N{sup 12} is shown to have a half life of 12.5 {+-} 1 milliseconds, and a positron upper limit of 16.6 {+-} 0.2 Mev. It is produced by the reaction C{sup 12}(p,n)N{sup 12}, and has a threshold proton energy of 20.0 Mev. This indicates that N{sup 12} is within about 200 Kev of being unstable against proton emission. The mass of N{sup 12} is 12.0228 {+-} 0.00015, and the beta transition is allowed.

Report discussing change in absorptivity of some rare earth elements over time.

Purpose: "The purpose of this investigation was to determine whether or not the machinability of extruded beryllium rod could be improved by appropriate heat treatment. It was thought that this could be accomplished in the extruded Be rod by recrystallization without further growth of these grains. This should impart a certain degree of ductility to the metal. The investigations was divided into two parts: Part I - Heat Treatment of Beryllium Rod; Part II - Machinability of Beryllium Rod."

Report discussing an experiment to reinvestigate the spontaneous fission of 48 (Pu-238) in an effort to determine a more accurate value for the spontaneous fission constant that was found in a previous experiment.

Following the shutdown of the B Pile in March 1946 a method was devised for monitoring the sub-critical reactivity such that any significant change in neutron flux would be detected. This report summarizes the status of the unit until its start up in July 1948.

The fourteenth meeting of the Graphite Expansion Committee was held on February 7, 1947. Laboratory studies indicate that either the graphite thermocouples are reading low or that annealing effects at elevated temperatures within the pile are much greater than those encountered In the laboratory. Current difficulties with operation of some of the horizontal and vertical control rods seem to be attributable to graphite expansion, though no complete understanding of the phenomena has been obtained and one is unable to predict the time required for similar difficulties to develop in other rods. Changes in clearance between process tubes and pile graphite in the D Pile have been erratic in nature but have averaged much less than had been anticipated. The negligible decrease in clearance for central tubes indicates that the expanding cross-wise graphite layers are slipping with respect to the graphite layers which contain process tubes.

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The excess reactivity available in an operating pile is absorbed in poison columns and horizontal rods. The temperature distribution of the pile is determined by the relative strengths and locations of the poison columns and the configuration of control rods used. A method for adjusting poison columns and rods to improve upon the pile`s temperature distribution is given in Document {number_sign}7-2654, ``Procedure for Improving Temperature Distribution via Rods and Columns,`` Wheeler and Menegus to Jordan, September 9, 1945. A relationship between poison moment (inhour lattice units) and temperature moments (per coat) was theoretically derived in the above document and has since been measured on several occasions on the basis of operating experience. A survey of recent operating data for the F Pile has been made by H. A. Gauper, Jr. with the intent of improving the method for obtaining the temperature and poison moments and relating changes in the two. This study was concerned with only the horizontal and vertical dipole moments. The results of Mr. Gauper`s investigation are summarized in this memorandum.

This weekly report details technical activities for the week ending May 15, 1943.

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

From introduction: During 1948, the Isotope Research and Production Division undertook to obtain small quantities of nearly pure mercury isotopes by electromagnetic isotope separation. The possible use of a mercury isotope of even-numbered mass to establish an international standard of length required an isotopic purity greater than 99 per cent. It, became apparent that this degree of separation could only be achieved by preventing random diffusion of un-ionized mercury which otherwise would contaminate the isotope collectors.

This report contains the calculation of the number and spacing of poison columns required to hold a 105 pile in the following cases: (1) complete failure of horizontal rods, (2) complete failure of all rods. Using 10% Cd 90% Pb poison columns of 1.44 inch diameter, it is found that 17 poison columns are required to hold the pile in case of complete failure of horizontal rods, and 65 poison columns are required to hold the pile in case of complete failure of all rods.

This report covers work done by the Pile Engineering Groups and work done on special assignments. Topics covered include: slug blistering and corrosion; graphite allocation to DR pile; slug molding; segmental discharge; Van Stone corrosion; flow laboratory modifications; downcomer at B pile; downcomer at D pile; annealing of pile graphite; replacement of pile atmosphere with CO{sub 2}; unit motion; beta experiment; can opening; slug annealing; new technical building, 300 area; and ruptured slugs.

Reported are: physics (B Pile, D Pile, F Pile, general physics); and water, corrosion, and engineering (process water control and pressure drop studies, purging studies, corrosion, graphite expansion, downcomer -- B Area).

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Much of the cloud chamber work has been directed toward obtaining the angular distribution of protons bombarded by deuterons from the 184-inch cyclotron. The observations have been restricted to those protons arising from neutrons of energy greater than 65 Mev. The cloud chamber used for this work is of 16-inch diruneter and employs a magnetic field of 14000 gauss. The chamber is filled with hydrogen at a pressure of 1/2 atmosphere; the vapor used is water and alchohol. Nearly 800 proton tracks were measured and calculated before analysis of the data indicated that the measuring procedure should be revised. They gave the angular and energy distributions shown in Figures 1 and 2. The discrepencies between the theoretical and experimental energy distribution of the neutrons shows that serious errors were being made. As a first check of possible sources of error, random parts of the data were remeasured. They indicated that errors in the measurements of the angles were being made that gave a mean deviation of about {+-} 2{sup o} in the beam angle and {+-} 4{sup o} in the dip angle. These errors were largest at large scatter angles. In addition, a more serious error occured in the measurements …

Report compiled regarding financial statements for a component of the Plosser-Prince Air Academy in Sweetwater, Texas, documented under the name "Texas Commissary Company." It includes explanations from the auditors and two exhibits showing the financial condition of the organization (as of September 30) and a statement of profit and loss (for June 7-September 30).

Technical report: Measurements have been made on the equilibrium between Cu, Cu2+, U4+, and UO22+ in H2SO4 in an attempt to establish the value of the U4+ - UO22+ couple potential. The value of the formal potential for the U3+ - U4+ couple in 1N HCl at 0 degrees C was determined to be + 0.65 v.

After it had been decided that aluminum was to be used as a corrosion-resistant material with good heat transfer properties, it was desired to determine the operating conditions to be used in the water-cooled Handford plant in order to avoid danger of corrosion penetration of thin aluminum parts. The studies here reported were undertaken with the object of determining these conditions by investigating the effects of all the known variables which might influence the corrosion behavior of aluminum in a water-coolded plant at HEW. The addition of hydrogen peroxide to the testing solutions was the only effort made to simulate special conditions at the plant.

Abstract: "The heat of solution of UCl4 solid has been measured and found to change appreciably with changing concentration of H+ or ionic strength. The heat of hydrolysis of U+4 to form UOH+3 is probably of the order of +11 kcal per mole" (p. 1).

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