An experimental method of indirectly measuring the potential difference across a single mercury-electrolyte interface is suggested. By choosing a model for the moving electrolyte-mercury-electrolyte system, the maximum output voltage (which is mathematically the potential difference across a single interface) is obtained when the back end of the moving mercury drop becomes a hemisphere and the front end becomes a flat circular disc. It has been shown that the U-effect II and the U-effect III are essentially the manifestations of the same effect namely, that the output voltage is due to the distortion of the surface areas of the two ends of the moving mercury drop while the number of dipoles across each interface remains fixed. The output voltage has been found to be dependent on the velocity and the acceleration of the mercury drop and not on the relative displacement of this drop with respect to the capillary wall. The dependence of the output voltage on the acceleration of the mercury drop is opposite to that of the velocity. / Ph. D.

Neutron diffusion parameter measurements have been made at 21°C in 20, 50, and 80 percent concentrations of heavy and light water, including pure H20 and D2 0 as moderators. Pulsed neutron techniques were used with a 250-kv Cockcroft-Walton accelerator as the pulsed source. The range of bucklings used was from 0.05 cm⁻² to 0.70 cm⁻². The values for the diffusion coefficient, Dₒ; the diffusion cooling coefficient, C; and the transport mean free path, A_tr, were determined from the expansion of the decay constant to second order using iteration procedure. The values of Dₒ, C, and A_tr are tabulated below for the various concentrations, including pure H₂O and D₂O. <table style="width:100%"> <tr> <th>Percent D₂0</th> <th>Dₒ x 10⁻⁴ (cm²sec⁻¹)</th> <th>C x 10⁻⁵ (cm⁴sec⁻¹)</th> <th>λ_tr (cm)</th> </tr> <tr> <td>0</td> <td>3.634±0.048</td> <td>0.161±0.008</td> <td>0.443</td> </tr> <tr> <td>20</td> <td>3.779±0.017</td> <td>0.170±0.032</td> <td>0.515</td> </tr> <tr> <td>50</td> <td>6.964±0.044</td> <td>0.74±0.12</td> <td>0.915</td> </tr> <tr> <td>80</td> <td>11.75±0.68</td> <td>2.19±0.42</td> <td>1.602</td> </tr> <tr> <td>100</td> <td>19.66±1.37</td> <td>3.56±1.08</td> <td>2.670</td> </tr> </table> / Doctor of Philosophy

The problem of an interacting electron gas in a static lattice (an inhomogeneous electron gas) at zero temperature is treated by use of field theoretic perturbation theory. The unperturbed system is taken to be a non-interacting electron gas in a static lattice. The electron-electron interactions are then treated as a perturbation or;. this system. One-particle basis functions, Bloch functions, are introduced explicitly into the perturbation series for the Green functions, and diagrams associated with the various terms are defined. Certain formal results in integral equation form are noted. Using the method of DuBois, the plasmon excited state is studied. In particular, plasmon energies and lifetimes are calculated in the pair approximation for several insulators. / Ph. D.

When beryllium is thermally diffused into silicon, it gives rise to acceptor levels 191 meV and 145 meV above the valence band. Quenching and annealing studies indicate that the 145 meV level is due to a more complex beryllium configuration than the 191 meV level. When lithium is thermally diffused into a beryllium doped silicon sample it produces two new acceptor levels at 106 meV and 81 meV. Quenching and annealing studies indicate that these new levels are due to lithium forming a complex with the defects responsible for the 191 meV and 145 meV beryllium levels, respectively. Electrical measurements imply that the lithium impurity ions are physically close to the beryllium impurity atoms. The ground state of the 106 meV beryllium-lithium level is split into two levels, presumably by internal strains. Tentative models are proposed to explain these results. / Ph. D.

Integral measurements with a ³He spectrometer have been made to test the validity of the differential data of the ENOF/B-II files for thorium, natural uranium and heavy water. The experimental measurements of fast neutron spectra have been in two lattices of thorium metal and D₂O, a cylindrical array of close-packed natural uranium metal slugs in air, a D₂O sphere and cylinder, and a cylinder of thorium nitrate. A ²³⁵U fission disc, irradiated by a beam of thermal neutrons from the V.P.I. & S.U. reactor. provided a fast neutron source. Neutron leakage spectra were taken over the energy range between 100 keV and l.65 MeV. The spectrometer was calibrated using neutrons from the ³H(p,n)³He reaction in a Van de Graaff accelerator. Experimental results were compared with leakage spectra calculated. with the multigroup transport code, ANISN. For the thorium metal and D₂O lattices and for the D₂O sphere and cylinder, agreement between calculated and measured spectra was attained confirming the validity of the ENDF/B-II cross-sections and pointing to the usefulness of the ³He spectrometer for fast neutron leakage spectra determinations. For the natural uranium assembly, the calculated leakage spectrum between about 0.743 MeV and 1.65 MeV was significantly below the measured spectrum. This discrepancy supports a recent suggestion by H. Alter of Atomics International that the ENOF/B-II data files contain significant errors in the transport cross-sections for ²³⁸U and that the suspect data are in need of closer examination and revision. As a further test of the applicability of the calculational procedures and ²³⁸U cross-sections, transport analysis using the ANISN code was applied to predict the central spectrum of the Japanese Atomic Research Institute (JAERI) I-5 fast assembly. These calculations were compared with the results of published ³He spectrometer measurements of the fast neutron spectrum for this 20% enriched uranium assembly. The results of the comparison reveal a measured spectrum slightly harder than the spectrum determined by the calculations using ENDF/BII cross-section data, and gives further evidence to support the conclusions regarding the suspect ²³⁸U data files. / Ph. D.

A search has been performed for the reaction µ⁻ + Cu ⟶ e⁺ + Co, which is allowed by the lepton conservation scheme that assigns the same lepton number to the µ⁻, e⁺, v_µ , and vₑ. Momentum analysis of particles emitted following muon capture was performed using a magnetic spectrometer with magnetostrictive readout wire spark chambers. The time of flight through the spectrometer and energy loss in a scintillation counter were measured for each event. One event was observed, at momentum 89.9 ± 3.5 MeV/c, which is consistent with the above process. Background from radiative muon capture was expected to produce ~ 0.01 events that could simulate the searched for reaction. However, there exists uncertainty in the relative yield and cutoff for high energy photons from radiative muon capture. Although we cannot be certain whether or not the reaction µ⁻ + Cu ⟶ e⁺ + Co has been detected, we can set an upper limit on the branching ratio relative to ordinary muon capture of R < 2.6 x 10⁻⁸ (90% confidence level). According to a calculation by Kisslinger, this can be related to an upper limit on the coupling constant of this type of interaction relative to the vector coupling constant of (G_Δ I Gᵥ) ≤ 0.10^+0.05_-0.03. / Ph. D.

We have studied 2250 events with 6 charged tracks in the final state from 7.0 GeV/c π⁻p film taken at the BNL 80-inch bubble chamber. The events were fitted to the final states π⁻p → π⁻π⁻π⁻π⁺π⁺p 211 events (1) π⁻p → π⁻π⁻π⁻π⁺π⁺pπ⁰ 535 events (2) π⁻p → π⁻π⁻π⁻π⁺π⁺π⁺n 230 events (3) We find the total six-prong cross section to be 2.40 ± 0.27 mb. The partial cross sections are: 0.22 ± 0.04 mb for reaction (1), 0.58 ± 0.09 mb for reaction (2), and 0.24 ± 0.05 mb for reaction (3). Final state (1) shows significant ρ(760) and Δ⁺⁺(1238) production. In reaction (2) there is Δ⁺⁺(1238) production and a u bump at 1540 ± 20 MeV/c² with width 100 ± 40 MeV/c² in the pπ⁰ mass distribution (interpreted as N*(l520)). The π⁺π⁻π⁺π⁻ mass plot shows peaks at 1085 ± 20 MeV/c² and 1470 ± 20 MeV/c² with widths 70 ± 30 MeV/c² and 60 ± 25 MeV/c². These peaks appear less prominently in reaction (3). The transverse momentum distributions are analyzed in terms of statistical model predictions. In particular the Hagedorn statistical thermodynamical model gives temperatures of 120 MeV for pions and 150 MeV for nucleons. The influence of Bose-Einstein statistics as found by Goldhaber is observed in the angles between pion pairs. / Ph. D.

A large number of atomic helium states are excited by inelastic collisions. That excitation may be induced by various methods, including gas discharges, flowing afterglows and electron beams. The first negative nitrogen bands, N₂⁺(B²Σᵤ⁺- X²Σ_g⁺), have been observed with relatively high intensity from small quantities of nitrogen in helium, also induced by such methods. These bands have been studied by passing 26 kev electrons through mixtures. The resolved rotational spectra of the (0,0) and (0,1) bands have been analyzed as functions of pressure and mixture. An observed enhancement of the intensities has been interpreted in terms of selectively enhanced N₂⁺B rotational state populations. The particular helium species responsible for the enhancement are discussed. Experimental results are compared with a general"phase space" approach for calculating the reaction cross sections. / Ph. D.

Using a detector developed in a VPI-BNL collaboration, we have searched for multi-photon events from pp interactions at 300 GeV/c. We measured the multiplicity, energy and angular distributions of approximately 340,000 events. Of the 80,000 events that have been analysed, the angular distributions are consistent with photon production by known processes. The energy distribution of photons shows a rise in cross-section at approximately 150 GeV, an anomaly which can not be explained by known processes. / Ph. D.

A direct method for measuring the resonance escape probability, p, in thorium-water lattices was experimentally examined. The system under investigation consisted of a square, close-packed, lattice of hollow aluminum clad thorium metal slugs (1.207 inch O.D., 0.495 inch I.D.) in. water, spaced to give a water to thorium ratio of 2 to 1 by volume (water to metal 1.45 to 1). A substitute lattice, in which the thorium was repla~ed by lead, was also used to give the same scattering properties as thorium but no resonance capture. The neutron source consisted of a fission plate made of a disc of U-235 (0.900 inch in diameter, 5 mgs in weight) mounted at the end of a Cd-covered aluminum tube which conducted a beam of neutrons from inside the thermal column of the VPI reactor into the lattice. Cd-covered indium foils were used to measure. flux traverses in two perpendicular directions, parallel to the slugs (denoted by II ) and perpendicular to the slugs (denoted by ⊥ ). 2 The curves of Ar² vs r, where A is the normalized relative activation of the foils, corrected for activation by epithermal neutrons from the primary source (reactor), were integrated to infinity and the ratio of the integrals in the thorium and lead lattices yielded p. It was found that p_⊥ and p₁₁ differed by only one percent, which was within the experimental error. It was therefore concluded that there was no anisotropy in the resonance absorption and the average of the two values, 0.88 ± 0.015, was taken as the value of p for the lattice. The experiment yielded also the age 𝛕 to indium resonance energy: In thorium lattice, 𝛕_⊥ = 44 ± 2 cm², 𝛕₁₁ = 46 ± 2 cm² In lead lattice, 𝛕_⊥ = 47 ± 2 cm², 𝛕₁₁ = 49 ± 2 cm² / Ph. D.