Praezisions-Gammaspektroskopie Abschlussbericht

Available from TIB Hannover: DtF QN1(51,23) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Solid state reactions after ion implantation detected by nuclear methods Proceedings

SIGLECopy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Ionenstrahlmischen: Statisches und dynamisches Ionenstrahlmischen

Available from TIB Hannover: F93B436 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Ein neues Doppelkristallspektrometer fuer Praezisionskernspektroskopie Abschlussbericht

Available from TIB Hannover: DtF QN1(35,45) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Gamma-ray induced Doppler broadening and the determination of lifetimes of excited nuclear states

Measurements of lifetimes of excited states in nuclei yield crucial information for sensitive tests of nuclear models. Here a novel method will be discussed which involves the GRID (Gamma Ray Induced Doppler broadening) technique, in which Doppler broadening is observed in a transition from a nucleus recoiling from the emission of a previous gamma ray. As the recoil energy is extremely small, ultra-high energy resolving power has to be used. To date all such experiments have been carried out at ILL using the GAMS4 double flat crystal spectrometer which is operated in a NIST-ILL collaboration. The method can be used for all lifetimes below a few picoseconds. The wide range of applicability, together with the very exhaustive set of data often obtained, is an advantage with respect to many other methods. The characteristic features of GRID will be discussed using some selected examples. 21 refs., 8 figs

Structure of high spin states in "1"0"4Sn - E2 and E3 polarization of the "1"0"0Sn core

High spin states in "1"0"4Sn were identified in the reaction "5"8Ni("5"0Cr,2p2n) at 200 MeV and 205 MeV beam energies. The #gamma#-ray energies, intensities, multipolarities, and lifetimes of high spin states were measured with the GASP spectrometer array in combination with a plunger apparatus by means of the recoil distance Doppler shift method. The deduced level scheme and transition probabilities are compared to the results of large-scale shell model calculations using three independent two-body interactions. The agreement of the level energies is satisfactory, except for a cascade of dipole transitions at high spins. The general good agreement found for E2 transition strengths implies a large effective neutron polarization charge. The shell-model calculations do not account for the measured enhanced E3 transitions for which a core excited octupole phonon admixture is indicated. (orig.)Available from TIB Hannover: RO 801(98-18) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Nuclear structure from N #approx =# Z to N >> Z - "1"0"0Sn, "7"8Ni, "2"0"8Pb

The single particle (hole) energies in "1"0"0Sn, as extrapolated by a shell model analysis of the neighbouring nuclei, show a remarkable similarity to those in "5"6Ni, one major shell lower. This is borne out in nearly identical I"#pi#=2"+ excitation energies, implying E(2"+)#approx =#3 MeV in "1"0"0Sn, and a large neutron effective E2 charge e#>=#1.6e. In contrast a small proton polarisation charge #delta#e#<=#0.3e is found, pointing to a large isovector charge. In "1"0"4Sn for the first time in this region strong E3 transitions with B(E3)#>=#17 Wu were identified, indicating E(3"-)#approx =#3 MeV in "1"0"0Sn. Isomer spectroscopy beyond "6"8Ni following fragmentation of a 60.3 A MeV "8"6Kr beam has provided first evidence on the neutron polarisation charge and the occupation of the #nu#g_9_/_2 orbital beyond N=40, which is at variance with shell model calculations using realistic interactions. The N=40 subshell effect seen in E(2"+) is not borne out in 2n separation energies. On the other hand the #nu#g_9_/_2-f_5_/_2 splitting of single quasiparticle energies in Ni, Fe and Cr isotopes, as deduced from M2 isomers, give no hint for deformation at Z<28, N#approx =#40. In neutron-rich nuclei around "2"0"8Pb a number of new isomers were observed in the fragmentation of a 1000 A MeV "2"3"8U beam, while 3"-excitations on high spin configurations in and adjacent to "2"0"8Pb were identified in inelastic collisions of "2"0"8Pb+"2"0"8Pb. E2 and E3 strengths from stretched configurations are compared to model expectations. (orig.)SIGLEAvailable from TIB Hannover: RO 801(98-41) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman