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Physics group progress report, May 1--31, 1948

Description: Various studies conducted at Mound Laboratory concerning physical properties of postum (Polonium 210) are described. Some studies are entitled Purity of Postum (Vacuum Balance Method); Vapor Pressure of Postum; X-ray Studies; Vapor Pressure by Effusion; Molecular Weigh of Postum; and Weighing Procedures for Macroassay.
Date: December 31, 1948
Creator: Knauss, H.P.
Partner: UNT Libraries Government Documents Department

Density of metallic polonium

Description: Determinations of the density and coefficient of thermal expansions of postum (Polonium 210) were attempted on 20 curies of polonium as obtained from production foils.
Date: May 18, 1948
Creator: Brody, B.
Partner: UNT Libraries Government Documents Department

Preliminary results from the lunar prospector alpha particle spectrometer

Description: The Lunar Prospector Alpha Particle Spectrometer (LP APS) builds on Apollo heritage and maps the distribution of outgassing sites on the Moon. The APS searches for lunar surface gas release events and maps their distribution by detecting alpha particles produced by the decay of gaseous radon-222 (5.5 MeV, 3.8 day half-life) and solid polonium-210 (5.3 MeV, 138 day half-life, but remains on the surface with a 21 year half-life as lead-210), which are radioactive daughters from the decay of uranium-238. Radon is in such small quantities that it is not released directly from the lunar interior, rather it is entrained in a stream of gases and serves as a tracer for such gases. Once released, the radon spreads out by 'bouncing' across the surface on ballistic trajectories in a random-walk process. The 3.8 day half-life of radon-222 allows the gas to spread out by several 100 km before it decays and allows the APS to detect gas release events up to a few days after they occur. The long residence time (10s of years) of the lead-210 precursor to the polonium-210 allows the mapping of gas vents which have been active over the last approximately 50 years. Because radon and polonium are daughter products of the decay of uranium, the background level of alpha particle activity is a function of the lunar crustal uranium distribution. Using radioactive radon and polonium as tracers, the Apollo 15 and 16 Command Module orbital alpha particle experiments obtained evidence for the release of gases at several sites beneath the orbit tracks, especially over the Aristarchus Plateau and Mare Fecunditatis [1]. Aristarchus crater had previously been identified by ground-based observers as the site of transient optical events [2]. The Apollo 17 surface mass spectrometer showed that argon-40 is released from the lunar interior every few ...
Date: January 1, 2001
Creator: Lawson, S. L. (Stefanie L.)
Partner: UNT Libraries Government Documents Department

THE PRESENT EXPERIMENTAL AND THEORETICAL STATUS OF THE PROBLEM OF ELECTRON EJECTION IN THE ALPHA DECAY OF Po$sup 21$$sup 0$

Description: The experimental measurements of electron ejection in Po/sup 210/ decay are discussed, and the theory of the process is outlined. The order-of-magnitude discrepancy between theory and experiment that was evident a decade ago has not yet been definitively resolved. The discrepancy is ascribed to an inadequacy of the theory, in particular to the use of an asymptotic expansion in that theory. Brief mention is made of some very recent unpublished calculations by G. W. Schaefer in which a reasonable estimate of the K-ejection probability is obtained by a procedure that avoids the asymptotic expansion. (auth)
Date: January 1, 1963
Creator: Rubinson, W.
Partner: UNT Libraries Government Documents Department

Production division progress report, May 1--31, 1948

Description: A long term study on the possible effect of time on the micro-assay purity of postum product solutions is reported. It was determined that within the time periods studied (up to 102 days) time has no discernible effect on the mass purity of the postum electrodeposited from product solutions.
Date: December 31, 1948
Creator: Burbage, J.J.
Partner: UNT Libraries Government Documents Department

Production electrolysis studies V

Description: 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.
Date: December 31, 1948
Creator: Power, W.H. & Ford, M.
Partner: UNT Libraries Government Documents Department

Physics group progress report, July 1--31, 1948

Description: 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.
Date: December 31, 1948
Creator: Knauss, H.P.
Partner: UNT Libraries Government Documents Department

RAPID DETERMINATION OF {sup 210} PO IN WATER SAMPLES

Description: A new rapid method for the determination of {sup 210}Po in water samples has been developed at the Savannah River National Laboratory (SRNL) that can be used for emergency response or routine water analyses. If a radiological dispersive device (RDD) event or a radiological attack associated with drinking water supplies occurs, there will be an urgent need for rapid analyses of water samples, including drinking water, ground water and other water effluents. Current analytical methods for the assay of {sup 210}Po in water samples have typically involved spontaneous auto-deposition of {sup 210}Po onto silver or other metal disks followed by counting by alpha spectrometry. The auto-deposition times range from 90 minutes to 24 hours or more, at times with yields that may be less than desirable. If sample interferences are present, decreased yields and degraded alpha spectrums can occur due to unpredictable thickening in the deposited layer. Separation methods have focused on the use of Sr Resin�, often in combination with 210Pb analysis. A new rapid method for {sup 210}Po in water samples has been developed at the Savannah River National Laboratory (SRNL) that utilizes a rapid calcium phosphate co-precipitation method, separation using DGA Resin� (N,N,N�,N� tetraoctyldiglycolamide extractant-coated resin, Eichrom Technologies or Triskem-International), followed by rapid microprecipitation of {sup 210}Po using bismuth phosphate for counting by alpha spectrometry. This new method can be performed quickly with excellent removal of interferences, high chemical yields and very good alpha peak resolution, eliminating any potential problems with the alpha source preparation for emergency or routine samples. A rapid sequential separation method to separate {sup 210} Po and actinide isotopes was also developed. This new approach, rapid separation with DGA Resin plus microprecipitation for alpha source preparation, is a significant advance in radiochemistry for the rapid determination of {sup 210}Po.
Date: May 22, 2013
Creator: Maxwell, S.
Partner: UNT Libraries Government Documents Department

Spatial variations of scavenging rates within the central and northern Adriatic Sea: Use of U-Th disequilibria

Description: Dissolved and particulate concentrations of {sup 234}Th, {sup 210}Pb and {sup 210}Po were measured in surface waters of the central and northern Adriatic Sea. The half-lives and biogeochemistry of {sup 234}Th (t{sub 1/2} = 24.1 days), {sup 210}Po (t{sub 1/2} = 138.4 days) and {sup 210}Pb (t{sub 1/2} = 22.3 years) are ideal for studying particle dynamics in the upper water column. It has been observed that the residence time of dissolved {sup 234}Th with respect to removal on biogenic particles is inversely proportional to primary productivity and may be used to predict export from or new production in the euphotic zone. Model-derived {sup 234}Th fluxes can also be used to help validate sediment trap collections in the upper water column. The aim of the present study was to gain an insight into the intensity and variability of active scavenging and particle removal processes in the central and northern Adriatic Sea. This semi-enclosed sea is strongly influenced by fresh water runoff from rivers carrying large quantities of dissolved nutrients and suspended particles. These inputs of nutrients and suspended particles are expected to give rise to large biological and biogeochemical gradients across the Continental Shelf and offer a range of environments for studying particle scavenging and removal processes. The authors have examined the relationships between {sup 234}Th scavenging rates and residence times of dissolved and particulate phases as a function of other physical and biological parameters (primary productivity, POC, chlorophyll, C/N and total suspended matter). Particular reference is made to the two contrasting environments of the Adriatic--a eutrophic zone near the Po River outflow and in the largely oligotrophic waters of the Jabuka Pit.
Date: April 1, 1996
Creator: Hamilton, T.; Heilmann, J.; Fowler, S. & Miquel, J.C.
Partner: UNT Libraries Government Documents Department

Electrodeposition research progress report, July 1--31, 1948

Description: 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 teflon sheet. It was found that the spongy teflon used in this experiment had a porosity of about 16.5 microns. It was possible to reduce the size by compression to about 2.0 microns. In this way any porosity of material can be obtained depending on the original size of the pores and on the pressure used to compress it.
Date: December 31, 1948
Creator: Orban, E.
Partner: UNT Libraries Government Documents Department

Gamma scale chemistry progress report, May 1--31, 1948

Description: 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.
Date: December 31, 1948
Creator: Martin, A.
Partner: UNT Libraries Government Documents Department