Harrison and Paskin (HP) have calculated the ordering energy of β-CuZn using recent theoretical techniques of treating electron screening and Mott's polar model of an alloy. Good agreement is obtained between the calculated total energy of the order-disorder transformation and specific heat measurements. A consequence of the HP calculation is that the ordering energy is long-range and oscillates in sign. Walker and Keating recently measured the neutron diffuse scattering of β-CuZn above the critical temperature Tc and find their data is in agreement with order calculated by only considering a nearest neighbor interaction. Using the Cowley statistical theory of order, we compare the order generated by a nearest-neighbor interaction and the long-range interaction of HP at a temperature 1.1Tc. we find the average behavior of the order generated by the nearest-neighbor and long range interaction to be similar, The major difference is the nearest-neighbor interaction generates order that asymptotically, varies smoothly with neighbor distance whereas the order resulting from the long-range interaction fluctuates markedly about the nearest-neighbor generated order. This result may explain the success of statistical theories, based on nearest-neighbor interactions, in both order-disorder of alloys as well as in some magnetic systems which are also believed to have …

The solution time of analogue multipliers using field-effect transistors is investigated. This time is ultimately limited by the charging time of the field-effect transistor junction. In typical devices suitable for analogue multiplication the charging time is found to be about 10-20 nsec less than one percent. A four quadrant pulse amplitude multiplier circuit is described, whose solution time is equal to the field-effect transistor charging time.

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.

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.

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.

For momentum measurements in bubble chambers a magnetic field has to e provided. The following discussion summarizes approximate calculations to determine the necessary amounts of copper and iron for our projected 80" liquid hydrogen bubble chamber magnet. Without any refinements, the accuracy of momentum measurements is proportional to the square of the track length and therefore to the square of the linear dimension of the chamber. If the scale factor for the size of the chamber is λ, [equation not transcribed].

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.

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

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 …

On the basis of measurements made upon analogues of the proposed magnet, it was decided that the distribution of ampere-turns between the two exciting coils should be in a ratio of about 1:33:1. This distribution is expected to minimize the variation of the magnetic field intensity over the depth. of the chamber. Simplicity of construction demands that there be an integral number of turns in each layer of conductors. If no water connections are to be made at the inside of the coils, each coil must contain an even integral number of layers.

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.

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.

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 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.

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 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.

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 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.

This paper is a review of the presently available experimental information about the K-meson decay interaction. The charge dependance of the interaction is not discussed since this has been treated in another paper at this conference. Most of the information derives from the three body decays, but there is one piece of information which can be obtained from the two body decays.

TbMn2 crystallizers with the cubic Laves-phase structure which may be regarded as the spinel structure without the anions. The "A" sites are occupied by Tb ions and the "B" sites by Mn ions. Neutron diffraction powder patterns run at 4.2°K exhibit a number of extra reflections characteristic of a modulated magnetic structure. These additional reflections can be indexed on the basis of a spiral modification propaganda along with a wavelength of 50.3 Å. The spiral axis is along. The "B" sites are ordered in a manner which is entirely analogous to the low-temperature ordering of Fe3O4: the two sublattice spirals being 180° out of phase. The A sublattice is in phase with a particular one of the two B sublattices. The combination of the internally compensated B sites and the ferromagnetically coupled A sites leads to a ferrimagnetic spiral.

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.