This is the University of California, Radiation Laboratory monthly progress report for May 1948. It discusses the following: (1) 184-inch Cyclotron Program; (2) 60-inch Cyclotron Program; (3) Synchrotron Program; (4) Linear Accelerator Program; (5) Experimental Physics; (6) Theoretical Physics, (7) Isotope Separation Program; (8) Chemistry Departments; (9) Medical Physics; and (10) Health Physics and Chemistry.

This is a progress report from the Brookhaven National Laboratory during the period July 1-December 31, 1948.

Solubilities -- Orban: The solubility of postum in various concentrations of nitric acid was determined at 25.4{degrees}C. Hydrofluoric and Trifluoroacetic Acids -- Abel and Raiff: Details of this work will be reported in the next Progress Report. Conversion of Nitric Acid Solutions to Hydrofluoric Acid Solutions -- Bell: Conversion of production solutions to hydrofluoric acid solutions was tried by precipitation with ammonium oxalate, aluminum hydroxide, ammonium hydroxide, and sodium carbonate. Silver and Teflon discs were used.

The high rate neutron scaler has been removed from service for repair. Consequent study has led to the discovery of a double counting effect. The vacuum system of the vacuum balance is being redesigned and rebuilt so as to obtain a higher vacuum. The vapor pressure of postum was measured with a quartz sickle gauge between 0.3 and 90 mm. of mercury pressure at temperatures between 430{degrees} and 745{degrees}C. The least square representation of the data is the following: Log p = {sub T}{und 5377.8} + 7.2345 where p is the pressure in mm. of mercury and T is the absolute temperature. From this least square equation the extrapolated boiling point is 962.1{degrees}1{degrees}C. and the latent heat of vaporization is 24,597 calories per mole. A single crystal study of potassium chloride is being made since it is the crystal which is most nearly like a simple cubic lattice. The Geiger counter X-ray spectrometer belonging to Unit I was set up and a recorder attached so that certain patterns could be obtained more quickly. Continuation of the effusion experiment showed that data obtained were violently Inconsistent. The experimental work Is being dropped. At the end of the Physics Group Progress Report …

Progress is reported on the following projects: Quartz-fiber microbalance research, quartz-fiber construction and maintenance, design of multiple stirrer plating unit, and design of rotating stage for foil photography.

Studies on the conversion of production nitric acid solutions to bismuth free postum (Polonium 210) solutions and the plating of postum from the hydrofluoric acid solution.

Equipment and supplies are being packed for moving to Mound Laboratory. Work was started on the development of a cathode-follower circuit to match a B-wall tube to its connecting cable. The final report and maintenance manual for the scaler-multiplier are almost finished. The 10 millivolt Speedomax recorder used by Group 3 in the study of electrodeposition potentials has been replaced with a 150 millivolt Speedomax, utilizing two recording points for simultaneous recording of radioactive deposition and the plating cell current. Three two-input B-wall mixers, three scaler-multipliers, one four-input Geiger-Mueller mixer and five Thyratron heater controls were delivered to Group 24. One high-current plating control, EL-173, was delivered to Group 17. The following instruments are complete: portable pulse generator, EL-261, the instruction book and photographs will be submitted for approval at an early date. Portable regulation checker, EL-258. Preliminary tests have been made, instructions are being written and drawings are being made.

This monthly report provides brief progress descriptions of a number of projects being conducted at Mound Laboratory. Projects include sensitivity of the scaler used for neutron counting, purity of postum (Polonium 210), vapor pressure of postum, resistivity of postum, vapor pressure of selenium,and x-ray diffraction studies to determine the coefficients of expansion for aluminum, copper, lead,and gold.

The Process group reports that material processing is on schedule and that process laboratories 2 and 3 are being overhauled. The Electrodeposition group reports that they are on schedule but that they are somewhat handicapped due to a lack of coveralls. Administration reports that Site W schedules have been prepared.

This monthly progress report describes efforts to prepare neutron sources with postum (Polonium 210) and either beryllium, boron or lithium by volatilization and by electrochemical deposition.

This document presents details about health concerns resulting from the activities of the Mound Laboratory during the month of August 1948.

Preparation and analytical chemistry of postum (Polonium 210) dibromide and tetrabromide by bromination of metallic postum are described.

Three studies are described: diffusion of postum (Polonium 210), measurement of standard potential of postum, and polarography with the cathode controller.

Two difficulties which have been encountered in the attempts to prepare hydrofluoric acid solutions by precipitation and resolution are (1) dissolution of postum out of the solid precipitate leaving behind a solid bismuth compound and (2) the plastics used for a reaction vessel. Plastics tried have not held up under the combined effects of hydrofluoric acid, moderate heat, and alpha bombardment and the overall yield of the method is rather low. The plastics problem may be solved by the use of ``Fluorothene`` which is on order from the Atomic Energy Commission and should arrive soon. The problem of leaching the postum from the precipitate may be solved by careful control of pH during precipitation procedure to avoid the precipitation of as much bismuth as possible.

This report presents the details of the activities of the Mound Laboratory health sciences group during the month of July 1948.

This study seeks to determine the decomposition of bismuth trioxide by polarography. Results gained confirmed that at decomposition potentials observed that bismuth will not be reduced under normal plating conditions observed during production.

Word was received that the Eimco filter has been shipped from the Salt Lake City plant. It is expected within two weeks or about May 10, 1948. In place of a float gauge referred to in the Process Research Progress Report, March 1--31, 1984, a Uehling Tank-O-Meter will be used on the chemical solution tanks for the W. D. Building. Word was also received that the steam ejector has been shipped. It can be expected within the next few days. This item will complete the equipment to be used for the removal of activity from the flue gases produced in the incinerator. Laboratory experiments using synthetic bismuth chloride solutions are considered as completed for the time being. The experiments have shown that good yields, and adherent deposits can be obtained from solutions containing 0.18 g. bismuth/ml. with a 7 N hydrochloric acid concentration, providing a diaphragm is inserted between the anode and cathode. Neither calcium chloride nor pyrogallol are necessary under the conditions mentioned above. Bismuth was plated from a production solution in Run EP-1 in which the activity has been reduced from 4.2 {times} 10{sup 7} c./min./ml. to 4. 2 {times} 10{sup 4} c./min./ml. A yield of 2.48 g./amp.-hr. …

A brief description of the construction of three quartz fiber microbalances is provided.

Preparatory work is described for the determination of the vapor pressure of postum (Polonium 210), selenium being used as a surrogate in construction and testing of the apparatus to measure vapor pressure. Design modifications of a vacuum balance are also described.

Ten individuals received an average of 0.211 roentgens of gamma radiation per week for a 77 period week (December 1946-June 1948) for a total average dose of 16.21 roentgens. During this period these 10 men carried out an experiment involving materials which emit gamma radiation and were monitored by daily film badges. The radiation delivered during a week was received in a five day work week and usually they received approximately one-half of their weekly dosage during one of the five days. A significant fall in total white blood count and absolute neutrophil and lymphocytes count was observed during the 77 week period. The degree of fall in counts would not have been predicted from experimental irradiation in animals and so other unknown factors may have been causal agents. It is suggested that hematological and exposure data from other laboratories be analyzed statistically to confirm or disprove the effect of such low- dosages of ionizing radiation on humans.

Studies to test the conversion of production solutions to postum (polonium 210) solutions of hydrofluoric acid involving compressed teflon are documented. Several experiments to assess the effect on production plating yields are described including varying time between rinses, current density, and use of detergents. Varying the time between rinses showed no correlation with the neutron counts on the finished gauzes.

Plating of Postum out of Nitric Acid and Hydrofluoric Acid Solutions -- W. Abel and W. Raiff. Postum was plated out of 1.5 normal nitric acid and 1.0 normal hydrofluoric acid under similar conditions. The hydrofluoric acid plate was better appearing, and had a much higher curie density. However, neutron counts in these runs were quite similar. Neutron Counts -- W. Abel and W. Raiff. A study of the change of neutron counts over a period of time was started. Conversion of Active Hydrofluoric Acid Solutions to Hydrochloric Acid Solutions -- W. Raiff. A 99.99+ per cent conversion was effected. Conversion of Production Solutions to 1.0 Normal Hydrofluoric Add Solutions -- R. Bell. Good conversion has been achieved; however, further work needs to be done on complete change of postum from the production solution to 1.0 normal hydrofluoric acid solutions.

The equipment for the Bismuth-II process has been installed at Unit IV., and two runs have been made. The results on the potential of bismuth in bismuth chloride solutions have been summarized and calculations made on the concentration of silver in solution which must be present if silver is to be reduced to the metal by Metallic bismuth. The results have been compared with earlier experiments in which the deposition of silver on bismuth was investigated by the use of gamma active silver as a tracer. From the results it becomes quite evident that the scrubbing of silver on bismuth, under the present conditions employed in the production process, cannot be attributed to the reduction of silver to the metal, but must result from the adsorption of silver ions on the surface of the bismuth powder. From these same calculations it is also evident that when silver is employed as a scrubbing medium, bismuth will be deposited on the silver surface until the silver concentration in the bismuth chloride solution reaches a concentration of 20--200 ppM of silver in the bismuth, depending on the chloride concentration of the solution.

From the Assay group, information is given for production concerning routine assaying, calorimetry, and neutron detection, unit 5, and future plans. The Micro-Assay group reports on production, development, research, units 5 & 6, and future plans. The Inventory group gives a report on production relating to alpha and DM slides, development of hoods,poppy counters and safe barriers, research, and future plans. Control Section Administration also reports on production of neutron counters, development of the Logac-L chamber, research, and unit 5.