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0-2 kv Flash Tube Supplies
In order to perform the various experiments with a bubble chamber, a high intensity flash tube is used. This report briefly describes the power supplies designed and constructed to power these lamps.
6 kv Capacitor Charging Supply
The power supplies designed and constructed to power high intensity flash tubes used in bubble chamber experiments are briefly described and are accompanied by a schematic diagram of the layout. (D.C.W.)
80" Bubble Chamber Expansion System Preliminary Operating Procedures
These procedures are intended to be used for the initial operation of the expansion system and serve as a basis for a more complete and revised form to be written once operating experience has been gained. An attempt has been made to offer a logical and systematic presentation to facilitate operation and maintenance of the system by the operating personnel. Thus, the sequence of valve actuations has been presented in matrix and check list form to minimize errors; this also has the advantage of making it easier to adapt certain expansion system procedures to programmed control by a process control computer.
80" Bubble Chamber Expansion System Summary of Piston Motion Studies
Prior to assembly into the 80" bubble chamber, the expansion system was subjected to a series of tests to check piston dynamics and gain information on the reliability of the various components. Furthermore, the rest provided operating personnel with the opportunity to become familiar with the operation and maintenance of the expansion system. Two separate tests were performed with the apparatus that was located at the north end of the AGS experimental area; one during the week of Oct. 15 and the other during the week of Nov. 12. The system was run with helium gas supplied from AGS compressor room and the piston was operated at room temperature.
80" Chamber - Low Energy Beams
One of the major, as well as first, decisions which must be taken on a large chamber is to decide on the direction of the magnetic field, i.e., vertical or horizontal. Either alternative has advantages and disadvantages ad it is the intention of this note to discuss these features.
Abscopal Effects of Localized Irradiation by Accelerator Beams
The aim of this series of experiments was to evaluate the existence of abscopal effects of irradiation. No attempt was made towards the elucidation of mechanisms. Very early in the history of radiological research it was noticed radiation produces both local and general effects involving the entire body. Gauss and Lembcke introduced the term "Roentgenkater" (radiation sickness). They ascribed these "General Effects" to the circulation of toxic substances released from cells that disintegrated following irradiation.
The Absolute Yield of the Ferrous Sulfate Oxidation Reaction
The absolute yield of the ferrous sulfate oxidation reaction, under the influence of ionizing radiation, has been determined. A polystyrene, parallel plate ionization chamber, filled with argon, nitrogen, or air, was used to measure the energy absorbed per unit volume of the solution through the application of the Bragg-Gray principle. The ionization current was extrapolated to zero chamber spacing. In related experiments the average ionization potential of polystyrene was determined to be 34.3 ev by comparison with argon and nitrogen. The G value obtained in this experiment using the three gases was 15.9 ± 0.5 ions/100 ev, in good agreement with calorimetric and cathode-ray bombardment measurements.
Absorption and Turnover Rates of Iron Measured by the Whole Body Counter
Human iron metabolism has been extensively studied in the past twenty-five years with the radioisotopes iron⁵⁵ and iron⁵⁹. Before the availability of the whole body counter, however, iron absorption studies were performed by the indirect methods of fecal assay of unabsorbed radioiron, and estimation of red cell incorporation of absorbed tracer. The few long-term excretion studies performed required numerous assumptions, since human iron excretion was less well understood. Whole body counting provides a simple and accurate method of measuring the total body retention of administrative tracer iron⁵⁹, thus making absorption and subsequent excretion determinations possible with a single radioiron study. The energetic gamma emissions of iron⁵⁹ permit ready external detection with small quantities of isotope, Normal radioiron distribution is uniform throughout the circulating red cell mass and thus minimize geometry influences on the counting efficiency, 0nly the 45.1 day half-life of iron⁵⁹ limits long term iron turnover studies. Measurements of iron⁵⁹ absorption and long-term body turnover have been under way at Brookhaven National Laboratory for over two years. The present paper outlines some of the results of these studies, and discusses some implications of the method.
Abstract for the Glasgow Meeting - "International Conference on Nuclear Physics": Gamma Transitions and the Shell Model
The study of the interaction of the electromagnetic field with nuclei has proved very fruitful for the elucidation of many details of nuclear structure. The γ-ray transitions observed in either absorption or emission can be divided into three classes, depending on whether the matrix elements of the transition are (1) much larger, (2) approximately equal or (3) much smaller than those expected for single proton transitions which are usually taken as a norm. In class (1) we find (a) the broad transitions leading to the "giant resonances" in the nuclear photo-electric effect, and (b) the "fast" transitions between low lying states, especially for even-even nuclei far removed from magic numbers. The large matrix elements and the regular dependence of their magnitude on the atomic weight speak for cooperative phenomena in which many nucleons or the nuclei as a whole are involved. In class (2) we find the much studied M4 transitions which give strong support for the single particle model; they have rather uniform matrix elements. Some finer points remain to be understood, especially why some odd nuclei do not show the expected ratio for |M|^2 of ~ 2:1. The transitions belonging to class (3) require further selection rules and are more difficult to describe in general terms. Among the better understood "slow" transitions are some electric transitions which have a reduced transition probability either because they correspond to neutron jumps, or because they involve more than one particle in the transitions.
Acceleration Design Studies for Production of High Center-of-Mass Energies
To aid in planning Brookhaven's future program in high-energy physics, we have just completed a summer study on possible experimentation with super-high-energy accelerators and with storage rings. I should like to review a few of our conclusions and to describe an experiment on coasting beams in progress at Brookhaven. First, however, to provide background for this review, I shall present a short history of the past year. During 1962, many proposals were submitted to the United States Government for design or construction of accelerators for energies above 700 Mev. In order to decide which of these proposals should receive support, an advisory panel was set up under the chairmanship of Professor Norman Ramsey of Harvard. Last April this panel submitted its report. During last April the Brookhaven Laboratory received an official authorization to proceed with studies aimed at the recommended storage rings and super-energy accelerator.
Acceleration of Deuterons or Alpha Particles in the AGS
The magnetic field of the AGS ring can contain particles of magnetic rigidity about 34 Bv/c. This includes not only protons of kinetic energy 33 Bev, but also 32 Bev deuterons, 64 Bev alpha particles, and conceivably heavier nuclei such as 188 Bev carbon nuclei. It will be shown in this paper that such nuclei can be injected and accelerated in the AGS if some rather small modifications are made in the injection and acceleration systems. What physics could be done with such beams? Several types of experiments may be suggested. In the first place, since the deuteron is a rather loosely bound combination of a neutron and a proton, it is likely to break up when it hits a target nucleus (stripping reaction). In a considerable fraction of the collisions the neutron will go straight on with essentially unchanged energy (half the deuteron energy). Therefore, with an internal target bombarded by 30 Bev deuterons one should obtain an intense, rather well collimated and monochromatic beam of 15 Bev neutrons in the forward direction.
Acceleration of Polarized Protons to Relativistic Energies
Maintenance of polarization of polarized protons in a linear accelerator is known to be feasible. Circular accelerators present a different problem, and the investigation of the interaction of orbit dynamics and particle polarization in general is undertaken. The equation of motion of the spin vector of a charged particle in a magnetic field as formulated by Bargmann, Michel, and Telegdi is utilized in the study of depolarization for several accelerators. High values of depolarization are obtained, and means for avoiding such depolarization are suggested. (D.C.W.)
Accelerator Development Department Internal Report
In this report we present solutions of the design problem in which a system of quadruple lenses is required to carry a particle beam from given focal lines in the x and y planes to other given focal lines. Particular attention will be given to the case of the anastigmatic lens system which takes a beam from one focal point to another focal point. Since the general problem is almost impossibly complicated a simplification is introduced by breaking the lens system into two parts. The first part of the lens system is required to bring the initial beam to the state where it is parallel to the z axis in both planes. The second part carries the initially parallel beam to the required final condition. Each part will involve two quadrupoles so that the complete system will consist of four quadruples; usually, however, the field gradients in the second and third quadrupoles can be made identical so that those quadrupoles can be combined into one and the system becomes a three quadrupole system. The configuration of the lens element will be as shown in the figures below. These figures indicate also the general character of the beam path in the two planes.
Accident in Continuous-Dissolver Pilot Plant of Fluoride Volatility Project on May 15, 1957
The so-called Fluoride Volatility Processes refer to several proposed non-aqueous methods of processing irradiated fuel elements. In each of these methods, the uranium is fluorinated to UF6 and then decontaminated by distillation. One of those methods, involving the direct fluorination of the uranium by bromine trifluoride (BTF), has been under investigation at BNL since 1950. In 1952, it was demonstrated at BNL that uranium, as UF6, could be satisfactorily decontaminated by distillation in small-scale pilot plant equipment; end in 1953, BNL undertook the job of determining the technical feasibility of a continuous dissolver on a pilot-plant scale. The reason for the project was that the economic superiority of the process seemed to depend upon its amenability to continuous operation.
Accuracy of Relaxation Length Measurements
We consider here the accuracy of relaxation lengths measured during the water-uranium lattice experiments. Since such an analysis for all measurements would take a great deal of time, we have applied it to just one lattice. This one (2:1 water-to-metal ratio) was chosen completely at random.
Adaptation of a Commercial Counter X-Ray Diffractometer for Investigations to 3000°C
The rapid advances in many technologically important areas have not only served to accentuate the increased demands for high temperature metals and ceramics but have necessitated a more through knowledge of their physical properties when exposed to high temperature service. Toward this latter end, the use of X-ray diffraction has proved an invaluable tool in providing data of regions of thermal stability, expansion coefficients, solid solubility limits, and phase transformations by direct examination at temperature. Since this Laboratory has for some time now been engaged in the study of refractory nuclear materials, it was thought desirable to employ and possibly extend this technique to temperatures ranging up to 3000°C. This communication will describe the equipment developed for this purpose, with experimental results to be described in subsequent publications.
Additional Experiments on Stored Energy in BNL Reactor Graphite
In the memorandum entitled "Stored Energy in BNL Reactor Graphite", dated February 25, 1953, there is described an experiment conducted by Gurinsky's group to determine the energy per gram of irradiated graphite released in a 200°C anneal. Similar experiments were subsequently conducted by W. Kosiba, differing from the original in two particulars: a) Instead of two graphite samples, one normal, and one irradiated, Kosiba used only an irradiated sample which he heated first to release the stored energy, and then again after the energy was released. In this way, he obtained time against temperature curves for both normal and irradiated graphite from the same sample. (These curves are graphed for each run in Figs. 1 thru 5.) b) The vycor tubing used in the original experiment was not used by Kosiba. Five runs of this experiment were selected, Runs 4P, 13, 36, and 40 at furnace temperatures of 200°C, and Run 45 at a furnace temperature of 400°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.
Adsorption Studies on Clay Minerals. III. A Torsion Pendulum Adsorption Balance
Many of the most important properties of the clay minerals are in reality properties of the complex systems clay-water. Since water enters directly into the equilibria between clays and ionic solutions, determination of the water content of the minerals under specified conditions are an obvious necessity in any complete study of these equilibria. A formulation of the thermodynamics involved indicates what information is necessary and how to take it into account. Furthermore, recent results of others indicate that a knowledge of the water adsorption isotherms can profitably be used to help elucidate the structures of the clay minerals.
AEC Research and Development Report: Yield of Kr-85 and Xe-133 in the Thermal Neutron Fission of U-235 and Yield of Kr-85 in the Thermal Neutron Fission of Pu-239
We have made absolute radiochemical measurements of the yields of Kr-85 and Xe-133 in the thermal neutron fission of U-235, and of Kr-85 in the thermal neutron fission of Pu-239. For Kr-85 in U-235 fission, the mean of eight measurements gives the ratio, X/T, of fission yield to half-life: X/T = 0.0253%/yr; σ = 1.59%; 99-1 error of the mean = 2.41%. For Kr-85 in Pu-239 fission, the mean of three measurements gives X/T = 0.0092%/yr; σ = 4.3%. Here σ is the standard deviation of a single measurement expressed as percent of the mean. If the Kr-85 half-life is 10.8 (±4%) yr, the yields are U-235 fission: X = 0.273% (±5% of X). Pu- 239 fission: X = .0994%. The error estimate in the U-235 yield is an accuracy estimate compounded of estimated accuracies of 3% in the X/T value and 4% in the half life. For Xe-133 in U-235 fission, the mean of five measurements gives the yield: X = 6.62%; σ = 0.095% of X; accuracy = ±3% of X. The accuracy estimates are based on a detailed investigation of the possible sources of error in the fission counting, the chemical procedure, and the beta-counting (gas-phase proportional counter). A separate measurement of the yield ratio Xe-133/Kr-85 in U fission agreed closely with the same ratio computed from the absolute yield measurement above. As by-products of this work, we have found: 1) The independent yield of Xe-133 in U-235 fission is not greater than 0.1% of the 133 chain yield. 2) The independent yield of Xe-135 in U-235 fission is 3.5 (± 1.0) percent of the 135 chain yield. 3) The half-life of I-133 is 20.8 (± 0.2) hours. The Kr-85 and Xe-133 absolute yields in U-235 fission, together with the accurate relative yields of Kr and Xe …
"Ages" of the Sikhote Alin Meteorite
The potassium-argon age of the Sikhote Alin iron meteorite has been determined. The value is 1.7 + 0.2 x 10⁹ years. Previous lead data suggest an age of 4.6 x 10⁹ years . The date of solidification may be the sum of these two ages.
AGS Performance and Plans
The scope of the AGS complex has expanded rapidly during the three years since an accelerated beam was first obtained. Demand for research time far exceeds the amount available although facilities have been much increased. At the same time, experiments are being designed which are more complicated than previous ones and which make more stringent demands on the accelerator and on its auxiliary equipment. There is a continuous trend of experiments to particle beams of greater momentum, as the experimental techniques are refined. This use of increased momentum means that larger areas are required for the apparatus and that more power is necessary for the magnetic optics. All beam-sharing at the AGS is done by multiple use of each accelerated pulse because our experience indicates that pulse-by-pulse beam-sharing is relatively inefficient. (Expansion chambers have seldom been used at the AGS.) The problems of scheduling experiments becomes increasingly complex since combinations must be found satisfying the criteria: maximum number of experiments to run simultaneously; minimum downtime to be taken for rearrangement between successive experimental arrays
An Alcohol Drip Apparatus for the Sliding Microtome
In wet sectioning of celloidin embedded tissue it is necessary to maintain a layer of alcohol on the knife and on the surface of the block. The alcohol acts as a lubricant and also prevents drying of the block. The application of alcohol may be done by hand or mechanically. To apply the alcohol by hand while operating the microtome slows down the cutting operation, unless the operator is ambidextrous. In addition, stopping and starting the knife to apply alcohol results in an extensive wasting of tissue due to half-sections and sections of uneven thickness. Unless the knife can be kept moving smoothly at a constant rate the result will be sections of non-uniform thickness regardless of the setting on the microtome.
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.
Analysis of Cell Population Kinetics
The relation between trace kinetic parameters of cell populations and the statistics used in studies on cell populations is discussed. It is pointed out that responses in cell populations are complex and subject to many perturbations. Some of these are discussed. It is concluded that a complete check list of sources of error is required for studies of great accuracy, and a calculus to help in combining heterogeneous data is needed for studies of systems of great complexity.
Analysis of Meteorological Tower Data, April 1950 - March 1952, Brookhaven National Laboratory
Report issued by the Brookhaven National Laboratory discussing data collected from two BNL meteorological towers. As stated in the introduction, "results are presented in graphic form rather than tabular form" (p. 1). This report includes tables, maps, illustrations, and photographs.
Analysis with a New Type Mass Spectrometer
The purpose of this paper is to describe the application of a magnetic time of flight mass spectrometer to analytical problems. This new spectrometer has a number of advantageous features. It has a linear mass scale and heavy masses are easily resolved. The whole mass spectrum can be observed continuously on an oscilloscope and changes in its composition are seen instantaneously. The voltage of the ionizing electron beam can be varied continuously while viewing the spectrum, giving additional information about characteristic break-up patterns of complex molecules.
Analytic Spin Functions of a Single Variable
There has been considerable recent interest in the development of spin representations which are operations upon analytical functions. The familiar Pauli spin matrix representation, has been sufficient for the solutions of most problems involving nonrelativistic electron spin, but it is to be hoped that, for some problems, an "analytic" representation could be found which has greater physical significance. The new representations that have been presented all hae spin functions of two or more variables.
Antibody Formation by Transplanted Bone Marrow, Spleen, Lymph Node and Thymus Cells in Irradiated Recipients
The role of the marrow as a site for antibody formation has been considered for many years. In 1912 Ludke reported the appearance of antibody in cultures of marrow cells obtained from previously immunized rabbits. Specific agglutinins for killed typhoid bacilli and lysins for ox red cells and sheep red cells were detected in the culture media 2 to 5 days later. However, the cultured cells failed to produce antibody when these antigens were added to the media. Similar findings by Reiter, Przygode, and Schilf appeared in the early literature with regard to the appearance of antibodies to various antigens in tissue cultures of bone marrow from immunized animals, along with failure to elicit antibody formation by addition of antigen to the culture resulted from the addition of excess amounts of antigen, so that if antibody synthesis occurred, the excess antigen combined with antibody and significant amounts of free antibody could not be detected in the culture media. Thorbecke and Keuning observed an increase in antibody in culture fluids when bone marrow fragments from rabbits immunized to paratyphoid B vaccine were cultured in roller tubes.
Antiproton-Proton Two-Prong Interactions at 3.25 Bev/c
A study is being made of two-prong antiproton interactions in hydrogen at 3.25 Bev/c. About 2250 two-prong events were measured on automatic digitized machines and their reconstruction and analysis were performed with standard programs. Of the total number of events 1003 were classified as elastic interactions. About 500 inelastic events were examined using bubble density estimates in addition to criteria based on distribution values in the classification procedure. The inelastic events in which a secondary nucleon or antinucleon was unambiguously identified were used to obtain limits for annihilation and non-annihilation partial cross sections. The two-prong events were 57% of the total. Results for angular distributions and cross sections are presented in graphs and tables. (M.C.G.)
The Application of Inert Fluidized Beds to the Volatility Reprocessing of Reactor Fuels
In the reprocessing of spent solid fuels from nuclear reactors by direct volatilization, one of the major problems is the removal of heat from the highly exothermic gas-solid reactions. The use of fluidized beds of inert granular material as heat transfer media to control these exothermic reactions forms the basis of one approach to volatile reprocessing which is under development at BNL The engineering scale work carried out under this development program is discussed.
The Approximation with Anisotropic Effects for Cylindrical Geometry
The method of spherical harmonic tensors developed Mark for solving the Boltzmann transport equation in isotropic media is herein extended to anisotropic media for cylindrical geometry. A formal solution is given for the case of two concentric cylindrical media, A and B, but no numerical work has yet been done. The following treatment differs from a similar one by the H. K. Ferguson Co. in that the external medium B is assumed to be both a neutron absorber and finite in extent rather than a non-absorber and infinite in extent.
Automatic Bubble Density Measurement with the Hough-Powell System
The Brookhaven Bubble Chamber Group is developing a Hough-Powell fast analysis system (HPD)1 for bubble chamber photographs. High precision measurements are made with a computer controlled flying spot digitizer. We are currently testing the track selection programs for the system. We have just completed a study of a method for automatic bubble density measurements.
Autoradiographic Study on the Origin and Fate of Small Lymphoid Cells in the Dog Bone Marrow: Effect of Femoral Artery Clamping During in Vivo Availability of Thymidine-H
Mammalian bone marrow contains a considerable number of small lymphoid cells (small lymphocytes and small lymphocyte-like cells). The total number of these cells (50,000 to 500,000 per mm3) depends on species, age and other factors. The origin, function and fate of these cells remain obscure in many respects. In particular, it has not been shown beyond doubt, if and to what extent small lymphoid cells enter the bone marrow via the blood stream or if their origin is in part or entirely within the bone marrow. In addition it has not been clearly shown whether or not these cells may function as multipotential hemopoietic stem cells. Results obtained from experiments with irradiated parabiotic animals and animals given regional fractioned doses of X-irradiation, and transplantation of leukocytes from peripheral blood into lethally irradiated recipients afford indirect evidence that peripheral blood of mice and rats may contain stem cells capable of DNA synthesis and division.
Bacterial Virus: Radiation and Function
One of the materials most extensively studied with the dry state ionizing particle approach described in the preceding papers has been T-1 bacteriophage. It was one of the earliest materials subjected to cyclotron bombardment in the Yale biophysics group (Pollard and Forro, 1951) and a number of workers associated with the group have from time to time returned to it (Pollard and Jane Setlow, 1954). One reason is that investigation of various functional properties of a single material is relatively easy for bacteriophage, and among the T-series coliphages T-1 is the most easily handled dry. Another reason is that the bacteriophage work, as represented to a large extent by T-1, does not fit the one primary ionization - one inactivation conclusion stated in the preceding paper by Dr. R. B. Setlow for many other materials. T-1 is one of the exceptions and we have kept coming back to it to see more clearly why is is exceptional.
The Ball Tuner Change Tables
Technique used in deriving values of the linac ball tuner settings to produce various fields is discussed briefly, and tables showing ball tuner change numbers and values used in making up the ball tuner change numbers are given.
Beam Current Integrator
The object of this report is to acquaint the operator with the operational and technical aspects of the beam current integrator as well as the theory of the system operation. The design and operation of a beam current integrator are described, and the theory of operation is discussed. The instrument has two channels. The console channel is designed to measure the accumulation of charge received by a target during a period of a day no matter what the range used in the experimenter's channel. An analysis indicated that this unit will measure the accumulation of charge by a target to an accuracy of 0.1215% assuming that the constant error due to shorting the integrating capacitor is accounted for. The instrument is ranged to handle from 0.5 to 500 mu a of beam current. (M.C.G.)
Beam Separators for Bev Particles
The problem of separation of beams of particles of different masses but of the same momentum at Bev energies is the subject of a great deal of study at several high energy laboratories. In this note we shall describe the problem and tabulate a few of the cogent parameters. Frequently the student of high energy interactions is faced with a beam of miscellaneous particles coming from an accelerator. By standard techniques this beam can be rendered approximately parallel and an inch or so in diameter. By passage through a magnetic field the beam can be analyzed in momentum. Now it frequently happens that the particles in which the experimenter is particularly interested make up only a small fraction of the beam and the exigencies of the proposed experiment may well demand that the background of undesired particles be drastically reduced. The problem is difficult because the velocities of the various particles are almost equal to each other and to the velocity of lights; this makes time-of-flight techniques relatively ineffective. The energies of the particles are almost equal so electrostatic separation also is difficult. Since the beam is already analyzed in momentum, further separation by magnetic means is impossible.
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.
Boiling Burnout Newsletter No.1
Preliminary data are enclosed in Tables I, II, II, IV, V, and VI. Tables I to V are data for round nickel tubes in a vertical and inclined (45°) position. Table VI contains some preliminary data for nickel rectangular channels (0.060" and 0.050" spacings) in a vertical position.
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.
Brookhaven Chemo-Nuclear In-Pile Research Loop
The purpose of the Chemo-nuclear In-pile Research Loop is to provide a versatile facility for investigating chemo-nuclear reactions under flow conditions. The loop os designed to handle gaseous systems in conjunction with fixed packages of solid fuel.
Bubble Chamber Vacuum System
The vacuum system for the bubble chamber must evacuate rapidly a volume of approximately 500 cubic feet and eliminate the outgassing of a surface area of approximately 50,000 square inches. The backstreaming of oil from the diffusion pump must be kept to an absolute minimum to prevent oil films forming on the window. The vacuum system must also provide the protection against liquid nitrogen and hydrogen/leaks to prevent pressure buildup.
Calculation of Average Flux in Moderator of Water Lattices by Means of a Relaxation Method
The following report concerns the application of a relaxation mesh method for the determination of the average flux within the moderator of a light water moderated, 1.027 per cent U-235, hexagonal lattice with a volume ratio (V_H2O + V_Al)/V_Uranium of 4:1. It was hoped that the calculation would enable one to determine any differences in flux which might result from the fact that the unit cell is a hexagon instead of a cylinder. Because we were primarily interested in the effect due to geometry we applied the same theory, diffusion theory, to the hexagon by means of the mesh method and to the equivalent cylinder.
Calculation of Transport Cross-Sections of Uranium
In recent months, experiments investigating the total, non-elastic, transport, etc., cross-sections of U-238 have been performed. It is the purpose of this memo to examine these data and to obtain from them information which will be of use in refinements pile calculations. In cases, e.g. transport cross-sections, where experimental data do not suffice, the theory developed pertaining to the continuum model of the nucleus has been depended upon. One of the fundamental requirements of this model is that the spacings of the energy levels in the compound nucleus are small compared to their widths and that consequently many levels are excited by the incoming particles. As a result there are many more modes of decay and the continuum model is an average over these levels.
The Calculation of Zero-Point Energies of Molecules by Perturbation Methods
Two methods are proposed for calculating zero-point energies of molecules. The first makes use of the fact that one can easily write down the quantum mechanical Hamiltonian for a vibration system. The zero-point energy can then be obtained by a perturbation scheme without solving the secular equation. The second method requires a knowledge of the normal modes and frequencies of a reference molecule, but then enables one to calculate isotope effects by a perturbation scheme. The methods are applied to some examples and the convergence of the perturbation series is investigated. The approximate validity of the law of the mean for the isotope effect on zero-point energies is explored within the framework of the methods.
Cell Population Kinetics of an Osteogenetic Tissue, I
Cell proliferation on the actively growing periosteal surface of the femur of rabbits aged two weeks, has been investigated using autoradiographic techniques. Injections of tritiated glycine and tritiated thymidine were given simultaneously and the animals sacrificed at intervals from one hour to 5 days after injection. The glycine labelled the position of the bone surface at the time of injection and the thymidine labelled the cells which were synthesizing DNA . The rate of increase in the cell population was determined by counting the number of cells beyond the glycine label at different times after injection. The cell kinetics of the fibroblast--pre-osteoblast--osteoblast--osteocyte system has been studied. The fibroblasts are relatively unimportant from the point of view of increase in the cell population. The main site of cell proliferation is the layer of preosteoblasts on the periosteal surface. The rate of movement of cells from the pre-osteoblast to the osteoblast and osteocyte compartments has been measured. The incorporation of osteoblasts into the bone is not a random process, but it appears that the osteoblast must spend a certain time on the periosteal surface before becoming either an osteocyte or a relatively inactive osteoblast lining a haversian canal. During its most active period on the periosteal surface it was estimated that on an average, an osteoblast produces 2 or 3 times its own volume of matrix.
Cell Population Kinetics of an Osteogenetic Tissue, II
A study of the cell kinetics on the actively growing periosteal surface of the femur of rabbits ages two weeks has been continues. A single injection of tritiated thymidine was given and the rabbits killed from one hour to four days after injection. The grain count spectra of the different cell types, pre-osteoblast, osteoblast and osteocyte, have been compared at different times after injection. The results showed evidence for the uptake of thymidine in nuclei which is not associated with cell division. A small percentage of osteoblasts was initially labelled at one hour and there was evidence that the majority of these had not divided by 3 or 4 days after injection. Some thymidine labelled cells had also become osteocytes without division. Furthermore, it appeared that a considerable fraction of the initially labelled pre-osteoblasts did not divide. The S-period for the pre-osteoblasts and osteoblasts was measured using a double-labelled thymidine technique.
The Cellular Differences Between Acute and Chronic Neutron and Gamma Ray Irradiation in Mice
It has been well established that even small doses of radiation will shorten life expectancy of animals, and that in general the causes of death are the same for the irradiated as for the normal animals. When x or γ rays are compared with neutrons in their ability to shorten the life span, some interesting differences appear. All available data from different laboratories on the shortening of the life span by x or γ on the one hand and neutrons on the other, have been compared. In spite of the obvious difficulties in comparing such data, if one expresses dose in terms of the LD 50/30 dose required for acute survival, one can pool the data from other laboratories and plot them on a single graph without excessive error. Results of such a compilation for single acute exposures are shown for x or γ rays in Figure 1 and for neutrons in Figure 2.
Chemistry of Anhydrous Systems Containing Hydrogen Fluoride and Nitrogen Oxides
Nitrosyl and fluoride ions are formed in liquid anhydrous hydrogen fluoride when nitric oxide, nitrogen sesquioxide, nitrogen tetroxide, or nitrosyl fluoride, are dissolved. Vapor infrared analysis was used to study the solution composition and gaseous reaction products. These solutions react with metallic uranium, plutonium, zirconium, iron, and aluminum, as well as ceramic uranium oxide and uranium carbide, forming soluble nitrosyl metal fluoride complexes and liberating nitric oxide. The uranium compound identified as nitrosylium hexafluorouranate, NOUF₆, was made volatile by passing nitrosyl fluoride gas over the dry salt at 500 deg C.
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