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Neutron-induced Reactions

Neutron-induced Reactions. n-TOF CERN. Neutron-induced Reactions. n_TOF CERN. Neutron-induced Reactions. Charged Particle Reactions. What is the Gamow Peak?. Nuclear Radius. Charged Particle Reactions. Electron Screening. Charged Particle Reactions. HW 37. e 2 = 1.44x10 -12 keV.m

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Neutron-induced Reactions

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  1. Nuclear and Radiation Physics, BAU, First Semester, 2007-2008 (Saed Dababneh).

  2. Neutron-induced Reactions n-TOF CERN Nuclear and Radiation Physics, BAU, First Semester, 2007-2008 (Saed Dababneh).

  3. Nuclear and Radiation Physics, BAU, First Semester, 2007-2008 (Saed Dababneh).

  4. Neutron-induced Reactions n_TOF CERN Nuclear and Radiation Physics, BAU, First Semester, 2007-2008 (Saed Dababneh).

  5. Neutron-induced Reactions Nuclear and Radiation Physics, BAU, First Semester, 2007-2008 (Saed Dababneh).

  6. Charged Particle Reactions What is the Gamow Peak? Nuclear Radius Nuclear and Radiation Physics, BAU, First Semester, 2007-2008 (Saed Dababneh).

  7. Charged Particle Reactions Electron Screening Nuclear and Radiation Physics, BAU, First Semester, 2007-2008 (Saed Dababneh).

  8. Charged Particle Reactions HW 37 e2 = 1.44x10-12 keV.m Tunneling probability: In numerical units: For -ray emission: Sommerfeld parameter Gamow factor Multipolarity Nuclear and Radiation Physics, BAU, First Semester, 2007-2008 (Saed Dababneh).

  9. Charged Particle Reactions Nuclear (or astrophysical) S-factor Nuclear and Radiation Physics, BAU, First Semester, 2007-2008 (Saed Dababneh).

  10. Charged Particle Reactions EC = ?? Nuclear and Radiation Physics, BAU, First Semester, 2007-2008 (Saed Dababneh).

  11. Resonance Reactions E t CN  particle emission  E E > spacing between virtual states  continuum. (Lower part  larger spacing  isolated resonances). D  bound states  -emission  E  isolated states. Nuclear and Radiation Physics, BAU, First Semester, 2007-2008 (Saed Dababneh).

  12. Resonance Reactions HW 38 • In the 19F(p,) reaction: • The Q-value is 8.??? MeV. • The Q-value for the formation of the C.N. is 12.??? MeV. • For a proton resonance at 668 keV in the lab system, the corresponding energy level in the C.N. is at 13.??? MeV. • If for this resonance the observed gamma energy is 6.13 MeV, what is the corresponding alpha particle energy? • If for this resonance there has been no gamma emission observed, what would then be the alpha particle energy? Nuclear and Radiation Physics, BAU, First Semester, 2007-2008 (Saed Dababneh).

  13. Resonance Reactions J Ex a + X  Y + b Q > 0 b + Y  X + a Q < 0 Excited State Entrance Channel a + X Exit Channel b + Y Inverse Reaction Compound Nucleus C* Identical particles • Nature of force(s). • Time-reversal invariance. Statistical Factor () QM HW 39 Nuclear and Radiation Physics, BAU, First Semester, 2007-2008 (Saed Dababneh).

  14. Resonance Reactions Projectile Projectile Target Target Q-value Q-value Q + ER = Er E = E + Q - Eex Resonant Capture (selected energies with large X-section) Non-resonant Capture (all energies) Nuclear and Radiation Physics, BAU, First Semester, 2007-2008 (Saed Dababneh).

  15. Nuclear and Radiation Physics, BAU, First Semester, 2007-2008 (Saed Dababneh).

  16. Resonance Reactions HW 40  Nuclear and Radiation Physics, BAU, First Semester, 2007-2008 (Saed Dababneh).

  17. Resonance Reactions Damped Oscillator Oscillator strength Damping factor eigenfrequency Nuclear and Radiation Physics, BAU, First Semester, 2007-2008 (Saed Dababneh).

  18. Resonance Reactions Breit-Wigner formula • All quantities in CM system • Only for isolated resonances. Reaction Elastic scattering Usually a>> b. HW 41 When does R take its maximum value? Nuclear and Radiation Physics, BAU, First Semester, 2007-2008 (Saed Dababneh).

  19. Resonance Reactions Exit Channel b + Y Ja + JX + l = J (-1)l(Ja) (JX) = (J) (-1)l = (J) Natural parity. J Ex Excited State Entrance Channel a + X Compound Nucleus C* Nuclear and Radiation Physics, BAU, First Semester, 2007-2008 (Saed Dababneh).

  20. Resonance Reactions What is the “Resonance Strength” …? What is its significance? In what units is it measured? HW 42 Charged particle radiative capture (a,) (What about neutrons?) Cross section EC a  Energy Nuclear and Radiation Physics, BAU, First Semester, 2007-2008 (Saed Dababneh).

  21. Resonance Reactions 14N(p,) HW 43 • Q = ?? • EC = ?? • ER = 2.0 MeV • Formation via s-wave protons, Take J = ½, p = 0.1 MeV, • dipole radiation E = 9.3 MeV,  = 1 eV. • Show that  = 0.33 eV. • If same resonance but at ER = 10 keV • p = ?? E = ??  = ?? • Show that  = 3.3x10-23 eV. Huge challenge to experimentalists Nuclear and Radiation Physics, BAU, First Semester, 2007-2008 (Saed Dababneh).

  22. -transfer reactions Angular distribution Resonance J Estimated Energy (keV)  (eV) 566 2+ 1.9 3- 0.15 4+ 0.01 470 0+ 0.6 1- 0.2 Experimental upper limit < 1.7 eV 18O(, )22Ne Nuclear and Radiation Physics, BAU, First Semester, 2007-2008 (Saed Dababneh).

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