An empirical relation is presented which represents a boundary between no vacuum sparking and possible vacuum sparking. Metal electrodes and r.f. or d.c. voltages are used. The criterion fits several orders of surface gradient, voltage, gap, and frequency. Current due to field emission is considered necessary for sparking but in addition, energetic particles are required to initiate a cascade process which increases the field emission currents to the point of sparking. An elementary cascade process is outlined, but the data upon which it is based is not fully stated.

The structure and operation of cyclotrons are discussed. Factors limiting cyclotron size and energy are given. Improvements to the basic continuous-wave cyclotron are described, including frequency modulation, strong focusing, and variable-energy facilities.

Abstract: "A cylindrical coil has been designed for pulsed field operation suitable for use in a model thermonuclear reactor. The coil has an eight-inch inside diameter and a length of fifty-one inches. Magnetic mirrors at the ends consist of double-layer solenoids six and one-half inches long designed to slip over the main coil. Subsequent models of this coil have been fabricated which improved the electrical insulation provided by the bonding materials and the mechanical rigidity of the coil. Peak central fields of fifteen kilogauss and mirror fields of thirty kilogauss have been obtained."

A problem proposed by E. Hart to determine whether there are locally high or low neutron densities at the corners of a cubical cavity in a graphite lattice. To simplify the computations consider an infinite two dimensional lattice with a square cavity that has a point source of neutrons at the center (see Figure 1).

Recent experience in instrumentation of several nuclear-physics experiments has demonstrated the feasibility of automating the data-acquisition phases of the experiment. Electronic circuits are employed wherever the rate of data flow would be slowed by the use of human operations. Information is selected, temporarily stored, and then recorded in a form suitable for immediate entry into a computer. Experimenters thus freed from the tedious aspects of data collection can devote their time to studying the results of the experiments. Potentially useful nuclear events are first selected by the fast-logic part of the instrumentation. Circuits performing simple logical functions are packaged in modular form for easy grouping into particular coincidence, gating, and mixing configurations. Circuits with slower response times are used for temporary storage and recording operations. Automatic test routines are used to initially align the equipment as well as provide continuous calibration during the experiments. Some of the high-speed circuits are described as well as the methods used to incorporate them into a large counting system.

Abstract: "The quantities of interest in a confined plasma include the electric and magnetic fields, current density, diffusion velocity, temperature, pressure, and particle density. Equations governing the distribution of these seven variables are given in this report and special cases of a one-dimensional steady-state plasma are examined in detail. The solutions are given in graphical form."

The free streaming of neutrons in a cylindrical cavity is investigated. Using experimental data for the flux distribution along the walls, the direct beam hole loss and leakage into the target from the lattice is estimated for the MTA system.

The relative yield of neutral photopions from various elements was determined as a function of the quantum limit energy of the Berkeley synchrotron. Single decay photons from neutral pions were observed at 45, 90, and 135 deg to the incident bremsstrahlung in the laboratory system. Mean free paths for neutral pions in nuclear matter were obtained, an optical model prediction of the photopion yields based upon pion-nucleus scattering data was confirmed, and the presence of coherent pion production in the forward direction was detected.

Report that discusses the possibility of testing the T-invariance in μ-meson decay. The author describes a past experiment performed by Lee and Yang, as well as the specifics of the proposed experiment to test the time reversal in μ-meson decay.

Various figures depicting views and components of a device for coating the "Model 100" 8-faced metallic rotating mirror with an equal amount of material on each mirror face.

Report discussing both the probability of having a reactor accident that would release fission products, as well as the probable extent of the release of the products. This information, along with the contents of the fission products themselves, are based on statistical analysis and educated guesses.

Report describing the proceedings of the second symposium on the application of pulsed neutron source techniques.

A system for scintillations from nuclear events has been developed and is presently in use at the Lawrence Radiation Laboratory. This paper primarily describes the pulsed light source used to simulate nuclear events; it also describes the necessary nanosecond pulse techniques to measure the light source parameters and to operate large numbers of lamps. Considerations concerning distribution networks are shown. Use of the light source as a spark gap trigger is also discussed.

"The e-folding time for the free-molecule pump-out time of the vacuum tank used for the β⁺ ray experiment (N¹⁹ at 20°C) is found to be of the order of 46 millisec, and that used for the Felix experiment (D₂ at 20°C) of the order of 12 millisec. In the Felix tank a particle bounces off of the walls on the average about 30 times before escaping, hence a "getter" material coated on the walls of the tube should result in a slightly more rapid pump-out time."

Report discussing details of the design for the Bevatron at the University of California Radiation Laboratory. The Bevatron is a "6-billion-electron-volt (Bev) proton synchotron. This device will receive a 10-million-electron-volt (Mev) proton beam from a linear accelerator, and further accelerate a reasonable percentage of these protons, at a nominally constant radius of 600 inches, to a final energy greater than 6 Bev."

Abstract. A systematic procedure for preparing purchase specification on electronic instrumentation or control systems has been developed. This procedure results in preparation of specifications which: 1) make it possible to find any particular specification requirement quickly; and 2) insure that no important requirement has been omitted. Details of this systematic specification preparing procedure presented.

Report containing information regarding the design of the Tory II-A nuclear ramjet engine, and descriptions of its locale, test program, and possible hazards.