The lifetime of negative muons has been measured in 50 elements plus 8 isotopes. For light elements the accuracy of 2 to 3 ns is a significant improvement over most previous measurements. In heavier elements the accuracy is 1 to 2 ns, which is comparable to, or better than, previous results, with reasonable agreement in most cases. For "0, Sc, Dy, and Er there were no previous data. The total capture rates have been deduced and compared to various calculations.

ARSTRACT 'I'he reaction Xij8(r,77)Ni" has been it~vcstigated between 12-and 24-Mev maximum photon energy. The absolute yield value a t 22 Mev was found to be much lower than reported previously. Also, a shorter half-life of Ni57 was obtained. The cross section was determined using two different methods.'Manuscript rcceived February 16, 1050.

Gamma–gamma coincidence measurements on the decay of 9.3-hour 127Te to 127I form the basis of the decay scheme presented, which confirms the accepted decay sequence. Directional correlation measurements have been made on the 215–203 keV and 360–58 keV cascades. The respective correlation functions are:[Formula: see text]The directional correlation results have been interpreted in terms of the accepted spin sequence, and limits of multipole mixtures are presented. A short discussion of the collective properties of the levels is presented.

Self-absorption and backscattering of β-particles have been studied in a proportional flow-counter, and empirical formulae are obtained to correct for these factors in absolute β-counting. The correction factors will depend on the thickness of the sample, the atomic number of the backscattering material, and the maximum energy of the β-particles. Relationships between the mass-absorption coefficient and the maximum energy of the β-particles for the primary β-particles, and between the mass-absorption coefficient, the maximum energy of the β-particles, and the atomic number of the backscattering material for the backscattered β-particles, are obtained. The backscattering function is found to depend on the atomic number of the backscattering material alone.

Absolute yields of the reactions C12(γ,n)C11 and O16(γ,n)O15 have been determined at 22-Mev maximum bremsstrahlung energy using the University of Saskatchewan 24-Mev betatron. For the reaction C12(γ,n)C11 a yield curve from threshold to 24 Mev has been obtained and the cross-section curve for the reaction computed. A thorough comparison with other results has been made.

Approximately 35 000 K~-capture stars in an emulsion stack were examined for hyperfragments. Using a mass selection criterion for all events, a sample of 13 7r~-mesonic decays and one nonmesonic decay of hydrogen hyperfragments was identified for the purpose of estimating the relative rates of decay for the 7r~-mesonic and nonmesonic modes.

Approximately 35 000 K~~ capture stars in an emulsion stack were examined for hyperfragments. A sample of 7r~-mesonic and nonmesonic He hyperfragments was selected for the purpose of estimating the nonmesonic-to-7r~"-mesonic decay ratios for AHe and for AHe 6 . The following values were obtained: Q(AHC) = 1.02±0.15, Q(AHe 5 ) = 1.21 ±0.19, for the nonmesonic-to-7r~ mesonic decay ratios of AHe and AHe 5 , respectively. Also, an attempt was made to estimate the ratio of proton stimulation to neutron stimulation for the nonmesonic decays of AHe and AHe 5 , for various cutoff energies of the observed "fast protons." Furthermore, by combining our data with previous results, we obtained estimates of the nonmesonic and the total decay rates of AHe 4 and AHe 5 .

Angular-correlation measurements have been made of the cascade gamma rays following the beta decay of Rb 84 . The results show that the spin and parity of the second excited state of Kr 84 is 2+. The energies of the gamma rays in this decay have also been remeasured using a lithium-drifted germanium detector and are SS3,1018, and 1901 keV with errors of ±2 keV and relative intensities of 100:0.53:1.06, respectively.