Diffusion theory and transport theory approaches to the problem of a nuclear reactor with a transverse air gap are compared. It is suggested that the differences in results for thin gaps is due to the fact that diffusion theory does not adequately represent the flux distribution in the immediate vicinity of the gap. For mathematical conveniences previous treatments of the gap problem have made use of fictitious image piles which exaggerate the neutron losses. The extent of the error is estimated by direct neutron leakage calculations.

Preliminary data are enclosed in Tables I, II, II, IV, V, and VI. Tables I to V are data for round nickel tubes in a vertical and inclined (45°) position. Table VI contains some preliminary data for nickel rectangular channels (0.060" and 0.050" spacings) in a vertical position.

The rapid development of the field of atomic energy during the past few years now permits the exploration of applications to medicine involving new concepts in the treatment of cancer. One such has been the study of neutron capture therapy which is being developed at the Brookhaven National Laboratory.

As a result of an operating nuclear reactor, several accelerators and many laboratories using radioactive isotopes, considerable amounts of radioactive gaseous, liquid and solid wastes are generated at Brookhaven.

One might expect that the Cosmotron would offer certain advantages over cosmic rays for the study of heavy unstable particles; provided, of course, that it can produce them. In the first place, the conditions under which they are produced could be controlled to a considerably greater extent. In the second place, it might be possible to arrange conditions under which they would be observed more abundantly, an actual beam of heavy mesons being the ideal situation.

The study of the interaction of the electromagnetic field with nuclei has proved very fruitful for the elucidation of many details of nuclear structure. The γ-ray transitions observed in either absorption or emission can be divided into three classes, depending on whether the matrix elements of the transition are (1) much larger, (2) approximately equal or (3) much smaller than those expected for single proton transitions which are usually taken as a norm. In class (1) we find (a) the broad transitions leading to the "giant resonances" in the nuclear photo-electric effect, and (b) the "fast" transitions between low lying states, especially for even-even nuclei far removed from magic numbers. The large matrix elements and the regular dependence of their magnitude on the atomic weight speak for cooperative phenomena in which many nucleons or the nuclei as a whole are involved. In class (2) we find the much studied M4 transitions which give strong support for the single particle model; they have rather uniform matrix elements. Some finer points remain to be understood, especially why some odd nuclei do not show the expected ratio for |M|^2 of ~ 2:1. The transitions belonging to class (3) require further selection rules and …

The absorption bands induced in α-Al2O3 by gamma and reactor irradiation have been studied. The slight coloration due to γ-rays saturates. Bands specific to reactor irradiation have been found and their growth studied.

Report issued by the Brookhaven National Laboratory discussing corrosion behaviors of materials in bismuth. As stated in the introduction, "this report will present the details of the corrosion testing and the results obtained to date on materials tested under static conditions in bismuth media" (p. 1). This report includes tables, illustrations, and photographs.

Summary of miscellaneous updates related to the project. This includes information on the following. Simplified equations for modeling reactor conditions. Solubility tests involving thorium, bismuth, and protactinium. various other measurements and tests involving thorium, uranium, protactinium, bismuth, aluminum, and various other salts.

Summary of miscellaneous updates related to the project. This includes information on the following: the declassification of a relevant paper, solubility measurements, static corrosion tests, various other tests involving bismuth, magnesium, uranium, protactinium, and thorium.

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.

A study of the effects of gamma radiation with respect to the formation of nitro-hydrocarbons on the Purex and Redox systems shows that no appreciable formation of nitro-paraffins occurs.

The polymerization of vinyl monomers can be initiated by heat, ultraviolet radiation, and various catalysts. More recently, ionizing radiation has been shown to effectively initiate vinyl polymerization. However, polymerization in the solid state by ionizing radiation is not reported in the literature, although several papers have been published that describe briefly the thermal polymerization of divinyldiphenyl, Leuch's anhydride and in greater detail the peroxide catalyzed polymerization of acetaldehyde. The purpose of this note is to describe some experiments which demonstrate that crystalline acrylamide undergoes polymerization upon irradiation with γ-rays from an intense Co-60 source. Below its melting point the monomer shows little or no tendency to polymerize thermally.

A short review of the field of internal conversions. Isomeric transitions teach us many details of nuclear structure. In these studies electromagnetic theory is considered as a "tool". It is a quite quantitative tool in the case of "internal conversion" - a phenomenon which has been widely studied for many years. Internal conversion takes place in competition with γ-ray emission: a fraction of the nuclei in excited states decay by γ-ray emission, the remaining fraction by transferring the energy to K, or L, etc. electrons in the atomic shell. Thus the lifetime of an excited nuclear state depends on the internal conversion coefficient. As internal conversion must be expected to depend on the details of the electronic environment, the lifetime of an isomeric state depends on the state of chemical combination of the isomer - as was recently shown explicitly in one case, that of Te-99m(6hr.).