The subject of this paper is the experimental and technical aspects of the measurements of nuclear resonance parameters. I will confine my remarks to those reactions induced by low energy neutrons, i.e. neutrons of less than approximately 100 kilovolts. The bulk of these measurements have been performed by neutron time-of-flight techniques, and I will direct my attention to these techniques. The first half of this discussion will concern the apparatus with which these measurements are made; the second part will be a discussion of the various experiments by which these parameters are measured, with an emphasis in both areas of discussion on relatively recent developments in the field.

The BNL cold neutron facility has been used to obtain inelastic scattering cross section data from three first-row transition elements, titanium, vanadium, and nickel, and a random binary alloy Ti.67-Zr.33. From the data, we have computed vibrational frequency distributions exhibit peaks corresponding to major critical points. A comparison of the distributions from the different samples leads to the following conclusions: 1) The shape of the frequency distributions of the b.c.c. metal (V) and f.c.c. metal (Ni) are remarkably similar, the relative positions of the critical points being the same for both; 2) The frequency distribution of the h.c.p. metal (Ti), which has two atoms per primitive cell, shows structure corresponding to acoustical and "optical" modes of vibration; 3) The titanium-zirconium alloy has the h.c.p. structure, and its experimental frequency distribution is similar to that of titanium, except at low frequencies where alloying with the heavier mass zirconium atoms tends to smear out the peaks corresponding to acoustical modes. Measured frequency distributions were obtained for the titanium-zirconium alloy slightly above and below the critical temperature for the phase transition to b.c.c. structure. The frequency distributions in the two phases are different, the most striking feature being a shift of the high …

Progress reports on Accelerator Development Program, High Frequency Program, beam dynamics in strong focusing linear accelerators, spiral beam buncher experiments, dynamical properties of Mark I, mechanical design, and Target Physics Program.

A graph plotting pulse height analyzer of compact size and moderate cost is described. The operation is simple and flexible, and the instrument is easy to maintain.

Data were obtained in non-flowing and flowing (continuous) batch adsorption systems to serve as a guide to the operating conditions that should be used in a resin-in-pulp adsorption system for the recovery of uranium from ores.

A brief series of experiments was performed to study the high temperature reaction of the Zircaloy-uranium-aluminum system at the request of Reactor Engineering Operation, Irradiation Processing Department. Knowledge of the high temperature behavior of this combination of materials is important to the evaluation of reactor behavior during possible accidental over-heating of a fuel channel.

It is proposed in this report to describe a new two-phase flow mixing length model. It consists of treating the two-phase system as a continuous medium and applying to it the methods and assumptions so widely accepted in single-phase turbulent flow. Because it reduces a two-phase problem to an equivalent one in single-phase flow, the proposed model can be readily used to predict the effects of flow rate, channel geometry, and channel direction in two-phase flow.

Calculations are presented regarding the effect of delayed neutrons in reactors fueled with mixtures of Pu²³⁹ and U²³⁵. Results are plotted to illustrate the change in thermal flux as a function of time for various positive or negative step changes in reactivity.

This report contains a listing of the bound-proton kernels for neutron scattering which were calculated in conjunction with the USAEC Control Rod Materials Program.

Ultrasonic testing has been investigated as a possible non-destructive method for checking the bond integrity of certain type fuel elements. Equipment has been developed to inspect experimental fuel elements for various research programs. Circuits have been devised to discriminate the size of defects and to map the areas which are unbonded.

"The phase and amplitude functions describing the betatron oscillations in the synchrotron are calculated using the revised parameters of the Cambridge Electron Accelerator. The results are given numerically and plotted in a graph for one machine period."

Measurements of the interfacial tension between water and tributyl phosphate solutions were made for application to the analysis of Marengoni effect in solvent extraction. A 24 hr flame calcination run to product Th02 particles yielded 40% as product and 54% collected from the furnace walls and from a coarse particle trap. The elution rates of uranyl ion from Dowex 21K using sodium nitrate could be approximated by assuming apparent diffusion coefficients of 1.67 x 10^-7 and 1.18 x 10 ^-7 cm^2/sec, respectively for 960µ and 820µ resn while the corresponding apparent coefficients using sodium chloride were 1. 78 x 10^-7 and 1.27 x 1-^-7 cm^2/sec. The reacting surface of ThO2 Universal Match Co. pellets was determined as a function of fraction dissolved. The lead scews and companion nuts from both the multipurpose saw and dejacketing machine were coated with a baked on lubricant. In Zirflex decladding studies using 4.5 M NH4F - 0.5 M NH4NO3, the average dissolution rate of Zircaloy-2 was decreased only 10% when the overhead condensate was withdrawn and 1.0 M NH4OH was added to maintain the volume.

The results of this paper show that a variation is sensing voltage produces an error in timing which increases logarithmically with time interval. Also, variation in supply voltage produces the same type of errors, but the errors are decreased by the ratio of the sensing to supply voltage. An interesting conclusion from this analysis is that if the ratio of supply to sensing voltages is maintained constant, no change in timing will result.

A transistorized binary counter circuit is described that operates over a temperature range of -65 degree F to +165 degree F. the supply voltage is 28 + 4 volts and the maximum trigger repetition rate is 5 kilocycles. the binary circuit is pre-settable and resettable by means of a switching arrangement that can be mechanized. Texas Instrument type 904 silicon transistors whose large signal current gain is 2.8 or greater at a -65 degree F can be used in this circuit.

Five irradiated and five unirradiated wafers were analyzed. Each wafer was analyzed for samarium by emission spectrography. The unirradiated wafers were analyzed for uranium by coulometric and potentiometric methods and for uranium isotopes by mass spectrometry. The irradiated wafers were analyzed for uranium and plutonium by coulometric methods, for plutonium isotopes by the 256-channel alpha pulse analyzer, and for the isotopes of uranium and of plutonium by mass spectrometry. The methods of preparing wafers for analysis are discussed; the data are tabulated.

Summarizing and presenting the interpretations and conclusions based on the drilling through Phase II of the program.

The feasibility of improving the mechanical properties at 1700-1800°F of oxidation-resistant Fe-Al-Cr alloys by means of a refractory dispersion has been explored. A literature search was conducted, preliminary experimental determinations of properties of the alloy and its oxides were carried out, and certain mathematical relations between dispersion characteristics and metallurgical variables were derived. The results indicate that the alloys can be strengthened sufficiently by using a dispersion with an interparticle spacing of about 2-3 µ. High-temperature native oxides of the Fe-Al-Cr alloy consist largely of Al2O3 and in theory would serve as a satisfactory second phase.