Report issued by the Brookhaven National Laboratory discussing the formats and procedures used at the ENDF Neutron Cross Section Library. As stated in the introduction, "this report describes the philosophy, data formats, and procedures that have been developed for the Evaluated Nuclear Data File (ENDF)" (p. 1-1). This report includes tables, and illustrations.

The desired neutron spectrum for the High Flux Beam Reactor under construction at BNL requires use of U-Al fuel elements with more then 30 wt% U235 in the meat. The operating cycle of this reactor requires a minimum burn-up of 20%, and preferably 40% of the uranium in the element.

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.

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 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.

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.

Reciprocal labelling in double-labelling experiments with H3- and C14- thymidine showed that when H3- thymidine (1μc/ml for 0.5 hr) was given first in the labelling sequence followed by a 4 hr interval before the C14- thymidine treatment, that passage of cells into and out of DNA synthesis was normal. When C14 was first in the sequence, the rate at which cells entered DNA synthesis was decreased. This was attributed to a radiation effect produced by the β-rays from the C14. The rate at which cells entered DNA synthesis was studied after 0.1, 1 and 10 rads of x-rays. A dose of 1 and 10 rads decidedly depressed the rate. Treatment of roots with 2, 20, and 200 μc/ml of tritiated water for 0.5 hr showed that the 2 higher concentrations produced an effect similar to the x-rays. This indicated that somewhere between 1 and 8 disintegrations per cell per 0.5 hr will produce a decrease in the rate at which cells enter DNA synthesis. In both the x-ray and H32O experiments the depression of the rate that cells entered DNA synthesis seemed to reach saturation at the higher doses.

An accurate determination of the parameters of the resonance excited by the interaction of the 132 eV neutrons with the Co 59 target nucleus has been made, using the fast choppers at Brookhaven National Laboratory in the United States and Chalk River Laboratory in Canada. Neutron transmission through thick and thin samples resulted in the following parameters: [parameters not transcribed]. In addition, measurements of the resonance capture γ-ray intensity gave the value for the radiation width Γγ= 0.40 ± 0.04 eV, based on the known thermal capture cross section of cobalt of 37.5 barns. The reduced and total resonance capture integrals are calculated from the above parameters to be 50.5 ± 5.5 and 67.0 ± 5.5 barns, respectively. The above results are compared with previously determined resonance parameters and also with direct measurements of the total resonance capture integral.

The rapid advances in many technologically important areas have not only served to accentuate the increased demands for high temperature metals and ceramics but have necessitated a more through knowledge of their physical properties when exposed to high temperature service. Toward this latter end, the use of X-ray diffraction has proved an invaluable tool in providing data of regions of thermal stability, expansion coefficients, solid solubility limits, and phase transformations by direct examination at temperature. Since this Laboratory has for some time now been engaged in the study of refractory nuclear materials, it was thought desirable to employ and possibly extend this technique to temperatures ranging up to 3000°C. This communication will describe the equipment developed for this purpose, with experimental results to be described in subsequent publications.

Cell proliferation on the actively growing periosteal surface of the femur of rabbits aged two weeks, has been investigated using autoradiographic techniques. Injections of tritiated glycine and tritiated thymidine were given simultaneously and the animals sacrificed at intervals from one hour to 5 days after injection. The glycine labelled the position of the bone surface at the time of injection and the thymidine labelled the cells which were synthesizing DNA . The rate of increase in the cell population was determined by counting the number of cells beyond the glycine label at different times after injection. The cell kinetics of the fibroblast--pre-osteoblast--osteoblast--osteocyte system has been studied. The fibroblasts are relatively unimportant from the point of view of increase in the cell population. The main site of cell proliferation is the layer of preosteoblasts on the periosteal surface. The rate of movement of cells from the pre-osteoblast to the osteoblast and osteocyte compartments has been measured. The incorporation of osteoblasts into the bone is not a random process, but it appears that the osteoblast must spend a certain time on the periosteal surface before becoming either an osteocyte or a relatively inactive osteoblast lining a haversian canal. During its most active …

A study of the cell kinetics on the actively growing periosteal surface of the femur of rabbits ages two weeks has been continues. A single injection of tritiated thymidine was given and the rabbits killed from one hour to four days after injection. The grain count spectra of the different cell types, pre-osteoblast, osteoblast and osteocyte, have been compared at different times after injection. The results showed evidence for the uptake of thymidine in nuclei which is not associated with cell division. A small percentage of osteoblasts was initially labelled at one hour and there was evidence that the majority of these had not divided by 3 or 4 days after injection. Some thymidine labelled cells had also become osteocytes without division. Furthermore, it appeared that a considerable fraction of the initially labelled pre-osteoblasts did not divide. The S-period for the pre-osteoblasts and osteoblasts was measured using a double-labelled thymidine technique.

Studies carried on since 1956 indicate that the prosaic breeding procedure of sibbing among the most perennial segregates in the hybrid of 4n maize x 4n perennial teosinte quickly restores perennialism to 50% maize tetraploids through increasing the expression of the rhizomatous habit under selection pressure. Similarly, only two generations of selection at the 75% maize level have resulted in a progressive recovery of the perennial expressive. A high degree of maize-likeness therefore appears to be compatible with the perennial expression at the 4n level.

Studies of linkage in polyploids have been exceedingly rare. Only three previous studies of linkage in autotetraploid maize have been reported. Murray (1944), in a limited analysis of crossing over among 4 linked markers in chromosome 2, found varying degree of difference in linkage values between 2n and 4n maize in the three interposed segments. Dempsey (1956) found linkage values wx - c region of chromosome 9 to correspond closely between autotetraploid and diploid maize. More recently Welch (1962), in a more extensive analysis of linkage among the same group of chromosome 2 markers studied earlier by Murray, concluded that although individual progenies varied, linkage values in diploid and tetraploid maize, with some exceptions, are similar. Limited data from one segment of the allotetraploid of perennial teosinte x maize (Emerson and Beadle 1932) probably represent the only reported linkage tabulation in this type of polyploid. A further study of linkage of Zea polyploids seemed worthwhile because of the increasing practical importance of polyploids, of the possibility of adding to fundamental knowledge of tetraploid cytology and genetics, and of the bearing such work may have upon the question of the taxonomic affinities of maize.

Initiation of reactions by intermittent irradiation is frequently encountered in physical, chemical, and biological systems. Mathematical expressions for transient and steady state concentrations of reactive species in these systems are useful for predicting performance and for research purposes. A general method of formulation of the intermittent irradiation problem is presented herein, and illustrative solutions are obtained for radioactive decay chains and for the rotating sector method.

The spectra of KHF2, KH2F3, NaH2F3, liquid and solid HF were measured between 1200 and 30 cm-1 by the inelastic scattering of "cold neutrons" (0.005e.v.). The spectrum of KHF2 is in agreement with previous infrared measurements and shows a peak at 147 mV corresponding to a deformation frequency v2 of the F-H-F group and a broad peak at 13 mV due to a libration of this group. The observed spectra for KH2F3, NaH2F3 solid and liquid HF were compared with that for KHF2 considering the known results that the F-F distance increases, the position of the H atom between the two fluorines becomes more asymmetrical, and the strength of the hydrogen bond decreases in going from the HF2- ion to H2F3- ion to HF. In this comparison the known structure of the H2F3- ion is considered as being intermediate between that of HF2- and the zig-zag hydrogen bonded chains in solid HF. As a result, the lines observed at 112 mV and 67 mV in the H2F3- spectra and in HF respectively are associated with the deformation frequency v2 of the H-F-H group in these compounds. In addition the spectra of H2F3- ions show a peak at a 15 mV …

The synthesis of several rare earth dodecaborides, isomorphous with UB12 and ZrB12, and crystallographic data for these phases were reported recently. The unit cells are face centered cubic with four formula weights of MeB12 per unit cell; the structures may be visualized in terms of boron atoms linked in a rigid three-dimensional network, with the metal atoms in large cubo-octahedral holes.

The History, Current Significance and Status of the Field Hot atom chemistry, like many other fields of scientific research, can trace its origin to a single experiment, that of Szilard and Chalmers, performed in 1934. This is true even though recoil effects had been known and used for a long time. Almost immediately Szilard and Chalmers put their discovery to practical use: they employed the recoil effect in ethyl iodide as a neutron detector and observed the γ,n reaction in beryllium. The ingenuity of Fermi soon provided the correct explanation of the chemical separation observed by Szilard and Chalmers, and Fermi's co-workers, especially D'Agostino put the effect to a further practical use: the preparation of radioisotopes in high specific activity. These Roman scientists carried out the first Szilard-Chalmers studies in solids (sodium bromate, chlorate, iodate, and perchlorate, cacodylic acid and potassium permanganate) and reported some quantitative results: for example a quite accurate recoil yield of 80% of the Mn 56 in potassium permanganate. Perhaps the most striking practical result of a Szilard-Chalmers experiment lay in the discovery, by Kourtchatow and co-workers, of the important isotope Br 82 in extracts from neutron-irradiated ethyl bromide.

The method of collection and the subsequent analysis of the hematological data accumulated by the Joint Commission of the Investigation of the Early Effects of the Atomic Bomb in Japan, have been described. In the present investigations, an additional analysis of the hematological data was made to investigate a possible relationship between leukopenia and the mortality rate within the first nine weeks following the bombings. It has been frequently observed in laboratory animals exposed to ionizing radiation that the extent of the fall in the white blood count reflects the dose of radiation received. Smith et al have demonstrated that in mice survival can be related to the depression of the granulocyte count at various times following radiation. Cronkite and Brecher and Cronkite, Bond and Dunham inferred that the hematological response could be used as a biologic dosimeter for exposed human beings. This report is concerned with the study of the response of the white blood cells to ionizing radiation resulting from the atomic bomb detonation in Japan.

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.

It is appropriate that a conference devoted to the interactions of fast neutrons with nuclei begin with a survey of the available sources of such neutrons. Since its discovery in 1932, the neutron has provided a highly useful tool in attempts to understand the nucleus, and the types of nuclear phenomenon which could be studied and the nature of the results obtained are very dependent on the sources available.

In calculating diffusion coefficients for gases diffusing from solids, the numerical solutions tabulated by Darken and Gurry, were found to lack the required precision, and the intervals between the arguments were too great to permit precise interpolations. Consequently the diffusion equation solutions of interest (diffusion from a sphere, cylinder, and plate, for the condition that the concentration of the diffusing species initially uniform) were re-evaluated. Computer programs for the three cases were written in FORTRAN for the IBM 7090. The solutions programmed are given in Crank. Values of the fractional completion were computed at approximately 0.01 increments, to the nearest 0.00001, and are tabulated in Table 1 to the nearest 0.0001. The table covers the fractional range from about 0.04 to 0.99. For smaller fractions satisfactory approximations are available. The table may be conveniently interpolated by plotting points about the region of interest and drawing a curve.

Before discussing personnel monitoring of high energy radiations, it is appropriate to comment briefly on two basic methods of dosimetry applicable to such situations. In the first of these methods, one measures the rad dose in air with a tissue-equivalent ionization chamber that is operated with enough voltage on the collecting electrode to insure saturation even when the radiation is concentrated in short pulses, as is frequently the case. The linear energy transfer (LET) spectrum of the radiation is then determined and an average value of relative biological effectiveness (RBE) is determined. An experimental evaluation of the depth dose situation completes the data necessary for a full evaluation of the biological hazards. The method is completely general but is most applicable to situations where a substantial proportion of high energy components is present in the mixed radiation. It should be noted that the detailed composition of the radiation need not be known. Thus, components of dosage to which an RBE of 1 is assigned may be due to X-rays, gamma rays, or the ionization tracks produced by protons in the Gev energy range as well as by many other types of radiation. This method is applied frequently to the situation …

A neutron diffraction study of polycrystalline HCrO2 and DCrO2 (chromous acid) is described. Intensity data from the two substances were refined together by the least-squares method, with the constraint that the Cr-O distance be the same in the two substances. Estimates of individual contributions to multiple peaks were included in the least-squares refinement through the use of a non-diagonal weight matrix. The O-D-O bond is found to be asymmetric, O-D = 0.96 ± 0.04 A, O...O - 2.55 ± 0.02 A. The symmetry of the O-H-O bond cannot be determined, but agreement with observation is as good with a symmetric bond as with any other model. The O-H-O bond length is 2.49 ± 0.02 A. These results are consistent with those from previous studies of the HCrO2-DCrO2 system by nuclear magnetic resonance and infrared techniques.

Methods of calculating the "Snell Experiment" (the exponential experiment in natural uranium) are examined. It is found that integral transport theory is required for accurate predictions. The effect of spatial transients upon measured quantities is studied and it is found that experiments have not been done in a large enough mass of uranium to achieve an asymptotic neutron distribution. However deviations from the asymptotic values of integral quantities are not large and corrections are calculated and applied to recent experiments. It is shown that the use of recent cross section data improves the agreement between theory and experiment. The relaxation length and all spectral indices are in fairly good agreement except for Np237 to U238 average fission cross section ratio.