B. D. Kern

UNISOR on-line nuclear orientation facility (UNISOR/NOF)

The UNISOR on-line nuclear orientation facility (UNISOR/NOF) consists of a3He−4He dilution refrigerator on line to the isotope separator. Nuclei are implanted directly into a target foil which is soldered to the bottom accessed cold finger of the refrigerator. A 1.5 T superconducting magnet polarizes the ferromagnetic target foils and determines the axis of symmetry. Up to eight gamma detectors can be positioned around the refrigerator, each 9 cm from the target. A unique feature of this system is that the k=4 term in the directional distribution function can be directly and unambigously deduced so that a single solution for the mixing ratio can be found. The first on-line experiment at this facility reported here was a study of the decay of the191Hg and193Hg isotopes.

Unisor on‐line nuclear orientation facility

The UNISOR on‐line nuclear orientation facility consists of a He3–He4 dilution refrigerator on line to the isotope separator. Nuclei are implanted directly onto a target foil soldered to the bottom accessed cold finger of the refrigerator. A 1.5 T superconducting magnet polarizes the ferromagnetic target foils and determines the axis of symmetry. Up to eight gamma detectors can be positioned around the refrigerator, each 9 cm from the target. A unique feature of this system is that the k=4 term in the directional distribution function can be deduced so that a single solution for the mixing ratio can be found.

The measurement of beta asymmetries at UNISOR/NOF using external plastic scintillator detectors

The performance of two external plastic scintillator detectors has been tested in an off-line mode using a source of106RuFe at UNISOR/NOF. The measurement of beta asymmetries at various temperatures has resulted in the reproduction of the previously-determined magnetic dipole moment for the 1+ ground state of106Rh and in addition the conclusion that the sign of this moment is positive.

On-line nuclear orientation of116m,gSb,116In and114Sb

Angular distribution data for gamma radiation from separated116,116m,114Sb and116In oriented on-line at mK temperatures at the UNISOR Nuclear Orientation Facility, Oak Ridge, is reported. Mixing ratios of three 2+ states in116Sn are deduced. The magnetic moments of116mSb, (+)2.59(22) µN and114Sb, (+)1.72(8) µN, are extracted with full allowance for incomplete spin-lattice relaxation. Single particle descriptions of these states are briefly discussed.

Non-yrast level structure of35Nd via beta decay of135Pm

The isotope135Nd has been studied through the β-decay of mass-separated135pm. He-jet transported samples without mass-separation were also studied. The parent135Pm has isomers with β-decay half-lives of 40±3 s and 49±3 s. The low-lying non-yrast structure of135Nd is shown to consist of a group of levels which decay to a 65.1-keV isomeric level which is not reached in the yrast cascades.

Energy levels and structure of light rare‐earth nuclei 136,138,140Sm and 132,134,136Nd, via beta decay

Levels in 136,138,140Sm were populated by the beta decay of Eu, following (HI,pxn) reactions and on‐line mass separation, Members of the γ band were observed in all three daughter nuclei. Spectroscopic calculations were made using the triaxial rotor model, with all parameters derived microscopically from Woods–Saxon deformed shell model. Comparison with the data supports the characterization of these nuclei in terms of a triaxial intrinsic shape. Improved decay schemes for 132,134,136Nd are given.