A reanalysis of (p, p') data taken on 2+i and 3, states of 37 even-even A )40 nuclei at energies of E (50 MeV has been performed with a consistent procedure involving coupled-channels calculations and Becchetti-Greenlees optical model parameters. The matrix elements extracted from this analysis have been compared to matrix elements deduced from electromagnetic measurements of the same excitations. It is concluded that the differences between (p, p') and electromagnetic results which are often observed do not result from variations in the method of analysis of the (p, p') data. Instead, the differences are caused by experimental errors and nuclear structure effects. The nuclear structure effects are examined by extracting the ratios M"/M"of the neutron and proton multipole matrix elements for both the 2i and 3i states from the proton and electromagnetic data. PACS number(s): 21.60.Ev, 25.40.Ep, 23.20.Js

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The level scheme of ' Ra established via a study of the 2 Pb('"C, 3n) ' Ra reaction is presented. The structure of the rotational band based on the ground state is interpreted as reflecting a g9~2 valence neutron weakly coupled to a spherical ' Ra core. A non-yrast side band is observed, having tentative 15-, . . . level assignments. An 2 state could result from the anomalous J= j -2 intermediatẽ 11strength coupling of a j1~~2 neutron to the ' Ra core. The relevance of a weak coupling model to the understanding of high spin (J )j) parity doublets and the surprisingly different experimentally observed level schemes of 2/Ra and 2QAc are discussed.Studies of odd-A nuclei have been shown to provide useful information on the structure of the even-even core as well as on the behavior of the valence nucleons. This is particularly the case where weak-coupling phenomena are observed for example, in Z & 50 odd-A nuclei. hen the core is a prolate spheroid, weak coupling of a valence nucleon in an orbit having total angular momentum j leads to the occurrence of the state J "=j+J""ata lo~er excitation than the state having J = J, "-1 and to a b J = 2 band; in contrast, for the case of a valence hole the order of the J,"and J, "-1 states is reversed and a 5J = 1 band occurs. The separation of the J,"and J, "-1 states is related directly to the diagonal (first order) matrix elements of the quadrupole operator for the core' ' and thus provides information on the core structure.Recently, a number of detailed studies~" on actinide nuclei and subsequent attempts' '4 at understanding the results on the basis of cluster configurations" or static octupole deformations' ' have focused attention on the validity and relationship of these two approaches. Comparable success in reproducing the known characteristics of even-even nuclei in this mass region has been obtained with the two approaches; both can reproduce the observed bands of states having alternating parities and strongly enhanced electric dipole intraband deexcitation transitions as collective phenomena. Thus far only the static octupole model has been applied to odd mass nuclei in this region. ' Both models, in which reflection symmetry is broken in the intrinsic frame, predict parity doublets in odd-A nuclei.In this short note, a detailed level spectrum for '9Ra is presented. These results are compared with recently published results for the neighboring nuclei 2"Ac (Refs. 16 and 17) and 2'9Ac (Refs. 18 and 19) in order to examine the underlying structure and to seek an appropriate description.Our study of 2'9Ra was carried out via the '08Pb('4C, 3ny)"9Ra reaction, using a '4C beam from the Brookhaven MP'7 tandem accelerator. Unambiguous identification of 2'9Ra was achieved in measurements of the excitation function for this reaction over the range 60~E(' C) «78 MeV using a target comprised of 450 p, g/cm' of '08Pb on a 225 p, g/cm2 Au backing. Gamma radiation was detected at 90' to the beam in a single Ge(Li) detector. Since detailed information on 2'sRa (the 4n channel) and ...

Low-lying excited states of the neutron-rich calcium isotopes 48−52 Ca have been studied via γ-ray spectroscopy following inverse-kinematics proton scattering on a liquid hydrogen target using the GRETINA γ-ray tracking array. The energies and strengths of the octupole states in these isotopes are remarkably constant, indicating that these states are dominated by proton excitations.2

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We report the results of a study of the yrast excitation spectrum for ' Rn via the Pb(' C,n2n) ' Rn reaction. Measurements of y-y coincidences, y-ray angular distributions, and y-x-ray coincidences were made. We propose a level spectrum up to J =(10+) which does not exhibit the alternating parity structure observed in several isotopes of radium and thorium. From an examination of information on ' Rn and the neighboring nuclei, we can tentatively determine that the radon isotopes of masses 216 to 222 and the N =128 isotones " Ra and "Th define a lower mass boundary of a region beyond which static intrinsic reflection asymmetric shapes may exist in the nuclear ground states.