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16 pages, 2 tables, 4 figures.-- PACS nrs.: 23.40.-s; 23.20.-g; 27.20.+n.-- Printed version published May 17, 2004., The γ-ray spectrum following β-decay of Li-11 has been remeasured at the ISOLDE facility at CERN. Two new transitions were observed through the use of large Ge-detectors. Most γ-decays will follow β-delayed neutron emission. Information on the energy of the neutron is derived from analysis of the γ line-shape and used to construct a partial decay scheme for Li-11. Lifetime values for the 1(-) and 2(-) levels in Be-10 are also derived. A new partial decay scheme is presented., This work has been partially supported by the Swedish Research Council VR.

Beta-delayed neutron decay of 33 Na has been studied using the on-line mass separator ISOLDE. The delayed neutron spectra were measured by time-of-flight technique using fast scintillators. Two main neutron groups at 800(60) and 1020(80) keV were assigned to the 33 Na decay, showing evidence for strong feeding of states at about 4 MeV in 33 Mg. By simultaneous β–γ–n counting the delayed neutron emission probabilities P 1n =47(6)% and P 2n =13(3)% were determined. The half-life value for 33 Na, T 1/2 =8.0(3) ms , was measured by three different techniques, one employing identifying gamma transitions and two employing beta and neutron counting.

The magnitude of the Coulomb mixing parameter δ 1 has been experimentally deduced, for the first time, for the β decay of 74 Rb. The estimated magnitude is derived from the feeding of the non-analog first excited 0 + state in 74 Kr. The inferred upper limit of 0.07% is small compared to theoretical predictions. The half-life was measured to be 64.90(9) ms.  2001 Published by Elsevier Science B.V.