Biomedical subjects

A Zilges

Publications and source records attributed to A Zilges.

At least 19 recordsLinked to original sources

PubMed2006

Nature of the pygmy dipole resonance in 140Ce studied in (alpha, alpha' gamma) experiments.

A concentration of electric-dipole excitations below the particle threshold, which is frequently denoted as the pygmy dipole resonance, has been studied in the semimagic nucleus 140Ce in (alpha, alpha' gamma) experiments at E alpha = 136 MeV. The technique of alpha-gamma coincidence experiments allows the separation of E1 excitations from states of other multipolarities in the same energy region and provides an excellent energy resolution to allow a detailed analysis for each state. The experimental results show that the PDR splits into two parts with different nuclear structure: one part which is excited in (alpha, alpha' gamma) as well as (gamma, gamma') experiments and one part which is excited only in (gamma, gamma').

Journal Article↗

PubMed2004

Microscopic nature of the pygmy dipole resonance: the stable Ca isotopes.

The electric dipole strength distribution in 44Ca has been measured up to 10 MeV in high resolution photon scattering experiments for the first time. The data obtained have been compared to earlier measurements on (40,48)Ca in order to view the evolution of the electric pygmy dipole resonance (PDR). Calculations that were performed within the framework of the microscopic extended theory of finite Fermi systems, which adds contributions of the quasiparticle-phonon coupling to random phase approximation calculations, give a qualitative agreement with the experimental data for all three isotopes. We have shown that it is necessary to include this coupling to describe the PDR.

Journal Article↗

PubMed2000

Measurement of the dipole and electric quadrupole strength distributions up to 10 MeV in the doubly magic nuclei 40Ca and 48Ca

The doubly magic nuclei 40Ca and 48Ca have been studied in high resolution photon scattering experiments. We have derived absolute dipole and quadrupole excitation strengths up to 10 MeV. Evidence was found for a two-phonon quadrupole-octupole state in 48Ca. At higher energies in contrast to 40Ca, a concentration of dipole strength is observed in 48Ca which is discussed in terms of a pygmy resonance originating from the large neutron excess.

Journal Article↗

PubMed1996