The proper roof thickness to correspond with a given side wall thickness has been estimated fro experience with the 184 feet cyclotron, which has indicated that a roof of about 1 1/2 feet should accompany a wall of 5 feet, and a roof of 4 feet should accompany a wall of 15 feet. For the roof area involved, this should bring about the condition that down-scattered neutrons in the working areas are but a small fraction of the neutrons coming through the side walls.

A quarterly summary of reports that have been published on research being conducted at the University of California Radiation Laboratory

Early in the design of the Mark I accelerator it was decided to install magnetic lenses in the drift tubes. A number of model magnets were constructed and tested to determine the best design for these lenses. This report includes only the results of the tests on the final models of the magnets that are designed for Mark I.

Isotopes of americium and curium with mass numbers less than 242 have been produced by cyclotron bombardment techniques, and several of their nuclear properties have been investigated. The partial alpha half-lives of Am(239), Cm(241), and Cm(240) and the partial half-life for spontaneous fission of Cm(240) were measured. The alpha decay daughter of Cm(238) was found and evidence for the discovery of Am(237) (an -1 hour electron capture activity) and Cm(239) (an -10 hour electron capture activity) has been presented. An Appendix indicating the conditions for separation of the plus three actinides by selective elution from ion exchange resin with citric acid has been included.

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.

Quarterly summary report of studies conducted through the University of California Radiation Laboratory. Some results reported in the report may be of a preliminary or incomplete nature.

A buncher and pre-accelerator for A-12 is described that has 360 degree acceptance and could handle a current of one ampere from a low voltage source.

Secondary charge effects from a 10 kilovolt proton beam and their effect upon beam current measurement are investigated. A collector is designed for beam current metering of a 60 kilovolt proton beam by means of charge measurement and energy measurement.

An outline is given for mismatch and delay measurements methods on air dielectric transmission line components, and techniques for square wave testing are outlined. Equipment design of the needed pulsers, attenuation and delay sections, and high speed oscilloscopes is disclosed. The final section of this report is devoted to measurements and how to analyze results

In the past it was felt that the easiest way to treat a three group equation for a MTA lattice was to solve it without certain terms. This iterative procedure converged rapidly for a medium with depleted uranium fuel, and in fact, a second iteration was not needed.