141 Matching Results

Search Results

Advanced search parameters have been applied.

Preparation of Some Protactinium Compounds and the Metal

Description: Report discussing methods for preparing various protactinium compounds, including protactinium oxides, tetrafluoride, and oxysulfide. Additionally, a method for making the protactinium metal is mentioned.
Date: April 6, 1951
Creator: Sellers, Philip A.; Fried, Sherman; Elson, Robert E. & Zachariasen, William H.
Partner: UNT Libraries Government Documents Department

The Counting Efficiency of Pa²³³

Description: Abstract: "The counting efficiency of Pa²³³ has been determined by comparison of the counting rate of Pa²³³, under stated conditions, with the disintegration rate of U²³³ produced by Pa²³³ decay."
Date: February 27, 1951
Creator: Karraker, David George, 1923-
Partner: UNT Libraries Government Documents Department

Electron Spectrum of Pa²³³

Description: The following report describes the electron spectrum of protactinium derived from 23 minute thorium 233 that was produced by neutron capture in stable thorium.
Date: May 9, 1950
Creator: Keller, H. B. & Cork, James M.
Partner: UNT Libraries Government Documents Department

Protactinium Chemistry

Description: Report discussing protactinium, including the element's history and the results of various experiments.
Date: March 15, 1950
Creator: Elson, R. E.; Sullivan, J. C.; Studier, N. H. & Sullens, P. A.
Partner: UNT Libraries Government Documents Department


Description: Atomic Mass Evaluations have had a major impact on the values of the atomic weights for the twenty mononuclidic elements plus two elements, Thorium and Protactinium, which have no stable nuclides but a characteristic terrestrial isotopic composition. This paper reviews the history of the atomic weight values of these elements in the years, since the reference mass standard changed from {sup 16}O to {sup 12}C. There is a problem for Thorium, which is considered to have an abundance value of 100%, but is not treated as such in the Standard Atomic Weights' Table. Recommendations for handling the Standard Atomic Weight values for 2001 are presented.
Date: June 29, 2001
Creator: HOLDEN, N.E.
Partner: UNT Libraries Government Documents Department

Artificial Collateral Chains to the Thorium and ActiniumFamilies

Description: The authors have produced and identified two new series of alpha-particle emitting radioactive elements; one is a 'collateral' branch of the actinium (4n + 3) radioactive family and the other is collateral to the thorium (4n) family. The series are of considerable interest in that they are the first whose early members lie on the neutron deficient side of beta stability. They have been produced in high yield of irradiation of thorium with deuterons of energy about {sup 80}Mev in the Berkeley 184-inch cyclotron. So far as the present observations are concerned both of these series begin with isotopes of protactinium (atomic number 91), although progenitors with higher atomic numbers are to be expected and will possibly be produced and identified. These protactinium isotopes are Pa{sup 227} and Pa{sup 228} formed by d,7n and d,6n reactions respectively.
Date: July 1, 1948
Creator: Ghiorso, A.; Meinke, W.W. & Seaborg, G.T.
Partner: UNT Libraries Government Documents Department

Gas-phase energies of actinide oxides -- an assessment of neutral and cationic monoxides and dioxides from thorium to curium

Description: An assessment of the gas-phase energetics of neutral and singly and doubly charged cationic actinide monoxides and dioxides of thorium, protactinium, uranium, neptunium, plutonium, americium, and curium is presented. A consistent set of metal-oxygen bond dissociation enthalpies, ionization energies, and enthalpies of formation, including new or revised values, is proposed, mainly based on recent experimental data and on correlations with the electronic energetics of the atoms or cations and with condensed-phase thermochemistry.
Date: August 10, 2009
Creator: Marcalo, Joaquim & Gibson, John K.
Partner: UNT Libraries Government Documents Department

Forecast of Standard Atomic Weights for the Mononuclidic Elements – 2011

Description: In this short report, I will provide an early warning about potential changes to the standard atomic weight values for the twenty mononuclidic and the so-called pseudo-mononuclidic ({sup 232}Th and {sup 231}Pa) chemical elements due to the estimated changes in the mass values to be published in the next Atomic Mass Tables within the next two years. There have been many new measurements of atomic masses, since the last published Atomic Mass Table. The Atomic Mass Data Center has released an unpublished version of the present status of the atomic mass values as a private communication. We can not update the Standard Atomic Weight Table at this time based on these unpublished values but we can anticipate how many changes are probably going to be expected in the next few years on the basis of the forthcoming publication of the Atomic Mass Table. I will briefly discuss the procedures that the Atomic Weights Commission used in deriving the recommended Standard Atomic Weight values and their uncertainties from the atomic mass values. I will also discuss some concern raised about a proposed change in the definition of the mole. The definition of the mole is now connected directly to the mass of a {sup 12}C isotope (which is defined as 12 exactly) and to the kilogram. A change in the definition of the mole will probably impact the mass of {sup 12}C.
Date: July 27, 2011
Creator: Holden, N.E.; Holden, N. & Holden,N.E.
Partner: UNT Libraries Government Documents Department

Peak Stripping Methodology for Plutonium Analysis in the Presence of Neptunium

Description: Quantitative Plutonium analysis depends upon the accurate identification of the assay peak. The Np[Pa] equilibrium pair introduces interfering peaks in {sup 239}Pu, {sup 238}Pu, and {sup 235}U assay peak region. When an interfering peak is present, it negates the assay unless an appropriate technique can be developed to deal with the interference. Peak Stripping is one such technique. Peak stripping involves an algorithm to strip an entire peak from another, resulting in a spectrum that can then be analyzed for the isotope of interest. A simpler method is a ''pseudo-peak-stripping'' whereby the effects of the interfering peak are quantified and those effects are stripped from the assay data. In this case the integrated peak areas are analyzed and corrected. There are two methods presented in this paper. Both assimilate the integrated data for the assay peak regions (in this case {sup 238}Pu, {sup 239}Pu, and {sup 235}U) and for the Neptunium/Protactinium secular equilibrium pair (Np[Pa]). Using Np[Pa] assumes that the Protactinium has come to equilibrium with Neptunium. This requires only {approx}6 months from the time chemical purification. Therefore it is a valid assumption in most cases. A correction is then applied to the assay peak areas to ''strip'' the underlying effects of Np[Pa].
Date: May 17, 2005
Creator: Hodge, Christ
Partner: UNT Libraries Government Documents Department

Extension of Alpha- and Beta-Decay Systematics of ProtactiniumIsotopes

Description: As part of the program for obtaining data to extend the scope of the systematics of alpha-radioactivity and to obtain more data pertaining to the energy surface in the heavy region of elements, they have made some pertinent new measurements on protactinium isotopes. The heaviest isotope of protactinium hitherto reported is that of mass 234 and hence it would be of interest to know the beta-emission properties of heavier isotopes in order to tie them in with the known radioactive data in this general region. Since low-energy deuteron bombardment of U{sup 238} might be expected to lead to Pa{sup 235} and Pa{sup 236} by (d,{alpha}n) and (d,{alpha}) reactions and proton bombardment to Pa{sup 235} by the (p,{alpha}) reaction, these irradiations were made in the 60-inch cyclotron at energies of 19 and 9.5 Mev, respectively. The protactinium was chemically separated following the bombardment of natural uranium by a procedure which involved a number of manganese dioxide cycles coupled with extractions of protactinium from aqueous into organic solvents. The manganese dioxide cycles consisted of precipitating this compound from the solution of uranium in nitric acid, followed by centrifugation, dissolution of the solid with hydroxylamine solution, dilution, and reprecipitation. The dissolved precipitate from the last cycle was acidified, salted with ammonium nitrate, and the protactinium extracted with diisopropyl ketone, several washings with salted solutions being made to insure good separation from fission products. The protactinium was then washed back into a low acidity aqueous solution and after acidification was extracted into a benzene solution of thenoyltrifluoroacetone which forms a complex ion with the protactinium. This solution was then evaporated to dryness on a platinum counting plate leaving a weightless deposit of protactinium.
Date: January 30, 1950
Creator: Meinke, W. Wayne & Seaborg, Glenn T.
Partner: UNT Libraries Government Documents Department


Description: The accuracy with which the breeding ratio of HRE-3 could be determined after a period of reactor operation was investigated. Inaccuracies in measurement of the core U/sup 233/ inventory and blanket U/sup 233/ and Pa/sup 233/ inventories appear to be the major sources of error. Appreciable errors could result from attempting to determine these inventories by sampling the reactor contents. For example, if generalized attack on stainless steel is at a rate of 1.0 mpy and if the associated film of corrosion products is 1% uranium, failure to account for this fuel in evaluation of the core inventory would cause an error of about 5% in the breeding ratio. (auth)
Date: May 27, 1958
Creator: Rosenthal, M.W.
Partner: UNT Libraries Government Documents Department