UNT Libraries Government Documents Department - 542 Matching Results

Search Results

Results: 1 - 50 next
Polymerization in Solid Solutions of Acrylamide in Propionamide
It has previously been shown that the polymer formed in solid state polymerization of acrylamide is amorphous in spite of the fact that the reaction takes place within a crystalline solid. The stage at which it becomes amorphous is not known at present. Work with dilute solid solutions of acrylamide in propionamide suggests that this occurs after the addition of, at most, a very few monomer units.
Effects of Gamma-ray Irradiation on the Mechanical Properties of NaCl Single Crystals
The plastic behavior of both unirradiated and gamma-ray irradiated NaCl single crystals has been studied with a variety of techniques. These include the determination of stress-strain curves, and photoelastic, surface, topography, and F-center absorption band, measurements, The different stages of deformation in unirradiated crystals are compared with the corresponding stages of irradiated ones. One effect is that irradiation greatly extends the easy glide region. Some insight into this behavior is obtained from the photoelastic and topography measurements. In unirradiated crystals almost all glide occurs on one slip system and there is considerable pile up. In irradiated crystals slip occurs on two perpendicular systems, the number of operating glide planes is, at least, doubled, and the pile up is very much reduced. Both the yield-point and F-center concentration increases rapidly with dose up to approximately 10 7 r and at a much slower rate for larger doses. Also investigated was the effect of crystal shape (or geometry) on the stress strain curves obtained from unirradiated crystals. The most interesting results are, the yield-point decreases with increasing cross section and that the slope of the linear strain hardening region depends on the radio of the crystals shortest dimension to its height.
Radiation Damage to Water
Water may decompose under radiation to give hydrogen and oxygen gases and small amounts of hydrogen peroxide. The amount of decomposition depends critically on the nature of the radiation, the kind and amount of dissolved materials present, and the temperature. Destruction of dissolved material may proceed to a greater extent than that of the water itself. The basic theory of these effects is briefly outlined. Engineering problems resulting from radiation chemical effects in water are discussed for various cases in which ordinary or heavy water is used in reactors as moderator, coolant or shielding material.
Neutron Diffraction Studies at the Puerto Rico Nuclear Center
A neutron diffraction program was initiated recently at the Puerto Rico Nuclear Center. The two double crystal spectrometers in use were assembled with the aid of staff members of the Brookhaven National Laboratory. The first research problem to be completed was a single crystal structure analysis of CaWO4. Choosing the origin at the 4(a) tungsten site in the tetragonal I41/a cell. the 16(f) oxygen parameters were found to be as follows: x=0.2413 ± 0.0005, y=0.1511 ± 0.0006, z=0.0861 ± 0.0001. Anisotropic temperature parameters were also determined for all atoms in the least squares analysis of the structure. The magnetic structure of CuSO4 has been determined in a continuation of a study started at Brookhaven in collaboration with Dr. P.J. Brown. Using the Wollan-Koehler-Bertaut notation, the antiferromagnetic spin ordering mode in the orthorhombic Pbnm cell is Ax, with the spin axis parallel to a. A moment of approximately 1 μB was found for the Cu2_ ion. The crystal structure of BaNiO2 was re-examined in a neutron powder diffraction study, and it was found that the earlier x-ray study of Lander is essentially correct. An alternative oxygen arrangement, for which x-rays would not have been very sensitive, had been suspected. BaNiO2 was also investigated for magnetic order at 4.2°K but conclusive results have not been obtained. A magnetic transition has been found in Fe2SiO4 in the neighborhood of 30°K. This compound has an olivine type structure with eight Fe2+ ions in the 4(a) and 4(c) positions of the Pbnm space group. Analysis of the magnetic structure is still in progress, but some preliminary results are discussed.
Occurrence of Technetium-98 in Nature
The non-existence of technetium in nature, long considered a fact of axiomatic validity, has become subject to considerable doubt in recent years due to the discovery of technetium in the sun and in S-type stars.
Remarks by R. Christian Anderson of the Brookhaven National Laboratory, Upton, L.I., New York, at the conclusion of Professor Scott's talk on "The Light Metal Carbonyls".
Our interest in the light metal carbonyls is twofold. One phase concerns the general chemistry and structure of these compounds inasmuch as they provide interesting and important organic materials and may be considered to be organometallic substances. Secondly and secondarily, these materials afford a convenient synthetic route to isotopically labeled compounds since the labeled precursor, carbon monoxide, is readily available.
Some Considerations on the Configuration and Stability of the H2 Temperature Control Loops of the 80" Bubble Chamber
There is but little known about the thermal process involving the dynamics and thermodynamics of the cycling liquid H2 in the chamber and those of the H2 fluid flow in the cooling coil as well as the geometrical characteristics of the chamber body. This the physical equations governing this process are involving so many variables that this analysis becomes rather complex even if simplifying assumptions are made. To those difficulties is added the ignorance even of an approximative expression for some physical quantities such as film heat transfer coefficients entering as major parameters the process equation.
Biological Effects of Thermal Neutrons and the B10 (n,c) Li7 Reaction
Boron-10 has a high thermal neutron capture cross section (3880 barns). Following neutron capture, the subsequent nuclear disintegration produces an alpha particle and a lithium-7 nucleus with the release of an average of 2.34 MeV for the particle irradiation, and in 93% of the reactions there is also the emission of an 0.48 MeV gamma ray: [equation not transcribed]. The kinetic energy is divided between the lithium-7 nucleus and the alpha particle giving the equal and opposite momentums with a range in tissue of about 8-14μ or approximately 1 cell diameter (1). This fact and the reported favorable partition of boron between tumor and the normal brain suggested a possible therapeutic usefulness which has been investigated clinically. The object of our study is to document the biological effects of the B10 (n,α) Li7 reaction on the brain of dogs injected with boron-10 30 minutes prior to irradiation with thermal neutrons. For this, we felt it desirable to estimate a dose for the boron-10 reaction which if exceeded, produces destruction of normal tissue. This dose could then be a reference dose to be utilized as a maximal limit for the irradiation of normal tissue. We have assured that the largest fluence of thermal neutrons that permits a healing radioepidermitis in pigs injected with 35 mg/kg of boron-10, 30 minutes prior to irradiation would be suitable first approximation.
Dose-survival Curves for HeLa Cell Cultures Using Thermal Neutrons and the B10 (n,α)Li7 Reaction
The biological evaluation of the thermal neutron capture reaction of boron-10, B10 (n,α)Li7 + 2.786 MeV, has previously been studied, using different particles from the boron-10 thermal neutron capture reaction compared with 250 kvp x-rays has been reported as 1.05 for spleen-thymic weight reduction (1), as 1.5 to 2.0 for skin lesions in pigs (2), and 1.87 for skin lesions of the rabbit's ear (3). The significance of such a calculation is felt to be unreliable for the boron-10 reaction in animals because of the vagaries of dose determination resulting from irregular boron distribution, and by the presence of an adventitious irradiation from fast neutrons and capture gammas that is inadequately determined at present. Our present experiment attempts to circumvent the difficulties attendent to studies of the boron-10 reaction in animals by comparing the effect of this reaction on the proliferative capacity of HeLa cells with those produced with 250 kvp x-ray.
The Effects of 250-kv X-Ray on the Dog's Pancreas: Morphological and Functional Changes
Previous investigations that the pancreas is a radioresistant organ. Ivy in 1924 noted the presence of a fibrotic atrophic pancreas in a dog which had received one erythema dose to the epigastrium. Fisher in 1923 reported that four to five erythema doses delivered in a single application caused complete disappearance of the irradiated pancreatic remnant in about two months. These dogs died because of uncontrolled diabetes. One dog that received four erythema doses (possibly 200 r) was sacrificed after five months. At autopsy the irradiated pancreas had disappeared, but 275 mgm of regenerated pancreas were found at the base of the main duct and 100 mgm at the base of the accessory duct. Leven in 1933 implanted radon seeds into the pancreas. Dosages varied from 528 to 1584 millicurie hours. At postmorten the pancreas surrounding the seeds demonstrated fibrous atropy and foci of necrosis. The islets appeared normal but were relatively larger in size. Rauch in 1952 reported that dogs given 200 r in air over the pancreas on alternate days until a total of 1600 r was received failed to show any histological changes after two months. Lushbaugh and Spalding and Lushbaugh reported that over 1500 r of whole-body gamma irradiation were required to produce histologic changes in alpha cells in 8 hours, and over 5000 r to produce changes in the beta cells in the same time. These changes had disappeared by 24 hours.
Comfort and Support of the Cancer Patient
This paper considers the duty of the physician to provide comfort and care for cancer patients and suggests four tenants for physicians to follow to assist with this: 1) No matter what the patient's condition, the physician shall be always available, even if only to listen and talk. 2) In spite of the ravages of cancer, the patient lives with it. 3.) The patient is an adult under guarantees of the constitution. and 4) The physician will always communicate with the patient. The paper ends with a discussion of the objectives for management of cancer patients.
An Isochronal Differential Microcalorimeter
An isochronal differential-type microcalorimeter has been designed and constructed. As a result of its simple design it is very easy to handle the samples and assemble the calorimeter. Important to the operation of the calorimeter is a program, also working on the differential principle, that provides linear temperature rise of the samples. This calorimeter is used to measure very small energy releases such as those found in precipitation, stored energy, etc. It is demonstrated that the calorimeter is easily capable of measuring 0.0005 cal with a probable error of the order of 1% to 2%.
Bromine Exchange in Graphite-Bromine Lamellar Compounds
A kinetic study of the exchange of normal and radioactive bromine in graphite-bromine lamellar compounds has been made at temperatures of 30° to 50°C. Natural and synthetic graphite powders were investigated. Two alternative mechanisms for the exchange, volume diffusion and surface exchange, were considered. The data were in better agreement with the diffusion mechanism. Diffusion coefficients of 10 -9 to 10 -8 cm2/sec and an activation energy of 11 to 14 kcal/mole were calculated for the natural graphite powders. The diffusion coefficients increased with increasing bromine content. Reversibly absorbed bromine exchanged more rapidly than irreversibly absorbed bromine.
LMFR-9 Static Corrosion Behavior of Materials in Bismuth and Uranium-Bismuth Solution at 550°C
Report issued by the Brookhaven National Laboratory discussing corrosion behaviors of materials in bismuth. As stated in the introduction, "this report will present the details of the corrosion testing and the results obtained to date on materials tested under static conditions in bismuth media" (p. 1). This report includes tables, illustrations, and photographs.
Disposition of Radiation Products and Energy Transfer in Radiobiological Processes
Technical report outlining the nature and effects of energy loss and radiation in biological materials during radiobiological processes.
Numerical Solutions for Diffusion in a Sphere, Cylinder, and Plate
In calculating diffusion coefficients for gases diffusing from solids, the numerical solutions tabulated by Darken and Gurry, were found to lack the required precision, and the intervals between the arguments were too great to permit precise interpolations. Consequently the diffusion equation solutions of interest (diffusion from a sphere, cylinder, and plate, for the condition that the concentration of the diffusing species initially uniform) were re-evaluated. Computer programs for the three cases were written in FORTRAN for the IBM 7090. The solutions programmed are given in Crank. Values of the fractional completion were computed at approximately 0.01 increments, to the nearest 0.00001, and are tabulated in Table 1 to the nearest 0.0001. The table covers the fractional range from about 0.04 to 0.99. For smaller fractions satisfactory approximations are available. The table may be conveniently interpolated by plotting points about the region of interest and drawing a curve.
A Versatile Bubble-Chamber Track Measuring Stage
Technical report describing a bubble chamber film track measuring stage designed for maximum versatility that was build at Brookhaven National Laboratory. The report includes photographs and diagrams of the device.
A Bubble Chamber Track-Centering Device with Digitized Output
Technical report describing "A means for automatically determining the coordinates of a point at the center of a bubble chamber track." from the abstract.
A Computer Program to Optimize Magnets in a Beam Transport System*
A computer program which optimizes the locations and strengths of magnets in a beam transport system has been written for the IBM 704 and 7090 computers Programs have been previously written which trace a ray through a system of magnets and determine its focusing properties When using such a program, one examines the characteristics of the emergent beam and then varies the parameters of the system manually to optimize it In the program which will now be described, the computer itself performs the examination and varies the parameters.
Total Cross Sections for K Mesons and π Mesons on Protons and Deuterons between 2.5 and 6 BeV/c
Recent measurements of the pion-proton total cross section, taken with small statistical errors, have shown the existence of two new maxima in the momentum range between 2 and 3 BeV/c. Measurements of comparable statistical accuracy, covering the momentum range from 2.5 to 8 BeV/c are reported in the present paper. In addition to the total cross sections for π± mesons on protons, their total cross sections on deuterons have also been determined. Some data were also taken on the total cross sections for K+ mesons on protons and deuterons and for K- mesons on protons.
Computations for AGS Experimental Beams: Description of Computer Program
Description of a computer program which optimizes the locations and strengths of magnets for experimental beams at the Brookhaven AGS written for the IBM 7090 computer. Layout, method, and routines are given particular attention, and representative data cards are shown.
Interactions of High Energy Antiprotons in Hydrogen
In the fall of 1961 an extensive program of investigation of high energy p-p interactions was begun at the Brookhaven AGS. The BNL 20" liquid hydrogen bubble chamber and an electrostatically separated beam were used to obtain a total (to date) of 300,000 exposure with about 15 antiprotons per pulse. The exposures were made at antiproton momenta of 3.25 Bev/c and 3.69 Bev/c in the laboratory. Approximately 80% of the exposures were made 3.69 Bev/c antiprotons. A wide variety of reactions occur in these collisions. Some of these such as elastic scattering, pion production, and associated production of hyperons and K-mesons have analogues in p-p collisions. The similarities and differences between the p-p and p-p results can usually be understood in a qualitative way and in some cases quantitative comparison with theory has been possible. The annihilation reactions leading to final states containing pions alone or pions with K-mesons are unique to the nucleon-antinucleon system as are the reactions in which a hyperon, anti-hyperon pair is produced. In the following, we report the principal characteristics of proton-antiproton reactions. Although the scope of this paper is comprehensive it is not a definitive report of the experiment as much of the work is still in progress.
Hyperon Production by 3.25 Bev/c Antiprotons in Hydrogen
Preliminary results are presented on hyperon-anti-hyperon production in proton-anti-proton collisions at 3.25 Bev/c. The exposure consisted of approximately 40,000 pictures taken in the Brookhaven National Laboratory 20" liquid hydrogen bubble chamber. The anti-proton beam was extracted from the A.G.S. and electro-statically separated. An average of approximately 15 anti-protons per picture was obtained at this momentum with an estimated beam contamination of less than 10K. The beam momentum was determined from kinematical analysis of a large sample of events. The scanning and measuring of the film has been done both at Yale and at Brookhaven, as well as the analysis of the data. A combination of the data from both laboratories is presented.
The Separated Beam at the AGS - Performance with Antiprotons and π⁺ Mesons
During 1961 and 1962, a separated beam was designed and installed at the AGS for use with the 20 inch hydrogen bubble chamber. The beam utilizes electromagnetic velocity spectrometers in two stages of separation. Since the fall of 1962, the bubble chamber has taken 600,000 pictures containing antiprotons, K± mesons, and π± mesons as beam tracks. This paper concerns the use of the separated beam for antiprotons and π⁺ mesons.
Cool-Down Refrigeration Requirements for 80" Bubble Chambers
The purpose of this report is to determine the amount of refrigeration capacity required to cool down the 80" bubble chamber from ambient temperature to liquid hydrogen temperature.
General Description of the 80" Bubble Chamber Refrigeration System
Reliability of individual components and the ability to produce refrigeration even if one or two of these components should be in operable are the prime design parameters of this cycle. Each component was looked at with these two parameters in mind and any item that had obvious objections was either rejected or backed up with another piece of equipment. Along this line, you will notice (refer to line schematic) two hydrogen compressors and two nitrogen compressors; for full capacity all are required. However, in the event of the loss of use of one of these compressors, it will still be possible to produce at least 50% of the rated capacity. To eliminate outside influences, the cycle was designed around what may be called a closed cycle cascade system; with the assumption that there is no loss of power, cooling water, the equipment can run indefinitely. The nitrogen and hydrogen cycles are of the Simple Linde type with pre-cooling making use of the Joule-Thompson Effect for the refrigeration produced. The low-temperature components of the cycle have no moving parts other than valves, consisting entirely of counter-flow heat exchangers to lower the temperature of the incoming high-pressure gas to a level where an economical amount of refrigeration can be produced by expansion through the Joule-Thompson valves. These cycles use relatively high-pressure gasses (2000 psig hydrogen and 3000 psig nitrogen); however, past experience in the handling of high-pressure gases and the known reliability of the Simple Linde Cycle overcomes any obvious objections to the use of high-pressure
Hydrogen Refrigerator Design Capacity for 80" Chamber
When the design of the refrigerator was begun, one of the important parameters was refrigeration capacity required. In order to estimate the required hydrogen refrigeration load the following had to be considered: 1. Dynamic Load due to pulsing of the chamber. Although this has been determined some two years ago through test work, it has not been published as of this date and will be presented here. 2. Static losses due to conduction, radiation, and convection. This is covered by Eng. Note BC-03-0-B. 3. Cool-down requirements. This is covered by Eng. Note BC-03-0-C.
Adenosinetriphosphate Cleavage During the G-Actin to F-Actin Transformation and the Binding of Adenosinetriphosphate to F-Actin
Since the discovery of the Straub and Feuer as well as Laki et al. that ATP bound to G-actin is transformed to ADP and inorganic phosphate during polymerization of actin (1, 2), it has become increasingly clear that the chemical changes in the nucleotide are related to the change in the physical state of the protein. Barany, Biro, Molnar and Straub have shown that highly purified actin preparation free of any enzyme which would use ATP, ADP or AMP as a substrate still catalyze the breakdown of ATP (3) thus supporting the original idea that the ATP to ADP transformation is related to the globular to fibrous transformation of the actin protein itself. Mommaerts was the first to show that the ADP formed during polymerization remains bound to F-actin and Ulbrecht et al. while extending Mommaert's finding on exhaustively purified actin preparations have shown that the P1 formed during polymerization is not bound to F-actin. The stoichiometry of the splitting and the tightness of binding of the ADP lead inevitably to questions in regard to the position of bond breaking during the hydrolysis and to the nature of the forces involved in the tight binding of ADP to F-actin. To aid in the clarification of these problems, this study using O18 isotope was initiated.
A Continuous Fission Product Separation Process; I. Removal of the Rare Earths (Lanthanum Cerium, Praseodymium, and Neodymium) From a Typical Liquid Bismuth-Uranium Reactor Fuel by Contact with Fused LiCl-KCl Mixtures
Technical report investigating the distribution of rare earth elements between a liquid bismuth-uranium solution and fused KCI-LiCi mixtures. Report warrants further research on the liquid bismuth-uranium-fused salt system due to the benefit of continuous fission removal processes.
Liquid Reactor Fuels: Bismuth-Uranium System
Technical report about the liquidus curve for the nuclear reactors bismuth-uranium system and the need for a suitable container for this fuel.
Studies of the Rapid Beam Ejector at the Cosmotron
For an experiment to measure the magnetic moment of the Λ hyperon, it was necessary to extract the external beam of the Cosmotron with maximum efficiency and with minimum time duration. To accomplish this end, the standard external beam of the machine was supplemented with the Rapid Beam Ejector. It was found that, unfortunately, the ejection efficiency of the beam was less than normal when the RBE was used. Measurements of the ejection efficiency were made by irradiating polyethylene foils at the second focus of Beam 1 with 3 BeV protons. The external beam was tuned up and optimized in a standard manner. It was found that the ratio of the number of protons ejected with the RBE to the number ejected without the RBE was 0.3 in one run and 0.22 in another try. It was also observed that the RBE did not shift the position of the external proton beam focus to within ± 1/8 in.
Time Dependence of Space Charge Beam Losses in the Cosmotron
An investigation was made of Cosmotron intensity versus time through the entire time interval from the beginning of injection to the completion of r-f capture. The induction electrode signal was used for the instantaneous measurement of beam intensity. Oscilloscope displays of the signal were photographed and traced. Base lines were filled in on the tracings and the area of the pulses measured with a polar planimeter. It was found that the relation losses of beam intensity increase with injection intensity (total injected charge), and that most of the losses take place in the time interval between the end of injection and the completion of the first synchrotron oscillation
The Effects of Radiations of Different let on Early Responses in the Mammal
This paper will first note briefly the place and status of radiobiotopical investigations with fast neutrons. The monoenergetic (fast) neutron technique employed at this laboratory will be then described and results of studies with various criteria-of-effect in the mouse will be reviewed. Finally, certain general patterns of response for these systems will be pointed out as functions of neutron energy.
Lens Opacification in Mice Exposed to Monoenergetic Fast Neutrons
Early effects obtained with monoenergetic fast neutrons in mice have been described elsewhere. Emphasis in this report will be placed on the late effects of lens opacification (cataractogenesis), particularly during the period soon after irradiation with low or fractionated doses of neutrons at two energy levels, or X-rays. Considerations will also be given to the influence of age at time of irradiation upon the induction of lens opacities. Both studies are continuing, with periodic slit-lamp microscope examinations, but findings to date warrant this initial report at this conference.
On the Crystal Chemistry of Salt Hydrates, II. A Neutron Diffraction Study of MgSO4·4H2O
The crystal structure of MgSO4·4H2O has been refined using single crystal neutron diffraction data for the three main zones. The hydrogen positions which were found are essentially those which have been deduced from X-ray data in an earlier investigation.The mean value of the O-H bond lengths is 0.97Å. The O-H-O bonds are bent considerably. One hydrogen atom does not participate in hydrogen bonding, as can be concluded from the geometry of its surroundings and its thermal motion.
On the Crystal Chemistry of Salt Hydrates, III. The Determination of the Crystal Structure of FeSO4·7H2O (Melanterite)*
Monoclinic FeSO4·7H2O is the stable solid phase between -1.82° and 56.6° C in contact with a saturated water solution of FeSO4. It occurs in nature as an oxidation product of Fe-containing sulfides an is called melanterite. FeSO4·7H2O belongs to a series of compounds Me2+SO4·nH2O, where Mn2+ is a cation with an approximate ionic radius of 0.7Å. The 1-, 4- and 5-hydrates are known to crystalize each in only one form, whereas the hexa- and the heptahydrates occur both in two different forms. The crystal structure of the tetragonal NiSO4·6H2O; Zalkin, Ruben and Templeton reported the structure of the monoclinic CoSO·6H2O. Of the structure of the heptahydrates but one was described: the orthorhombic form of NiSO4·7H2O. No details were known about one of the monoclinic heptahydrates, though Leonhardt and Ness published the cell constants and the space group of FeSO4·7H2O.. In addition they stated essentially correct positional parameters for the sulfur atom and gave the correct positions of the iron atoms. The present investigation has been undertaken as part of an extensive study of salt hydrates. A preliminary account has been published before.
Studies of the Localization, Physiochemical Properties, and Action of Phycocyanin in Anacystis Nidulans
The blue-green algae, classed as primitive monerans, represent the lowest level of organization known to possess a higher plant type of photosynthesis. The role in photosynthesis of the phycocyanin in these organisms is particularly interesting from the point of view of ultrastructural biochemistry. It has been shown repeatedly that despite the primacy normally assigned to chlorophyll, the light absorbed by phycocyanin is used more efficiently for photosynthesis (equated with photosynthetic oxygen evolution). This property is all the more intriguing since Hill activity is very labile in these organisms; the loss being correlated with the release of phycocyanin. Then too, it has been observed that fluorescence at about 685 mμ, attributed to chlorophyll, is proportionately greater for wavelengths absorbed by phycocyanin. French and Young attributed the differential to inactive absorption by carotenoids in the "Soret" region of chlorophyll, but Duysens concluded that the magnitude of the difference observed by him was too great to be explained by screening. Duysens proposed the existence of two pools of chlorophyll of about equal size; one containing fluorescent, photosynthetically active chlorophyll in proximity to phycocyanin, the other nonfluorescent, photosynthetically inactive and remote from phycocyanin.
A Needle in a Haystack
Abstract: "Production of [rho]'s and [omega]'s in [pi]- + p and p + [letter p with a bar over it] interactions is discussed. The [rho] is presumably a J = 1-, 1 = 1 state and thus can decay into 2[pi]'s via a strong coupling. The [omega] is probably J = 1-, 1 = 0 which can also decay into 2[pi]'s via electromagnetic coupling. A theoretical description of this situation is presented in terms of coupled time-dependent Schroedinger equations which mix [rho] and [omega] states that are assumed to be isotopically pure at the time of production. The interference between the two resonances was found to have the effect of extending the 2[pi] spectrum toward the [omega] mass."
A Simple Theory of the Process P+P → D+W+
The discovery of the vector meson which mediates the weak interactions, W,1 would be of extreme importance for weak interaction physics and for field theory in general. The W, if it exists, will be made in a variety of processes such as v+N →W+ + e- + N, or n- + P →W- + P, or, as studied in this note, P + P → D + W+. The W couples to leptons with a dimensionless constant [constant not transcribed] where G is the Feral constant defined t=so that [constant not transcribed]. Thus for [equation not transcribed] and the smallness of this constant is, evidently, what makes any of the above processes difficult to detect. The W may have a variety of decay modes.
Progress Report - Studies on the Propagation of Gamma Rays in Air
Initial rough measurements of the quality of the gamma radiation from Co-60 in air indicated agreement with the theoretical calculations of Spencer and Fano for an infinite water medium. Further experiments were performed, duplicating the conditions assumed in the calculations. Since the spectral region between 100 kev and 1 mev has already been examined by Hayward, it was decided to investigate in detail the region below 100 kev and above 1.0 mev. Total radiation dosage measurements were made in water using Victoreen ion chambers. The build-up factor was measured as a function of distance. Good agreement was obtained with the results of White. The spectrum below 150 kev was examined with a small NaI(Tl) scintillation counter and both the shape of the spectrum and the attenuation as a function of distance was in good agreement with the calculations. At distance less than 30 cm from the source the spectral shape changed, gradually broadening with the peak shifting to higher energies. The primary region above 1.0 mev was examined using a large NaI(Tl) crystal, and the gradual loss of resolution in the two primaries as a function of distance with an increase in lower energy events was shown. The measurements to be conducted in air are as follows, using the configurations indicated: 1. Detector in a hole in the ground, and the sources at various distances from the hole but not in the direct line of sight. Both total dose rates and spectrum shapes will be studied. 2. Both detector and source on the ground shielded from each other. The scattered radiation will be studied. 3. Measurements with the detector and source both off the ground are also contemplated.
The K"p Interaction at 2.24 Bev/c I: Effective Mass Distributions
The purpose of this note is to discuss results based on the 2 and 3 particle effective mass distributions of selected production channels from K~-p interactions at 2.24 BeV/c. The experimental distributions show clearly that the production of intermediate resonant states is still important at higher energies. We present below preliminary information concerning the resonant states: K*9 Y*9 co, and Y*9 m = 1520. Further, the effective mass distribution of the heretofore unobserved channels, AKK and EnK show a marked departure from phase space in the (KK) system at 1020 MeV and in the (En) system at 1535 MeV.
K⁻ -p Interactions at 2.24 Bev/c II: Production Properties
The purpose of this note is to report various properties of the production modes of K -p interactions at 2.24 Bev/c. Specifically, we present 1) preliminary estimates of the partial cross sections, 2) production angular distributions for those combinations of channels which we believe to be well identified, and 3) for channels of particular interest, we present up-down decay distributions from which hyperon polarization information is obtained. Many of the observed final states which are called "production channels" are in reality the decay products of resonant intermediate states.
Alternating Gradient Magnets
The angle by which a magnet deflects the trajectory of a particle in the x-z plane is proportional to the integral [integral not transcribed] taken over the trajectory wherever B≠0. Alternating gradient focusing is achieved by designing magnets so that I=I(x) varies linearly with x over a suitable x interval. Usually this is done by shaping the poles to give a linear variation of By with x while keeping the length of the magnet constant for different x. Certain advantaged may be gained by varying the effective length of the magnet with x and keeping By constant so that the integral varies properly with x. Figure 1 shows several such poles for which the trajectory length, and hence the integral (1), varies approximately from 2/3 to 4/3 of the mean value.
Long Coil Measurements Satisfy Two-Dimensional Field Equations
The amount by which the field of a magnet bends the path of a charged particle is proportional to the integral of Btds along the trajectory. Instead of making tedious point by point measurements of B in magnets and performing the integrations numerically, it has been found useful to measure directly, by using a search coil whose winding consists of long and narrow turns extending through the magnet gap from z1 and z2 in the direction of the trajectory. It should be noted that the integral Iy is taken along a straight x=constant, y=constant lines and not along the actual curved trajectory path; for small curvature the difference is small.
Fluorimetric Assay of α-Chymotrypsin
The enzymolysis by α-chymotrypsin of the substrates, N-acetyl-L-tryptophane ethyl ester and N-acetyl-L-tyrosine ethyl ester, was followed by means of fluorescence whose intensity increased fourfold and threefold per mole respectively as substrate was transformed into amino acid. The assay by fluorescence was several orders of magnitude more sensitive than the assay by differential absorption spectra of these substances and was in agreement with it in those concentration regions where both methods overlap. To maintain linearity between concentration and fluorescence intensity, the concentration of substrate should be no greater than 10-4 M/1. In such solutions the rate of esterolysis could be followed with the enzyme at 10-11 M/1.
Molecular Geometry and the Vapor Pressure of the Isotopic Ethylenes; Chemical and Structural Isomers
This report details a study of the vapor pressures of deuteroethylenes and C13 ethylene.
Correlation of Kinetic Isotope Effects with Chemical Bonding in Three Center Reactions
We consider the kinetic isotope effect in three center reactions of the type of A+BC→AB+C. Such model calculations are a good approximation to primary hydrogen isotope effects. For abstraction or transfer reactions, B becomes H, D, or T. The dynamics of the three storm system are calculated for a general quadratic potential, with the assumption that the potential energy is constant along the reaction coordinate (flat top barrier). This model system can be calculated in detail and serves to illustrate the relationship between kinetic isotope effect and chemical bonding in the transition state. The statistical mechanical part of the calculation can be carried out exactly within the framework transition state theory or in any one of a number of approximations. The γ bar method gives particularly good insight into the chemistry of the problem with a minimum of arithmetic.
Vapor Pressures of Isotopic Molecules
It is apparent that major progress has been made both in the experimental and theoretical study of the vapor pressures of isotopic molecules in the last five years. Vapor pressure measurements are being made in different laboratories by different methods which agree with one another within a few hundredths of one percent. The theory has advanced to the point where a large body o experimental data can be systematized and understood. Quantitative calculations have been carried out which verify the mass, temperature, and potential energy dependence aspects of the theory. An old subject has been revived by advances in modern experimental and theoretical methods and is now useful for the study of quantum effects and structural effects in liquids and solids.
Molecular Geometry and the Vapor Pressures of Isotopic Ethylenes: Chemical and Structural Isomers
The theory of isotope effects on vapor pressures for systems with large quantum effects, as manifested by the cross-over phenomenon and deviation from the rule of the mean, is illustrated by the large body of experimental data on the isotopic ethylenes which has recently become available. An effect of molecular geometry was found, viz. a difference in vapor pressures of cis-, trans- . and gemdideuteroethylenes. This was shown to be related to the hindered rotation about the C=C axis in the liquid. A further consequence of the hindered rotation was established, namely a perturbation of the out of plane molecular vibrations. This is a new effect for which a one to one correspondence with the molecular symmetry was established. Quantitative calculations show that this rotation-vibration coupling further enhances the effect of the hindered rotation. A theoretical calculation of the vapor pressure differences of the isotopic ethylenes from molecular data is made through statistical mechanical theory and the calculation of the energy states of the isotopic ethylenes. The agreement with the experimental data, which encompasses a significant number of different parameters, is quantitative.
Molecular Geometry and the Vapor Pressure of Isotopic Molecules: C₂H₃D and C¹²H₂=C¹³H₂
The isotopic vapor pressure ratio between monodeuteroethylene and ordinary ethylene has been measured in the temperature range 120°-180°K by differential manometry. The inverse isotope effect with C₂¹²H₃D is less than one‐half the effect observed with the dideuteroethylenes. This deviation from the rule of the geometric mean gives further support to the structural theory of isotopic vapor pressure effects and confirms the importance of quantum corrections of the order of (ℏ/kT)⁴ and higher. Vapor-liquid equilibrium studies of C₂¹²H₄ and C¹²H₂=C¹³H₂ were made in a packed column under total reflux using C₂¹²H₃D as an internal monitor to calibrate the column. Whereas C₂¹²H₃D goes to the top of the column, C¹²H₂=C¹³H₂ concentrates in the boiler. Absolute values of the carbon‐13 effect were calculated from the measured relative effects and the manometric data for C₂¹²H₃D, and the vapor pressure ratios were checked by analysis of the kinetic behavior of the column. A test of the data was made in the framework of the applicable theory. The temperature dependencies of the isotope effects are predicted from the theory within the experimental error. The relative deuterium and carbon‐13 isotope effects as well as the differences between the dideuteroethylene isomers are discussed in terms of the structure of the ethylene molecule. It is shown that there is a large normal A/T² dependence due to hindered rotation in the liquid. The zero‐point energy change on condensation leads to a term of the form B/T and accounts for the higher vapor pressures of the deutero‐compounds. The zero point energy changes obtained from the vapor pressure data are in quantitative agreement with theoretical calculations. A new type of effect is found, namely a perturbation of the internal vibrations by the hindered rotation. This perturbation is different for the different molecules and a strict correspondence is established with the molecular symmetry.
Back to Top of Screen