Atomic Energy

ATLANTIC

May 1948

on the World today

IN fundamental physical science, the most significant advance in a decade was announced in March. This was the artificial production of mesons, nuclear particles hitherto found only in the mysterious cosmic rays which constantly bombard the earth from some unknown origin in outer space.

The work was done in the University of California’s Radiation Laboratory, of which Dr. Ernest O. Lawrence — Nobel Prize winner for the invention of the cyclotron — is director. Dr. Eugene Gardner, research physicist of the laboratory, and Dr. C. M. G. Lattes, Brazilian scientist from the University of São Paulo, performed the experiments as part of research being carried on for the United States Atomic Energy Commission.

Exploring the subnuclear processes

Alpha particles — the nuclei of helium atoms, consisting of two protons and two neutrons — were hurled with an energy of 380 million electron volts against targets of carbon, beryllium, or other materials in the 4000-ton cyclotron of the Radiation Laboratory. Photographic emulsion plates placed near the target materials recorded the tracks of the mesons, which came into being when one of the protons of an alpha particle — temporarily possessed of more than its one-quarter average share of the bombarding voltage — encountered a proton of the target material at a moment when that proton was moving toward it, so that there was a compounding of energy amounting to about 390 million electron volts. This is apparently about the threshold for the release of mesons.

When this combination of circumstances occurred, one of the meeting protons was converted into a neutron and a negative meson. The mesons thus observed have an energy of only about 4 million electron volts — extremely low for a meson, but enough to enable it to travel some nine inches in a vacuum from its origin in the target to its destination in the photographic emulsion.

Techniques stemming from earlier research at the University of Bristol, England, and from field studies in the Pyrenees and the Andes, where observers hitherto have carried their equipment to detect the mesons resulting in nature from cosmic-ray bombardment, were utilized in the Berkeley experiments.

There have been dire predictions from laymen about the possibility of bombs even more titanic than those now known. Hence it should bo emphasized that the Berkeley announcement by Professor Lawrence and the Atomic Energy Commission stressed that no practical applications of the artificial production of mesons, such as fission, arc now in sight.

The significance of the accomplishment rests in the aid which it promises toward further understanding of the mysterious subnuelear processes — the force, for instance, which is both unknown and unlike any known force, that holds the nucleus of the atom together.

The Berkeley cyclotron is the most powerful in existence, and it possesses just barely enough power to produce mesons of low energy. Still more powerful instruments must be built, Dr. Lawrence declared, to produce mesons for exploration of why the repulsions between two positively charged particles — the protons of the helium nucleus, for example — do not rend the nucleus apart.

The meson which has been produced so far exists for only an almost unimaginably small fraction of a second, leaving as record in a photographic emulsion a track about four one-hundredths of an inch in length made by electrons which it knocks off the nuclei of atoms in the emulsion. To bring the tracks into view, the developed emulsion must be examined under a 600-power microscope. And this meson is but one of three types of mesons whose existence has been determined in nature from observations on cosmic rays. That there are probably others is current belief.

For research in cancer

The Atomic Energy Commission will spend some $3,000,000 in expanding its support of nation-wide cancer research. Radioisotopes useful in studies of the nature, diagnosis, and treatment of cancer are to be made available without charge except for handling and transportation. On April 1, iodine-131, phosphorus-32, and sodium-24 were put on the “free list” to qualified scientists and physicians. Other useful available isotopes will be added as soon as possible.

During 1947 more than 1600 shipments of radioisotopes were made to qualified users in the United States; and since President Truman’s announcement, on September 3, of the program of foreign distribution, forty-four shipments have gone to individuals and research groups in eight foreign countries — Australia, Argentina, the United Kingdom, Denmark, Peru, Canada, Italy, and Sweden. A number of other nations have made the necessary arrangements to obtain the artificially radioactive materials from the uranium chain-reacting pile at Oak Ridge, in furtherance of an important program of international coöperation and good will.

For leukemia and the thyroid gland

By far the most numerous among the foreign shipments of isotopes have been those of phosphorus-32 and iodine-131. Phosphorus-32 is used mainly in medical therapy for treatment of serious blood diseases, including leukemia; and iodine-131 is invaluable in the study and treatment of disorders of the thyroid gland, which absorbs the radioactive isotope especially.

Isotopes of carbon, sulphur, zinc, iron, and cobalt have gone to other foreign research groups working in chemistry, physics, biochemistry, physiology, and botany. Under the agreement by which other nations receive these materials from the United States, reports on the results of investigations are to be made at six-month intervals.

Radioisotopes are generally regarded as the most valuable new research tool since the invention of the microscope. In its third semiannual report the Atomic Energy Commission said: “If the development of atomic energy had produced nothing else, its cost would undoubtedly have been balanced within a few years by the gains in knowledge that the nation is making with isotopes in medicine, chemistry, industry, and agriculture.” The Commission regards it as of vital importance to make isotopes available to all qualified users in quantities as large as can be profitably used, in variety as great as can be developed, and at the lowest possible cost.

Broadening education

The Atomic Energy Commission is setting up and financing a training program to be administered for the Commission by the National Research Council of the National Academy of Sciences. Fellowships are to be distributed among doctors of medicine, doctors of philosophy in the biological sciences, and bachelors of arts or science, who will receive training in health physics — the medical specialization concerned with the protection ol people from radiation and radioactive materials.

Facilities to provide training for fellows are being established in North Carolina, New York, Texas, Colorado, California, and Oregon, and are expected to be ready in time for the academic year 1948-1949. Some will be operated by individual educational institutions; others will be coöperatively operated by two or more institutions. Joint participation is seen as valuable in permitting the integration of medical and biological training with physics, chemistry, and mathematics.

A complementary research fellowship program in the physical sciences basic to atomic research and development has been established, with an initial allocation of $1,500,000 from the Commission. Physics, chemistry, metallurgy, mathematics, geology, and astrophysics are examples of the fields involved, and indicate the ramifications of the nation’s atomic energy enterprise.

In addition to making radioisotopes more accessible for the treatment of cancer patients, the Commission will bring selected patients and investigators to its research centers for study with isotopes of such short periods of activity that they cannot be shipped away—minutes, for example. Physicians and scientists will also have the opportunity for investigation and treatment with direct radiation from high-voltage cyclotrons and other atomic particle accelerators. Hospitalization will be provided at or near laboratory sites for a limited number of patients selected by investigators studying certain types of tumors.

The series of studies will begin at Oak Ridge Hospital, where eight or ten beds and the necessary research facilities will soon become available. Similar programs near Argonne National Laboratory, Brookhaven National Laboratory, and Los Alamos Laboratory will be inaugurated during the next two years as hospital facilities are completed.

Weapons

Despite its promising nonmilitary accomplishments, the Commission’s primary responsibility remains production of atomic weapons. A longrange research program has been rounded out. The Los Alamos Laboratory — center of the work — has been restabilized, and the Commission’s intention is that it shall be operated “in the spiril of a permanent research center.”

Expansion of production facilities, and development and standardization of new designs and of procedures for handling atomic weapons, are the primary objectives of the weapons program. Testing activities are being carried on at the Eniwetok Atoll proving ground, and air and shipping authorities have been notified that a danger area of some 30,000 square miles surrounding the atoll will exist throughout this year.

Liaison between the Armed Forces and the Commission, whose mutual interests extend over an extremely broad range of subjects, has been good. Donald F. Carpenter, vice-president of the Remington Arms Company, has been appointed civilian chairman of the Military Liaison Committee by Secretary Forrestal, and Major General Kenneth D. Nichols, former engineer for the Manhattan District, has succeeded Lieutenant General Leslie R. Groves, who retired February 29, as head of the Armed Forces Special Weapons Project and as member of the Military Liaison Committee.

Security provisions—both those involving special physical precautions and those implied in loyalty reviews—have been further strengthened. These measures are of course of vital importance in a world where the political situation between great nations is highly charged.

They are underlined by the fact that General Andrew G. L. McNaughton, head of Canada’s delegation to the United Nations, speaking before the New York Herald Tribune Forum for high schools, referred to the United States as “the only nation now in possession of atomic bombs, at least on any scale which would suffice to make atomic war,” and by the fact that in an address before the Oak Ridge Education Association Commissioner Sumner T. Pike, characterizing the weapon as “a terrible fact,” said: “At the moment, we probably have a monopoly in this field.”