Selection of heavy ion reaction channels via particle K X-ray coincidences

To identify the residual nuclei in very asymmetric heavy-ion reactions heavy-ion K X-ray coincidences have been measured. The usefulness and limitations of this method are discussed, and its feasibility is demonstrated in a study of the 14N+197Au reaction at 140 MeV

High-spin states in 232U investigated with the 232Th(α, 4nγ) reaction

The ground-state rotational band of 232U is established up to Iπ = 16+ (tentatively 18+) through a study of the 232Th(α, 4nγ) reaction. Conversion electron spectroscopy is found to be especially useful in circumventing the difficulties caused by strong fission competition

Negative parity bands in 100Ru and 150Sm and the interacting boson approximation

Ground-state band members up to Jπ = 10+ in 100Ru and up to 14+ in 150Sm and odd-spin negative parity states up to 15− in both nuclei have been identified from (α, 4n) in-beam γ-ray and conversion electron spectra. The data are interpreted in terms of interacting quadrupole and octupole bosons

Search for short-lived axions in a nuclear isoscalar transition

Axions, if existing, can cause a strong signal of positron-electron pairs in isoscalar M1 transitions in competition with gamma-ray emission. We searched for such a signal in the 3.59 MeV transition in 10B with a fourfold Mini-Orange spectrometer. No axion events were found within two percent of the prediction for the standard axion- to γ-ray branching ratio

Search for high-spin isomeric states in the rare-earth region

Several new high-spin (I>10) isomeric states in the mass region A=144–164 are located in a systematic search with 12C induced reactions, employing a sixteen NaI (Tl)Ge(Li) detector multiplicity filter. The proximity to the N=82 neutron shell closure strongly suggests that shell effects contribute significantly to this isomerism

E0 transitions between lowest Kπ=0+ bands in 232U and 234U

Regular patterns of E0 transitions were observed after 232Th(α,xn reactions. They indicate that the moments of inertia of β- and ground-state bands are nearly equal in 234U, in contrast to its even-even neighbours 232Th, 232U and 236U

Band structures in 98Ru and 99Ru

The level schemes of 98, 99Ru were studied with the reactions 98Mo(α, 3nγ) and 98Mo(α, 4nγ) at Eα = 35 to 55 MeV, using a large variety of in-beam γ-ray detection techniques and conversion-electron measurements. A search for the 3− state was carried out with the reaction 98Ru(p, p′). The ground-state band of 98Ru was excited up to Jπ = (12)+ and a negative-parity band up to (15)−. New levels in 98Ru were found at Ex = 2285 (Jπ = 4+), 2435 (Jπ = (3−, 4+)), 2671, 3540, 4224, 4847, 4915 (Jπ = (12)+), 4989 (Jπ = (12+)), 5521 (Jπ = (13)−), 5889, 6591 (Jπ = (15)−), and 7621 keV. New unambiguous spin and parity assignments were made for the levels at Ex = 2014 and 3852 keV, as Jπ = 3+ and 9−, respectively. New levels in 99Ru were found at Ex = 1976, 2021 (), 2393, 2401 (), 2875 (π = (+)), 3037, 3201 (), 3460 (), 3484 (), 3985, 4224 (), and 5359 keV. The 1070 keV, level in 99Ru has a half-life of 2.8 ns. A strongly excited negative-parity band is built on this level. A positive-parity band based on the ground state was excited up to . The level schemes are well reproduced by the interacting boson model in the vibrational limit