As there is no accurate measurements of the energy distribution of neutrons emerging from large uranium blocks, it becomes of importance to see how much information of this kind can be derived from the slowing down distribution of the neutrons in a water tank.
Specimens suitable for transmission electron microscopy have been prepared from bulk polycrystalline molybdenum after tensile deformation and recovery. The resulting dislocation substructures are described. Some tentative conclusions concerning the mechanism of plastic deformation in molybdenum are discussed.
A controversy exists as to the effect of inositol and other lipotropic agents on serum cholesterol levels and atherosclerosis in humans and animals. There is no general agreement that these agents lower serum cholesterol levels or exert an inhibitory effect on the development of atherosclerosis.,
A group at the Berkeley Bevatron constructed a rapid beam ejector to produce the brief pulses of particles required for optimum bubble chamber photographs. Energy stored in a capacitor bank is transferred to an air-core magnet surrounding the proton beam of the Bevatron. The protons are displaced from their normal orbit and strike a suitably located target; particles from this target can then emerge from the Bevatron. A capacitor bank of 120 pf stores 13,500 joules at 15,000 volts. Two ignitrons in parallel connect the capacitor to the magnet. The magnet current rises to 52,000 amperes in 55 microseconds; at peak current a register is connected in parallel to damp the current decay.
The attenuation curve of the deuterons stripped from He3 has been measured with a Faraday cup. The corresponding curve at 190 Mev was fit by assuming that the deuterons were monoenergetic, with three processes taking place.
Pulse-amplitude discriminators are useful in nuclear counting to separate signals of greater amplitude from a background of unwanted or noise signals of lesser amplitude. As used here, the term "fast" implies circuits capable of responding to pulses between a nanosecond and a microsecond in duration. An ideal discriminator would produce for any incoming signal whose amplitude is greater than a threshold bias level, an output pulse of constant amplitude, duration, and delay with respect to the input signal, regardless of the incoming duration and rate; and for signals less than the threshold, zero output.
A systematic set of thermodynamic data for most of the known compounds of plutonium is presented. From earlier data present, it is now possible to extend the tabulation of data for the compounds of plutonium to include PuF(4), PuF(5), and PuF(6).
Volatile hydrides may be prepared from ether solutions by the reaction of the appropriate chlorides with lithium hydroaluminate. In this general method, it is necessary to work with strictly anhydrous reagents and solvents because of the great reactivity of lithium hydroaluminate toward water. The procedures described here are believed to be much more convenient because the reducing agent employed is potassium hydroborate, which is relatively insensitive toward water. Since only aqueous solutions are involved, there are no solvent-purification steps and there is no dissolution or contamination of stopcock grease, etc.
Quarterly summary report of studies conducted through the Radiation Laboratory, University of California. Some results reported in the report may be of a preliminary or incomplete nature.
The feasibility of rectified absorption for the recovery and purification of HD from H2 streams has been investigated. The absorbent considered was liquid nitrogen at 78 (degrees) K. The process appears to present no major engineering or operation problems. Cost calculations indicate that the process may be economically competitive with other processes. Process design was based on an estimated separation factor of 1.25 between H2 and HD in this system. Experimental work has been undertaken to check the validity of this estimate and to investigate the possibility of using other absorbents such as hydrocarbons and fluorocarbons.
It is the purpose of this paper (from a talk given at Mendeleev Chemistry Conference in Moscow) to give a brief progress report on work which is being done on very heavy elements at the Lawrence Radiation Laboratory in Berkeley. The subject matter is divided into three broad classifications. The first classification includes production of the isotopes, the second deals with investigations of their chemical properties and the third includes studies of the nuclear properties.
Energy determinations have been made using the conversion and photo electron spectra and scintillation crystal pulse height analysis for twelve y-rays associated with the Rb82 decay (6.3 hours, B+, K-capture). The B+ spectrum is found to contain four allowed components of maximum energies 1080, 890, 610 and 300 kev. A tentative decay scheme is suggested.
The design of the present time of light mass spectrograph is similar to that of the isotron devised some time ago for isotope separation. The spectrograph will employ the time of flight principle only for the isotopic analysis of small samples.
The last fifteen years have seen the discovery of ten transuranic elements. This paper (presented at the Mendeleev Chemistry Conference in Moscow) deals only with the transplutonium elements, i.e., those elements with atomic number greater than 94. This will be a detailed discussion of the techniques that have been devised for producing and identifying elements 101 and 102 and the possible applications of these methods to elements beyond. There will also be a brief review of the discovery of all the transplutonium elements to show the gradual change in experimental methods from the early days.
A variable-length vacuum-insulated liquid hydrogen transfer line is described. The vacuum system is semi-permanent, and segments of the line are assembled with only threaded vacuum fittings. Thermal stress calculations are presented for a statically indeterminate union coupling.
The probabilities for nine electronic transitions among the low lying excited states in the C2 molecule are calculated by the dipole moment operator method and are given in the form of oscillator strength (or f values).
In programming the sequence of events in the operational cycle of the bevatron, certain devices must be triggered at specific values of magnetic field strength in the gap. It is desirable that the time-jitter, which corresponds to field jitter, of the tirggering pulses be small. In the synchrotron this is done with peaking strips which are located in the fringing field of the gap.
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