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Chemical Evolution and the Origin of Life

Description: The formation of more complex carbon compounds from simple ones through the action of radiation is used in an interpretation of the original formation of such compounds on earth. The relation of plants and animals and evolution of photosynthesis is discussed in the light of the participation of sulfur compounds in the metabolism of both group.
Date: March 10, 1953
Creator: Calvin, Melvin
Partner: UNT Libraries Government Documents Department

Elastic Scattering of 190 MEV Deuterons by Protons

Description: The elastic differential scattering cross section of 190 MeV deuterons by protons has been measured from 15 degrees to 170 degrees in the center of mass system. The cross sections were obtained by subtracting the carbon counts from those received with a polyethylene target. Part I presents a description of the experiments. Results are shown in Table IV and Fig. 3. Part II compares these results with those expected from theory by making use of a method developed by Chew. A summary of this comparison is given in Table VII.
Date: June 3, 1953
Creator: Chamberlain, Owen & Stern, Martin O.
Partner: UNT Libraries Government Documents Department

Observations on the Radiation Decomposition of Some C14 LabeledCompounds

Description: Varying amounts of radiation decomposition during storage in the dry form have been found in the cases of C{sup 14}-labeled valine, norvaline, norleucine, choline chloride, calcium glycolate and cholesterol. These data indicate that investigators using labeled organic compounds should make frequent checks of the purity of these compounds in order to exclude the possibility of the presence of decomposition products.
Date: February 27, 1953
Creator: Tolbert, B.M.; Adams, P.T.; Bennett, Edward L.; Hughes, Ann M.; Kirk, Martha R.; Lemmon, R.M. et al.
Partner: UNT Libraries Government Documents Department

Summary - Bevatron Research Meeting II

Description: The operational characteristics of the Cosmotron were reviewed in brief. Since a rather complete account of this machine is now available in the September 1953 issue of Rev. Sci. Inst., this summary will include only the more recent utilization of the machine as a research instrument.
Date: October 13, 1953
Creator: Chamberlain, Owen
Partner: UNT Libraries Government Documents Department

Quadrupole Focusing Lenses for Charged Particles

Description: A set of four strong focusing magnetic quadrupole lenses has been constructed and operated. Each lens consists of four air cooled electromagnets with pole tips having a hyperbolic cross section. Each lens is 4 in. long and has an aperture 2 in. in diameter. Measurements of the magnetic field demonstrate that the hyperbolic cross section satisfies the requirements of a constant magnetic field gradient very well. The technique of deflecting a current carrying flexible wire has been used to measure the trajectory of charged particles through the system of lenses. It has been observed that the strong focusing requirements are satisfied. The system of lenses was then used to focus 0.5 Mev protons, 20 Mev deuterons, and 40 Mev alpha particles. The parallel beam of 0.5 Mev protons was detected by observing the incandescence of a quartz plate while the protons were bombarding it. The focused beam was less than 1 mm in diameter. The astigmatic 20 Mev deuteron beam from the 60 in. cyclotron was increased in current density by a factor greater than 30.
Date: April 15, 1953
Creator: Cork, Bruce & Zajec, Emery
Partner: UNT Libraries Government Documents Department

The Path of Carbon in Photosynthesis. XVIII The Identification ofNucleotide Coenzymes

Description: The radioactive compounds to be observed when algae or green leaves are allowed to photosynthesize in C{sup 14}O{sub 2} for short periods are almost all phosphorylated derivatives of sugars. Of these, phosphate esters of trioses, sedoheptulose and fructose are the first to incorporate C{sup 14} followed closely by ribulose diphosphate, glucose-6-phosphate and a phosphate of mannose. It has been noted, in earlier papers of this series, that on radiograms of the products of photosynthesis, a dark area appeared in a position occupied by no known sugar phosphate and which gave glucose on acid hydrolysis or on treatment with a phosphatase preparation. This has hitherto been referred to as an 'unknown glucose phosphate'. It was found that this substance was more labile to acid than glucose-l-phosphate, itself a readily hydrolysable phosphate, and furthermore that other labile glucose derivatives were formed as intermediates during the acid hydrolysis. Accumulation of labeled glucose in this area precedes that in sucrose and suggests its synthetic relationship to sucrose phosphate synthesis.
Date: January 19, 1953
Creator: Buchanan, J.G.; Lynch, V.H.; Benson, A.A.; Calvin, M. & Bradley,D.F.
Partner: UNT Libraries Government Documents Department

The Path of Carbon in Photosynthesis. XXI. The Cyclic Regenerationof Carbon Dioxide Acceptor

Description: Photosynthesizing plants have been exposed to C{sup 14}O{sub 2} for short periods of time (0.4 to 15 sec.) and the products of carbon dioxide reduction analyzed by paper chromatography and radio autography. Methods have been developed for the degradation of ribulose and sedoheptulose. These sugars, obtained as their phosphate esters from the above C{sup 14}O{sub 2} exposures and from other experiments, have been degraded and their distribution of radiocarbon determined. The distribution of radiocarbon in these sugars, and other data, indicate that sedoheptulose phosphate and ribulose diphosphates are formed during photosynthesis from triose and hexose phosphates, the latter being synthesized, in turn, by the reduction of 3-phosphoglyceric acid.
Date: October 1, 1953
Creator: Bassham, J.A.; Benson, A.A.; Kay, Lorel D.; Harris, Anne Z.; Wilson, A.T. & Calvin, M.
Partner: UNT Libraries Government Documents Department

Separation of Iron and Cobalt on Synthetic Resin

Description: In the separation of mixtures of radioactive iron and cobalt from neutron irradiated targets and in the removal of iron from cobalt targets for cyclotron production of radioiron, it is desirable to have a method superior to extraction from isopropyl ether in efficiency and ease of manipulation. Recent studies by Moore and Kraus on the separation of cobalt and nickel and on the behavior of iron in hydrochloric acid on Dowex-l resin in relation to the selective adsorption of chloride complexes of these elements have suggested the use of resin for the separation of iron and cobalt.
Date: August 5, 1953
Creator: Helwig, H. L.; Ashikawa, J. K.; Clokie, H. & Smith, E. R.
Partner: UNT Libraries Government Documents Department


Description: The targets and probes will be introduced 6-inches below the median plane so that adequate mechanical support can be effectively utilized without reducing the aperture. Probe heads will be of such configuration as to allow monitoring of any desired vertical strip of the aperture. It is probable that some space will be available in the quadrants after first performance tests have been on the machine. No targets or probes will be located in that 1-foot x 4-foot aperture initially. Provision will be made for driving the inner radius targets on the west tangent tank into the aperture during acceleration. The drive mechanism will locate the target (within an adjustable radius) in 1/2 a second. Because of the asymmetry in geometry of pole tip magnets with respect to the magnet yokes and the curvature of the quadrants, it will be difficult to remove positive charged meson beams. A re-entrant side plate on the inside radius of the west tangent tank is under study. While such a plate would provide a location for bending magnets and collimators for positive particles and would simplify the construction of some beam monitoring probes, its presence may introduce a first harmonic distortion in the magnet field of a prohibitive amplitude.
Date: October 27, 1953
Creator: Chupp, Warren
Partner: UNT Libraries Government Documents Department


Description: Despite the essentially independent development of the Cosmotron and Bevatron, these two accelerators have general specifications which are the same within a factor of 2-3 in their pertinent characteristics. An electron analogue of the Bevatron would be an electron synchrotron operating in the 5 kev to 3 Mev range.
Date: October 20, 1953
Creator: Smith, Lloyd
Partner: UNT Libraries Government Documents Department


Description: The relative probabilities for alternate processes initiated by a nucleon-nucleon collision depend on the dynamics involved and on the volume in phase space accessible to each final state. According to Fermi this last aspect alone may be of decisive importance. Such an assignment would follow were an approximate statistical equilibrium reached. The volume occupied by the incident nucleons and the associated pion clouds will have very large energy density at the instant of collision. Knowing that the interactions of the pion fields are strong, Fermi assumes that this energy is suddenly distributed among the various degrees of freedom present in the interaction volume in accord with statistical laws. He then computes the statistical probability that a certain number of pions will be created with a given energy distribution. It is then assumed that the energy will rapidly dissolve and that the particles into which the energy has been converted will fly out in all directions. Fermi argues that this approach may give a fairly good approximation to the actual case; since the number of possible states of the given energy is large and the probability of establishing a state to its average statistical weight will be increased by the number of ways by which that state may be attained. The statistical equilibrium assumed above should be qualified to the extent that certain laws such as conservation of charge and conservation of moment must be fulfilled. In addition, only those states easily obtainable from the initial state will reach statistical equilibrium; conservation of the differences of the number of nucleons and the anti-nucleons is implied.
Date: November 10, 1953
Creator: Lepore, Joseph
Partner: UNT Libraries Government Documents Department


Description: There are two different types of investigation of interest in high energy nuclear phenomena. One can observe gross effects such as the production of large numbers of heavy particles of different types, or one can study the elementary particles themselves which result from these collisions, for example, the kappa mesons, to determine modes of decay and the energy spectra of the resulting particles. This discussion will deal with the gross aspects of high energy interactions and will review the work of Fermi: High Energy Nuclear Interactions, Progress in Theoretical Physics, 5, No. 4, July-August, 1950.
Date: November 3, 1953
Creator: Lepore, Joseph
Partner: UNT Libraries Government Documents Department

Bevatron Research Meeting I - Bevatron as a Research Instrument

Description: The Bevatron status is: (1) Physical structure of magnet now assembled and being tested. Initial pulsing to rated field currents indicate that magnet is performing as designed. Currents of the order of 8500 amps peak have already been rendered. (About 15,000 gauss). (2) Pumpdown time to approximately 10{sup -5} mm Hg is of the order of 24 hours at present but is expected to improve to 12-15 hours as the high vapor pressure solvents are removed. Lofgren and Brobeck expect that it will be possible to make interval target, etc., changes between operating shifts without excessive loss of experimental time. (3) Injector and linear accelerator are now operating stably. Injected currents to Linac are approximately 3 x 10{sup -3} peak at 450 kev. Linac output is approximately 5% or 70 x 10{sup -6} amps peak with an angular divergence of 10{sup -3} rad. and a maximum energy spread of less than 0.8% at 9.8 kev. (4) Inflector and induction electrodes are to be installed after December 15, 1953. (5) Complete machine, both mechanical and electrical, will be ready for testing and 'de-bugging' approximately December 15; 1953. Initial operation as a research instrument should begin after the first of the year, perhaps January 15, 1954 to January 30, 1954. (6) Magnetic testing started October 2 and will continue for approximately 6 weeks (until about November 15). (7) Concrete shielding will be installed around the southwest quadrant of the machine and at the south and west straight sections before research operations begin.
Date: October 6, 1953
Creator: Lofgren, Edward
Partner: UNT Libraries Government Documents Department


Description: A large number of experiments relating to nuclear structure and materialization of energy will fall within the energy range of primary and secondary particles available from the Bevatron. Some experiments of interest are outlined below with pertinent comments. Proton-proton scattering can be extended to the high energy range using liquid hydrogen targets and hydrogenous materials by bombarding the target with the internal beam or using externally scattered protons. Proton-deuteron scattering measurements using liquid deuterium targets or solid materials can also be extended. Proton scattering from heavier nuclei may be found less difficult to interpret at these level energies as the nucleons will interact more or less independently. The wavelength of the bombarding particles will now be much smaller than nucleon diameters. Nuclear collisions represent by far the most important interaction between high energy nucleons and matter. Proton-neutron charge exchange interaction within the internal target will provide an external flux of neutrons which can be used directly for total nuclear cross section measurements and neutron-proton scattering. Low energy measurements, say below 200 Mev; show that nuclear interaction cross sections do not go down as 1/{lambda} as reactions become predominantly nuclear rather than electromagnetic. Measurements can now be extended into the Bev range to investigate the complex as opposed to the point charge concept of nuclear interactions. The external neutron beam may also provide high energy protons in charge exchange interactions with external targets. Mesons produced in the internal target will provide external meson beams of all types for cross section measurements over a large range of energies. Sufficient energy will be available for production of V particles with reasonable cross sections. The primary event leading to the production of V particles and the characteristic mode of decay can be studied. These events are best adapted to cloud chamber techniques wherein co-planer ...
Date: December 15, 1953
Creator: Karplus, Robert
Partner: UNT Libraries Government Documents Department


Description: This discussion will review the results of a survey of present plans for the Bevatron counting equipment. Proposed counting facilities, tentative specifications for desired counting equipment, a view of past counting techniques, and some of the later associated circuits will be considered.
Date: November 17, 1953
Creator: Wiegand, Clyde.
Partner: UNT Libraries Government Documents Department