You limited your search to:

  Partner: UNT Libraries Government Documents Department
 Decade: 1940-1949
 Year: 1949
A Proposed Experimental Test of the Neutrino Theory

A Proposed Experimental Test of the Neutrino Theory

Date: April 18, 1949
Creator: Alvarez, Luis W.
Description: The experiment outlined in this proposal has the possibility of giving an answer to the important question, 'Does the neutrino exist'? It is unfortunate that at the present time, there is no convincing experimental that neutrinos exist. Two recent articles review the status of various experiments which could give information about neutrinos. In general, these experiments give results in agreement with the predictions of beta decay theory. But actually, if even the most complete of the 'recoil type' experiments could be performed satisfactorily, all that could be concluded would be the following: the energy and momentum relationships in beta decay are consistent with the theory that the known energy deficit is carried away by a single particle. But to emphasize the fact that this would not constitute a proof of the real existence of that particle, the following quotations from the review articles should be noted. Crane says, 'All of the evidence about the neutrino is, as already pointed out, indirect in character since neutrinos have not yet been caught after leaving the nucleus. It can, of course, be argued on very general grounds that, if energy is not conserved between nucleus and electron, momentum should not be expected to ...
Contributing Partner: UNT Libraries Government Documents Department
Systematics of Alpha-Radioactivity

Systematics of Alpha-Radioactivity

Date: September 12, 1949
Creator: Perlman, I.; Ghiorso, A. & Seaborg, G.T.
Description: Correlations of alpha-decay energies in terms of mass number and atomic number have been made for all of the alpha-emitting species now numbering over 100. For each element isotopes show increase in alpha-energy with decrease in mass number except in the region of 126 neutrons where there is an explainable reversal. This reversal has the effect of creating a region of relatively low alpha-energy and long half-life at low mass numbers for such elements as astatine, emanation, francium, and possibly higher elements as had been noted already for bismuth and polonium. Methods and examples of using alpha-decay data to define the energy surface in the heavy element region are discussed. The regularities in alpha-decay are used for predictions of nuclear properties including prediction of the beta-stable nuclides among the heavy elements. The half-life vs. energy correlations show that the even-even nuclides conform well with existing alpha-decay theory, but all nuclear types with odd nucleons show prohibited decay. The reason for this prohibition is not found in spin changes in the alpha-emission but in the assembly of the components of the alpha particle, and this theory is discussed further in terms of observations made on nuclides having two or more alpha-groups. ...
Contributing Partner: UNT Libraries Government Documents Department
Carrier-free Radioisotopes from Cyclotron Targets I. Preparation and Isolation of Sn113 and In114 from Cadmium

Carrier-free Radioisotopes from Cyclotron Targets I. Preparation and Isolation of Sn113 and In114 from Cadmium

Date: August 11, 1949
Creator: Maxwell, R.D.; Haymond, H.R.; Bobmberger, D.R.; Garrison, W.M. & Hamilton, J.G.
Description: The cyclotron is the only practical source of many carrier-free radioisotopes. The preparation and radiochemical isolation of a number of these activities, produced in the 60-inch cyclotron of Crocker Laboratory, will be presented in this paper and in subsequent papers of this series. In most cases the carrier-free radioisotopes were prepared for use in biological systems and the final preparations were in the form of isotonic saline solutions at a range of pH from 5 to 8. The present paper reports the radiochemical isolation of carrier-free Sn{sup 113} and In{sup 114} produced by bombarding cadmium with 38 Mev alpha-particles. At this energy, Sn{sup 113} and In{sup 114} are produced in a thick target by the nuclear reactions; Cd{sup 110}({alpha},n)Sn{sup 113}, Cd{sup 111}({alpha},2n)Sn{sup 113}, Cd{sup 112}({alpha},3n)Sn{sup 113}, Cd{sup 111}({alpha},p)In{sup 114}, Cd{sup 112}({alpha},pn) In{sup 114}. The shorter-lived tin and indium activities together with the possible radioisotopes of silver produced by (n,p) reactions, were allowed to decay out prior to the chemical separations.
Contributing Partner: UNT Libraries Government Documents Department
Nitrogen 12

Nitrogen 12

Date: January 19, 1949
Creator: Alvarez, Luis W.
Description: N{sup 12} is shown to have a half life of 12.5 {+-} 1 milliseconds, and a positron upper limit of 16.6 {+-} 0.2 Mev. It is produced by the reaction C{sup 12}(p,n)N{sup 12}, and has a threshold proton energy of 20.0 Mev. This indicates that N{sup 12} is within about 200 Kev of being unstable against proton emission. The mass of N{sup 12} is 12.0228 {+-} 0.00015, and the beta transition is allowed.
Contributing Partner: UNT Libraries Government Documents Department
Alpha-Decay in Isotopes of Atomic Number Less Than 83

Alpha-Decay in Isotopes of Atomic Number Less Than 83

Date: September 5, 1949
Creator: Thompson, S.G.; Ghiorso, A.; Radmussen, J.O. & Seaborg, G.T.
Description: Some time ago we started work in an attempt to observe alpha-particle decay in isotopes of atomic number less than 83. In the first experiments, thin targets of gold leaf were bombarded with 190-Mev deuterons in the 184-inch cyclotron. Two alpha-decay periods were observed in these targets; one of 0.7 minutes half-life and another of 4.3 minutes half-life. The alpha-particle energies were 5.7 and 5.2 Mev, respectively. Chemical separations proved that the 4.3-minute period is due to a gold isotope and suggested that the 0.7-minute period is due to a mercury isotope. The mass numbers of these new isotopes have not been determined. However, the results of excitation-functions in the production of the gold isotope by bombarding gold and platinum with protons suggest that its mass number lies in the range 185-188. The work on this isotope indicates that the alpha to electron capture branching ratio is of the order of magnitude of 10{sup -4}, and that positron activity accompanies the 4.3-minute alpha-period.
Contributing Partner: UNT Libraries Government Documents Department
New Low Mass Isotopes of Emanation (Element 86)

New Low Mass Isotopes of Emanation (Element 86)

Date: September 5, 1949
Creator: Ghiorso, A.; Meinke, W.W. & Seaborg, G.T.
Description: Among the spallation products obtained from the 350-Mev proton bombardment of Th{sup 232} they have identified two gaseous alpha-emitters which apparently do not decay into any presently known alpha-decay chains. The half-lives observed for the decay of the alpha-activities are 23 minutes and 2.1 hours. These half-lives may be principally determined by an unknown amount of orbital electron capture. At least one alpha-emitting daughter (about 4 hours half-life) has been observed to grow from a gaseous parent, but it has not been determined whether it arises from alpha-decay or electron-capture. Since these gaseous atoms emit alpha-particles it is assumed that they are isotopes of element 86 (emanation or radon) rather than a lighter rare gas. if they were heavy isotopes such as Em{sup 221} or Em{sup 223}, both unknown, they would decay into known alpha-decay series, the neptunium and actinium series, respectively, and so would grow known short lived alpha-emitters which would have been detected. It thus appears reasonable that they must be lighter than the known emanation isotopes.
Contributing Partner: UNT Libraries Government Documents Department
Half-Life for Double Beta-Decay

Half-Life for Double Beta-Decay

Date: October 21, 1949
Creator: Levine, C.A.; Ghiorso, A. & Seaborg, G.T.
Description: Fireman(1) has reported the results of a rather difficult beta-particle coincidence counting experiment in which the decay of Sn{sup 124} by the simultaneous emission of two negative beta-particles, with a half-life between 0.4 x 10{sup 16} years and 0.9 x 10{sup 16} years, seems to have been observed. This note reports the results obtained from a different and somewhat simpler method of looking for the phenomenon of simultaneous emission of two beta-particles. These results are negative so far and show that this process is considerably less probable in the case chosen by us than in that reported by Fireman. The method consists of looking in uranium samples for 90-year Pu{sup 238} which would come from U{sup 238} by the double beta-particle mechanism since Np{sup 238} is heavier than U{sup 238}, which in turn is substantially heavier than Pu{sup 238}, in the isobaric triplet {sub 92}U{sup 238}-{sub 93}Np{sup 238}-{sub 94}Pu{sup 238}. This chemical method of investigation is particularly applicable to this isobaric triplet because there appears to be no other mechanisms to account for the Pu{sup 238} should it be found. The energetics of the situation are summarized in the following diagram, where the disintegration energies are derived from sources which ...
Contributing Partner: UNT Libraries Government Documents Department
Production for Mesons by X-rays

Production for Mesons by X-rays

Date: September 15, 1949
Creator: McMillan, Edwin M.; Peterson, Jack & White, R. Stephen
Description: At the spring, 1949, meeting of the National Academy of Sciences(l) a preliminary account was given of some observations of mesons produced by the 335 Mev x-ray beam from the Berkeley synchrotron. The present paper is a progress report of this work; no claim is made for completeness, but sufficient new data are available to make publication at this time worth while, especially since some of the numerical results given in the earlier report require revision. The x-ray beam, produced by the impact of 335 Mev electrons on a 20 mil thick platinum target, has a width at half maximum of 0.0135 radian (about 1 inch at 6 feet from the target). In all but the earliest experiments the beam was further defined by a 1 inch hole in a lead block, then passed through a piece of carbon which served as the meson source. The x-ray intensity at one meter from the target was about 3500 r per hour (measured behind 1/8 inch of lead) under the best running conditions; the average was about half this. The actual exposures at the carbon meson source (6 feet from the target) ranged from 500 to 2000 r in the later runs. ...
Contributing Partner: UNT Libraries Government Documents Department
Experiments on the Effect of Atomic Electrons on the DecayConstant of Be7 II.

Experiments on the Effect of Atomic Electrons on the DecayConstant of Be7 II.

Date: June 15, 1949
Creator: Leininger, R.F.; Segre, E. & Wiegand, C.
Description: A comparison of the decay constants of Be{sup 7} in beryllium oxide and in beryllium fluoride has given {lambda}{sub BeO}-{lambda}{sub BeF{sub 2}} = (+1.375 {+-} 0.053)10{sup -3}{lambda}{sub BeO} thus showing a definite effect of the chemical binding on the radioactive decay constant.
Contributing Partner: UNT Libraries Government Documents Department
Low Mass Francium and Emanation Isotopes of High AlphaStability

Low Mass Francium and Emanation Isotopes of High AlphaStability

Date: October 10, 1949
Creator: Hyde, E.K.; Ghiorso, A. & Seaborg, G.T.
Description: Isotopes of francium with 126 or fewer neutrons have been looked for in bombardments of Th{sup 232} with 350 Mev protons from the 184-inch cyclotron. Fr{sup 212} with an apparent half-life of 19.3 minutes for branching decay by alpha emission (44%) to At{sup 208} and by orbital electron capture (56%) to Em{sup 212} has been found. Em{sup 212} is shown to be a 23-minute alpha-emitter. At{sup 208} decays primarily (99.5%) by orbital electron capture to Po{sup 208}, but shows 0.5% alpha-branching. The francium and emanation isotopes have alpha half-lives completely out of line with the predictions based on the previously known isotopes of these elements. Their high alpha stability is believed to be due to a closed shell of 126 neutrons in analogy to the behavior of elements 83-85. The non-existence of long-lived francium in nature is discussed in the terms of this and other recent work on francium isotopes.
Contributing Partner: UNT Libraries Government Documents Department
A Two Liquid Phase Distribution Method for the Separation ofMetallic Elements

A Two Liquid Phase Distribution Method for the Separation ofMetallic Elements

Date: August 1, 1949
Creator: Calvin, M.
Description: The general principles of a liquid-liquid solvent extraction method for the separation of metallic elements are outlined.
Contributing Partner: UNT Libraries Government Documents Department
A PreliminaryReport on the Mechanism of the Decomposition ofDiacetyl Peroxide in Acetic Acid

A PreliminaryReport on the Mechanism of the Decomposition ofDiacetyl Peroxide in Acetic Acid

Date: December 29, 1949
Creator: Fry, A.J.; Tolbert, B.M. & Calvin, Melvin
Description: The decomposition of diacetyl peroxide in acetic acid-2-C{sup 14} has been studied, The activity of the products in general confirmed the mechanism of the reaction as proposed by Kharasch and Gladstone, The presence and distribution of activity in the methyl acetate produced in this reaction is not explained by the previously proposed mechanism. There was no appreciable exchange of acetic acid and diacetyl peroxide under the conditions of the reaction. Essentially no exchange of methyl acetate and acetic acid was observed when those reagents mere heated at 100 for five hours.
Contributing Partner: UNT Libraries Government Documents Department
The Path of Carbon in Photosynthesis VI.

The Path of Carbon in Photosynthesis VI.

Date: June 30, 1949
Creator: Calvin, M.
Description: This paper is a compilation of the essential results of our experimental work in the determination of the path of carbon in photosynthesis. There are discussions of the dark fixation of photosynthesis and methods of separation and identification including paper chromatography and radioautography. The definition of the path of carbon in photosynthesis by the distribution of radioactivity Within the compounds is described.
Contributing Partner: UNT Libraries Government Documents Department
The Path of Carbon in Photosynthesis VII Respiration andPhotosynthesis

The Path of Carbon in Photosynthesis VII Respiration andPhotosynthesis

Date: July 21, 1949
Creator: Benson, A.A. & Calvin, M.
Description: The relationship of respiration to photosynthesis in barley seedling leaves and the algae, Chlorella and Scenedesmus, has been investigated using radioactive carbon dioxide and the techniques of paper chromatography and radioautography. The plants are allowed to photosynthesize normally for thirty seconds in c{sup 14}O{sub 2} after which they are allowed to respire in air or helium in the light or dark. Respiration of photosynthetic intermediates as evidenced by the appearance of labeled glutomic, isocitric, fumaric and succinic acids is slower in the light than in the dark. Labeled glycolic acid is observed in barley and algae. It disappears rapidly in the dark and is maintained and increased in quantity in the light in C0{sub 2}-free air.
Contributing Partner: UNT Libraries Government Documents Department
THERMAL STRESS TESTS OF KS GRAPHITE

THERMAL STRESS TESTS OF KS GRAPHITE

Date: July 19, 1949
Creator: Crocker, A.R.
Description: A program was initiated to determine the thermal rupture characteristics of KS graphite under steady-state operating conditions simulating the thermal conditions of an uninhibited rocket reactor. The maximum thermal stress calculated using room-temperature properties was 3090 psi. The maximum net specific power obtained was 5.2 Btu/cu in.-sec. (B.O.G.)
Contributing Partner: UNT Libraries Government Documents Department
PUREX PROCESS FOR PLUTONIUM AND URANIUM RECOVERY

PUREX PROCESS FOR PLUTONIUM AND URANIUM RECOVERY

Date: October 1, 1949
Creator: Lanham, W.B. & Runion, T.C.
Description: Labcratory data which indicate that the recovery of Pu and U and decontamination from fission products are feasible in a solvent extraction process using tributyl phosphate are given. The procedure consists of extracting Pu(IV) and U with 15% TBP--85% Varsol using 5.0 N HNO/sub 3/ as a salting agent. (J.R.D.)
Contributing Partner: UNT Libraries Government Documents Department
Magnets and Magnetic Measuring Techniques

Magnets and Magnetic Measuring Techniques

Date: June 1949
Creator: Wakerling, R. K. & Guthrie, Andrew
Description: Preface: The existence of adequate experimental equipment, in particular the two operating cyclotrons of the Radiation Laboratory and the large 184-inch unit under construction, together with a nucleus of trained personnel, made it inevitable that work in connection with the war effort would be prosecuted vigorously at the University of California.
Contributing Partner: UNT Libraries Government Documents Department
Electrical Circuits for Calutrons

Electrical Circuits for Calutrons

Date: June 1949
Creator: Wakerling, R. K. & Guthrie, Andrew
Description: Preface: The existence of adequate experimental equipment, in particular the two operating cyclotrons of the Radiation Laboratory and the large 184-inch unit under construction, together with a nucleus of trained personnel, made it inevitable that work in connection with the war effort would be prosecuted vigorously at the University of California.
Contributing Partner: UNT Libraries Government Documents Department
Correlation of Soil Properties with Geologic Information: Report Number 1, Simplification of the Liquid Limit Test Procedure

Correlation of Soil Properties with Geologic Information: Report Number 1, Simplification of the Liquid Limit Test Procedure

Date: June 1949
Creator: Waterways Experiment Station (U.S.)
Description: Introduction: The general project of correlating soil properties with geologic information, one phase of which is described in this report, consists in comparing soil properties with soil types and with their geologic history and environment in order to determine what correlations are possible.
Contributing Partner: UNT Libraries Government Documents Department
Technical Cooperation Program Visit of Lawroski and Stevenson (U.S.) to Chalk River on December 9-10, 1948

Technical Cooperation Program Visit of Lawroski and Stevenson (U.S.) to Chalk River on December 9-10, 1948

Date: April 8, 1949
Creator: Lawroski, S. & Stevenson, C.E.
Description: Minutes of conferences held at Chalk River, Ontario. The subjects discussed related primarily to separations processes.
Contributing Partner: UNT Libraries Government Documents Department
Progress Report No. 69. Dec. 15, 1948 to Jan. 15, 1949

Progress Report No. 69. Dec. 15, 1948 to Jan. 15, 1949

Date: January 30, 1949
Creator: Authors, Various
Description: This is the progress report for the University of California, Radiation Laboratory for December 15, 1948-January 15, 1949. It discusses the following: (1) Bevatron; (2) 184-inch Cyclotron Program; (3) 60-inch Cyclotron Program; (4) Synchrotron Operation; (5) Linear Accelerator and Van de Graaff Operation; (6) Experimental Physics; (7) Theoretical Physics, (8) Isotope Separation; (9) Chemistry Departments; (10) Medical Physics; and (11) Health Physics and Chemistry.
Contributing Partner: UNT Libraries Government Documents Department
Master-Slave Manipulator

Master-Slave Manipulator

Date: March 7, 1949
Creator: Goertz, R.C.
Description: A device for manipulating a pair of tongs behind a shielding barrier has been built and tested. It is called a Master-Slave Manipulator because the slave tongs move in exact correspondence with a master handle. The "slave hands" follow the master hands in complete synchronism. This is the first completely master-slave manipulator known to exist and has proved that this type of manipulation is very successful when the unit is prooperly engineered and built.
Contributing Partner: UNT Libraries Government Documents Department
Nomograms for Obtaining the Compound Composition of Hydrated Limes from the Oxide Analysis

Nomograms for Obtaining the Compound Composition of Hydrated Limes from the Oxide Analysis

Date: December 30, 1949
Creator: Levin, Ernest M.
Description: Report with two nomograms presented for rapidly obtaining the compound composition of hydrated limes from the oxide analysis. The general nomogram can be applied to any commercial hydrated lime and gives values accurate to within 0.3 percent while the special nomogram is applicable only to regularly hydrated and highly hydrated dolomitic limes and is accurate to within 0.1 percent.
Contributing Partner: UNT Libraries Government Documents Department
A Modified Decade Scaler: Final Report on Project Authorization Number CMR-3-5

A Modified Decade Scaler: Final Report on Project Authorization Number CMR-3-5

Date: June 9, 1949
Creator: Rupert, George N.
Description: Final report describing the development and usage of an automatic decade scaler which operates for a fixed number of counts, developed for use with a Geiger tube.
Contributing Partner: UNT Libraries Government Documents Department
FIRST PREV 1 2 3 4 5 NEXT LAST