Group 10 - The following items were shipped to Scioto Laboratory: 6 Thyratron Heater Controls (TR-1-A), 2 Switch Boxes (for P & E), 1 Log Amplifier (AM-1); 1 Pulse Generator (PG-1-B). The following are completed, tested, and awaiting transportation: 3 Two-Input B-wall Mixers (MX-2-A), 1 Pulse Generator (PG-1-B),1 Regulation Checker (RC-1) (for plating control power supplies), 1 Preamplifier (AM-2) (for Berkeley decimal scaler). The following are under construction: 6 Pulse Generators (PG-1-B) (for Health Division) (EO-508) 90%, 10 Switch Boxes (8 for P & E, Scioto, 2 for P& E, "T" Building) 85%, 6 Junction Boxes (for P&E, "T" Building, EO-486) 90%, 2 Four-Input G. M. Mixers. One on EO-17, one from Unit III. The mixers have been finished and tested for some time. The scalers (Nuclear Instrument Model 161-G) have just been received and are being modified for use with the mixers. A prototype preamplifier for the Berkeley decimal scaler was constructed and tested. Group 11 - A special pulse generator having output pulses fixed in time, and adjacent pulses variable in time with respect to the fixed pulse is under development. An initial mock-up of such a generator showed promise in that the variable pulses could be shifted …

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This report details events of importance as reported by the Hanford Operations Office for the week ending September 28, 1949.

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This monthly report details 100 Area technical activities of the Physics Group for the month of August 1949.

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At the spring, 1949, meeting of the National Academy of Sciences(l) a preliminary account was given of some observations of mesons produced by the 335 Mev x-ray beam from the Berkeley synchrotron. The present paper is a progress report of this work; no claim is made for completeness, but sufficient new data are available to make publication at this time worth while, especially since some of the numerical results given in the earlier report require revision. The x-ray beam, produced by the impact of 335 Mev electrons on a 20 mil thick platinum target, has a width at half maximum of 0.0135 radian (about 1 inch at 6 feet from the target). In all but the earliest experiments the beam was further defined by a 1 inch hole in a lead block, then passed through a piece of carbon which served as the meson source. The x-ray intensity at one meter from the target was about 3500 r per hour (measured behind 1/8 inch of lead) under the best running conditions; the average was about half this. The actual exposures at the carbon meson source (6 feet from the target) ranged from 500 to 2000 r in the later runs. …

Correlations of alpha-decay energies in terms of mass number and atomic number have been made for all of the alpha-emitting species now numbering over 100. For each element isotopes show increase in alpha-energy with decrease in mass number except in the region of 126 neutrons where there is an explainable reversal. This reversal has the effect of creating a region of relatively low alpha-energy and long half-life at low mass numbers for such elements as astatine, emanation, francium, and possibly higher elements as had been noted already for bismuth and polonium. Methods and examples of using alpha-decay data to define the energy surface in the heavy element region are discussed. The regularities in alpha-decay are used for predictions of nuclear properties including prediction of the beta-stable nuclides among the heavy elements. The half-life vs. energy correlations show that the even-even nuclides conform well with existing alpha-decay theory, but all nuclear types with odd nucleons show prohibited decay. The reason for this prohibition is not found in spin changes in the alpha-emission but in the assembly of the components of the alpha particle, and this theory is discussed further in terms of observations made on nuclides having two or more alpha-groups. …

By test duplicating actual operating conditions the average load was found to have a power factor of 95 percent and to be about 75 percent rated load. Since the Sola transformers must be operating into a load having a power factor of 90 percent and about 85 percent rated to attain proper output voltage, power factor corrective networks consisting of inductance and resistance in series were paralleled with the load. When these networks were added, the desired output voltage was attained. Several units have been successfully correction be used on the remaining units.

No administrative or operations significant events are reported. Construction in the pile areas, separations areas, and the technical center is reported. The Southern Railroad connection, Richland paving and related work, and housing work is described. Personnel and visitor data is presented.

An experimental range-energy relation in Ilford C-2 emulsion has been obtained for proteins up to 39.5 Mev. In the region from 17 to 33 Mev the relation for dry emulsion is fitted by the empirical equation E{sub (MeV)} = 0.251 R{sub ({mu})} 0.581. Variations in water content due to changes in atmospheric humidity make several percent difference in range. The range in Ilford glass is found to be 18 {+-} 4 percent longer than in dry C-2 emulsion.

Some time ago we started work in an attempt to observe alpha-particle decay in isotopes of atomic number less than 83. In the first experiments, thin targets of gold leaf were bombarded with 190-Mev deuterons in the 184-inch cyclotron. Two alpha-decay periods were observed in these targets; one of 0.7 minutes half-life and another of 4.3 minutes half-life. The alpha-particle energies were 5.7 and 5.2 Mev, respectively. Chemical separations proved that the 4.3-minute period is due to a gold isotope and suggested that the 0.7-minute period is due to a mercury isotope. The mass numbers of these new isotopes have not been determined. However, the results of excitation-functions in the production of the gold isotope by bombarding gold and platinum with protons suggest that its mass number lies in the range 185-188. The work on this isotope indicates that the alpha to electron capture branching ratio is of the order of magnitude of 10{sup -4}, and that positron activity accompanies the 4.3-minute alpha-period.

Among the spallation products obtained from the 350-Mev proton bombardment of Th{sup 232} they have identified two gaseous alpha-emitters which apparently do not decay into any presently known alpha-decay chains. The half-lives observed for the decay of the alpha-activities are 23 minutes and 2.1 hours. These half-lives may be principally determined by an unknown amount of orbital electron capture. At least one alpha-emitting daughter (about 4 hours half-life) has been observed to grow from a gaseous parent, but it has not been determined whether it arises from alpha-decay or electron-capture. Since these gaseous atoms emit alpha-particles it is assumed that they are isotopes of element 86 (emanation or radon) rather than a lighter rare gas. if they were heavy isotopes such as Em{sup 221} or Em{sup 223}, both unknown, they would decay into known alpha-decay series, the neptunium and actinium series, respectively, and so would grow known short lived alpha-emitters which would have been detected. It thus appears reasonable that they must be lighter than the known emanation isotopes.