The following quarterly report covers the period of July through September of 1950, split into three reports discussing the metabolic properties of plutonium and allied materials, biological studies of radiation effects, and health chemistry and physics.

Since the 25 content of the uranium to be used in a MTA multiplying lattice is quite uncertain at present, it is necessary to assume various degrees of depletion in order to estimate the multiplication constant K-o and the production of 49 in an infinite uranium-graphite lattice

The question has arisen of how the beam in A-12 as a long resonant cavity might effect the frequency of operation and the field distribution. This study is published to make available the calculation of the direct beam effect as an illustration of general methods of attacking perturbing effects in resonant cavities.

Summary of progress on various research projects conducted during January, 1952.

The intuitive concept that a sector shaped centrifuge cell is free from convection is criticized. Not only is a form of convection present for a single sedimenting species, but a more insidious type occurs in a mixture having an appreciable Johnston-Ogston effect. Rather than striving for convection-free sedimentation, the proposal is to utilize if possible an apparently harmless type of convection occurring in a very thin annulus in order to avoid the convection extending between boundaries in a mixture. The requirement that the concentrations be independent of time meets this condition and yields a hyperbolic cell, which is approximated by a sector cell placed in the rotor backwards. Simultaneously, area measurements and calculations involving the Johnston-Ogston anomaly are simplified because of the time independence.

Let F be the flux of radiation going from a sample of radius R2 to a counter of radius B1 then the emitted intensity of radiation per unit solid angle. Then the flux between two elements of area do1 and do2 will be given by [equation] since [equation] and [equation]. Calculations and equations follow.

MTA quarterly progress report for June-August 1952

Abstract: A device is proposed for confining charged particles to a localized region of space by means of the alternating electric field of a resonant cavity. The motion of single electrons in the field is stable. The limitations to particle density and temperature are discussed, and found to be too severe to allow the device to serve as a reactor, although it might be a useful laboratory tool.

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.

Introduction: "This report covers the contributions of UCRL to MTA research and development program during the period June 1 to November 30, 1953. In this program UCRL continues to work in close collaboration with the California Research and Development Company (CRD)."

Abstract: "The analysis of an immobilized plasma by trajectories for the Cartesian case has been adapted to machine calculation and the results of such calculations are described. Their most surprising features is the thinness of the transition layer between a vacuum and a uniform plasma, which is possible without assuming too extreme physical circumstances."

Abstract: Beehive is a five energy group, two region, time independent spherical reactor code. It considers the problem of reactor system in which the core material is assumed to be at a higher energy (temperature) than the reflector material. The code obtains a closed solution for the critical reactor assembly by a procedure which is a logical extension of normal two group theory. The companion code, Hornet, computes the neutron fluxes for the critical assembly determined by the Beehive calculation. Both codes have been programmed for the IBM Magnetic Drum Data-Processing Machine, Type 650. The codes, together with the flow diagrams, are included with this report.

This report follows the study of a perturbation in the fringing magnetic field of a synchrocyclotron, using the computed unperturbed orbits of the modified Berkeley 184-inch synchrocyclotron, and introduces the peeler extraction to overcome limitations by using a perturbation that recedes with increasing radial amplitude.

The method of detecting unpaired electrons in liquid and solid systems by electron spin resonance is discussed. The significance of the hyperfine structure in electron spin resonance is discussed and the possible use of these structural features of the electron spin resonance spectrum to elucidate the nature of the photoproduced unpaired electrons in photosynthesizing systems is introduced.

An experiment has been performed using nuclear emulsions to measure the neutron flux and energy spectrum from a thick uranium target bombarded by 18-Mev electrons. The total integrated flux of 3.6 x 10(-4) neutrons/electron found here is considerably lower than the figure reported by other investigators. We attribute this discrepancy primarily to a wandering of the electron beam. The neutron spectrum should be unaffected. In addition to the expected peak at 1 Mev the energy spectrum shows a secondary peak at about 5 Mev. The shape of the experimental spectrum excluding this secondary peak, is fitted theoretically by a combination of the "evaporative" and "resonance direct" effects.

A modification of the Bridgeman anvils is described. This modification permits studies to be made to a load of 400 kbars, about twice that previously available.