Three new americium activities (Am{sup 238}?, Am{sup 243}, and Am{sup 244?}, the latter two formed by n,{gamma} reactions) are described and some additional information is given on previously reported americium isotopes.

An isotope of the element with atomic number 97 has been discovered as a product of the helium-ion bombardment of americium. This isotope decays with the emission of alpha-particles of maximum energy 6.72 Mev (30 percent) and it emits lower energy alpha-particles of energies 6.55 Mev (53 percent) and 6.20 Mev (17 percent). The half-life of this isotope is 4.6 hours and it decays primarily by electron capture with about 0.1 percent branching decay by alpha-particle emission. The mass number is probably 243 as indicated by chemical separation of the alpha-particle and electron-capture daughters. The name berkelium, symbol Bk, is proposed for element 97. The chemical separation of element 97 from the target material and other reaction products was made by combinations of precipitation and ion exchange adsorption methods making use of its anticipated (III) and (IV) oxidation states and its position as a member of the actinide transition series. The distinctive chemical properties made use of in its separation and the equally distinctive decay properties of the particular isotope constitute the principal evidence for the new element.

This report summarizes the measurements made for radioactive contamination in the environs of the Hanford Works for the quarter April through June 1949. This belated document is issued for the records to fill in the gap for the quarterly reports not issued in 1949 because of personnel shortage at that time. Although the data summarized in this report were already reported in the H. I. Evirons Reports for the months involved, it is still of value to study the data combining the three months of data which give better opportunity to evaluate the trends and patterns of the levels of radioactive contamination emanating from the various sources at the Hanford Works. This document discusses: meteorological data and radioactive contamination in vegetation, the atmosphere, rain, Hanford wastes, the Columbia River, and in drinking water and test wells.

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The thermal conductivity of the gradient medium plays a very important part in the development of a calorimeter. It is a large factor in determining the sensitivity. The thermal conductivity apparatus was built primarily to find out why the measured sensitivities of the microcalorimeters were so much smaller than the calculated values. This question haa been resolved. The apparatus is now being used to study the thermal conductivity of Santocel, a granular insulating material produced by Monsanto Chemical Company. The Interesting fact is that though this material is in the solid phase it has a lower thermal conductivity than air. In a previous quarterly report approximate evidence was submitted to show that Santocel A has a lower conductivity than air at room temperatures. This result was worth verification, since this material would then prove useful in the construction of microcalorimeters. A verification is submitted in this report.

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Evidence in favor of the existence of a gamma unstable neutral meson; report on the detection of the coincidences between the two gamma rays produced by the bombardment of various nuclei in the x-ray beam of the Berkeley synchrotron.

The conclusions which have been drawn from the results of C{sup 14}O{sub 2} fixation experiments with a variety of plants are developed in this paper. The evidence for thermochemical reduction of carbon dioxide fixation intermediates is presented and the results are interpreted from such a viewpoint.

Helium, carbon dioxide, and helium-carbon dioxide mixtures are being considered for use as the pile gas in `G` pile. Coring the graphite tube block to provide a gas gap between the process tube centered in the graphite and the graphite tube block has been suggested as a means of maintaining high graphite temperatures in the tube blocks. It has been established that graphite damage during irradiation in minimized at high temperatures.

The method for calculating relative heat generation as a function of radius of an equivalent ``G`` type cylindrical pile for specified inhours of ideal flattening is given in INDC-3833. The report has been extended to include flattening curves for the range of zero to 800 inhours. Equations have been integrated to determine average relative power per tube for a fixed amount of flattening. Average relative power per tube, number of effective tubes, kw per effective tube, and maximum temperature rise per tube for 34.6 gpm water flow rate per effective tube are tabulated in Table 1 for several values of flattening of an 800 MW--2,220 tube pile.

The uses of radioactive isotopes in medical research can be conveniently divided into three principal categories; namely, the applications as tracers for the study of metabolic phenomena, as diagnostic aids in clinical medicine, and finally their role in therapy. Frequently radioisotopes available from the chain-reacting pile do not have a sufficient degree of specific activity for satisfactory use. A number of radioisotopes which can be produced with high specific activity in the pile possess half-lives too short to be of any practical value. Then, there are a few cases in which the desired radioisotope may be made in the pile with high specific activity, but concomitantly there is formed another radioisotope of the same element whose half-life is of such duration as to render its use hazardous in man. Finally, there are several elements of biological and medical interest whose radioactive isotopes can be produced only by the cyclotron.

This is the first of a series of Quarterly Reports. These reports will deal primarily with the progress made in our scientific program during a three months period. Those interested in matters pertaining to organization, administration, complete scientific program, personnel and other matters not directly involved in current scientific progress are referred to our Annual Progress Report which is issued in January. We have attempted to describe new information that appears significant, or of interest, to other scientists within the Atomic Energy Commission Laboratories. No effort has been made, however, to detail progress in each and every research project. Little or no reference will therefore be found to the projects in which progress during the current period is considered too inconclusive. Since our organizational structure is departmental, the work described herein is arranged in the following sequence: (1) Accelerator Project; (2) Biology Department; (3) Chemistry Department; (4) Instrumentation and Health Physic8 Department; (5) Medical Department; (6) Physics Department; and (7) Reactor Science and Engineering Department.

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)