Diffusion theory and transport theory approaches to the problem of a nuclear reactor with a transverse air gap are compared. It is suggested that the differences in results for thin gaps is due to the fact that diffusion theory does not adequately represent the flux distribution in the immediate vicinity of the gap. For mathematical conveniences previous treatments of the gap problem have made use of fictitious image piles which exaggerate the neutron losses. The extent of the error is estimated by direct neutron leakage calculations.

The importance of the examination of paper and textile supported art objects by means of low energy X-rays has been ably discussed in the preceding papers of this session. The apparatus used for such radiography, however, has tended to be both expensive and confined to laboratory use. A lack of mobility arises from the weight and size of X-ray apparatus and the fact that its installation frequently requires shielding and special electric power lines. An inexpensive radiographic apparatus that required no special installation or external power and is small and light enough to be easily portable should be quite useful.

The heavy metal intoxications involving the brain may be divided into two groups: One, in which the offending metal is clearly a poison, such as mercury or lead; and a second, in which the offending agent is normally an essential constituent of the body. The latter category would include manganese poisoning, copper poisoning (or Wilson's disease) and, if some recent data are valid, Huntington's chorea, in which iron seems to have been implicated. Our interest in the second category of diseases is due to the fact that these conditions represent special aberrations of normal homeostasis. Homeostasis is the sum of the processes which maintain constant structure, function and constitution in the body and its organs. In manganese poisoning, the homeostatic control is disturbed by virtue of oversupply of this element via an abnormal route (the respiratory tract), while in Wilson's disease homeostasis is disturbed by virtue of genetically transmitted abnormal avidity of the body for dietary copper. In the present paper, we will discuss first some of the clinical features of chronic manganese poisoning in order to raise some questions about extrapyramidal syndrome in general. Thereafter, we will allude to some investigations conducted at this center during the last ten …

Brookhaven has sponsored a summer program to study possible experimentation with super-high-energy accelerators of ~ 1000 BeV and to examine the feasibility of colliding beam experiments. A group of about fifty physicists took part in this study program. These investigations are a continuation and supplementary to our previous studies at Brookhaven about two years ago.

A strong motivation for metabolic investigations of essential metals lies with the simple fact that these elements are primordial metabolites and building blocks of living matter, a truism largely forgotten today. Among them, the metals of the first transition group display high physical and chemical flexibility: They can concomitantly coordinate natural or artificial ligands; they can regulate electron and proton transport; they can act as catalysts or as cofactors to catalysis.

A model has been developed for the analysis of current reversal chronopotentiograms in systems where the electrode process is followed by a homogeneous second order reaction. The model is analyzed using the IBM 7094 digital computer programed in FORTRAN language. Working curved, derived with the aid of dimensional analysis, can be used to evaluate rate constants from experimental data. The electroreducation of uranium (VI) to uranium (V) with subsequent second order disproportionation of uranium (V) has been studied as an experimental test of the model. Disproportionation rate constants thus obtained are in satisfactory agreement with previously reported values. Other possible applications of the model are discussed.

The basic similarity in cytochrome physiology between Anacystis nidulans ad Euglena gracilis, strains Z, is impressive in view of their gross dissimilarities in size, structure, and pigment content. We have investigated the cytochrome reactions by sensitive spectrophotometric methods in order to gain some insight into the patterns of energy transfer from the various light receptors to the reaction centers involved in the two photochemical reactions of green plant photosynthesis and also to elucidate the pathways of photosynthetic electron transfer. The major thrust of this presentation will be the implications of experiments on whole cells in which both wavelength and intensity of monochromatic actinic light have been systematically varied. Some preliminary observations of the effect of carbonyl cyanide-m chlorophenylhydrazone (CCCP) are presented, and the light-driven reduction of cytochrome b6 in Euglena chloroplast fragments is described.

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.

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.

The proton beam in the Cosmotron is accelerated to an energy of 2.3 billion electron volts by a radio frequency voltage which is impressed across an insulated gap in the ferrite loaded accelerating cavity of the vacuum chamber. To maintain a constant orbit radius as the beam is accelerated, the frequency of the accelerating voltage must increase from the initial value of 370 kc/sec to 4200 kc/sec during the one second magnet pulse. Over the entire 11:1 frequency range, a minimum gap voltage of 2000 volts rms must be maintained. At every instant throughout the magnet pulse, the frequency of this voltage must be a predetermined function of the magnet field to a high degree of accuracy. Frequency errors greater than about .2 percent result in loss of beam due to excessive radius changes. Smaller errors than this however, can excite fatal phase oscillations in the beam if they occur rapidly. As little as .005 percent frequency modulation can result in total beam loss if it occurs at a rate of several kc/sec, where the beam is most sensitive to such disturbances.

A short review of the field of internal conversions. Isomeric transitions teach us many details of nuclear structure. In these studies electromagnetic theory is considered as a "tool". It is a quite quantitative tool in the case of "internal conversion" - a phenomenon which has been widely studied for many years. Internal conversion takes place in competition with γ-ray emission: a fraction of the nuclei in excited states decay by γ-ray emission, the remaining fraction by transferring the energy to K, or L, etc. electrons in the atomic shell. Thus the lifetime of an excited nuclear state depends on the internal conversion coefficient. As internal conversion must be expected to depend on the details of the electronic environment, the lifetime of an isomeric state depends on the state of chemical combination of the isomer - as was recently shown explicitly in one case, that of Te-99m(6hr.).