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Two new positron active isotopes, B{sup 8} and Na{sup 20}, have been found to decay to excited states of Be{sup 8} and Ne{sup 20}, which in turn decay 'instantaneously' by alpha emission. Their half-lives are 0.65 {+-} 0.1 sec. and 1/4 sec. respectively. N{sup 12} is also found to have a low energy positron group which leads to an {alpha}-unstable excited state in C{sup 12}. The masses of B{sup 8} and Na{sup 20} are 8.027 and 20.015 respectively. B{sup 8} decays by a 13.7 {+-} 0.3 Mev positron, through the same excited state of Be{sup 8} as does Li{sup 8}. Estimates of the energies of the excited state in C{sup 12} and Ne{sup 20} are made.

This HAPO report discusses the toxic effects of methyl isobutyl ketone, known commercially as hexone. Explosive limits are discussed, in addition to animal experimentation results.

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Paper describes procedures used at Hanford to bioassay plutonium in urine samples.

This volume is a quarterly progress report for the University of Chicago Toxicology Laboratory. Thirteen individual reports are contain herein and each has been separately indexed and abstracted for the database.

This quarterly progress report gives an overview of the University of Rochester Atomic Energy Project for April 1, 1950 thru June 30, 1950. Sections included are entitled (1) Biological Effects of External Radiation (X-rays and gamma rays), (2) Biological Effects of External Radiation (Infra-red and ultraviolet), (3) Biological effects of radioactive materials (polonium, radon, thoron, and miscellaneous project materials), (4) Uranium, (5) Beryllium, (7) thorium, (8) fluoride, (9) zirconium, (10) special materials, (11) Isotopes, (12) Outside services, (12) Project health, (13) Health physics, (14) Special Clinical Service, and (15) Instrumentation (Spectroscopy, electron microscopy, x-ray and nuclear radiation detectors, x-ray diffraction, and electronics).

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Criteria are presented for a horizontal cocurrent spray nozzle scrubbing system designed to remove fluorine and hydrogen fluoride from the 3000 cfm of ventilation air passing through the Volatility Pilot Plant. A reduction of fluorine concentration from 1520 to <2 ppm during a total release of 68 lbs, and a reduction of hydrogen fluoride concentration from 4090 to <1 ppm during a total release of 200 lbs, will adequately protect the Fiberglas media filters. Six scrubbing states each containing four nozzle-throat spray units are needed with a 5 to 10% aqueous caustic potash recycle system pumping at a maximum rate of approximately 180 gal/min, with a range per nozzle from 3 to 7 gal/min. The scrubber will be 4 ft x 4 ft x approximately 25 ft, containing a deentrainment section of baffles and demister. The associated ventilation system hardware, services, and instrumentation requirements are given. (auth)

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Recent attempts to displace fixed plutonium from the body by zirconium therapy have made an analytical method for the determination of zirconium in urine salts advisable. Standard chemical analytical methods for zirconium in rock were not adaptable to urine salts. The poor results obtained from these standard methods necessitated the development of a modified analytical procedure. The results of this work are reported herein.

A zirconium crystal bar, weighing 29 pounds and 1 5/16 inches in diameter by 8 feet in over-all length, was prepared, using pear-shaped zirconium couples to join the filament to the electrodes. This crystal bar was the largest produced to date in the 16-in.-diam. de Boer unit. The design of the couplings was modified to incorporate improvements indicated by the initial run, and another run is in progress. Binary alloys of Zr and Ni, Cr, and Si, as well as a zirconium alloy containing Fe, Al, and Si, were prepared for use as feed material in the small pyrex de Boer bulbs. The transfer of these elements from the feed to the crystal bar is being investigated. The rate of deposition and the type of crystal structure obtained with additions of various amounts of iodine are being studied. (auth)