In order to perform the various experiments with a bubble chamber, a high intensity flash tube is used. This report briefly describes the power supplies designed and constructed to power these lamps.

The power supplies designed and constructed to power high intensity flash tubes used in bubble chamber experiments are briefly described and are accompanied by a schematic diagram of the layout. (D.C.W.)

Recently, there has been some evidence to point to possible ordering in the α-brasses. Masumoto et al. have concluded from their specific heat measurements that there is a possibility of ordering in the α-brasses. In particular they observed an anomaly in the specific heat curves for the α-brasses for the temperature range from 200 to 260°C and explained these results upon the basis of a change in local or short range order in α-brasses at these temperatures. In connection with the study of radiation damage effects in α-brass ordering has been suspected. Rosenblatt has annealed 70-30 α-brass previously annealed at 350°C and cooled to room temperature at 190°C for six weeks. He observed a decrease of .90 ± .03% in the electrical resistivity of α-brass measured at -196°C after the anneal at 190°C.

In a third run with the fluorine torch, the settling chamber wells were kept hotter than before (≥ 625°C); the flame was cooled by diluting the fluorine with helium. In the analysis of the products, 99% of the thorium fluoride fed in was accounted for, but only 64% of the protactinium activity. Part of this was carried in the exhaust gases past the cold trap and into the soda line disposal column, where it was detected by survey meters. The stripping of protactinium from the solid was somewhat more efficient than before; 77% of the feed which was recovered from the settling chamber had lost 72% of its original specific activity. About 15% of the input activity was trapped on the cold fingers with very little thorium fluoride.

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.

This report is a summary of the neutron attenuation data which have been obtained at the Brookhaven shielding facility on a mock-up of the fuel-rod-unloading plug used in the KAPL Reactor. Before this program was initiated, a number of small scale tests had been made in the ORNL lid tank on carbon steel mock-ups of components of the rotating plug. The results of the tests indicated considerable neutron streaming through the vertical steel and air members of the plug. However, the lid tank source strength and dimensions did not permit the tests to be extended to the full plug height. In view of the concern aroused by the ORNL tests and the absence of fundamental information on the transmission of neutrons through steel and the addition height (12') available here resulted in a request for BNL to construct and test a mock-up of a sector of the SIR top plug in accordance with KAPL specifications.

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.

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.

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.

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 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.

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.

In recent years a good deal of understanding about the structure of the α-acid glycoprotein of human plasma (orosomucoid) has been obtained. Since the isolation of the protein in an apparently pure state, it has been shown to have a molecular weight of approximately 45000 and to be made up of about 40% carbohydrate and 60% polypeptide. The latter apparently is in the form of a single polypeptide chain. The carbohydrate, on the other hand, has been shown to have at least 16 non-reducing chain ends terminating in sialic acid, and may also have 1-3 further chains with fucose on the non-reducing end. At least in those chains terminating in sialic acid, galactose is in the next position followed by N-acetyl glucosamine. The recent report of the isolation, from a partial acid hydrolysate of the α-glycoprotein, of an octasaccharide containing 2 residues each of galactose and mannose, and 4 residues of N-acetylglucosamine, indicates that at least part of the carbohydrate in the protein is the form of units no smaller than this. However, the number and nature of the firm covalent linkages between carbohydrate and protein remain uncertain, and it was for this reason that the present study was undertaken.

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.

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 …

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.

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.

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.

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.

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.

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.