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

Sixty-eight samples were assayed. The 5 calorimeters of type 30 were finished. Calorimeter 36, whose construction has been started, is an improved version of 30. A system of switches has been devised. A simple, fast, insensitive calorimeter for measuring high activity samples is being tested. The calculations on the half-life of postum were checked.

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.

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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.

The general points being considered in the construction of equipment for the production of High Level Postum Gauzes were mentioned in the last progress report. A more detailed discussion of the progress to date will be made here. The development work of plating postum out of hydrofluoric acid has proceeded to the point where it is desired to make some runs plating out quantities of postum from 10--250 units per gauze. The following points have been considered in a report for limited distribution.

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.

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.

The cell used in production plating has a platinum anode and a platinum cathode. The potential at which the platinum cathode rests is not independent of the current, bat varies with it. In order to separate postum from other cations by electroplating out of solution, it is necessary to establish the plating potential at a value which will allow complete plating of postum, but will preclude the deposition of as many other cations as possible. This potential has been found to be about 0.00 v. to the normal calomel electrode. The procedure for determining the amount of loss postum as related to the time between the removal from the plating bath and the immersion into the water rinse has been worked out. Two runs have been made, neither of which were very successful because of mechanical difficulties which occurred during the runs. The second run showed, however, that as the time increased the amount remaining in the water rinse also increased very rapidly. It has been found that a very excellent method of removing suspended material from a solution of aqueous hydrogen fluoride is to filter it through a funnel machined out of teflon with a disc of a porous …

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.

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.

Various studies centering on problems and their solutions encountered in electroplating production at Mound Laboratory. Some studies described include construction of the Scaler-Multiplier EL-229, operation of a methane-flow proportional counter, life-time decreases of production half-cells, and use of vibrating reed electrometer.

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.

Upon completion of preliminary tests on the satisfactory operation of the Vibrating Reed Electrometer as a sensitive indication of alpha activity at the cathode of a plating cell, attention was directed toward the study of the detection of activity at the anode of the cell. Group 3 anticipates a lengthy study of cathodic and anodic deposition potentials of radioactive elements in solution. With the standard Research Plating Control, cathodic studies could be accomplished with relative ease, but the study of anodic deposition could only be done in an exploratory manner. This would provide meager information and lengthen the study considerably. To overcome the above objections, it was decided to modify the plating control so that it would provide linear control of the anode-solution potential. Study of the problem indicated that two simple changes were necessary; namely the reversal of current through the plating cell (since the anode instead of the cathode would be at ground potential) and the addition of a phase inverter in the amplifier circuit of the plating control to supply the control tube with a voltage change of the proper phase. Several tests made by Group 3 indicate that the use of the modified plating control will …

This document details gamma scale chemistry activities at Mound Laboratory during the month of April 1948.

Attempts for preparation and x-ray diffraction studies of postum (polonium 210) bromide and dioxide are described. Surrogate parallel studies employing parallel compounds of tellurium and thorium are also related.

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

An attempt has been made to prepare a compound of postum (Polonium 210) analogous to K{sub 2}{sup TeBr}{sub 6}. A preliminary experiment indicates possible preparation of bromides of postum and that these bromides are analogous to the chloride of postum. Photomicrographs of two crystalline forms of a product resulting from the reaction of bromine and postum are included in this report together with procedure used to form these crystals. Intermediate compounds formed in the attempted preparation of potassium postum bromide include a white residue from nitric acid containing postum and a yellow material formed on the ignition of this white residue. This yellow residue was identical in appearance to the yellow dioxide of postum. A red crystalline precipitate resulted when the yellow residue, which may well be QO{sub 2}, was treated with solution of hydrobromic acid and potassium bromide. Investigation of the use of titanium trichloride as a reducing agent to titrate, quantitatively tellurium dioxide has not yielded concordant results. An effort is being made to determine the best conditions for such a titration potentiometrically. Variations in concentrations, temperature of titration, electrode surface, acid concentration, and degree of agitation are in suspect.

This report details gamma scale chemistry activities at Mound Laboratory during the month of November1948.

This document details gamma scale chemistry activities at Mound Laboratory during the month of October 1948.

This document details gamma scale chemistry activities at Mound Laboratory during the month of November 1948.

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

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