E. Radermacher

The response of the Euroball Cluster detector to γ-radiation up to 10 MeV

The Euroball Cluster detector consists of seven closely packed hexagonal encapsulated germanium detectors which are mounted in a common cryostat and surrounded by a BGO suppression shield. By adding back the Compton scattered events between the seven germanium detectors the detector system behaves similar as a single germanium detector with a volume of 2000 cm3. The response of this very large germanium detector to γ-rays up to 10 MeV has been measured using a short lived 24Al source produced at the Cologne FN Tandem accelerator. At 10 MeV the efficiency of the Cluster detector is nearly one order of magnitude larger than that of a 30% germanium detector.

The γ-decay of single-particle states in 205Pb and 207Pb using an Euroball Cluster detector

Abstract Single-particle states in the odd lead isotopes 205 Pb and 207 Pb were investigated using an Euroball Cluster detector and five usual Ge detectors at the Osiris cube spectrometer of the Cologne FN-Tandem accelerator. The states were populated by the subCoulomb neutron stripping reaction ( d , pγ ) at 10 MeV. About 102 γ-transitions could be observed for the first time. The energy of most of the observed states could be determined to an accuracy of about 0.2 keV. The ground state wave function of 206 Pb could be determined to contain: 66(5) % ν3 p 1 2 −2 , 19(3) % ν2 f 5 2 −2 , 10(3) % ν3 p 3 2 −2 , and 2(1) % ν2 f 7 2 −2 .

Identification of sum up lines in γ-ray spectra using a composite germanium detector

Abstract A method to decompose a line in a γ-ray spectrum registered with a composite Ge detector into a sum up and a direct part is presented. The method has been tested using an Euroball Cluster detector.

High spin states in147Tb

The level scheme of147Tb has been extended to 116 levels and 198 transitions in two experiments with the OSIRIS Compton suppressed detector array at the HMI Berlin with the reactions122Sn(31P, 6n)147Tb at 160 MeV and120Sn(31P, 4n)147Tb at 152 MeV. Evidence for a new high spin isomer atE=7664.1 keV with a life-time of the order of 2 ns has been found.

Crossing of the high-spin members of the and multiplets in

The nucleus was studied through two experiments, at MeV and at MeV. From measured angular distributions of the scattered deuterons and from a DCO analysis of the observed -rays, spin-parity assignments and information about the structure of the states were obtained. We discuss only the results for the high-spin members of the and multiplets and show that a crossing of the and states from the two multiplets appears due to the interaction of the quadrupole moments of the and core states with the quadrupole moment of the hole.

High spin states in148Tb

The level scheme of148Tb has been extended to an excitation energyEx=14.0 MeV and a spinI≈ 38ħ in two experiments with the OSIRIS Comptom suppressed detector array at the HMI Berlin using the reactions122Sn(31P,5n)148Tb at 160 MeV and120Sn(31P,3n)148Tb at 152 MeV.

High spin states in145Gd

The data from two experiments with heavy ion induced reactions at the OSIRIS Compton suppressed Ge detector array has been analyzed to study high spin states in145Gd. The level scheme of145Gd has been extended up to an excitation energy of 12 MeV and an estimated spin of 25 ħ. No evidence for high spin isomers was found.