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Observation of Antiprotons

Description: One of the striking features of Dirac's theory of the electron was the appearance of solutions to his equations which required the existence of an antiparticle, later identified as the positron.
Date: October 19, 1955
Creator: Chamberlain, Owen; Segre, Emilio; Wiegand, Clyde & Ypsilantis,Thomas
Partner: UNT Libraries Government Documents Department

The New ELement Mendelevium, Atomic Number 101

Description: We have produced and chemically identified for the first time a few atoms of the element with atomic number 101. Very intense helium ion bombardments of tiny targets of 99{sup 253} have produced a few spontaneously fissionable atoms which elute in the eka-thulium position on a cation resin column.
Date: April 4, 1955
Creator: Ghiorso, A.; Harvey, B.G.; Choppin, G.R.; Thompson, S.G. & Seaborg, G.T.
Partner: UNT Libraries Government Documents Department

Synthesis and Metabolism of Carbonyl-C14 Pyruvic andHydroxypyruvic Acids in Algae

Description: 1. Pyruvic and hydroxypyruvic acids a r e metabolized by Scenedesmus. 2. The products of metabolism of pyruvic -2 -C{sup 14} and hydroxypyruvic-2 -C{sup 14} acids a r e essentially identical to those of C{sup 14}-O fixations. 3. Lipids a r e rapidly formed i n the light from both substrates. In the dark the major products a r e intermediates of the tricarboxylic acid cycle. 4. Zt does not appear likely that f r e e hydroxypyruvic acid is a photosynthetic intermediate, 5 . Tricarboxylic acid cycle intermediates a r e formed from exogenous pyruvate a s fast in the light a s in the dark.
Date: March 30, 1955
Creator: Milhaud, Gerhard; Benson, Andrew A. & Calvin, M.
Partner: UNT Libraries Government Documents Department

The Effect of Coenzyme A on the Metabolic Oxidation of LabeledFatty Acids: Rate Studies, Instrumentation, and Liver Fractionation

Description: The effect of pantothenic acid deficiency on the rate of C{sup 14}O{sub 2} excretion and on distribution of radioactivity in liver fractions has been studied in rats given sodium acetate-2-C{sup 14} and sodium heptanoate-7-C{sup 14} The rate of excretion of breath C{sub 14}O has been measured by use of a method in which a sensitive ionization chamber and electrometer directly and continuously record carbon-14 excretion. The labeled fatty acids are more rapidly metabolized to C{sup 14}O{sub 2} in PAD rats than in normal rats. CoA depresses the C{sup 14}O excretion 2 in both normal and PAD rats in experiments with either labeled acid. There are differences in the oxidation of these two fatty acids, and the differences are consistent with postulated metabolic schemes. CoA increases radioactivity deposited in the fat of the liver, but does not appreciably change the radioactivity incorporated in the protein and nonsaponifiable lipid fractions.
Date: April 18, 1955
Creator: Tolbert, B.M.; Hughes, Ann M.; Kirk, Martha R. & Calvin, M.
Partner: UNT Libraries Government Documents Department

S-Acyl Thioctic Acid Derivatives in Aerobacter Aerogenes andScenedesmus

Description: 1. Acetyl thioctic acid has been prepared chemically and i t s chromatographic and acetylating behavior i s described. 2. A C{sup 14} -containing substance has been found in Scenedesmus, photosynthesizing in the presence of a-C{sup 14}-pyruvate, which has properties suggesting that it i s acetyl thioctic acid. 3 . A C{sup 14}-containing substance has been found in Aerobacter aerogenes, metabolizing a-C{sup 14}-pyruvate, which shows the properties of a labile conjugate of thioctic acid with some relatively polar groups. 4. Acetyl thioctic acid i s formed in vitro when light acts on a solution of thioctic acid and pyruvate.
Date: March 30, 1955
Creator: Milhaud, Gerard; Benson, Andrew A.; Fuller, R. Clinton; Milhaud,Vera & Calvin, M.
Partner: UNT Libraries Government Documents Department

High Energy Physics

Description: Without a little further explanation the title of this article may not convey a definite meaning to all readers, so I would like to start by pointing out that ''high energy'' refers to the energy of individual bombarding particles used to produce nuclear disintegrations, and not to situations where a large aggregate amount of energy is involved, as in an atomic power plant. The next question might be, when is energy considered ''high?'' To discuss this, we need a scale for measuring particle energies, and some feeling for the meaning of magnitudes on this scale. The basic scale unit is the ''electron volt'', which is the amount of energy acquired by a particle bearing an electric charge equal to that of an electron, when it falls through an electrical potential difference of one volt. This unit is rather small for use in nuclear physics, so a million electron volts, abbreviated ''MeV'', is the commonly used unit.
Date: January 1, 1955
Creator: McMillan, Edwin M.
Partner: UNT Libraries Government Documents Department

Chemical Evolution and the Origin of Life

Description: A discussion is presented of the elements, or at least most of the elements, that are usually thought of as required and characteristic of living materials. A continuous evolutionary process is conceived, beginning with a bare earth and leading to the random formation of more or less complex molecules from simple ones, and gradually, by the processes of random variation, autocatalysis, and selection, to more complex systems and the ordered array of desoxynucleic acid molecules which are the units that carry the continuity and order of present-day living systems.
Date: August 11, 1955
Creator: Calvin, Melvin
Partner: UNT Libraries Government Documents Department

Particle Accelerators

Description: In the most general sense, an accelerator is any device designed to give kinetic energy to ions or electrons. According to this definition the earliest cathode ray and canal ray tubes, made before the turn of the century were accelerators, the same principle is used in the x-ray tube, the cathode ray oscilloscope, the mass spectrograph, the electron microscope, and many other modern devices. However, we shall limit this discussion to those accelerators made for the particular purpose of inducing nuclear reactions, and to a few others that may be of interest in this connection, although they were originally designed for other purposes, such as high-voltage x-ray tubes intended for deep therapy or the radiography of metals. Although much work related to accelerators is thus omitted, it must not be forgotten that the principles learned and the practical experience gained by this work were of great importance in the development of the machiens now used in nuclear physics.
Date: January 1, 1955
Creator: McMillan, Edwin M.
Partner: UNT Libraries Government Documents Department

The Relation of Quantum Requirement in Photosynthesis toRespiration

Description: 1. The r a t e s of photosynthesis and subsequent respiration of Chlorella pyrenoidosa were measured using an oxygen analyzer (sensitive to paramagnetism). The energy absorbed during the photosynthesis periods was determined and the quantum requirement was calculated. 2. Dark respiration r a t e was found to depend on the r a t e of light absorption during the period of photosynthesis, and increased with increasing photosynthesis rate. 3 . The quantum requirement, corrected for respiration, varied from 4. 9 ( a t a ratio of photosynthesis to respiration of 1.4) to 6. 9 (at a r a t i o of 12). Both uncorrected and corrected quantum requirements approach an experimental value of 7. 4 a t high light intensity. 4. The lower quantum requirement obtained a t low light intensity is believed to be due to a relatively greater importance of contribution of energy from respiration t o photosynthesis. An expression i s derived for the relation between this contribution and the enhancement of dark respiration due to the level of photosynthesis to which the plants a r e conditioned. 5. Attempts to obtain the blue -light stimulation of photosynthesis with algae photosynthesizing in r e d light were unsuccessful.
Date: January 21, 1955
Creator: Bassham, James A.; Shibata, Kazuo & Calvin, M.
Partner: UNT Libraries Government Documents Department

Bevatron Operation and Development. V

Description: A considerable number of major improvements have been made in experimental facilities this quarter. These include four targets, three air locks, a deep well, and several thin windows for beam extraction in the target area. Simultaneous operation of up to five experiments has been achieved with a relay-controlled automatic operations selector. A beam-amplitude regulating device has been used to set the beam level on any pulse to within a few percent. The range of this equipment is 1000:1. Experimentation on the accelerator this quarter included measurements of start frequency and frequency-tracking jitter, beam-versus-radial-aperture measurements, empirical study of gas scattering effects, and preliminary testing of an automatic beam-controlled frequency-tracking system. High-energy physics experiments have been performed by ten groups within this laboratory. These groups are using counter techniques for the elastic proton-proton scattering, K-particle half-life determination, and {pi}{sup -}-meson cross-section measurements. A high-pressure hydrogen diffusion chamber is being used to study multiple production of {pi}{sup -} mesons. A strong-focusing pair spectrometer has been used to produce beams of K particles. Emulsion exposures have been made to determine the masses and mean lifetimes of K mesons. The interactions and modes of decay of K{sup {+-}} mesons at rest, as well as in flight, have been studied in emulsions.
Date: August 24, 1955
Creator: Lofgren, Edward J. & Heard, Harry G.
Partner: UNT Libraries Government Documents Department

Bevatron Operation and Development, VII - August, Septemper,October 1955

Description: The major physics research effort this quarter was directed toward the detection of the antiproton. Negative particles of proton mass were first counted on September 22, 1955. On October 19, 1955 the discovery and identification of the antiproton was announced. Total cross-section measurements for {pi}{sup +} and {pi}{sup -} mesons continued. A study was made of neutron interactions and of the {gamma}-ray decay products of mesons. Proton-proton scattering was done at 2 Bev and 4 Bev using counters, and at 5.5 Bev using a 35-atmos diffusion cloud chamber. Emulsion exposure s to protons were made for three groups outside the laboratory. The bevatron facilities were improved this quarter by the addition of a heavy-duty inner-radius platform at the experimental area. New thin windows, an improved plunging beam clipper, a new 4-in. quadrupole-magnet set, and a new 12-by-60-in. analyzing magnet were added to the experimental facilities. Improvements were made in magnet-current stabilization and in reliability of the radiofrequency-accelerating systems. The beam was successfully tracked during a step in peak magnet current, and for a short time into inversion.
Date: December 16, 1955
Creator: Hartsough, Walter
Partner: UNT Libraries Government Documents Department

Antiproton Star Observed in Emulsion

Description: In connection with the antiproton investigation at the Bevatron we planned and carried out a photographic-emulsion exposure in a magnetically selected beam of negative particles. The magnetic system was identical to the first half (one deflecting magnet and one magnetic lens) of the system used in the antiproton experiment of Chamberlain, Segre, Wiegand, and Ypsilantis. The selected particles left the copper target in the forward direction with momentum 1.09 Bev/c.
Date: December 1, 1955
Creator: Chamberlain, Owen; Chupp, Warren W.; Goldhaber, Gerson; Segre,Emilio; Wiegand, Clyde; Amaldi, E. et al.
Partner: UNT Libraries Government Documents Department


Description: Since the development of Dirac's theory of the electron and the brilliant confirmation of one of its most startling predictions by the discovery of the positron by Anderson, it has been assumed most likely that the proton would also have its charge conjugate, the antiproton. The properties that define the antiproton are: (a) charge equal to the electron charge (also in sign); (b) mass equal to the proton mass; (c) stability against spontaneous decay; (d) ability to annihilate by interaction with a proton or neutron, probably generating pions and releasing in some manner the energy 2 mc{sup 2}; (e) generation in pairs with ordinary nucleons; (f) magnetic moment equal but opposite to that of the proton; (g) fermion of spin 1/2. Not all these properties are independent, but all might ultimately be subjected to experiment.
Date: November 29, 1955
Creator: Chamberlain, Owen; Segre, Emilio & Wiegand, Clyde
Partner: UNT Libraries Government Documents Department

Bevatron Operation and Development, VI

Description: A large fraction of the effort on high-energy physics this quarter was devoted to the study of K particles. Ten of the fourteen external laboratory groups, as well as seven of the internal laboratory groups, used the K{sup {+-}}-beam facilities. These experiments included measurements of lifetimes, modes of decay; and excitation functions. Counters and cloud-chamber techniques were used in addition to nuclear emulsions. Measurements of total and differential cross-sections for {pi}{sup -} mesons continued. Work on proton-proton scattering was extended to 4.8 Bev. Radiochemical investigations of spallation products in light and heavy elements were extended. A new target plunger, a 4-inch quadrupole magnet, and two new steel collimators were added to the experimental facilities. Accelerator development this quarter included experiments on increasing the acceptance time of the Bevatron, self-tracking of the radiofrequency equipment, and the substitution of an analogue computer for the 3D-point curve corrector.
Date: November 18, 1955
Partner: UNT Libraries Government Documents Department