeler – liquid drop model Mayer, Jensen – shell model (1949) Hofstadter – electron scattering (1953-) measured the charge density of various nuclei discovered structure in the proton (not point-like particle)

Nuclear potential Hofstadter, electron scattering strong force + Coulomb repulsion (p-p) ~ finite square potential hard core – const. density Hofstadter, electron scattering

Liquid drop model of the nucleus constant density like a liquid R = R0 A1/3 where R0 ~ 1.2 fm  = A / (4/3 R3) = 1014 g/cm3 ! finite square potential p,n act as free particles inside of drop states filled to Fermi energy ‘surface tension’ normally prevents breakup excitation can induce split into smaller drops with lower overall energy

Shell model of the nucleus 1949 – M. Mayer, J.H.D. Jensen similar to atomic orbitals quantized angular momentum energy levels multi-particle wave function difference: no ‘central’ potential (nucleus) effective finite square potential complicated nuclear force strong dependence on spin two particles: p, n more types of decays nucleus atom

Chart of Nuclides – binding energy AZXNq ex. 1H, 2H, 3He, 4He A = Z + N = # protons + # neutrons B = Z MHc2 + N mnc2 - MAc2 nuclides – Z,N isotope – constant Z (‘same place’) isotone – constant N (isoto‘n’e) isobar – constant A (‘same weight’) isomer – excited state or nuclide

Chart of Nuclides – lifetime magic numbers http://www.nndc.bnl.gov/chart

Chart of Nuclides – decay mode magic numbers stable nuclide - decay , electron capture decay p decay n decay spontaneous fission http://www.nndc.bnl.gov/chart

Chart of Nuclides – island of stability magic numbers http://en.wikipedia.org/wiki/Island_of_stability

Nuclear decay modes: Z N ++ decay - decay (isobar) + decay (isobar)  electron capture (isobar) p decay (isotone) n decay (isotope)  decay (isomers) electron conversion (EC) spontaneous fission (SF) double beta decay (2) neutrino-less double beta decay (0) beta-delayed n,p, decay ISOBARS ISOTONES ISOMERS ISOTOPES Z N

Alpha-decay

Beta-decay