Twenty-seven tours were conducted during the past 6 months for a total of 825 students and teachers.

The Argonne National Laboratory conducts frequent tours of its unclassified facilities. Ninety-five tours for college and high school students and faculty were conducted during the past academic year for a total of 2,085 students and 141 faculty members representing 59 colleges and 54 high schools.

International Educational Programs

As part of its Atoms for Peace program, described earlier in this report, the Commission sponsored courses for foreign students as well as domestic students. These include the curricula of the International School of Nuclear Science and Engineering at Argonne National Laboratory and associated universities and training courses in the uses of radioisotopes at the Oak Ridge Institute of Nuclear Studies. Among other activities, the Commission is preparing to open additional courses at the Argonne School, is helping to arrange for entrance of foreign students into colleges and universities for courses related to nuclear training, and is working with the University of Puerto Rico to establish a Spanish-language Puerto Rico Nuclear Center.

Physical Research

Research in high energy and nuclear physics, chemistry and metallurgy continued during the January-June reporting period to contribute basic knowledge to help advance nuclear science and technology. In addition to sponsoring research in Federal laboratories and through contracts with university and industry organizations, the Commission contributed to the design and construction of the large experimental machines required for this research.

During the last 6 months, among other developments, the new high-flux Oak Ridge Research Reactor went critical; construction and design advanced rapidly on Brookhaven National Laboratory's Alternating Gradient Synchrotron; Argonne National Laboratory successfully tested a scale model magnet for its proton-synchrotron; intensive design studies were carried by the Midwestern Universities Research Association on a 15-billion electron volt accelerator using colliding beams in a fixed field alternating gradient configuration. Both new heavy-ion linear accelerators, at Berkeley, Calif., and at New Haven, Conn., were in operation. The nation's two most powerful accelerators, the Cosmotron and the Bevatron, went out of service because of breakdowns; the Bevatron is operating at less than maxi

mum efficiency while repairs are made; the Cosmotron will be shut down until about December 1958 while redesign and repairs are carried out.

In high energy physics research, among other recent projects, the properties of the recently identified particle, the neutrino, were further analyzed; the basic interactions of antiprotons with ordinary matter were studied; and tools and techniques were devised for advancing experiments with the so-called "strange" nuclear particles. Physicists continued to test the ramifications of the new Yang and Lee theory of nonconservation of parity in weak interactions.

In addition to chemical studies on special nuclear materials and on newly created elements at the upper end of the atomic table, chemical research has devised new methods of nuclear spectroscopy, and among other projects, has worked with molten salts. In metallurgy, studies supporting reactor work on liquid metal fuels were carried out, and oxidation, self-diffusion of metals, radiation effects, and powder metallurgy were investigated.

At the request of the Joint Committee on Atomic Energy, Subcommittee on Research and Development, the Commission presented testimony in public hearings during the first 2 weeks of February on the status and progress of research in physics, chemistry, metallurgy and materials, and on controlled thermonuclear reactions. The Commission also reviewed for the committee its administration of the total research program and gave estimates of requirements for financial support.

RESEARCH EQUIPMENT

The Oak Ridge Research Reactor, a high-flux instrument for research, was being tested during this reporting period, and two other major research machines, the heavy-ion accelerators at University of California Radiation Laboratory, at Berkeley, and Yale University were in service. Progress in design of new high energy accelerators by Argonne National Laboratory and by the Midwestern Universities Research Associations is described in this report, and details are given on construction of the alternating gradient synchrotron at Brookhaven National Laboratory. Causes of Bevatron and Cosmotron breakdowns, and plans for repairs, are reported.

Oak Ridge Research Reactor Critical

The Oak Ridge Research Reactor (ORR) went critical March 21. Authorized in 1954, the reactor has cost approximately $5 million. The reactor operated at its design power level of 20,000 kilowatts of

heat on May 29. It is a high flux reactor immersed in a pool and is moderated and cooled with demineralized water. The ORR is designed to operate at a power level of 20 to 30 thermal megawatts with an average flux greater than 1 x 101 neutrons per square centimeter. The reactor will be used primarily in reactor development, physical research, and biology and medicine programs, and for fundamental research and engineering studies on the effects of nuclear radiations on reactor materials, particularly fuel elements and structural materials.

Major emphasis in design was placed on flexibility of use to permit many kinds of experiments close to the reactor core, and on accessibility to the core itself for numerous experiments within the high flux region. Entire fuel systems as well as individual samples may be placed easily in the area of high flux.

Progress on Brookhaven Alternating Gradient Synchrotron

The building complex of the Alternating Gradient Synchrotron (AGS) was completed during the reporting period at Brookhaven National Laboratory. (See photograph.) Design of the AGS magnet has been completed, and testing of sample cores and design studies of other smaller magnet units are under way. The injection system of the AGS comprises a 50 million electron volt (Mev) linear accelerator, on which work is on schedule, and a 750 kilovolt (kv.) CockroftWalton preaccelerator which has been delivered and tested. Final design on power amplifiers for the AGS radiofrequency system has been established, and details on the synchrotron vacuum chamber have been largely completed.

The controls for the AGS will be designed at the time that the mode of desired operation of component systems has been established. At present, detailed circuit drawings have been prepared for the main. synchrotron water control system and a communications system. Preliminary work has started on the vacuum control system.

Authorized under the Second Independent Offices Appropriation Act of 1954, construction began on the AGS in March 1954.35 It will be an enormous machine, the magnet ring that controls the particle beam within the vacuum chamber has a diameter of 842 feet, and a circumference of about a half-mile. Protons will be injected into the vacuum chamber with velocities of some 50 Mev and, in the course of some 300,000 revolutions, are expected to attain a maximum energy of 25 to 30 billion electron volts (Bev). During these revolu

a See p. 34, Fourteenth Semiannual Report to Congress (January-June 1953), and p. 37, Fifteenth Semiannual Report to Congress (July-December 1953).

Brookhaven's AGS accelerator. The photograph above is an aerial view of the 30 billion electron volt Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratory, Upton, Long Island, N. Y., now under construction and expected to become operational in 1960.

The large ring in the upper center portion of the photograph is the half-mile track of the AGS magnet enclosure covered with earth. At the extreme left of the magnet ring is the building that will house the 50 Mev linear accelerator injector for the machine. On the right side of the ring is the Target Building and Experimental Areas. The large building to the right is the Service Building. Around the magnet ring are five air-conditioned stations necessary to provide the constant temperatures for the machine's operation.

At the top of the photograph is the AGS diffusion basin for the machine cool

tions, the particles must be maintained in a circuit within lateral displacements of the order of 1% inch from the ideal orbit. Tolerances of the order of about 0.02 inch over the distance of one-half mile for the placement of magnets have required extremely exacting engineering and design work.

Building progress. With the buildings for the accelerator completed, auxiliary building services were installed, fabrication of magnets and the linear accelerator was begun and a large part of the detailed design of other components was finished.

Supplementary contracts were awarded for the building complex, including installation of equipment and piping in the pump room; excavation of a suitable foundation for the main magnet power supply, and completion of the power room wing of the synchrotron service building. Sections of the Target Building and Linac Building are now occupied, and machine equipment was moved into position.

The section of the synchrotron ring which passes through the Target Building will be covered with 14,000 tons of high density concrete shielding blocks. The pouring of these blocks is nearing completion.

Progress on magnets. With design of the AGS magnet completed, a contract for fabrication of the cores was awarded to Baldwin-LimaHamilton Corp. and a contract for the magnet exciting coils was awarded to National Coil Co. After intensive tooling preparations, Baldwin-Lima-Hamilton ordered its steel requirements from Allegheny-Ludlum Steel Corp., and at present has 1,000 tons on hand. The average magnetic properties of this material have been tested. and will be satisfactory for use in the AGS magnet.

Before a production release can be given for the 240 magnet cores needed for the synchrotron, the contract requires that three pilot units be assembled and submitted to the Laboratory for measurement and approval. Measurements on the first unit completed indicated that, while the core did not meet the specifications in all respects, it came encouragingly close. The experience gained on core No. 1 resulted in some modifications to the fabrication plan, and pilot core

ing system. At the lower right half of the photograph is the Cosmotron External Beam Trap Dike. The Cosmotron Building which houses the Cosmotron and the Nuclear Engineering Department are in the lower center of the photograph. The diameter of the Cosmotron is 70 feet, while the diameter of the AGS is 842. The photograph provides a dramatic comparison between the sizes of the new AGS and what is presently the second highest energy accelerator in the United States, the 3.2 Bev Cosmotron.