K. Freitag

Nuclear orientation of111mCd in Zn and Be and the quadrupole moment of the 245keV state

The 48.7 m111mCd activity was implanted in Zn and Be single crystals which were soldered to the cold finger of a dilution refrigerator and kept below 0.2 K during implantation. Subsequent nuclear orientation experiments allowed the determination of the quadrupole interaction frequencyvQ of the 11/2− isomeric state of111Cd in Zn and Be as −139 (15) MHz and +43(16) MHz respectively. With these results we derive the quadrupole moment of the 5/2+ 245 keV level of111Cd including sign asQ = +0.83(13) b and the sign of the electric field gradient for Cd in Be. The half-life of111mCd was redetermined as 48.67 (6) m.

A dilution refrigerator for low temperature nuclear orientation experiments on line to an isotope separator

A system for low temperature nuclear orientation studies is presented where the sample can be prepared by in situ implantation of ions from an isotope separator into a host lattice at temperatures <0.5 K. The special construction of the cryostat necessary for this purpose as well as the beam line from the isotope separator to the cryostat are described in detail. A description of the data acquisition arrangement appropriate to the experiments planned is given. The cooling characteristics of the refrigerator under different operating conditions are discussed. A first successful nuclear magnetic resonance experiment on oriented 197mHg implanted in situ at T<0.5 K is reported.

Nuclear orientation and NMR/ON of205,207Po

Abstract205,207Po have keen implanted with an isotope separator on-line into cold host matrices of Fe, Ni, Zn and Be. Nuclear magnetic resonance of oriented207Po has been observed in Fe and Ni, of205Po in Fe. The resonance frequencies for zero external field are

Annealing behavior and lattice site location of Hf implanted GaN

\begin{gathered} v_L (^{207} Po\underline {Fe} ) = 575.08(20)MHz \hfill \\ v_L (^{207} Po\underline {Ni} ) = 160.1(8)MHz \hfill \\ v_L (^{205} Po\underline {Fe} ) = 551.7(8)MHz. \hfill \\ \end{gathered}

Quadrupole interaction at Ta and lattice location of Hf in Be

From the dependence of the resonance frequency on external magnetic field theg-factor of207Po was derived as

The electric quadrupole interaction of the 134 keV state of197Hg in the metal hosts Cd, Zn, Sn and Ti studied by e−-γ TDPAC measurements

g(^{207} Po) = + 0.31(22).