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)

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The extended form of the Jones and Furry theory, which describes the behavior of a multicomponent heavy isotopic gas in a Clusius-Dickel thermal diffusion column, is tested. Experimental and theoretical values of the thermal diffusion column transport equation coefficients Hsub{ik},Ksub{c}, and Ksub{d}, are determined for krypton, a heavy isotopic gas with six isotopes. The experiments are carried out in a column of the hotwire type, at three wire temperatures: Tsub{H}=350 degrees C, 500 degrees C and 800 degrees C. Good agreement is found between the theoretical and experimental values of the coefficients. Seven of nine of the experimentally determined values of the coefficients agree within +- 10% with the corressponding theoretical values. The remaining two experimental values agree within +- 20% with the corresponding theoretical values.

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The spectral distribution of the flux of positrons inside a beta radioactive medium was experimentally determined using an anthracene coincidence scintillation spectrometer. Positrons leaving a copper cavity source containing Cu/sup 64/ were absorbed in a thin anthracene crystal. The light pulse from the anthracene was recorded in a 256 channel analyzer if a NaI scintillation spectrometer nearby recorded simultaneously a count under the total absorption peak for annihilation radiation. Thus, discrimination against negative and secondary electrons was obtained which permitted observation of the primary positron slowing down flux. Data were corrected for the non-linear pulse height vs energy relationship in anthracene by a semi-empirical theory due to Birks, the validity of which was demonstrated by its use in obtaining a linear Fermi plot of Pm/sup 147/. Positron spectra were corrected also for Compton absorption of the annihilation radiation in the anthracene. Results were compared with the theoretical continuous-slowing-down model. Over the energy range measured (20-- 650 kev) it was concluded that the continuous-slowing-down model gives the correct shape for the primary slowing-down spectrum. 43 references. (auth)