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.

In these lectures we will discuss some examples of information about magnetic properties of solids which can be obtained by neutron scattering. We consider a scattering process in which a neutron with wave vector k and spin σ is incident upon a solid in state q>. (Here q stands for all of the quantum numbers which describe the state of the solid, such as spin and orbital electronic states, phonon numbers, etc.) After interacting with the solid, the neutron goes off with wave-vector k' and spin σ', leaving the solid in state q'>. In performing an experiment of this sort one does not usually observe the initial and final spin states of the neutron or the initial and final states of the solid. We must then sum over all possible final states and average over all initial states.

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.

Optical absorption and photoconductivity measurements have been made on single crystals of pure synthetic rutile (TiO2). Reactor irradiations at 70°C totaling 4.8 x 10 18 nvt fast and 1.69 x10 19 nvt slow did not produce any discernible optical absorption bands; however, the transmission decreased 5 percent at all wavelengths. Reactor irradiation induced a [illegible] five photoconduction peaks in the wavelength range 4200 to 14,000 A. In addition the photopeak at 4065 A (3.05 eV) was enhanced and there were drastic changes in the dependence of photocurrent with light intensity. Gamma-ray irradiations as large as 10 9 r do not change the conduction properties. The photocurrent is proportional to a power of the light intensity; the power range from 0.65 to 1.24, for the crystals described in this work. The photocurrent vs. voltage dependence is more complex.

The present core of the Brookhaven Graphite Reactor consists of some 4900 highly enriched uranium fuel loaded in 615 horizontal fuel channels passing through a 25 foot cube of graphite moderator and reflector. The core is divided into two halves (north and south) by an 8 cm. wide vertical gap in the center of the graphite. The cooling air enters the reactor through inlet filters, at the rate of 270,000 CFM, passes into the central gap and flows bi-directionally through the north and south halves of the core. It then enters the collecting plenums and flows into the north and south ducts. The air is first monitored by the north and south exit air monitors located within the pile building. These are moving filter tape monitors with beta scintillation detectors. They are essentially operational monitors and are maintained by reactor operations. They are essentially operational monitors and are maintained by a reactor operations. The air then passes through the exit air filters, heat exchanger, venturi and on to the fan house where the north and south ducts join. After the fan house the air is monitored by Argon-41 by a Kanne ion chamber syste.

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 …

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.

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.

The undercarriage system is required for translating, rotating, and lifting the 450 ton magnet and bubble chamber assemblies so that it can be accurately positioned in the experimental proton beam of the synchrotron. The system must make provision for the two magnet sections to be separated for the purpose of adjustment and maintenance of internal components.

The following general description of the theory and operation of a bubble chamber is presented so that firms who are interested in fabricating components for the Brookhaven 80" chamber will have a better understanding of the design parameters associated with it. This understanding, coupled with the fabricator's knowledge of manufacturing techniques, should enable the fabricators to suggest solutions to manufacturing problems consistent with requirements for chamber operation. In an effort to increase knowledge of fundamental nuclear particles and their interactions at high energies, various types of detecting equipment have been developed. One of these detectors recently developed is the bubble chamber. While there are variations as to liquids used, expansion techniques, means of illumination, etc. the basic concepts upon which all bubble chambers operate are similar. Therefore, it will be sufficient in this report to consider only one specific type, that is a chamber using liquid hydrogen

The desired neutron spectrum for the High Flux Beam Reactor under construction at BNL requires use of U-Al fuel elements with more then 30 wt% U235 in the meat. The operating cycle of this reactor requires a minimum burn-up of 20%, and preferably 40% of the uranium in the element.

Report issued by the Brookhaven National Laboratory discussing papers presented at the International Conference on Fundamental Aspects of Weak Interactions. Each paper that was presented at the conference is included. This report includes tables, illustrations, and photographs.

In the course of a general study of K- p interactions at 2.24 Bev/c incident K- momentum, we have investigated the following reactions, the experimentally detectable final states of Ξ Κ π system. In this report we shall discuss the possible existence of Ξ π resonances above 1530 Mev and the evidence for possible structure in the overlap regions. An evaluation of the isospin of the Ξ * will be made. In addition, production and decay angular distribution of the Ξ * will be presented.

The inelastic scattering of low energy neutrons from condensed matter offers a means of investigating the motions of atoms in liquids or solids down to times in the order of 10-12 to 10-13 seconds. The theoretical framework and techniques of such measurements are discussed and the results of cold neutron measurements with liquid H2O and Pb are presented. In H2O the neutron data show that for times in the order of 10-12 seconds the water molecule tends to maintain some average position with respect to its neighbors. In this sense the short time behavior of water is similar to that of a solid. Diffusion characteristic of a liquid occurs at later times. Measurements in liquid lead just above the melting point also show the same effect but not as markedly.

Programs are under way at Brookhaven National Laboratory to study the behavior of fission products released from reactor fuel materials. Major emphasis has been placed on fission product iodine because of the physiological hazard associated with the I131 isotope. A complete reactor safety analysis, considering either a slow or rapid release of fission products, requires a knowledge of the chemical and physical states of the fission products during release, the extent of their release, and an understanding of their chemical interactions with the reactor environment.

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.

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.

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.

We have decided to try pressure-moulding coathangers, and this is a report on the specifications and tolerances R. R. Rau and I have calculated

Speed limits of decimal counting schemes based on binary-to-decimal conversion are considered. A simple "1-2-4-8" decimal logic is described, which is inherently as fast as the basic bistable. A decade for counting in 100-200 Mc/sec range, based on this logic and the tunnel diode-transistor bistable, is presented.

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.

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.

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.

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.