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5 pages, 1 table, 2 figures.-- Presented at the International Conference on Finite Fermionic Systems: Nilsson Model 50 years (Lund University, Sweden, June 14–18, 2005).-- PACS nrs.: 23.40.Hc, 27.20.+n, 24.80.+y., A newly developed technique for dealing with three-body decays of broad isolated levels is extended to deal with the broad, overlapping levels found at 2-9 MeV excitation energy in Be-9. The levels are populated through beta-decay of Li-9. The method gives firm evidence for the existence of several levels. Angular correlation studies allow spin values to be assigned.

An analytical expression for the E1 strength function for two-neutron halo nuclei is derived in a three-body model. Yukawa type wavefunctions for the ground state and three-body plane waves for the final state were used. The expression reproduces the shape and the position of the maximum of the experimental strength function for well. It is shown that the exact expression can be approximated over a large energy range with a simple function by introducing an effective two-neutron separation energy. This provides a theoretical approach for quick estimates of the E1 strength function for two-body halo nuclei.

The existing data from a kinematically complete experiment of 11Li fragmentation on a heavy target have been analysed in a direct electric-dipole excitation model within a strict three-body formulation. The nn and 9Li-2n relative energy distributions have been calculated from the measured 11Li excitation energy distribution and compared with the experimental data.

Beta-delayed proton emission may occur at very low rates in the decays of the light nuclei 11Be and 8B. This paper explores the potential physical significance of such decays, estimates their rates and reports on first attempts to detect them: an experiment at ISOLDE/CERN gives a branching ratio for 11Be of (2.5 ± 2.5) × 10−6 and an experiment at JYFL a 95% confidence upper limit of 2.6 × 10−5 for 8B.

Empirical evidence suggests that neutron pairing plays an important role for the stability of nuclei near the neutron drip line. It is shown that the low binding of these nuclei will lead to a neutronization of the nuclear surface and possibly to large cross-sections for Coulomb dissociation, which then offers a new way to study clusters and their binding energies.

Internal bremsstrahlung spectra following electron-capture (EC) beta decay have been calculated in two versions of an extended Glauber-Martin theory. The case of 193Pt which has a QEC-value that falls 20 keV below the 1s resonance point, is ideally suited for a test of this theory. The experimental data, both singles and L X-ray-bremsstrahlung coincidences, show that all the main features of the spectra are understood, although the absolute intensities agree to within a factor 1.5-2 only. The same calculations have been applied to 163Ho, with a QEC of 2.82 keV, one of the main cases for an accurate measurement of the electron neutrino mass. The predicted occurence of an interference minimum near the end-point, however, makes the m(ve) experiment less attractive than one might have hoped for.

The decay of 210Rn to 210At has been investigated. Gamma rays were recorded in singles and coincidence using Ge(Li) detectors. Conversion electrons were studied with a Si(Li) detector and a double focusing magnetic spectrometer. Internal conversion coefficients have been deduced and several transition multipolarities have been determined. A decay scheme is presented and spin assignments are made. The electron capture decay from 210Rn has been found to proceed mainly to three levels in 210At: 2 280.8 keV (0-, (1-)), 1 525.5 keV (1+) and 1 488.6 keV (1+), with log ft values

The decay of 209Rn to levels in 209At has been investigated. Gamma rays were studied in singles and coincidences using Ge(Li) detectors. Conversion electrons were recorded with a Si(Li) detector. A decay scheme is suggested, indicating electron capture branches to positive parity states at 1 954, 2 136 and 2 415 keV. These states are interpreted in terms of core excitations in conformity with the 207Bi isotone. Two levels at 408 and 746 keV, tentatively assigned spin 7/2-, are fed by electron capture with log ft values of 6.8 and 6.4, respectively.

A target of 16.1 h 76Br, prepared by on-line isotope separation at the ISOLDE facility, CERN, has been exposed to thermal neutrons from the Grenoble high-flux reactor. Four proton branches from the capturing state at 11 MeV in 77Br to the 0+ ground state and the three lowest 2+ states of 76Se were observed. The total (nth, p) cross-section was measured as 224 ± 42 b and the Q-value for the reaction as 5730 ± 15 keV.