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A study was conducted to determine the adequacy of silver metaphosphate glass as a dosimeter for gamma radiation coexistent with fast neutrons. The fast-neutron response in the energy region encompassing a major pcrtion of the fission spectrum was determined and a method of decreasing the photon-energy dependence was developed. The size of the dosimeter and reprcducibility of results make this system a useful addition to gamma -ray dosimetry. particularly for gamma rays coexistent with neutrons. In some experiments the greatly increased sensitivity to low-energy photons permits accurate measurement of exposure doses as small as a few hundred milliroentgens. (auth)

S>Studies of the separation process known as zone melting were enclosed in 5 to 10 mm glass tubes and pulled through a stationary heater, which generated a liquid zone. The separation increased as the zone travel rate decreased, as the size of the tube increased, and as the difference in liquid density between the belk solid and the freezing interface increased. It was also found that, for vertical tubes, the separation was much greater when the fluid of lower density Between the buld zone and the freezing interface) was on the bottom the When it was on the top. Insertion of an axial thbe or rod of metal or glass into the zone also increased the separation. A correlation was developed which enables estimation of the separation for various - sithations in zone melting, Equations and principles were developed which enable estimation of the thermal requirements for zone melting and a theoretical study of pure diffusional mass transfer in some melting was also made. A general expression for concentration profiles was derived for materials with a constant distribution coefficient and a method for the rapid estimation of these concentration profiles was developed, Numerical results for eutectic-forming systems were obtained, and …

Experimental determinations of the longitudinal dispersion coefficient and the Peclet number were made for three binary gas systems. The experimental technique involved measuring the dispersion of a step function input to a column packed with glass beads. The diffusional model was employed to obtain the differential equation describing longitudinal dispersion in a packed column. This equation was solved with suitable boundary conditions, and the solution was used in the analysis of the experimental dispersion data. The experimental results show a variation in the Peclet number from 0.1 to 0.6, and in the eddy dispersion coefficient from 0.03 to 1.0 cm/sup 2//sec for the Reynolds number range from 0.03 to 1.0. (auth)

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By means of the Mandelstam representation, expressions are obtained for the two-pion-exchange contributions to the higher partial waves of N-N scattering. A set of ten invariant amplitudes is selected, of which each member obeys the Mandelstam representation. Dispersion relations are written for the amplitudes in which the discontinuities are absorptive parts for N-bar-N scattering. By means of the unitarity condition the absorptive parts are expressed as a partial- wave expansion in terms of the pi pi - NN partialwave amplitudes of Frazer and Fulco, except for the contributions of the pole in the pi -N system which are treated exactly in order to ensure better convergence of the partial-wave expansion. The N-N transition amplitudes in the angular-momentum representation are expressed in terms of the invariant amplitudes. (auth)

The reactions pi /sup -/ + p yields p + p + n and pi /sup -/ + p yields p + d were investigated. The calculations are based on thirdorder perturbation theory with pseudoscalar coupling between nucleons and pions and with a phenomenological treatment of the nucleon-nucleon interaction in the final state. The final-state interactions of the antinucleon are neglected. Cross sections are given in graphical form for the reactions and for trsnsitions between eigenstates of isotopic spin. The final-state nucleon-nucleon interaction is shown to have a lnrge effect on the cross sections. The cross section for the reaction pi /sup -/ + p yields p + d is found to be relatively large. At an energy of 10 Mev abcve threshold in the center-of-momentum system the ratio of this cross section to that for pi /sup -/ + p yields p + p + n is about 5: 1. At an energy of 40 Mev above threshold this ratio hns decreased to 1: I. The total cross section for the reaction leading to the unbound final state is calculated by assuming a modified Fermi statistical model. At an energy 100 Mev above threshold, this cross section is approximately …

An investigation of the effusive behavior of saturated vapors over a range of source pressures from 10/sup -6/ atm in the molecular flow region to 1 atm is reported. The purposes of the investigation were to clarify the situation regarding the upper pressure limit to effusive flow, to examine the transition of effusive flow from molecular to viscous behavior, and to clarify some limited aspects concerning the question of vapor saturation within an effusion cell. Mass flow rates of mercury vapor effusing through a thin-edged orifice or long channels into a vacuum from a region of nearly saturated vapor were obtained. (W.D.M.)

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To determine the nature of the interactions between antinucleons and nucleons, it has been necessary to do an experiment in which the elastic, inelastic, and charge-exchange interactions could be measured. Improvements in the 6-Bev Bevatron have permitted production of a considerably larger flux of antiprotons, than was available in earlier studies. With the use of strong-focusing magnetic quadrupoles, a crossed electric- and magnetic-field spectrometer, and time-of-flight scintillation counters it has been possible to detect approximately 30 antiprotons per minute. By means of a system of 4{pi} solid-angle scintillation counters, it has been possible to measure these cross sections, including the angular distribution of elastic scattering. These cross sections have been measured for antiprotons scattered from hydrogen, beryllium, and carbon in the energy range from 133 to 333 Mev. Ball and Chew have assumed that pion exchange is responsible for the nucleon-nucleon interaction, and have used field theory to calculate the antinucleon-nucleon interaction. They have assumed that the pionic charge of the antinucleon is opposite that of the nucleon; thus, the exchange of an odd number of pions should change the sign of the potential. Outside the hard core, the exchange is assumed to be due to two pions, and the …

Measurements were made in the Process Revelopment Pile (PDP) of the distribution of the thermal neutron flux in ten different D/sub 2/O-moderated lattices of natural uranium tubes. Both single and double fuel tubes were used at lattice spacings of 7 and 14 inches. Special corrections were required for epithermal flux shielding by the manganese detector foils. After these corrections were applied, good agreement was obtained between the measured flux distributions and correspending distributions calculated by the P/sub 3/ approximation to transport theory. (auth)