From American Nuclear Society Meeting, New York, Nov. 1963. In computer-coupled automated activation analysis such as in the Mark II system, conventional methods of data readout impose a serious restriction on the minimum handling time per sample. A data coupler for operating between the data accumulation system and the computer tape unit was developed which contributes nothing to the handling time per sample, does not distort the data, and prepares the data for direct computer entry. In addition to activation analysis, the coupler may be used to obtain successive spectra separated in time by 0.16 sec in the study of short-lived isotopes. (D.L.C.)

Several difficulties involved in accelerating heavy ions in a tandem Van de Graaff are discussed, and experiments with Br and I ions to determine the response of silicon detectors to fission fragments are described. The pulseheight spectra of the ions are given, and the stopping cross section for I ions in Au, Ni, Al, and C at 20--120 Mev are plotted. (C.E.S.)

Large-volume scintillation detectors are being developed for radioisotope control of unit processes. In the development work, mirror-finished aluminum foil reflectors were better than diffuse reflectors, argon flushing to remove dissolved oxygen from liquid scintillators improves the pulse amplitude, and liquid scintillators are superior to plastics. Dimethyl POPOP was found to be an excellent primary solute; optimum concentration is 2.5 g/l in toluene with argon flushing and no secondary solute. A test loop was constructed for testing the detectors in process control applications. Among the systems being tested are one using a solid-state magnetic comparator-control relay and an inexpensive solenoid valve as the final control element, at approximates 25% of the cost of a conventional system. (D. L.C.)

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Colloidal aggregates (10 to 20 m mu ) of human serum albumin /sup 131/I may be used safely by intravenous injection to perform photoscans of the heart, liver, spleen, stomach, and salivary glands in man. Large particle size suspensions (10 to 50 mu ) of the same material were investigated experimentally in animals for scanning the lungs after intravenous injection and the brain following injection into an internal carotid artery. The advantages of this test material are the relatively low radiation exposure to the target organs and the number of organs that may be examined. Radiation exposure is low because of the rapid turnover in the target organs and removal from the body, mainly by urinary excretion, within 72 hr. The mechanism of liverspleen localization with this organic colloid is the same as for inorganic colloidal /sup 198/Au, namely, rapid removal from the blood by the phagocytic cells of the liver and spleen. However, in contrast to the inorganic colloid, which remains in the phagocytic cells permanently, albumin is digested by proteolytic enzymes and the /sup 131/I label is set free to re-enter the general circulation. With the thyroid blocked, the / sup 131/ is excreted mainly in the urine …

The qualitative dependence of the neutron strength function upon optical model parameters is discussed with emphasis on the effects of variations in the magnitude and spatial dependence of the absorptive potential. A model is presented that gives a good account of strength functions and potential scattering radii, as well as neutron scattering cross sections below 1 Mev for spherical nuclei. (auth)

Methods for determination of calcium turnover in man with radioisotopes are presented and the clinical use of various techniques is evaluated. In the discussion of kinetic analyses, some important observations were made. The accretion rate calculation can be made independent of the number of compartments in the exchangeable calcium pool, and thus is not distorted by approximate estimations of this pool. However, if the exchangeable calcium pool is calculated with the isotope dilution technique, and the accretion rate obtained from this value by the total turnover equation, then an error is introduced into the value of the accretion rate. It was also pointed out that the multicompartment treatment is more appropriate than the customary single compartment analysis and utilizes all available information. Since the pool size has been of little clinical use so far, it was suggested that multicompantment analyses be used in the future. At present, no accepted model exists which can account for all data obtained in tracer studies and in particular for the last part of the serum disappearance curve. Preliminary results of long term studies of the retention in bones of strontium-85 was presented. These show that there is measurable turnover of tracer deposited in bone …

From 1963 American Society of Metals/Metals and Materials Show, Cleveland, Oct. 1963. 23rd National Convention of the Society for Nondestructive Testing. The factors which affect the attainment of optimum results in radiography are radiation source, specimen, filmscreen combination, film processing, and their mutual relationships. A general review is presented of radiographic practice and the effects of variations in the factors, at energies below 400 kvp, on radiographic contrast and sensitivity. (D.L.C.)

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A review was made of the effects of fluoride ions on the corrosion behavior of zirconium alloys in high-temperature water. Corrosion was found to occur as the result of contamination of the water or the zirconium surface. A major source of fluorides is undue delay in rinsing the HF--HNO/sub 3/ pickling solution during surface preparation. The oxide on corrosion-resistant material has been found to contain up to 7600 ppm fluoride from this source. The threshold concentration of fluoride in the oxide film which produces poor corrosion resistance ranges from 8500 to 17,000 ppm. Accelerated corrosion from fluorides in water at 300 to 360 deg C occurs at about 100 ppm, although increased corrosion has been reported at 10 ppm fluoride in water at 300 deg C. Fluorocarbon plastics degrade and contribute fluorides to the hightemperature water or to the alloy surface when in direct contact with zirconium. Chlorides (1 to 10,000 ppm) and iodides (1270 ppm) do not adversely affect the corrosion behavior of zirconium alloys in water at 360 deg C. The mechanism of corrosion is not well understood but apparently is related to the formation of insoluble zirconium oxyfluorides during pickling and during exposure to fluoride- contaminated water. …

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From International Conference on Nuclear Physics with Reactor Neutrons, Argonne, Ill., Oct. 1963. Experiments were performed in which the kinetic energies of correlated fragment pairs from thermal- and resonance-neutron-induced fission were measured. In addition, a three-parameter ternary fission experiment was performed in which the energies of correlated fragments were measured in coincidence with the energy of a third emitted particle, usually a long-range alpha particle. The detectors were large-area silicon surface barrier detectors. The instrumentation associated with these experiments is discussed in detail. The complete system is described, with attention given to the problems of background reduction (fast-coincidence requirements), stability, linearity, and resolution. Particular attention is given to the reduction of spectrum distortion by pile-up pulses (alphaon-fission pile-up within the amplifier resolving time). Methods and limitations of pile-up detection are discussed. A new method for inspection and removal of pile-up pulses is described. (auth)

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From American Nuclear Society Meeting, New York, Nov. 1963. The use of the asymptotic solution to the one-velocity transport equation is considered. The angular distribution for fast neutron elastic scattering by heavy elements is discussed. An exponential angular distributi on is assumed to simplify the decay length calculation. The diffusion length of 1 to 15 Mev neutrons in iron is calculated, as well as the vector flux angular dependence. The asymptotic solution for an arbitrary angular distribution of a plane delta -function source is also found. An isotropic source is investigated, and some applications of the model are examined. (auth)

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From American Nuclear Society Meeting, New York, Nov. 1963. The need for control of the flow distribution and/or steam quality in boiling reactors is discussed. A quality control device is being developed which consists of an entrance venturi and an exit venturi for measuring the flow rates into and out of the channel, means for comparing the two flow rate signals, and a value for regulating the flow rate. This device can be used either as a constantquality device or as a controlled-quality device. Results are given of air-water studies of two-phase flow in a vertical venturi. (D.L.C.)

l963. The Wisconsin tandem accelerator is used part of the time for experiments in neutron physics. In these experiments the properties of neutrons from charged-particle reactions as well as the interaction of neutrons with nuclei are studied. Some of the techniques used and some of the results obtained are described. (auth)

The effects of competition between resonances of different isotopes were investigated. Flux and reaction rate calculations on a Pu/sup 239/-- U/sup 238/ system revealed that U/sup 238/ exhibits both self-shielding and interference effects, the latter becoming noticeable at enrichnnents of a few per cent. Gold activation was also found to be depressed by the presence of U, but was insensitive at low enrichment values, Investigation of the Pu/sup 239/ resonance integral showed an asymmetric effect involving both interference between potential and resonant scattering and interferance with resonance absorption in another isotope. The interference scattering arising in each resonance level had a notable effect on the average change in the Doppler coefficient. (D.C.W.)