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.

Vacuum technology is germaine to and is utilized in an extroardinarily widespread scope of the scientific disciplines. From the medical technician freeze drying hog cholera vaccine to the solid state physicist studying thin film phenomena, vacuum technology is an important auxiliary. When one visits the NASA center at Langley and sees the clustered space environmental chambers, looking like a field of grotesque mushrooms, one realizes that vacuum technology is a vital adjunct in this most recent section of our total national scientific effort.

The amount by which the field of a magnet bends the path of a charged particle is proportional to the integral of Btds along the trajectory. Instead of making tedious point by point measurements of B in magnets and performing the integrations numerically, it has been found useful to measure directly, by using a search coil whose winding consists of long and narrow turns extending through the magnet gap from z1 and z2 in the direction of the trajectory. It should be noted that the integral Iy is taken along a straight x=constant, y=constant lines and not along the actual curved trajectory path; for small curvature the difference is small.

The model used to evaluate the single interstitial migration energy from property changes due to interstitials is extended to account for vacancy contributions. The annealing function obtained can be used to determine the relative contributions of the defects and is sufficiently sensitive to distinguish vacancy effects that are an order of magnitude less than interstitial effects. Application of the model to stored energy and thermal resistivity data yields the same values of the activation energy and temperature independent term obtained from c-axis and macroscopic length expansion rates. The results indicate that the stored energy associated with the di-interstitial is at least ten times greater than the stored energy associated with the vacancy. The minor role of vacancies in phonon scattering is discussed. Analysis of the annealing function obtained from electrical resistivity changes in irradiated graphite indicates that the ratios of charge-carriers to scattering centers varies with irradiation temperature below 55°C. Above this temperature the changes are attributed to equal contributions from vacancies and interstitials.

It has previously been shown that the polymer formed in solid state polymerization of acrylamide is amorphous in spite of the fact that the reaction takes place within a crystalline solid. The stage at which it becomes amorphous is not known at present. Work with dilute solid solutions of acrylamide in propionamide suggests that this occurs after the addition of, at most, a very few monomer units.

The evaluation of iron absorption using a single crystal whole-body counter is complicated by the inherent difficulty of determining a correct "100% value". Shortly after ingestion, tracer radioiron can be found in the stomach, upper small intestine, portal circulation and liver. Fourteen to twenty days later, the time at which absorption is measured most effectively, the radioiron will be distributed between the red cell mass, liver, spleen, bone marrow and other storage areas. With this mixed distribution there will always be an error because of geometric factors, and hence in counting efficiency, in using the relationship of [formula not transcribed] to calculate iron absorption. In a previous iron absorption study reported from this group, the radioiron retention measured 4 to 10 hours postingestion was used as the "100% value". The present experiments were designed to evaluate the clinical usefulness of the 4 hour postingestion count as the "100% value" as compared to the immediate postingestion body count, and to compare these values with an intravenous Fe59 calibrated absorption. These studies were performed with the realization that there is no absolute solution to the problem.

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.

During the early planning for experiments to be carried out at the Brookhaven AGS, it was decided that the beam-transport equipment should be kept to a minimum number of types, yet with sufficient flexibility that a wide variety of beams could be made up from the modules selected. This policy has been followed during the intervening years, with additions being made only in the total numbers of these modules and, as yet, no further types being fabricated. The types and their performance will be summarized herein.

When the Brookhaven AGS started operation in the summer of 1960 very little experience with targeting in strong focusing proton synchrotrons was available. While it was evident that targeting techniques would differ markedly from those used in weak focusing machines, only actual running experience would set the proper parameters for a truly satisfactory targeting system. It was, therefore, an advantage that temporary targeting devices were used initially. Work on a more permanent system was not started until the summer of 1961, and the first component of the system installed in January 1962. While further refinements are still continuing the essential features of this targeting system have now sufficiently proven themselves in actual operation to remain unchanged. This system in its present form is the subject of the first portion of this paper.

The subject of this paper is the experimental and technical aspects of the measurements of nuclear resonance parameters. I will confine my remarks to those reactions induced by low energy neutrons, i.e. neutrons of less than approximately 100 kilovolts. The bulk of these measurements have been performed by neutron time-of-flight techniques, and I will direct my attention to these techniques. The first half of this discussion will concern the apparatus with which these measurements are made; the second part will be a discussion of the various experiments by which these parameters are measured, with an emphasis in both areas of discussion on relatively recent developments in the field.

The BNL cold neutron facility has been used to obtain inelastic scattering cross section data from three first-row transition elements, titanium, vanadium, and nickel, and a random binary alloy Ti.67-Zr.33. From the data, we have computed vibrational frequency distributions exhibit peaks corresponding to major critical points. A comparison of the distributions from the different samples leads to the following conclusions: 1) The shape of the frequency distributions of the b.c.c. metal (V) and f.c.c. metal (Ni) are remarkably similar, the relative positions of the critical points being the same for both; 2) The frequency distribution of the h.c.p. metal (Ti), which has two atoms per primitive cell, shows structure corresponding to acoustical and "optical" modes of vibration; 3) The titanium-zirconium alloy has the h.c.p. structure, and its experimental frequency distribution is similar to that of titanium, except at low frequencies where alloying with the heavier mass zirconium atoms tends to smear out the peaks corresponding to acoustical modes. Measured frequency distributions were obtained for the titanium-zirconium alloy slightly above and below the critical temperature for the phase transition to b.c.c. structure. The frequency distributions in the two phases are different, the most striking feature being a shift of the high …

Tissue from etiolated or partially etiolated Pisum seedlings is widely used in work on growth substances and light responses. However, in the authors' experience growth under the conditions commonly employed is frequently irregular, and often affords little or no satisfactory experimental material. Although the literature records little evidence of such difficulties, personal communication with many investigators leaves no doubt they are widespread.

A working definition of homeostasis is the following: the sum total of the processes which maintain a steady level of various substances or functions within a living baby. Our own concern will be with the homeostasis of trace metals. I will begin with a slide which shows the total body concentration of various metals, including "trace" ones. Only metallic constituents which play a role in the maintenance of the body's structure and function are shown. The essential trace metals among them are represented by black bars. Iron is both black and white. Indeed, if one excludes the fixed sequestered iron of myoglobin and of hemoglobin, one is left with a trace fraction of iron about which I will be talking later on. Note that the scale is logarithmic, indicating that the concentrations of essential metals in the body fall off sharply and smoothly.

Recent measurements of the pion-proton total cross section, taken with small statistical errors, have shown the existence of two new maxima in the momentum range between 2 and 3 BeV/c. Measurements of comparable statistical accuracy, covering the momentum range from 2.5 to 8 BeV/c are reported in the present paper. In addition to the total cross sections for π± mesons on protons, their total cross sections on deuterons have also been determined. Some data were also taken on the total cross sections for K+ mesons on protons and deuterons and for K- mesons on protons.

The duration of mitosis is of great importance in an evaluation of growth rates in proliferating somatic tissues, since calculations are based on observations of mitotic activity, and therefore final results are directly proportional to an assumed value for mitotic time. This duration cannot be measured directly in vivo at a tissue level, since the mode of distribution of the single cell value is not known. This difficulty is not overcome in extrapolations from in vitro measurements. Also it is not overcome with the labeling of proliferating cells after tritiated thymidine injection in vivo if subsequent observation is limited to the rate of progression into mitosis of labeled cells that incorporated the tracer during the period of DNA-synthesis. Observation of separate mitotic phases, however, offers the possibility of following the progression of the wave of labeled cells at successive, short-lasting checking steps, and to analyze the variability in the times of passage through mitosis. In the present work, the progression of labeled cells as a function of time, after a single injection of tritiated thymidine, was followed in successive phases of mitosis in erythroblasts of dog bone marrow.

Studies on a large variety of plant species, particularly by Sparrow and his colleagues, have shown that radiosensitivity, as measured by growth inhibition and lethality, is strongly correlated with various parameters of the cell nucleus. Foremost among these are nuclear volume, SNA content and chromosome number. It is generally accepted that in proliferating cell systems chromosome damage may well be the principal radiobiological lesion, and the observed correlations are in line with the contention that loss of genetic materials following such fragmentation is a factor of a major importance in radiation-induced lethality and growth inhibition in plants.

The development of nuclear arms added the effects of ionizing radiation to the direct and indirect mechanical, chemical or thermal hazards of "conventional" weapons. The biological effects of ionizing radiation are the result of absorption of energy and the morphologically recognizable damage is poorly understood. Although new in their use in weapons and difficult to evaluate in their consequences, ionizing radiations are by no means new to physicians. Furthermore, medical experience has shown that clinical consequences of radiation injury are similar to those with which the clinician has to deal with every day in the treatment of neoplastic disorders and its complications. Soon after the discovery of x-rays by Roentgen and of the phenomenon of radioactivity by Bequerrel in the last decade of the last decade of the 19th century, it was found that ionizing radiation can produce marked biological effects by interfering with cell- and organ functions. Senn and Hussey were the first to effectively treat leukemia by this means. This, since about 60 years, ionizing radiation has been a powerful tool in the hands of physicians both in diagnostic procedures and for therapy of malignant disease. It should not be forgotten however, that the price paid for this …

Binary fluorides of the type XMnF3 (X= Na, Rb, Cs, and NH4), which were investigated previously by means of x-ray, electron spin resonance specific heat, and magnetization measurements, have been reported to be antiferromagnetic. The present study reports powder neutron diffraction measurements on these compounds undertaken to confirm the antiferromagnetism and to study details of the magnetic ordering. Some information was also obtained concerning the nuclear structures.

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

The crystal structure of MgSO4·4H2O has been refined using single crystal neutron diffraction data for the three main zones. The hydrogen positions which were found are essentially those which have been deduced from X-ray data in an earlier investigation.The mean value of the O-H bond lengths is 0.97Å. The O-H-O bonds are bent considerably. One hydrogen atom does not participate in hydrogen bonding, as can be concluded from the geometry of its surroundings and its thermal motion.

In high-energy particle physics the initial problem is to obtain information about the behavior of particles which are invisible by any known means (the radius of a proton is 10-13 cm) and which may be traveling at speeds greater than 180,000 miles per second, but at less than the speed of light. Some of the work is being done with the use of electronic counters, but the larger fraction is currently done by three techniques which employ the photographic process. These are the silver halide emulsion stack, the liquid hydrogen bubble chamber and the spark chamber. Counters provide immediate information but it is of a yes-or-no character, whereas the other methods are capable of actually mapping, with varying degrees of accuracy, an interaction between particles. The emulsion stack is quite familiar and need be discussed only briefly. Since individual silver halide crystals are rendered developable along the paths of charged particles, a sensitive detector may be built up with thick layers of specially sensitized emulsion having no base support. As the path of the particle may be through several emulsion having no base support. as the path of the particle may be through several emulsion layers and the track must …

A feedback technique has been developed to equalize the DC levels of two signal sources so that AC signal components which are much smaller than the DC levels can be compared accurately without introducing a low frequency cut-off and consequent rate-dependency into the system. A digital integrator in the feedback loop provides a highly stable long-term "memory" so that the correct level will be maintained during intervals when the signals are "frozen" at some arbitrary point.

In the vast field of radiation pathology we find pathologists, anatomists, and even physiologists busily at work, but the radiobiologist is conspicuously absent, although, according to Zirkle (1959), this field is clearly within his domain. Perhaps it is wise to take this broad hint of the scientifically so well equipped radiobiologist and to stay clear from an area in which an incalculable array of variables makes clearcut experimentation a hopeless venture, a priori. Perhaps it would be better if the pathologist, who must study pertinent material, restricts himself humbly to the recording of his observations, refraining from any attempt at interpretation. On the other hand, since seemingly audacious speculation has borne fruit in the past and the value of the information that results, if the speculation proves to be correct, is worth many times the effort, there is obvious justification for a thesis on the mechanism of delayed radionecrosis.

Evidence is rapidly accumulating that the genetic material carried in a chromosome is arranged in a highly organized manner. The nucleotides of DNA constituting a gene are grouped in sequence, like the letters of a word, and presumably each word uniformly consists of three letters. Successive words make up a sentence containing the information needed to build a protein molecule. Each word of the sentence is transcribed to form an amino acid of the protein for which the particular gene is responsible.