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.

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.

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.

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 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.

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.).

By heating the normally cool areas of graphite to temperatures of 200°C or higher, it is evident that a substantial portion of the energy stored will be released. The physical dimension change which is associated with the radiation damage of graphite has been noted to partially recover under laboratory conditions when this amount of stored energy is released. This latter phenomenon is of prime interest in this operation. If a dimension recovery is noted on the gross structure, a solution to certain formidable operating problems may have been achieved.

In the memorandum entitled "Stored Energy in BNL Reactor Graphite", dated February 25, 1953, there is described an experiment conducted by Gurinsky's group to determine the energy per gram of irradiated graphite released in a 200°C anneal. Similar experiments were subsequently conducted by W. Kosiba, differing from the original in two particulars: a) Instead of two graphite samples, one normal, and one irradiated, Kosiba used only an irradiated sample which he heated first to release the stored energy, and then again after the energy was released. In this way, he obtained time against temperature curves for both normal and irradiated graphite from the same sample. (These curves are graphed for each run in Figs. 1 thru 5.) b) The vycor tubing used in the original experiment was not used by Kosiba. Five runs of this experiment were selected, Runs 4P, 13, 36, and 40 at furnace temperatures of 200°C, and Run 45 at a furnace temperature of 400°C.

Radiation damage to graphite has several consequences of practical importance. The growth of graphite under radiation (Wigner's disease) in production reactors has always been a serious concern. The thermal conductivity of graphite decreases greatly with time of irradiation and is important in long range studies of reactor temperature problems.

The rotary rain indicator, an electrical device for recording the time of beginning and ending of periods of precipitation, was developed at the Brookhaven National Laboratory Meteorology Group and has operated successfully for eight months. Its sensitive element consists of a rotating grid whose circuit may be completed by a drop of water.

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.

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.

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.

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.

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 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.

Selective incorporation of radioactivity from proteins of labeled chorio-allantoic grafts of adult chicken tissues into proteins of homologous tissues of host chick embryos.

A series of measurements was performed to investigate the gamma ray spectra, in the region from about 100 kev to about 3 Mev, resulting from the capture of thermal neutrons in a number of elements. The purpose of the experiment was to supplement the high energy capture gamma ray data in order to remove some of the ambiguities from the proposed energy level schemes and to obtain information for the Shielding Group of Brookhaven National Laboratory on elements normally found in reactors.

The proton beam in the Cosmotron is accelerated to an energy of 2.3 billion electron volts by a radio frequency voltage which is impressed across an insulated gap in the ferrite loaded accelerating cavity of the vacuum chamber. To maintain a constant orbit radius as the beam is accelerated, the frequency of the accelerating voltage must increase from the initial value of 370 kc/sec to 4200 kc/sec during the one second magnet pulse. Over the entire 11:1 frequency range, a minimum gap voltage of 2000 volts rms must be maintained. At every instant throughout the magnet pulse, the frequency of this voltage must be a predetermined function of the magnet field to a high degree of accuracy. Frequency errors greater than about .2 percent result in loss of beam due to excessive radius changes. Smaller errors than this however, can excite fatal phase oscillations in the beam if they occur rapidly. As little as .005 percent frequency modulation can result in total beam loss if it occurs at a rate of several kc/sec, where the beam is most sensitive to such disturbances.

A study has been made of entrainment generation in a submerged coil evaporator and a vertical-tube natural circulation evaporator. Both evaporators generated about the same amount of entrainment at comparable boil-up rates. The decontamination efficiency of a submerged coil evaporator is correlated to the boil-up rate. The efficiency of a bubble-cap column, a Raschig ring packed tower, and a glass wool packed tower as de-entrainment devices was studied, the glass wool packed tower proving to be the most effective.

A series of measurements of ε in slightly enriched uranium, light water lattices is presently under way at Brookhaven. Figure 1 shows ε as a function of water-to-metal ratio for .600" diameter rods, of 1.3% enrichment. Because of interaction between neighboring groups of rods, ε increases rapidly as the water-to-metal ratio decreases.

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.