Magnetic susceptibilities per gram atomic weight of elements 92 to 95 in most of their oxidation states were measured on 0.1 ml of solution which was 0.007 to 0.09 M in heavy element. The values obtained (all paramagnetic) in c.g.s. units x 10{sup 6} were: U(IV), 3690; Np(VI), 2060; Np(V), 4120; Np(IV), 4000; Pu(IV), 1610; Pu(III), 370; Am(III), 720. The results could be interpreted only on the basis of electronic configurations 5f{sup n}, even though susceptibilities were generally lower than the theoretical values and lower than experimental values for corresponding lanthanide cations. The lower values should be expected as a result of the Stark effect produced by fields of anions and of water dipoles. Failure of the Russell-Saunders approximation to the coupling between electrons may account for some of the error in the theoretical calculations. Wider multiplet splitting in the actinides accounts for the fact that the susceptibilities of Pu(III) and Am(III) are many-fold lower than those of Sm(III) and Eu (III) respectively.

The decay scheme of a 4.2 second neutron emitter has been investigated in detail. Chemical and physical evidence shows that it is N{sup 17}, which emits beta rays to a broad excited state of O{sup 17}, which then breaks up into a neutron plus O{sup 16}. The energy spectrum of the neutrons is determined by measuring the energies of the O{sup 16} recoils in a proportional counter. The neutrons have a most probable energy of 0.9 Mev, a 'half width' of less than .5 Mev, and an upper limit of about 2 Mev. {beta}-recoil coincidences are observed, as predicted by the Bohr-Wheeler theory, and the {beta}-ray energy is measured by absorption. The beta rays in coincidence with neutrons have an upper limit of 3.7 {+-} 0.2 Mev. Beta-rays directly to the ground stat of O{sup 17} are not observed because of high background effects, but should have an energy of 8.7 Mev. Some evidence is presented to show that energy is conserved in the {beta}-n transition through the broad excited state in O{sup 17}.

This report compares the activity and disintegration energy of fission products from metal under two conditions of exposure: 200 Megawatt-days integrated exposure over a period of 180 days, and 400 Megawatt-days integrated exposure over a period of 360 days. (JL)

On June 1, 1948, a fire in the neoprene seal at 100-F Area potentially exposed nine to radioactive. An overnight collection of urine was made from these men and the samples submitted, along with a piece of neoprene seal, to the H.I. Development Laboratory for analysis. It is the purpose of this report to present the results of our investigation as to the type of contamination from the burning neoprene and the amount of contamination found in the urine sample.

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Since plutonium is manufactured at the Hanford Works in the 1940s, a study of its effect on biological materials is important. To determine the amount of plutonium deposited in a biological sample, it is necessary to have and accurate method for extracting plutonium from these samples. Some of the different methods for plutonium assay are reviewed and given in this paper dated November 16, 1948.

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On August 21, 1948, several smear samples of contamination from the inner rod room at 100-F Area were submitted for beta identification. This contamination was spread as a result of maintenance work on the horizontal rods. Urine sample were deemed advisable for two men who had been exposed while working on the rods. These urine samples were also submitted for beta analyses. The analyses of the smears showed the contamination to consist of primarily S{sup 35} (65%) and Fe{sup 59} (30%)and minor amounts of Ca (5%) and C{sup 14} (3%). No significant amount of radio iron or sulfur was found in either the feces or urine samples.

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The work to determine the feasibility of a pratical solution counter for alphas has been continued through this month. It has developed that the electronic technique using an Amperex mica-window GM tube (1.4 mg./cm{sup 2} mica) is reliable, and it now appears that the problem is mainly one of solution-mounting technique. Two four-input gamma mixers and three two-input B-wall mixers have been given a final check and assembled in cabinets with their associated scalers. These scalars, Instrument Development Laboratory Model 161-S, were modified for use with either type mixer and may also be used for straight GM counting. One Instrument Development Laboratory Model 161-S, scale of 256 gamma counter has been given performance tests before being placed in operation at Mound Laboratory. Tests are being run on the parallel plate alpha counter Model K-262.

This document is the report from a November 1948 meeting at Mound Laboratory on the measurement of the density of metallic polonium. Four determinations of the density of Polonium at 25 degrees C have been made. These values are 8.69 gm/cc, 9,34 gm/cc (twice) and 9.20 gm/cc. The probable error was 2%. The material used in the first determination was not subjected to a preliminary purification, which makes the value obtained doubtful. In this instance, production foils were used without a separation from their more volatile constituents. The difference in the reported value from that which appears in the Ad Interim Report is due to a recalculation based on the latest information on the physical constants of polonium. The value of using pure material and knowing the physical properties of polonium are clearly indicated.

Tube 1569-B ruptured on September 22, 1948 and was replaced. Between the time of failure and final isolation of this tube, considerable water escaped into the graphite packing. As a result, the unit start-up and subsequent operation was quite different from that usually followed. This report has been prepared to summarize the observations and activities related to this operation.

This document is a November 1948 Calorimetry Research Progress Report from the Mound Laboratory. Updates are given in the following areas: (1) development of micro and macrocalorimeters of the resistance-bridge type, (2) study and design of a rod calorimeter, (3) half-life of Postum, (4) evaluation of various calorimeter types, (5) applied mathematics, (6) materials, and (7) future efforts.

This document is the November 1948 Physics Division Progress Report from the Mound Laboratory. Items covered include: (1) measurement of the vapor pressure of Postum by effusion and the quartz-sickle gauge, (2) preparation of a Postum sample for x-ray emission spectroscopy studies, (3) possible errors in the vacuum balance, (4) construction of a gamma counter, and (5) preparation of a postum bromide sample.

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In the course of some kinetic studies on photosynthesis of barley seedlings, it has been found that plants utilize C{sup 12}O{sub 2} faster than C{sup 14}O{sub 2}. The plants were placed in a closed system containing an infra-red absorption-cell for the analysis of total CO{sub 2} and an ionization chamber for the determination of C{sup 14}O{sub 2} in the gas phase, both instruments recording continuously. Carbon dioxide, containing about 2% C{sup 14}O{sub 2}, was introduced in the dark and the specific activity at this point taken as unity. After a short dark period, the lights were turned on and photosynthesis was allowed to take place. A figure shows the result of a typical experiment. During the initial dark period the specific activity fell because of dilution by inactive respired CO{sub 2}. However, as photosynthesis proceeded, the specific activity of the residual CO{sub 2} rose until, when only 1/6 of it remained, the specific activity reached a peak some 20% higher than it had been at the start of photosynthesis. At this point the steady respiratory dilution became an appreciable fraction of the total remaining CO{sub 2}, and the specific activity dropped rapidly.