0000000000007915
AUTHOR
K. T. Knöpfle
showing 6 related works from this author
E1 andE2/E0 form factors and strength distributions fromSi28(e,e’p) andSi28(e,e’α) coincidence scattering
1986
A model-independent multipole analysis of $^{28}\mathrm{Si}$(e,e'p) and $^{28}\mathrm{Si}$(e,e'\ensuremath{\alpha}) coincidence data, taken at three momentum transfers 0.39lql0.68 ${\mathrm{fm}}^{\mathrm{\ensuremath{-}}1}$, yields both E1 and E2/E0 form factors and the respective multipole strength distributions in the giant-resonance region of $^{28}\mathrm{Si}$ (${E}_{x}$=14--22 MeV). While the deduced E1 strength agrees well with previous results, the total extracted E2/E0 strength is about twice the value found with isoscalar projectiles indicating the presence of large isovector E2/E0 contributions in the region of the isoscalar E2/E0 giant resonances.
(e,e'f) Coincidence experiments on 235U and 238U
1990
Abstract Coincidence experiments for (e, e'f) on the actinide nuclei 235 U and 238 U have been performed at the Mainz Microtron (MAMI A) concentrating on three subjects: multipole strength distributions and form factors for the lowest multipolarities, the mass split in the fission decay of various giant multipole resonances, and the separation of near barrier fission channels. Data were taken at four values of momentum transfer ( q eff ≈ 0.20, 0.28, 0.53, and 0.71 fm −1 for 238 U, q eff ≈ 0.20, 0.44, 0.57, and 0.71 fm −1 for 235 U) for excitation energies ω = 4–22 MeV. The fission fragments have been detected using the Giessen PPAC-Ball. A model-independent multipole analysis yields both fo…
Multipole strength distributions and form factors forE1,E2/E0, andE3 fromU238(e,e’f) coincidence experiments
1987
A model-independent multipole analysis of $^{238}\mathrm{U}$(e,e'f) coincidence data, taken at four momentum transfers (0.2\ensuremath{\le}${q}_{\mathrm{eff}\mathrm{\ensuremath{\le}}0.7}$ ${\mathrm{fm}}^{\mathrm{\ensuremath{-}}1}$; \ensuremath{\omega}=4--22 MeV) yields both E1, E2/E0, and E3 form factors and strength distributions. The E2/E0 strength distribution in the fission channel shows two distinct bumps centered at \ensuremath{\omega}\ensuremath{\simeq}10 and 14 MeV, exhausting up to 12 MeV (19\ifmmode\pm\else\textpm\fi{}2)% of the isoscalar E2 sum rule. The extracted form factors can be described within a hydrodynamical model by use of parameters ${c}_{\mathrm{tr}/{c}_{0}=1.2}$ and …
(e,e′f)-Coincidence Experiments on Uranium Isotopes
1986
(e,e′f)-coincidence experiments represent the most powerful tool to investigate the decay properties of giant multipole resonances, especially of the isoscalar giant quadrupole resonance (GQR), in heavy nuclei. Besides the advantages of the inelastic electron scattering, the coincidence between the fission fragments and the scattered electron causes a complete suppression of the huge radiation tail. The study of the fission decay of giant resonances in heavy nuclei provides interesting information about the coupling of the collective phenomena of fission and giant resonances. In particular the fission decay of the GQR has been subject of controversial experimental studies, using hadrons [1]…
Coincidence Electron Scattering (e, e′c) in the Giant Resonance Region of 28Si
1986
In the nuclear continuum region, the inherent power of inelastic electron scattering to map out the Fourier transforms of the transition charge and current densities is completely exploited only if the inelastically scattered electron is detected in coincidence with a nuclear decay product c. The coincidence requirement effectively eliminates the strong elastic radiative tail which hitherto plagued the analysis of single arm (e,e′) experiments.
Direct decay of the giant dipole resonance in58,60Ni and64Zn from (e, � c) experiments
1988
(e,e'c) coincidence experiments at a momentum transfer of q=0.27 fm−1 to study the decay of the giant dipole resonance in58,60Ni and64Zn show deviations from photonuclear results and reveal strong contributions of direct decay to proton hole states.