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A systematic on-line nuclear-orientation study of heavy isotopes using anisotropic ..cap alpha.. emission is reported for the first time. The anisotrophies recorded for /sup 199/At, /sup 201/At, and /sup 203/At are remarkably pronounced and strongly varying. At lower neutron number the ..cap alpha.. particles are more preferentially emitted perpendicularly to the nuclear-spin direction. This may be interpreted in terms of the high sensitivity of the ..cap alpha..-emission probability to changes in the nuclear shape.

We started a systematic determination of the beta-decay asymmetries of the mirror nuclei. Up to now only three such measurements exist, viz. the neutron, 19Ne and 35Ar [1–3]. For the neutron and for 19Ne, the values for the vector weak coupling constant Gy which can be extracted from the measured asymmetries yield values for the Cabibbo angle that are in good agreement with the ones derived from the Ft-values for superallowed 0+→0+ beta-transitions between T=1 states and from hyperon beta-decays. 35Ar on the other hand is anomalous for many years already, and suggests that the Cabibbo angle would be zero in nuclear beta-decay.

The technical realization of particle detection at very low temperatures (4K) has made it possible to study for the first time the anisotropic α‐decay of oriented nuclei which have been produced, separated and implanted on line. The measured α‐angular distributions reveal surprising new results on nuclear aspects as well as in solid state physics. The nuclear structure information from these data questions the older α‐decay theoretical interpretation and urges for a reaxamination of the earliest work on anisotropic α‐decay.

We have studied the induced magnetic moments of Ag in Ag/Fe multilayers with low temperature nuclear orientation. The experiments show that there are induced magnetic moments in the Ag spacer and these induced magnetic moments do not lie in the plane of the multilayer for 2 and 4 ML of Ag at low external field.

A first successful BF/NMR experiment was performed on 111In implanted in copper by use of the nuclear orientation technique. A historical survey of NMR/ON is given. The universal applicability of the BF/NMR technique, which allows the determination of Knight shifts and hyperfine anomalies is discussed.

The hyperfine field of xenon nuclei at lattice sites in iron has been determined from nuclear orientation experiments at temperatures between 11 mK and 80 mK obtained with a 3 He- 4 He dilution refrigerator. From the temperature dependence of the M4 γ-ray anisotropies of 133 Xe m and 131 Xe m implanted in iron by isotope separator, the fractions of xenon nuclei at high-field sites were determined, and a value H hf = 1510 ± 160 kG was deduced.