The ANGIE, one of a series of reactor neutronic programs for an IBM 709 or 7090 data processing system, solves the time-dependent, multi-group, neutron diffusion equation for 1 to 26 energy groups applied to a rectangular mesh superimposed on either an x-y or an r-z plane.

Pulse-amplitude discriminators are useful in nuclear counting to separate signals of greater amplitude from a background of unwanted or noise signals of lesser amplitude. As used here, the term "fast" implies circuits capable of responding to pulses between a nanosecond and a microsecond in duration. An ideal discriminator would produce for any incoming signal whose amplitude is greater than a threshold bias level, an output pulse of constant amplitude, duration, and delay with respect to the input signal, regardless of the incoming duration and rate; and for signals less than the threshold, zero output.

Both in magnetohydrodynamic shocks and in accelerated partially ionized gas flow across a magnetic field, space charge separation occurs that establishes very large electric fields in the direction of motion. The width of the current layers associated with the acceleration is never less than the electron Larmor radius with no collisions and is broadened by electron collisions to a width solely determined by the effective resistivity. The electrons gain an energy regardless of collisions equal to the electric potential difference across the layer. This potential corresponds to the change in kinetic energy of mass motion per ion. For slightly ionized gases, the additional stress of neutral ion collisions within the layer can make the electric potential and hence gain in electron energy very large for only modest changes in mass velocity. Hence ionization may occur when the change in kinetic energy of the ions is small compared to the ionization potential.

Specimens suitable for transmission electron microscopy have been prepared from bulk polycrystalline molybdenum after tensile deformation and recovery. The resulting dislocation substructures are described. Some tentative conclusions concerning the mechanism of plastic deformation in molybdenum are discussed.

Volatile hydrides may be prepared from ether solutions by the reaction of the appropriate chlorides with lithium hydroaluminate. In this general method, it is necessary to work with strictly anhydrous reagents and solvents because of the great reactivity of lithium hydroaluminate toward water. The procedures described here are believed to be much more convenient because the reducing agent employed is potassium hydroborate, which is relatively insensitive toward water. Since only aqueous solutions are involved, there are no solvent-purification steps and there is no dissolution or contamination of stopcock grease, etc.

Abstract. The region where exact thermodynamic description of the state of matter at high pressure and high temperature is possible is located. In the remaining region various approximate theories and empirical relations are discussed. These considerations are applied to hydrogen to locate the density and pressure at which the diatomic bond collapses. Also the approximate conditions are determined at which no bound electron states exist.

The probabilities for nine electronic transitions among the low lying excited states in the C2 molecule are calculated by the dipole moment operator method and are given in the form of oscillator strength (or f values).

A variable-length vacuum-insulated liquid hydrogen transfer line is described. The vacuum system is semi-permanent, and segments of the line are assembled with only threaded vacuum fittings. Thermal stress calculations are presented for a statically indeterminate union coupling.

Abstract. The Tory II-A reactor is a small, air cooled, high power-density reactor which is to operate at quite high temperatures. Design of the reactor is essentially complete. First operation is scheduled for late 1960 at the Nevada Test Site of the Atomic Energy Commission. Since the reactor is unshielded, the control room which houses the recording and indicting equipment is located approximately two miles from the test bunker. Signals from reactor and facility transducers are amplified in the test bunker and transmitted by cable to the control point. The kinds of quantities measures include neutron flux level, temperatures, pressures, vibration amplitudes, strain and air mass flow rate. The recording and indicating system is centered around 258 channels of 1.5 cycle per second, pulse-width modulation tape recording equipment and 72 channels of 120 cps, analogue strip-chart records. In addition, there is a number of the usual meters, scalers and slow-response strip-chart recorders.

Introduction. The Lawrence Radiation Laboratory of the University of California has developed a series of reactor neutronic programs for an IBM 709 Data Processing System.. This paper presents a brief outline of these codes and includes the results of one- and two-dimensional diffusion calculations used to interpret data from a series of enriched-uranium beryllium-oxide moderated critical measurements. These were performed for the specific purpose of evaluating the computer programs. The time-independent neutron diffusion theory criticality codes are 9ZOOM, a one-dimensional multigroup program; and 9ANGIE, a two-dimensional multigroup program. A series of codes, named SOPHIST, are described which prepare neutronic input data for the criticality codes. Examples of modification of the data to account for disadvantage factors, anisotropic scattering and for the (n,2n) reaction of Be9 are given. The critical assemblies include bare and graphite-reflected systems, using atomic BeO/U235 ratios from 247/1 to 7660/1, arranged in simple one- and two-dimensional rectangular parallelepiped arrays. All of the assemblies utilized heterogeneous arrangements of moderator and thin uranium foils. These systems are not truly thermal and are in a range where critical mass is extremely sensitive to size. The constants used in the multigroup (18 energy groups were used) calculations are presented in tabular …