Fermi, Anderson, and Nagle's experimental distribution of Indium resonance neutrons around a point source of fission neutrons in water has been fitted by analytic expressions which are source functions in the two-group, three-group, Fermi and Christy-Wheeler pile theory. The Christy-Wheeler function (exponential followed by a Gaussian) is the best fit; the two-group function (exponential) is slightly better than the Fermi Gaussian.

The change in the simple [formula] distribution of neutrons in a spherical lump of uranium caused by the distribution in velocities of thermal neutrons is calculated. If the calculated curve is fitted as well as possible by a simple [formula] curve, it is shown that the value of [formula] obtained in this way is a function of [formula], the radius of the sphere. For small radii the [formula] obtained in this manner will be as much as 25% greater than the [formula] corresponding to average velocity neutrons. The change in the thermal utilization caused by the distribution in velocities is discussed. The flux of neutrons into a sphere is calculated taking into account the velocity distribution and this is compared with the usual theory.

Aluminum oxide occupies a larger volume than the aluminum it contains would fill as metal, consequently, the assumption has been made that holes in metallic aluminum would close by a sufficient amount of oxidation. Therefore, we were asked to investigate the rate of plug formation under conditions to be expected in the pile. For the latter we were requested to approach the pile conditions as nearly as we could by employing the Chicago cyclotron. It seems to us that the problem divides itself into two separate questions: (1) under what conditions may holes be expected to close? (2) if holes do close how much corrosion of uranium may be expected before the closure becomes impervious to water vapor? In this report only the first question is considered. The experiments and theory coupled with the data collected by other workers on the project definitely define the limits within which pores in the aluminum cans may be expected to close by an oxidation process. Under the most favorable conditions only small holes may be sealed in this manner. In the large majority of the cases the holes not only fail to close but become larger.

The distribution of thermal neutrons in a W slug having a one centimeter aluminum end cap has been calculated on the basis of simple diffusion theory. It is found that the average neutron density, and therefore the power output, at the end of the slug is about 34% higher than the density far from the end cap. This result agrees well with the recent Argonne pile experiments (CP-1729).

Abstract. If a pile rod gets bowed within its cooling tube it becomes warmer on the side which approaches the tube wall, and thermal expansion tends to warp it in the same direction as the original displacement. This was discussed roughly in N-601, and it was there concluded that the mechanism was not important for an isolated short slug. In connection with current development of continuous jacket (cartridge) assemblies, it seems desirable to look at this question again. In this case it is possible that the effect may be of some concern.

Effect of aquadag coating on noise reduction in polyethylene coaxial cable was tested. A satisfactory combination of coaxial cables and connectors interconnecting sources of small ion currents or ionizing impulses with the measuring device is described.

Bi-Pb eutectic and pure Bi penetration of graphites of various densities under 300 degrees C and pressures up to 20 psi was found be of the order of magnitude of 1.0 g/cm(2) and was uniform throughout the graphite. Bi was absorbed less than the eutectic but the oxidation rate of Bi would be prohibitive. There was heavy nitriding in N atmospheres with the Bi and the eutectic.

This technical report discusses a method proposed to measure neutron energies by accurately determining the momenta of recoil protons in a magnetic spectrometer specially designed for this purpose. The main consideration in the design of the spectrometer is the shielding of the detector from the high radiation background associated with intense neutron beams.

Abstract. Slow neutron transmission measurements as a function of the time of flight of the incident neutron have been made for three different thicknesses of Beryllium. The energy region from 0.004 eV to 50 eV was investigated using the Columbia neutron beam spectrometer system. Particular emphasis was placed on the very low energy region (from 0.004 eV tp 0/2 eV or from 0.6 to 5 [length]) where pronounced crystal interference effects were observed. The effective slow neutron cross section (in the unity of X 10(-24)ce(2)atom) for several different energy values were: 6.1 at 0.2 [length], 3.5 at 1.5 [length], 2.3 at 2.5 [length] and 0.6 at 4.6 [length]. The positions of the discontinuities in the cross section agree fairly well with the values obtained from the X-ray measurements.

Abstract. The diffusion length of thermal neutrons in water as a function of the water temperature has been measured. The results are expressed as a linear relation: L = 2.644 + 0.0061T where L is the diffusion length in centimeters and T is the temperature in degrees centigrade.

Abstract. Temperatures are measured at two points in an internally heated jacketed slug which is cooled by water flowing in an off-center annulus around the slug. The variations of these temperatures with water velocity, water temperature, power, and the amount the annulus is off center are measured. The temperature near the slug surface which approaches and comes in contact with the water jacket does not increase as much as anticipated. The temperature near the slug surface on the side which is moved away from the water jacket increases nearly as much as on the side approaching the slug. An explanation for this unexpected increase of temperature as on side moving away from the jacket is given.

Abstract. A method for calculating jacket temperatures in a region of varying heat transfer coefficients is given Some applications are made for temperatures above a supporting rib.

Abstract. An apparatus for measuring the thermal conductivities materials which are moderately good conductors of heat is described. Results obtained with a sample of pure Th are given on p. 10, 12, and 13.

Abstract. Successive approximations ae obtained from transport theory for the neutron distribution around a black sphere surrounded by a spherical gap and a non-absorbing medium extending to infinity. Six cases are calculated numerically to show the difference between this treatment and simple diffusion theory. The extrapolation distance and a quantity that is essentially the thermal utilization are calculated in different approximations. It is found that the neutron density in the gap, instead of being a constant as predicted by the simple theory, may vary by a factor of one-third in cases of practical interest.

Abstract. The probability of exceeding assigned values of displacements or forces in simple rod models assembled from slugs picked at random is discussed, and some estimate for the statistical gain resulting from use of shorter slugs is obtained. The probability that a rod with self-warping will touch the top of the tube appears great enough to justify a recommendation of the use of top ribs.

Experiments wee performed to evaluate the feasibility of detecting swelled slug elements in Hanford reactors by measuring the force necessary to push the slug column in its tube. These experiments are described. The results indicate the method presents no unsolvable problems.

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Abstract: An ionization chamber for use in counting alpha particle activity from the air has been devised for counting samples collected with the electrostatic precipitator. The chamber is an adaptation of the breech-locking standard chamber, with a cylindrical high voltage electrode into which the collection foil is placed, and a coaxial rod as a collecting electrode. A geometrical efficiency of close to 50% is obtained.

Report detailing values of x-ray lives and limits for trans-uranic elements. Formulas and methods are detailed throughout the report.

Report of experimentation on mice of exposure to daily doses of gamma radiation at two rates and the resultant damage.

Abstract: "The advantages of high scaling ratios in counting random pulses are discussed. The mechanism of the basic circuit used in the Columbia University scaling circuits is described. The difficulties experienced in the performance of the earlier circuits are indicated and modified circuits to eliminate these difficulties are given. Precautions that must be observed in carrying out the constructional details are suggested. The complete circuit and specifications are given in detail for a Scale of 128 for use with linear-amplifier systems" (p. 1).

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