A reference design of a large high power density core has been established representing the available technology as of August, 1960. Reference core performance and cost should improve considerably after incorporation of improvements now under study.

"Evacuated electrical oscillating cavities frequently are found to exhibit a strong loading due to electron (or iron) multiplications, the so-called multipactor effect. This effect tends to prevent the buildup of dee voltage in cyclotrons. In conventional cyclotrons driven from external oscillators having their own resonant tank circuits the difficulties are usually slight, but in cyclotrons using a simple dee system as the tank circuit difficulties are encountered in getting the oscillator to break into full oscillation."

The spin of neodymium-141 was measured by the method of atomic beams and found to be 3/2. A lower limit placed on the hyperfine separation of the states with total angular momentum [formula] by second-order perturbation theory shows [formula]. A prerequisite for the determination of the nuclear spin from hyperfine-structure measurements is the knowledge of the electronic structure. The ground-state configuration of neodymium is known and the value is used throughout this work.

Studies are being made on the recovery of thorium (and uranium) from granitic rock, since this source represents a very large potential thorium reserve for the nuclear power industry. In preliminary leaching studies on 16 granite samples (containing 8-95 ppm thorium and 1.5-16 ppm uranium), maximum recoveries of thorium and uranium ranged 30-85% and 15-65% respectively, and sulfuric acid consumption was high (30-120 lbs H2SO4 per ton of granite). A relatively high acidity was needed to obtain rapid and efficient dissolution of the soluble thorium fraction. The cost of treating granite was estimated at $3.50-5.20 per ton, variations within this range being dependent primarily on differences in acid consumption for different granites. Estimated costs per pound of thorium plus uranium recovered ranged $30-500.