Safety procedures for the electron spectroscopy of actinides at the ALS

This is an addendum to the ALS Experimental Safety Form Renewal for the continuation of actinide microspot experiments on beamlines 7.0. There are several modifications to the previously approved. procedures. There is an increase in the amount of allowable material of the low activity isotopes {sup 238}U, {sup 237}Np, {sup 242}Pu, and {sup 248}Cm. There is also the addition of {sup 99}Tc and the activity isotopes {sup 232}Th and {sup 243}Am to the list of permissible sample materials. All of the materials are alpha-emitters with negligible gamma fields with the exception of {sup 99}Tc which is a beta-emitter. There is a series of new experiments that requires the use of a crystal cleaver in the preparation chamber of the ultraESCA end station. The beamline 7.0 ultraESCA endstation has been suitably modified to permit the safe cleave of YUPd alloy rectangular ingots. AR of the sample materials are solids. The exact nature and composition of the samples are delineated in the sample preparation section that follows. A corresponding Radiological Work Authorization (RWA) must be issued for this work at ALS since the material amounts exceed those in the Low Activity Source (LAS) guidelines in Table I and those in the Values for Exemption of Sealed Source Inventory in Table II. The preliminary date for the next run of these sample materials has been tentatively scheduled in early February 1996 and this will be with the uranium cleave alloys, not the transuranic materials

Nuclear chemistry. Annual report, 1974

The 1974 Nuclear Chemistry Annual Report contains information on research in the following areas: nuclear science (nuclear spectroscopy and radioactivity, nuclear reactions and scattering, nuclear theory); chemical and atomic physics (heavy ion-induced atomic reactions, atomic and molecular spectroscopy, photoelectron spectroscopy and hyperfine interactions); physical, inorganic, and analytical chemistry (x-ray crystallography, physical and inorganic chemistry, geochemistry); and instrumentation. Thesis abstracts, 1974 publication titles, and an author index are also included. Papers having a significant amount of information are listed separately by title. (RWR

Random Convex Hulls and Extreme Value Statistics

In this paper we study the statistical properties of convex hulls of $N$ random points in a plane chosen according to a given distribution. The points may be chosen independently or they may be correlated. After a non-exhaustive survey of the somewhat sporadic literature and diverse methods used in the random convex hull problem, we present a unifying approach, based on the notion of support function of a closed curve and the associated Cauchy's formulae, that allows us to compute exactly the mean perimeter and the mean area enclosed by the convex polygon both in case of independent as well as correlated points. Our method demonstrates a beautiful link between the random convex hull problem and the subject of extreme value statistics. As an example of correlated points, we study here in detail the case when the points represent the vertices of $n$ independent random walks. In the continuum time limit this reduces to $n$ independent planar Brownian trajectories for which we compute exactly, for all $n$, the mean perimeter and the mean area of their global convex hull. Our results have relevant applications in ecology in estimating the home range of a herd of animals. Some of these results were announced recently in a short communication [Phys. Rev. Lett. {\bf 103}, 140602 (2009)].Comment: 61 pages (pedagogical review); invited contribution to the special issue of J. Stat. Phys. celebrating the 50 years of Yeshiba/Rutgers meeting

Synthesis and characterization of Pa(IV), Np(IV), and Pu(IV) borohydrides

The actinide borohydrides of Pa, Np, and Pu have been prepared and some of their physical and optical properties measured. X-ray powder diffraction photographs of Pa(BH/sub 4/)/sub 4/ have shown that it is isostructural to Th(BH/sub 4/)/sub 4/ and U(BH/sub 4/)/sub 4/. Np(BH/sub 4/)/sub 4/ and Pu(BH/sub 4/)/sub 4/ are much more volatile than the borohydrides of Th, Pa, and U and are liquids at room temperature. Results from low-temperature single-crystal x-ray diffraction investigation of Np(BH/sub 4/)/sub 4/ show that its structure is very similar to Zr(BH/sub 4/)/sub 4/. With the data from low-temperature infrared and Raman spectra, a normal coordinate analysis on Np(BH/sub 4/)/sub 4/ and Np(BD/sub 4/)/sub 4/ has been completed. EPR experiments on Np(BH/sub 4/)/sub 4//Zr(BH/sub 4/)/sub 4/ and Np(BD/sub 4/)/sub 4//Zr(BD/sub 4/)/sub 4/ have characterized the ground electronic state. 5 figures

Magnetic Properties

The necessity of obtaining accurate thermodynamic quantities for the actinideelements and their compounds was recognized at the outset of the Manhattan Project, when a dedicated team of scientists and engineers initiated the program to exploit nuclear energy for military purposes. Since the end of World War II, both fundamental and applied objectives have motivated a great deal of further study of actinide thermodynamics. This chapter brings together many research papers and critical reviews on this subject. It also seeks to assess, to systematize, and to predict important properties of the actinide elements, ions, and compounds, especially for species in which there is significant interest and for which there is an experimental basis for the prediction. Many experimental and theoretical studies of thermochemical and thermophysical properties of thorium, uranium, and plutonium species were undertaken by Manhattan Project investigators. To find more information please see the attachment.JRC.E.6-Actinides researc