A quarterly report consisting of reports published on Transuranic Elements from the University of California Radiation Laboratory. Each report is a brief one to two page summaries of the article submitted for publication during the months of September-November, 1948.

Abstract: Part I: A series of extraction experiments has been performed to determine the distribution coefficient of uranium(VI) between dilute perchloric acid and benzene solutions of TTA. The data are interpreted to show that the principal species in the acid phase is a doubly charged ion, UO2++. The discrepancies revealed in previous work(1) were not found. Part II: The spectrophotometric method of analysis developed for use in Part I has shown the existence of previously unreported species of uranium(VI) in the presence of TTA: UO2K2-HK in benzene, and UO2K+ in dilute acid. The absorption spectra of all the principal species are reported.

Research at the University of California Radiation Laboratory has been directed toward the development of processes designed to recover plutonium and uranium from neutron-irradiated uranium. This report has been prepared in answer to requests for information by interested workers in the Atomic Energy programs. The material discussed herein represents the efforts of a sizable research group over several years, and summarizes both the current status of the investigation and the future program now contemplated.

Quarterly progress report on various research projects conducted at the University of California Radiation Laboratory.

The electrostatically deflected beam of the 184-inch cyclotron has been used with the stacked foil and absorber technique to determine the excitation functions. The data are presented graphically and discussed individually for each of the reactions. The results are discussed in terms of compound nucleus formation, transparency effects, and other factors in order to arrive at a qualitative picture for the mechanism of high energy nuclear reactions with heavy nuclei.

Summary of research progress conducted on subjects such heavy element energy cycles and scattering.

Summary of the research progress meeting of June 12, 1952

The geometry of the magnetic pole structure in the cloverleaf cyclotron suggests the use of three dees excited by three phase rf placed in the valleys out of the way of the beam. Experience with the model machines indicates that it is desirable to be able to vary the phase angles between the three dee voltages through 30 or 40 degrees and to be able to maintain them at any given value within plus or minus one degree. It is desirable, also, to be able to vary the phase angle independently of the amplitude of the dee voltages. There are several possible ways of meeting these requirements. The one which was chosen appears to be the most flexible and to best meet the problems presented by the center geometry of the machine.

Physics Division quarterly report - general physics research projects and accelerator operation and development.

Certain isotopes in the region of the heaviest elements have been produced by cyclotron and pile bombardment techniques, and their nuclear decay properties have been investigated. The orbital electron capture decay of At210, At211, Np234, Np235, Pu234, Pu237, and Am242m has been studied and decay schemes have been proposed. In addition, the alpha spectra of Po211, At210, and At211 have been observed.

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.

A preliminary study of positive pion production from proton-nucleus collisions revealed that positive pion production cross sections agree more favorably with a Z 2/3 variation than with a variation proportional to the atomic number. A similar study on negative pion production has shown that negative pion yields from proton-nucleus collisions tend to vary in proportion to the number of neutrons in the nucleus. As a result an experiment was performed to investigate if there is a significant change in positive pion production with changing atomic number at two lower pion energies.

One of the oldest properties of electrons is their emission of x-rays (discrete and continuous spectra) when impinging on matter. Cloud-chamber tracks show light ionization, and considerable multiple scattering, except for fast electrons. Tracks are long and range indefinite.

Diffusion equations for a cascade shower which include an energy cutoff and energy parameters for each particle have not previously been studied. In this paper it is found that an inclusion of both permits collision loss to be represented as a discrete process by modifying the differential radiation cross section.

Progress report on biological studies of radiation effects, metabolic properties of various materials, health chemistry, health physics.

Our aerosol program employing monkeys has been initiated. A plutonium oxilate solution was introduced into the trachea. Preliminary results of the fecal and urinary determinations appear here.

Quarterly updates on nuclear chemistry, bio-organic chemistry, general chemistry, chemical engineering (process chemistry).

Abstract: "The problem of maintaining livable oxygen and carbon dioxide pressures in a closed space in which men must live leads to consideration of the possible use of the photosynthesis of green algae. A calculation based on the known respiratory rate of man and the photosynthetic rates of Chlorella indicates that it would be feasible to use algae for this purpose."

Abstract: Numerical information necessary to an experimental study of the polarization of bremsstrahlung is presented. One may conclude that it is possible to produce significantly polarized γ-ray beams with existing electron accelerators. These beams will provide a new tool for the study of photonuclear reactions over a wide range of energy.

From abstract: "The relative differential neutron-proton scattering cross section has been measured in the range of center-of-mass angles from 5.1° to 36.0° for approximately 90-Mev neutrons and from 10.7° to 37.8° for approximately 290-Mev neutrons."

Report that summarizes unreported neutron-yield data for the MnSO₄ tank method. Other yield measurements had been reported in other quarterly reports prior to the completion of this one.

From abstract: "Within the framework of age theory an expression is developed which represents the probability of a neutron being reflected with an energy loss corresponding to age, v, as a function of reflector thickness."

Abstract: "From neutron-yield measurements made with a MnSO4 detecting solution, the average number of neutrons produced per inelastic event is determined for a series of elements from lithium to uranium for 340-Mev protons, 190-and 315-Mev deuterons, 490-Mev He3 ions, and 90- and 160-Mev neutrons. The results are analyzed in an attempt to understand the total yield measurements for thick targets and to explain the variation of yield with the atomic number of the target."

The following report covers mixing k-quantum numbers in Bohr-Mottelson states of spheroidal nuclei.