Experimental studies of the relative atomic mu --meson capture probabilities in the constituents of chemical compounds are described. Fermi and Teller had predicted that the atomic-capture probability is proportional to the nuclear charge of the atomic species weighted by its atomic concentration. This is sometimes referred to as the Fermi-Teller Z law.'' Previous experiments indicated no clear systematics to this capture process, and there are conflicts between the results of several measurements made with the same or similar compounds. In these experiments the capturing atom was identified by detection of either mesic x rays or decay electrons from mu /sup -/ mesons bound in the mesic K shell in the atomic species, In these experiments oxides and sulfides of some medium- and high-Z elements as well as two metallic solutions were used, and a nuclear capture product (neutron) rather than the decay electrons was detected. Results show that among the substances examIned, namely CuO, Sb/sub 2/O/sub 3, PbO, CuS, Sb/sub 2/S/sub 3/, PbS AgLi, and CuAu, the Z law'' behavior is not indicated either in insulators or in metals, although in all cases there is a preference for capturing in the atom of higher Z. If the atomic-capture probability is …

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The effects of certain pulse-shaping networks on the signal-to-noise ratio of a nuclear pulse amplifier were considered. The shaping networks discussed are: equal RC-integrating and RC-differentiating time constant, single- delay-line clipper and RC integrator, and doubledelay-line clipper and RC integrator. The effects of these networks on the signal, when high count rates and overload pulses are present, were also considered. Equations and curves were developed for the energy resolution (signal-tonoise ratio) and resolving time (related to the ability to operate at high counting rates) of the networks. Experimental results are shown for the energy resolution of the types of pulse- shaping networks considered. (auth)

The nuclear radiations of nuclides: U{sup 233}, Pu{sup 239}, Bk{sup 243}, Bk{sup 244}, Bk{sup 245}, Bk{sup 246}, Bk{sup 249}, Cf{sup 249}, and Fm{sup 255} were investigated with high-resolution spectrometers. The {alpha}-particle spectra of all nuclides except Bk{sup 249} were measured with 6 mm diameter surface-barrier detectors. Bk{sup 249} {alpha}-particles were analyzed with a double-focusing magnetic spectrograph. The {gamma}-singles were examined with the recently developed Ge(Li) and Si(Li) detectors coupled with very-low noise 'internal FET' preamplifiers. Weak alpha groups were observed in coincidence with {gamma}-rays, detected with a NaI(Tl) scintillation spectrometer. To improve the over-all coincidence efficiency a new coincidence apparatus was designed and built. This instrument consisted of a cooled 4.5 cm diameter semiconductor detector for {alpha}-particle detection and a 3 cm diameter by 2.7 cm long Ge(Li) detector for {gamma}-ray analysis. The Ge(Li) detector could also be replaced with a NaI(Tl) detector. Cf{sup 249} conversion electrons were measured with a cooled Si(Li) detector coupled with an internal FET preamplifier. On the basis of the present work and previous information, energy-level diagrams of the daughter nuclei have been constructed. The levels have been grouped into rotational bands built on Nilsson single-particle states. Because of identification of several rotational members of …

The development of rapid, selective, and sensitive methods for the determination of osmium in liquid samples is reported. The specific application of primary interest was the estimation of microgram or milligram quantities of osmium in homogeneous reactcr fuel solutions which contain uranyl sulfate as the major component and corrosion products of stainless steel as minor components. (W.L.H.)