Abstract. A brief review of the development of the subject of lattice defects in solids is given. The relation of this problem to field theory methodology is discussed; the defect is regarded as a particle imbedded in the phonon field. One may then discuss scattering states in the field, or “dressed” states of the particle. Specific application is then made to a defect in a simple cubic crystal including interactions between the defect site and its six nearest neighbors. Scattering solutions and scattering cross-sections are calculated and show that vacancies can cause strong resonant scattering, or pseudo-localized modes, at frequencies well below the Debye frequency. Applications to thermal conductivity and other experiments are discussed briefly.

Over the past six years, the hiring practices of the Reactor Operations Division of Argonne National Laboratory have been conducted to determine the highest level of personnel who would be willing to remain in the position of reactor operator. We have discontinued the hiring of personnel who have a bachelor's degree from an accredited institution or who are close to receiving such a degree. We now hire men from three general categories: (1) graduates from two-year technical institutes, (2) men who have had a number of years of experience in related operating jobs such as the petroleum industry or the chemical industry, and (3) men who have served in the nuclear programs of the armed forces. The following tests are given: (1) Wonderlic personnel Test, score above 43 percentile is mandatory, (2) Oral Directions Test, score above 80 percentile is expected, (3) mechanical Comprehension Test, score above 80 percentile is expected, (4) Arithmetic Reasoning Test, score above 60 percentile is expected, and (5) Primary Mental Abilities Test, used primarily as a check on the other tests given. Applicant is interviewed by at least three supervisors in the Division. All three supervisors must concur before an offer of employment is made.

This study is part of a research into trace element physiology of fresh water snails. As an average, biological materials contain [approximately] o.0% (fresh weight) NaCl ; this means [approximately] 3540 mg Na/1 (in snails, 0.4% NaCl [approximately] ms/1). Under these conditions, the application of neutron activation plus gamma spectrum analysis for the study of most trace elements as a routine method, is difficult. We will narrow down the scope some more and consider only the interference between Na24 and Cu64.

Introduction. Sorption of gases by surfaces is the primary step in many heterogeneous processes. Because sorption processes are in general pressure-dependent, and very fast at normal pressures, low pressure system are mandatory. In gas-metal interaction studies the flash filament technique with ribbons and filaments and Wagener's technique with evaporated films allow observations at the requisite low pressures. However, these method have two major drawbacks: (1) Since the pressure changes during the sorption experiment, pressure-dependent parameters can only be obtained from indirect evidence; (2) The pressure change in the sorption cell during the experiment may cause significant interaction between the sample and the rest of the system and thus experimental data must be corrected for this effect. These drawbacks have been eliminated in a new approach based on a flow system in which the sample is exposed to constant pressure. This new technique has been employed for the study of adsorption and absorption of gases by filaments and evaporated films. This method can also be used for studying gas-metal solution equilibria.

The Plutonium Recycle Test Reactor is a research and development tool supporting the Plutonium Recycle Program and the research activities at Hanford. The present organization directly associated with the PRTR is composed of Operating, Technical Assistance, Maintenance, and Engineering Groups. Liaison with research groups utilizing PRTR facilities is accomplished through the Technical Assistance Group. the other three groups serve the PRTR in the manner suggest by the group name. This paper limits its interest to the staffing experience of the Operating Group.

A sector gauge was developed for routine measurement and recording of wall thicknesses between the ribs and at the top of installed aluminum reactor power tubes. The basic criteria selected for the device were that it would measure and record wall thickness over the length of the tube with an accuracy of plus or minus 2 mils at an average rate of 3 min per tube. An eddy-current measuring system was used in the device.

The nature and types of internal molecular and thermal motions that polymer chains and polymer segments undergo have a great bearing on the physical behavior of polymeric solids. A relatively new tool is now available that permits us to observe and study internal thermally-induced motions directly at the atomic or molecular level rather than from macroscopic observations. this tool is nuclear magnetic resonance spectroscopy. This talk discusses (1) the nature of nuclear magnetic resonance, (2) NMR line shapes and the influence of temperature, (3) NMR line widths and second moments as a function of temperature, and (4) lists six general conclusions.

When a beam of X-rays penetrates through a layer of material, the intensity of the beam is reduced by absorption. some of the energy that has been absorbed may be re-emitted as X-ray quanta, by the atoms that absorbed it, at a wavelength characteristic of the emitting atom but longer than the quantum absorbed. Four methods of measuring thin films that use X-ray emission apparatus have been described, each of which is useful over a limited range of thickness, and for certain kinds of samples.

Training of Consumers Public Power District (CPPD) operating personnel for the Hallam Nuclear Power Facility (HNPF) was carried out under two formalized training programs. Both programs were organized and directed by Atomics International (AI). The first program was conducted in 1960 while he HNPF was under construction. The second program was begun in September 1961, prior to the initial HNPF dry critical loading experiment, and was completed in February 1963. The conventional portion of Sheldon Station has been a commercial power plant since July 1, 1961. Sheldon Station CPPD personnel were utilized extensively as instructors for the two formalized HNPF training programs and as responsible engineers for numerous test of the HNPF. CPPD shift personnel constituted the principal operating force throughout HNPF construction, reactor startup, and testing.

Many measurement of neutron spectra have been made in water assemblies. In these system a large part of the spectrum is given by an essentially Maxwellian distribution at the moderator temperature which is insensitive to the scattering model. Hence, the test of the energy exchange scattering kernel is in the difference of the spectrum and the fundamental or Maxwellian component. The figure shows the spectrum for the Nelkin model. Once the fundamental has been subtracted neither theoretical model seems to fit the data extremely well. Below kT the Nelkin model is a closer fit than the gas model but it underestimates the deviation from the Maxwellian whereas in the joining region it overestimates the distortion.