M J Godfrey

Bio: M J Godfrey is an academic researcher from University of Liverpool. The author has contributed to research in topics: Yrast & Decay scheme. The author has an hindex of 9, co-authored 18 publications receiving 283 citations.

Mean-lifetime measurements within the superdeformed second minimum in 132Ce.

Abstract: A rotational band has been studied in $^{132}\mathrm{Ce}$ to a spin above 50\ensuremath{\Elzxh}. Lifetime measurements have resulted in a large quadrupole moment corresponding to a deformation \ensuremath{\beta}\ensuremath{\sim}0.5. This is consistent with the moment of inertia determined from the energy-level spacing. These data are the first measurements of collectivity of discrete lines at high spin within the superdeformed second minimum.

The new spectroscopy of superdeformed states: systematics in the light rare earths and unexpected feeding patterns

Abstract: A systematic study in the light rare earth (N 82, indicating that there is not a 'magic' superdeformed nucleus in the region. Striking population intensity differences are observed which are not explained by standard potential energy calculations. Open problems, particularly in connection with feeding into and out of the superdeformed bands, are discussed.

The competition between collective and single particle behaviour in the odd-odd isotopes 128,130La

Abstract: Excited states in the odd-odd nuclei 128,130La have been investigated to high spin using gamma -ray spectroscopy. Two distinct bands are seen, one based on a pi h11/2(X) nu h11/2 structure and the other on a pi h11/2(X) nu g7/2 configuration. Backbends are observed in both configurations for both nuclei and the nature of the particles responsible can be conclusively proved. Experimental variation in the energy-level signature splitting and B(M1)/B(E2) ratios are discussed in terms of the polarising effects of the odd proton and odd neutron on the soft collective core. The results are discussed in terms of the cranked shell model, odd-odd particle-rotor calculations and total Routhian surface calculations. They are also compared to neighbouring odd and odd-odd systems.

Collective oblate structure in the odd-odd isotopes 128,130La

Abstract: Excited states in the nuclei 128,130La have been investigated to high spin using gamma -ray spectroscopy techniques. In addition to the main rotational structures based on a prolate collective rotor, and a superdeformed band in 130La, two bands are seen with properties similar to the collective oblate structure proposed for 131La. The experimental evidence for these bands is discussed in terms of the variation in energy-level signature splitting, B(M1)/B(E2) ratios and mixing ratios as a function of rotational frequency and single-particle configuration. These results are interpreted using odd-odd particle-rotor model calculations and self-consistent cranking calculations. They are compared with the proposed 'collective oblate' bands in other nuclei in the A=130 region and possible evidence for collective oblate shape co-existence is presented.

First observation of the i13/2 neutron orbital in the A=130 region: spectroscopy of 135Sm

Abstract: Gamma-ray transitions have been observed for the first time in 135Sm using the Daresbury Recoil Separator. A decay scheme has been developed from gamma-gamma coincidence data obtained using the TESSA3 spectrometer. The first clear evidence for the presence of the intruder i13/2 neutron orbital in this mass region has been seen.

Instabilities and spatial complexity in a laser

Abstract: We discuss the emergence of spatial structures in a ring laser model with transverse effects. The emphasis of this study is on the development of a description that can capture the essential features of transverse dynamics without the need for large-scale numerical efforts. We introduce an extension of the uniform field limit and derive a set of modal equations that we solve with conventional numerical methods. Our solutions show evidence of transverse mode competition in the laser dynamics, leading to both time-dependent and multimode stationary (cooperative frequency-locking) behaviors. In the time-dependent regime we analyze the resulting spatial structures and suggest a scheme for the investigation and characterization of spatial complexity.