[en] The NORDBALL is an array of 20 Compton suppressed Germanium spectrometers in a close packed geometry forming a truncated icosahedron; 12 pentagonal and 20 hexagonal surfaces inscribing a sphere. A variety of selective devices are introduced to work in conjunction with the Ge-spectrometers in order to provide unique sensitivity in nuclear structure studies. Charged particle detection as well as neutron multiplicity measurements in coincidence with Ge-spectrometers will be discussed. Two specific experiments both involving lifetime measurements by the DSAM (Doppler Shift Attenuation Method) will be discussed. A first report of a strongly deformed rotational band in ¹³¹Ce populated by oxygen beams and a report on deformation dependent transition rates in ¹⁵⁷Ho will be presented. (author)

No abstract available

[en] The connection between the super-deformed (SD) and the normal-deformed (ND) states has not been observed yet owing its difficulty to a statistical, highly fragmented decay path out of the SD bands. This leaves both the spin and the excitation energy of the SD bands undetermined. In the present contribution we are presenting results of a new experimental approach where we take advantage of triple and higher fold coincidences to study the decay out of a SD band. We carried out an experiment at the Niels Bohr Institute Tandem Accelerator Laboratory where we used the (160 MeV) ³⁷Cl + ¹¹⁰Pd → ¹⁴³Eu + 4n reaction. (Author)

[en] When producing compound nuclei far from the line of stability in HI-induced reactions, charged particle emission starts to compete strongly with the emission of neutrons in the decay process. In other words, the cross-section for production of very neutron deficient nuclei via (HI,xn) reactions drops rapidly. A tool to enhance these rare channels was developed and used at the Stockholm 225-cm cyclotron. By surrounding the target with a plastic scintillator, almost all emitted charged particles can be detected. Gamma spectra are then recorded in germanium detectors in anticoincidence with the charged particles. (author)

[en] The gamma radiation due to the de-excitation of the 2¹⁺ and 4¹⁺ levels in ₅₀Cr was studied as a function of the energy, which was varied in 10 keV steps. In particular, strong peaks in the cross sections were observed for scattering to the 4¹⁺ level. Using experimental data on spin-flip probability, the contribution of the statistical mechanism to the excitation of the 2¹⁺ level has been estimated. The estimated ratio GAMMA⁰/D⁰=0.24 was obtained for 11 MeV excitation of the compound nucleus. The contribution of direct reaction and isobaric analogue resonances to the cross section is discussed. (author)

No abstract available

[en] The ¹⁵⁰Sm nucleus has been studied to high spins in a measurement of γ radiation following the ¹³⁶Xe (¹⁸O, 4n)¹⁵⁰Sm, compound-nucleus reaction at beam energy of 76 MeV. The measurement was performed at NBI Risoe using the NORDBALL array. Alternating parity, s=+1 band in ¹⁵⁰Sm has been observed up to spin I = 22. This band is crossed by two aligned bands, corresponding to a reflection-symmetric shape. After the second crossing the s=+1 band ends abruptly, suggesting that the octupole shape vanishes in ¹⁵⁰Sm above spin I =22, as predicted by calculations. Other explanations, assuming continuation of the s = +1 band past the two alignments are also discussed. (author)

[en] Reaction cross sections for α-particles have been measured for ⁹Be, ¹²C, ¹⁶O, ²⁸Si, ⁴⁰Ca, ^58,60Ni, ^{112,116,120,124}Sn, and ²⁰⁸Pb at 117.2, 163.9 and 192.4 MeV and for the lighter nuclei also at 69.6 MeV. The results are compared with predictions from optical model calculations using phenomenological, global and double-folded optical potentials. Comparisons are also made with predictions using the Glauber model approach suggested by Bertsch, Brown and Sagawa

[en] The angular momentum input in incomplete fusion reactions induced by 151 MeV sup(14)N ions on sup(154)Sm was determined by measuring the γ-ray multiplicity in coincidence with emitted charged particles. The average multiplicity of γ-ray cascades following the emission of fast p, d and t particles in reactions leading to sup(158)Er amounts to 17.5 which is far below the value of 31, reported earlier for a bombarding energy of 167 MeV. Sum-rule model predictions for preequilibrium processes are in good agreement with the present results. (author)

[en] Reaction cross sections for 65.5 MeV protons have been measured for ⁹Be, ¹²C, ¹⁶O, ²⁸Si, ⁴⁰Ca, ^58,60Ni, ^{112,116,118,120,124}Sn, and ²⁰⁸Pb. The results are compared with optical model predictions using relativistic global potentials