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The lattice location of $^{147}$Nd and $^{147^{*}}$Pm in thin-film, single-crystalline hexagonal GaN was studied by means of the emission channeling technique. The angular emission yields of $\beta^{-}$-particles and conversion electrons emitted by the radioactive isotopes $^{147}$Nd and $^{147^{*}}$Pm were measured using a position-sensitive detector following 60 keV room temperature implantation at a dose of 1 $\times 10^{13}$ cm$^{-2}$ and annealing at 900°C. The emission patterns around the [0001], [1102], [1101], and [2113] crystal axes give direct evidence that the majority (70%) of Nd and Pm atoms occupy substitutional Ga sites.

On-line Perturbed Angular Correlation (PAC) experiments were performed on the 66.0 keV excited state of 127 Cs, using the γ (114.7 keV)–e − L (66.0 keV) cascade from the decay of the short-lived 127 Ba ( T 1/2 =13 min) isotope produced at the ISOLDE facility at CERN. The PAC experiments were performed with an optimized γ–e − spectrometer coupled to the ISOLDE beam line, which allowed simultaneous implantation and measurement. The optimization of the experiment is described and the first results on metallic foils and single crystals of Al, Be, Ga, Zn, and Ni are presented and discussed. The derived nuclear moments of the 66.0 keV excited state of 127 Cs are | μ |=2.9(2) μ N and | Q |=0.58(12) b . Applications of this new PAC isotope are outlined.

High quality YBa$_{2}$Cu$_{3}$O$_{6+x}$ (YBCO) superconducting thin films were implanted with the radioactive $^{197m}$Hg (T$_{1/2}$ = 24 h) isotope to low fluences of 10$^{13}$ atoms/cm$^{2}$ and 60 keV energy. The lattice location and stability of the implanted Hg were studied combining the Perturbed Angular Correlation (PAC) and Emission Channeling (EC) techniques. We show that Hg can be introduced into the YBCO lattice by ion implantation into unique regular sites. The EC data show that Hg is located on a highly symmetric site on the YBCO lattice, while the PAC data suggests that Hg occupies the Cu(1) site. Annealing studies were performed under vacuum and O$_{2}$ atmosphere and show that Hg starts to diffuse only above 653 K.