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.

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 …

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 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.

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 …

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.

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 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 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.

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.

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.

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.

The purpose of this report is to compare multi-layer insulation and liquid nitrogen shielding as methods of insulating the 80-inch Liquid Hydrogen Bubble Chamber.

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.

The analyzer can be operated either internally or externally. The 10 ma germanium discriminator is quiescently biased to 8.5 ma in its low-voltage state. An input signal current of 3.5 ma or more triggers it to its high voltage state. This triggers the oscillator. The oscillator signal is buffered and mixed in the bridge modulator with the reference radiofrequency signal from the cyclotron. The low-frequency beat note from the bridge modulator is squared up and passed to the beat zero univibrator which generates 0.7 mu sec signals each time the beat note passes through zero from positive to negative. The trailing edge of the beat zero univibrator is employed to terminate the time-of-flight measurement and to control the servo measurement. Drawings are included. (M.C.G.)

Internal-conversion coefficients may be thought of as consisting of two parts: a usually dominant part which depends only on the atomic number and the nuclear transition energy, and a usually small part depending explicitly on nuclear transition matrix elements. This latter part arises from the penetration of the converting atomic electrons within the transforming nucleus.

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.

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.)

Nusselt numbers have been calculated for heat transfer to fluids flowing through annuli under conditions of uniform heat flux and fully established velocity and temperature profiles. The following cases were considered: (a) laminar flow, (b) slug flow, (c) turbulent flow with molecular conduction only, and (d) turbulent flow with both molecular and eddy conduction. These Nusselt numbers were determined for two conditions: heat transfer from the inner wall only and heat transfer from the outer wall only. The results were correlated by semi-empirical equations. The final results obtained on cases (a), (b), and (c) are applicable to any fluid, whereas those obtained on (d) are for liquid metals only. Wall- and bulk-temperature relationships for the above four cases were also determined. These relationships were treated as dimensionless temperature ratios. Both the Nusselt numbers and temperature ratios were evaluated over the r1/r2 range, zero to unity; the former being the case of the circular pipe, and the latter, the case of infinite parallel plates.

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.

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.

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.

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.

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.