R. Schöneberg

Der Zerfall des Pt195m und des Au195

The decays of Pt195m(4.1 d) and Au195 (192 d) have been investigated with a Ge(Li)-counter and a Ge(Li)-NaJ coincidence circuit. Theγ-spectrum of Pt195m showed new lines with energies 239.5, 140.7 and 211.1 keV found earlier only in coulomb excitation experiments. Theγ-spectrum of Au195 established a new level of Pt195 at 199.8 keV with single particle character. These results led to a modified level scheme and modified reduced transition probabilities for the levels of Pt195. By comparison of theγ-spectrum of Pt195m and Au195 the ratios of electron capture branches of Au195→Pt195 decay have been determined.

Der Zerfall des Xe123,T1/2=2,08h

Xe123 (T1/2=2.08 h) was produced by bombarding Te122 with 48 MeV α-particles. The radioactive Xe123 gas was collected during irradiation in liquid air cooled glass ampoules.The gamma rays associated with the decay of Xe123 have been investigated using Ge(Li)- and NaJ(Tl)-counters and a Ge(Li)-NaJ(Tl)-coincidence circuit. 57 gamma transitions in the energy range from 148.7 keV to 2559.1 keV have been found.By depositing the radioactive Xe-ions on Ti-foils sources were obtained thin enough to study the conversion electrons using a Si(Li)-counter. The conversion coefficients for the intensive J123 transitions with low energy were determined.A level scheme for Xe123→J123 which accounts for almost all observed γ-transitions having 16 levels is proposed.Furthermore some new data for the J121 and J123 decay are presented.

Der Zerfall des Co56

Theγ-ray-spectrum of Fe56 associated with the E.C.- andβ+-decay of Co56 has been measured with Ge(Li)-crystals. 6 newγ-ray-transitions have been found in this spectrum deexciting 3 new levels in Fe56. The intensities of these transitions have been estimated and a new level-scheme is proposed. The new levels could be identified with some of previously reported levels found in Fe56(p, p′)-measurements.

Der Zerfall des Cu61

Theγ-ray-spectrum of Ni61 associated with the E.C. andΒ+-decay of Cu61 has been measured with a Ge(Li)-counter. The observed 14 newγ-ray-transitions led to a new level-scheme for this decay with Ni61-Ievels at: 67.7, 282.9, 656.0, 907.9, 1099.8, 1132.7, 1186.8, 1610.6, 1730.8 and 2128.0 keV. Five of these levels were known from earlier investigations of Cu61-decay, but all of them could be identified with some of previously reported levels found in scattering experiments. As far as possible spin and parity assignments have been made and are compared with the results of scattering experiments.

Der Zerfall des Pt191

Theγ-spectrum of Pt191 has been measured with a Ge(Li)-counter. In addition to earlier measurements about 20 newγ-rays have been found, 10 of them were known as conversion-lines in earlier investigations. The intensities of these conversion-lines and the estimatedγ-ray-intensities allowed the determination of conversion-coefficients. A new level-scheme with 5 new levels at 569, 602, 660, 865 and 940 keV is proposed.

Der Zerfall von Er171 und Er165

The gamma spectrum of a neutron-activated probe of natural Er/sub 2/O/ sub 3/ revealed an additional peak at 55 kev, which was attributed to the characteristic K x ray from the decay of Er/sup 165/ by measurement of its half life in a NaI crystal. The activation cross section for thermal reactor neutrons for Er/sup 164/(n, gamma )Er/sup 165/ was determined to be sigma /sub A/ = 20 plus or minus 7 bar n. The averaged conversion coefficient of the 111, 116, and 124 kev gamma rays from Er/sup 171/ yields Tm/sup 171/ was remeasured with scintillation counter equipment. (auth)Theγ-spectrum of a neutronactivated probe of natural Er2O3 revealed an additional peak at 55 keV, which was attributed to the characteristicK-Röntgenstrahlung from the decay of Er165 by measurement of its half-life in a NaJ-wellcrystal. The activation cross section for thermal reactor neutrons for Er164 (n, γ) Er165 has been determined to σA=20±7 barn. The averaged conversion coefficient of the 111, 116 and 124 keV γ-rays from Er171→Tm171 have been remeasured with scintillation counter equipment.

Der Zerfall des Cu60

Theγ-ray-spectrum of Ni60 associated with the E.C.- and β+-decay of Cu60 has been measured with Ge(Li)-crystals. The observedγ-ray-transitions led to a new levelscheme for this decay with Ni60-levels at: 1332, 2159, 2286, 2627, 3125, 3196, 3272, 3391, 4025, 4080, 4332, 4500, 4554 and 4584 keV, most of them could be identified with previously reported levels found in scattering experiments. As far as possible spin and parity assignments have been made, and the levels are compared with phonon and quasi-particle theory.

Verzögerte Neutronen beim Zerfall des Li9

The neutronspectrum of the delayed-neutron-emitter Li9 was measured with a cooled Li69J-crystal. Neutrons resulting from the decay of the 2,43 MeV level in Be9 revealed a continuum with endpoint-energy of 760 keV. The energy-region above this endpoint up to 7 MeV showed no evidence for deexcitation of higher excited levels of Be9 by monoenergetic neutrons. A discussion of the experimental results and the various models of the nuclear theory describing the Be9-nucleus and its excited levels will be given.

Der Zerfall des Xe 123 , T 1/2 =2,08h

Xe123 (T1/2=2.08 h) was produced by bombarding Te122 with 48 MeV α-particles. The radioactive Xe123 gas was collected during irradiation in liquid air cooled glass ampoules.The gamma rays associated with the decay of Xe123 have been investigated using Ge(Li)- and NaJ(Tl)-counters and a Ge(Li)-NaJ(Tl)-coincidence circuit. 57 gamma transitions in the energy range from 148.7 keV to 2559.1 keV have been found.By depositing the radioactive Xe-ions on Ti-foils sources were obtained thin enough to study the conversion electrons using a Si(Li)-counter. The conversion coefficients for the intensive J123 transitions with low energy were determined.A level scheme for Xe123→J123 which accounts for almost all observed γ-transitions having 16 levels is proposed.Furthermore some new data for the J121 and J123 decay are presented.

Der Zerfall des Xe123,T 1/2=2,08h@@@Decay of Xe123,T 1/2=2.08 h

Xe123 (T1/2=2.08 h) was produced by bombarding Te122 with 48 MeV α-particles. The radioactive Xe123 gas was collected during irradiation in liquid air cooled glass ampoules.The gamma rays associated with the decay of Xe123 have been investigated using Ge(Li)- and NaJ(Tl)-counters and a Ge(Li)-NaJ(Tl)-coincidence circuit. 57 gamma transitions in the energy range from 148.7 keV to 2559.1 keV have been found.By depositing the radioactive Xe-ions on Ti-foils sources were obtained thin enough to study the conversion electrons using a Si(Li)-counter. The conversion coefficients for the intensive J123 transitions with low energy were determined.A level scheme for Xe123→J123 which accounts for almost all observed γ-transitions having 16 levels is proposed.Furthermore some new data for the J121 and J123 decay are presented.