High production rates of a number of radioisotopes have been obtained with the 86-inch cyclotron, including the following: beryllium 7, fluorine 18, manganese 54, cobalt 57, zirconium 65, cadmium 109, arsenic 74, and gallium 67.

The commercial processing and distribution of cyclotron-produced radioisotopes by the Oak Ridge National Laboratory have been discontinued. The isotopes produced in the cyclotron in the future will be processed and distributed through industrial laboratories. The 86-inch cyclotron will continue to be available, however, to any qualified group for service bombardments (without processing) where the machine offers unique advantages and can be used without interference with the research program.

Neutron Physics

For a number of years, the Neutron Cross Section Compilation Group at Brookhaven has collected and evaluated the numerous cross sections that are important to nuclear theory and reactor development. The results of this work have appeared in the cross section compilation AECU-2040, published in 1952, together with various supplements. A new edition cf the compilation, containing many newly-declassified results regarding fissionable isotopes was prepared this year and distributed at the Geneva Conference on the Peaceful Uses of Atomic Energy. This new edition, BNL-325, also contains data on resonance parameters and inelastic scattering, which did not appear in AECU-2040. (For sale by Office of Technical Services, Department of Commerce, Washington 25, D. C.)

Because of the cooperation of other countries, it was possible to prepare in advance an addendum to BNL-325, containing cross sections to be presented at the International Conference on the Peaceful Uses of Atomic Energy, so that the addendum was available for distribution at Geneva. At the Geneva Conference, scientists from a number of countries, including the Union of Soviet Socialist Republics, combined their results to obtain a set of world's average cross sections of the fissionable isotopes uranium 233, uranium 235, and plutonium 239. The establishment of these cross sections is an example of the cooperation exhibited at Geneva, and will be of value in unifying reactor calculations throughout the world.

Spins and Magnetic Moments of Radioactice Materials

The technique of studying magnetic deflection of fine beams of atoms has been so perfected that it has become possible to determine the mag

netic properties of the nucleus even for radioactive atoms. Among the determinable properties of nuclei are the strengths of their spins and their strengths as magnets. These can be determined in a socalled "atomic beam" apparatus by observing the deflections in magnetic and radio fields of a beam of atoms emerging from a hot furnace. Such results for radioactive nuclei are of special interest because the spin is one of the quantities determining the probability of radioactive disintegration.

An apparatus has been built by Argonne National Laboratory which has so far obtained data on 39 different materials at each of 20 values of the energy below 1.7 million electron volts, scattering at five different angles being measured simultaneously. The data are being computed by the AVIDAC for analysis.

Angular Distribution of Scattered Neutrons of Medium Energy

Neutrons, upon striking other nuclei, scatter in various directions. By determining the numbers scattered to different angles away from the original direction, scientists can obtain some insight into the mechanics of the collision process. The distribution is of importance in fast reactors, because if the scattering is predominantly forward, the neutrons are held back less effectively by such collisions than they would be if they were uniformly scattered in all directions.

An apparatus has been built by Argonne National Laboratory to collect a large amount of such information, using neutrons at many energies up to an energy of 1.7 million electron volts and with a large variety of scattering materials.

Electromagnetic Isotope Separation

Techniques and equipment necessary for the production of extremely high-purity samples of certain isotopes have been developed, and gram quantities of chromium 52, iron 56, lithium 6, and lithium 7, containing only one part isotopic contaminant in 100,000 parts of the desired isotope, have been produced in the ORNL electromagnetic separators.

PROJECT SHERWOOD-CONTROLLED THERMONUCLEAR RESEARCH

During the Geneva Conference, Chairman Strauss announced that the United States has underway a long-range research program to develop the controlled release of energy from atomic fusion. It was emphasized at Geneva and in all subsequent discussions that the program called Project Sherwood-is considered a very long-range effort.

The major research effort in this field is being carried out at AEC laboratories operated by the University of California at Los Alamos, N. Mex., and Livermore, Calif.; and at Princeton University. In addition, there are smaller projects at Oak Ridge, Tenn., and New York University. The programs at Los Alamos and Princeton began in 1951 as experiments to test ideas for the containment and control of thermonuclear combustion at temperatures comparable to those of the sun. Previously such temperatures have been achieved on earth only in atomic explosions. Shortly thereafter, a third program was initiated at Livermore, Calif., by the University of California Radiation Laboratory.

The possibility of tapping this source of energy has long been intriging to scientists. Some of the problems to be overcome, however, are extremely difficult. One problem is that of heating an appropriate nuclear material (such as deuterium) to temperatures of several hundred million degrees and of confining it at that temperature for a sufficiently long period of time to allow an appreciable portion of the nuclei to fuse together, with the consequent release of energy in the form of energetic neutrons, charged particles and gamma radiation. Once this temperature has been achieved the main problem would be that of getting enough thermonuclear energy back from the material to repay the power used to achieve and maintain the high temperature.

Although the level of research has been greatly expanded since 1951, the program is still in the research stage. Many years of intensive theoretical and experimental effort will be required before the first prototype of an operating thermonuclear machine is developed.

CHEMISTRY

Rare-Earth Chemistry

Application of a liquid-liquid (tributyl phosphate-nitric acid) extraction process developed at the Oak Ridge National Laboratory for the separation of rare earths has greatly facilitated the production of 500 grams of the extremely rare element, europium. This is the largest known single quantity of this element, which is of interest because of its possible utilization in reactor control rods.

The Ames Laboratory isolated in its rare earth pilot plant more than 150 pounds of pure yttrium oxide which is being converted to the metal. This metal is presently of considerable interest in reactor development as are other rare earth metals and compounds.

Several industrial companies have shown interest in the production of rare earths on a pilot plant scale and are planning to use essentially the Ames Laboratory design and procedures.

Research at Ames on the separation of rare earths by ion exchange has been extended to new complexing agents which appear to be able to separate yttrium from other rare earths more readily.

Synthesis of Coffinite

Coffinite, since its discovery in 1951, has become recognized as a major uranium mineral of the Colorado Plateau. Its composition is believed to be USiO4, though the inability to obtain pure samples has prevented confirmation of the formula. Argonne National Laboratory scientists have now succeeded in synthesizing coffinite by a hydrothermal method, and its properties are under investigation. It is hoped that a study of the conditions required for the formation of coffinite in the laboratory will provide an explanation for its occurrence in nature and thus assist in the search for the mineral.

Elements 99 and 100

Through the cooperative work of the nuclear chemists of the University of California Radiation Laboratory, the Argonne National Laboratory, and the Los Alamos Scientific Laboratory, two new elements were identified in the debris of the "Mike" thermonuclear explosion which occurred in the Pacific Proving Grounds in November 1952. These new elements have the atomic numbers 99 and 100. Following their discovery the elements were produced and identified by laboratory methods. Earlier this year, element 101 was identified at the University of California Radiation Laboratory, Berkeley (see p. 51, Seventeenth Semiannual Report to Congress, January-June, 1955).

It has been suggested that element 99 be given the name Einsteinium (Symbol E) and element 100, the name Fermium (Symbol Fm) in honor of the important contributions of Albert Einstein and Enrico Fermi to nuclear science.

Inhibition of Corrosion of Steel in Water by Pertechnetate Ion

A number of agents for lessening the corrosion of steel have long been known, a typical one being the chromate ion. Oak Ridge National Laboratory tested the corrosion-inhibiting characteristics of an ion of a technetium compound-the pertechnetate ion-with the resulting discovery that it is by far the most effective ion of this type. About 30 parts per million in water suffice to protect ordinary carbon steel completely from corrosion by water.

2 See page 41, Sixteenth Semiannual Report to Congress (January-June 1954) for description of laboratory method of production.

Since technetium does not occur in nature, but is produced in nuclear reactors, its high cost will probably preclude extensive practical applications. Nevertheless, continuing research with pertechnetate as an inhibitor is advancing knowledge of the phenomena of inhibition and of the corrosion process itself.

Slurries in Liquid Metals as Possible Reactor Fuels

A program has been initiated at Argonne National Laboratory to investigate suspensions of uranium compounds in liquid metals with the goal of developing a suitable uranium or plutonium slurry for use as power reactor fuel. It has now been found that uranium dioxide which has been treated with hydrogen at 500° C can be readily suspended in liquid sodium-potassium alloy at room temperature and that it does not cake after prolonged settling. From the results obtained in a circulating loop, it may be concluded that a slurry containing 10 percent of uranium dioxide by volume can be easily maintained at uniform concentration. The slurry promises to be a useful reactor fuel.

Detecting the Free Neutrino

The neutrino is a hypothetical particle predicted to balance the energy and momentum in certain nuclear reactions. It has never yet been directly observed. Research at Brookhaven envisages the possibility of detecting the free neutrino by radiochemical methods.

The idea is to expose the chlorine nuclei in a large mass of carbon tetrachloride (about 1,000 gals.) to an intense flux of neutrinos from a nuclear reactor and to detect radioactive argon 37 produced by the capture of neutrinos in chlorine 37 nuclei. The technique has been refined to the point where neutrinos of the theoretically predicted properties could be detected-if they exist-and an experiment is being set up at one of the Savannah River reactors. A different experiment by Los Alamos scientists is aimed at detecting the neutrino by physical methods.3

Isotopic Labelling by Nuclear Recoil

Brookhaven National Laboratory has been conducting research on the chemical reactions of the "hot atoms" which recoil after a nuclear transformation. An outgrowth of this work has been the finding that these reactions can be used for labelling organic compounds with

See page 31, Fifteenth Semiannual Report to Congress (July-December 1953) and page 36. Sixteenth Semiannual Report to Congress (January-June 1954) for explanation of "free neutrino" and the Los Alamos Experiment.