INTER ACTIONS 1997

Not in My Football Field

by Ed Creutz

(talk given at the Saxonburg Cyclotron 50th reunion)

Looking over the plans. Left to right: Ed C. Creutz (Physics), Carl C. Monrad (Head, Chemical Engineering), Robert E. Doherty (President, Carnegie Tech), Webster N. Jones, (Dean, College of Engineering and Science), R.F. Mehl (Head, Metallurgical Engineering),John C. Warner (Head, Chemistry)

The year 1996 is the right time for a 50th anniversary of the start of the nuclear physics at Carnegie Institute of Technology, for it was early 1946 that Fred Seitz, then head of the department of physics, began to plan for a program in that rapidly growing field.

Only 10 years earlier, important physicists, including Ed Condon, predicted that the excitement of physics was on the wane, since the two great theories of relativity and quantum mechanics might clear up all the basic problems, even though the two theories could not yet be combined to fully describe gravitation, nor can they even today.

But during the next few years new data from cosmic rays and from laboratory-based accelerators indicated that there was more to the structures of matter than meets the eye, even when the eye is aided by precision atomic and nuclear spectroscopy.

With the discovery of fission by Hahn and Strassman in Germany in 1939, and the increasing use of accelerators, a significant fraction of the world's physicists turned their attention to the nucleus.

Immanuel Estermann, whose seminal work with Otto Stern had used molecular beams to measure nuclear spins, was the only one at Tech who had chipped away to see what was underneath the electron shells of atoms. And Fred, besides his own essential work on the Manhattan Project, foresaw the growth of nuclear physics as a significant part of the education of physicists. He obtained the support of Robert Doherty, president of Carnegie Tech, to move decisively into the new field. He hired Bert Corben, who had done early work on looking for a unified field theory, and experimentalists Jack Fox, Roger Sutton and me.

In 1946 many nuclear physicists thought the best way to tackle the questions of nuclear structure was to study in detail the energy levels of a wide variety of nuclei. A number of moderate energy electrostatic accelerators were to be under construction for this purpose, and we at first considered a rather modest model, of 15 or so Mev.

But great excitement was building because of the discovery of mesons in the cosmic rays as a possible key to understanding nuclear structure. The mu meson didn't really seem to fit current nuclear ideas, since it had the wrong spin and a strange mass, but that was the only meson clearly identified at that time.

Fred went to the Office of Research and Invention of the Navy, soon renamed the Office of Naval Research, whose programs in solid state physics Fred had helped considerably to develop, and asked for funding for a synchro-cyclotron to accelerate protons. In quick succession Fred secured promises of support from the Buhl Foundation, a local philanthropical group, and from Westinghouse. Westinghouse offered a gift of the former KDKA transmitter building and 50 acres of land at Saxonburg.

We planned a program with some first-class graduate students, including especially Martyn Foss, who had been a key member of the staffs at the Metallurgical Laboratory at Chicago and at Los Alamos during the war, Dave Rose, Dave Brower, Rolf Winter and others. We found an excellent mechanical designer, Henry Berman, and an outstanding draftsperson, Margaret Trimble, now Peg Lees. Later an electrical engineer, Dick Ankersen, joined us.

The magnet designed by Martyn Foss was indeed unique. His method was to shape the pole pieces very carefully to get the most of every pound of steel, and to design very compact coils. Our closest competitors for big cyclotrons those days were the University of Chicago and Columbia University. Foss' design used 1,500 tons of steel, while those of our competitors used upwards of 2,000 tons and produced protons of no higher energy. Foss also was principally responsible for the radio-frequency oscillator system and other key components.

The precision required by Foss' magnet design led to some interesting adventures. We asked that the pole pieces be kept within tolerance of five thousandths of an inch, and that the steel be free from slag and other imperfections. When the machining was in its final stages, a small region of porosity was discovered. We decided that the porous material could be drilled out and the cavity filled with a steel plug. A plug was prepared, cooled in liquid nitrogen to shrink it slightly, and inserted in the cavity. To ensure that it was well seated, a husky man stood above it, armed with a sledge hammer. I couldn't avoid wondering what would happen if he missed his target, and made a new dent in the pole piece. He did. But fortunately the scar could be machined way.

Two very important people were Jim Thompson and Homer Collins. I don't know whether they would prefer being called precision machinists or design engineers. They were clearly both. Many details of the cyclotron that required special excellence were due to their careful work.

We therefore decided to have the coils wound at the Brooklyn Navy Yard. They were completed in early spring, and the plan was to ship them by barge from New York to the Erie Canal, through the Great Lakes, to Lake Erie, and truck them to Saxonburg. Unfortunately the spring was late and the Erie Canal was frozen over when the coils were ready to be shipped.

We had originally contemplated shipping the coils by rail, but the only available flat car in the country, of sufficient size and load-carrying capacity, was tied up for six months. Because of the unusually wide load, in excess of 20 feet, the railroad surveyed the route and ground only one interference, where a sign post intruded on our required right-of-way by 3/8 inch. This was corrected by a hacksaw. But the delay in obtaining the flat car was intolerable.

We therefore reluctantly decided to ship them by ocean barge from New York, around Florida to New Orleans. There they would be transferred to a river barge, a different kind of animal, brought up the Mississippi River to the Allegheny River, then to Freeport, a site about 20 miles from Saxonburg, from where they would be trucked to Saxonburg.

Before Westinghouse so generously offered us the former KDKA transmitter site at Saxonburg, we of course thought a lot about where to build the cyclotron. Attractive to us was a football practice field on campus near the physics department.

Before embarking on the cyclotron project, the dean of engineering and science called a meeting of the faculty to get their views on such a new and large undertaking. Most faculty supported the new plan. More cautious were some of the chemists, who felt the school was not ready to jump into big science. It was clear that, to some, a football field was a more welcome neighbor than a cyclotron. Thus the gift of the Saxonburg site was most welcome. One chemist, Truman Kohman, later used the cyclotron in his discovery of aluminum 26, now an important tool for studying the history of the solar nebula, from which the planets formed.

Before the cyclotron was ready we made use of the University of Pittsburgh 12 Mev deuteron cyclotron, thanks to Alex Allen. Bernie Cohen was our first student to do his thesis work there. Other graduate students helped in our cyclotron design work. Rolf Winter worked on precision test of our unusual magnet.

The first published paper using the cyclotron beam was that by Don Grove and Jack Fox, showing the relationship between mass and velocity for relativistic protons. Although this was well known for electrons, and agreed with Einstein's theory, it had not been directly measured for heavier particles. Major topics to which the staff and students contributed were proton-proton and neutron-proton scattering, as well as meson behavior, including mesic atoms, those strange beasts where an electron in an atom is replaced by a meson. Sho Koo Kao specialized in using the new photographic plates to follow the paths of mesons and observe their collisions with nuclei. He made for me a 20,000 times enlargement of one such path, which still decorates a wall of my living room.

As new staff joined the department, several became interested in the cyclotron work. Julius Ashkin extended his mostly theoretical work to experiments. Lincoln Wolfenstein, who may possibly finally have his long-sought neutrino mass, was an important addition. Sergio de Benedetti came to us from Oak Ridge, and brought his technique of measuring time to a billionth of a second, and held classes in his home on the new field of quantum-electrodynamics.

Others who participated in the nuclear program were Donatella Baroncini and Felix Adler. Felix was the son of Freidrich Adler, whose opposition to World War I had led to his fatal shooting of the Prime Minister of Austria in 1916. It is interesting to speculate what emotion Felix must have felt in helping to develop a new world of international science shortly after the second world war.

Gian-Carlo Wick, who came to us in 1950, was one of the scientists at Berkeley who refused to sign a special University of California loyalty oath. He explained that he had already signed a State Oath, and felt that further oaths were not of deep significance after the first.

Visiting professors who came for academic year periods during this time included Christian Becker and Siegfried Flugge from Germany.

Becker liked to say that his principal contribution to physics was that he invented Eugene Wigner, who had indeed been Becker's student. Flugge was the first German physicist to calculate closely the critical mass of an assembly of uranium 235.

When the machine was nearly ready, Charles Wilson, the Secretary of Defense, visited. After I carefully explained to him what the cyclotron was and why it was important, he leaned back in his chair, opened his coat, and said, "See this shirt. It's nylon." I guess he wanted to show that he too was participating in the new science. I had expected him to ask if fast protons would make good bullets. In fairness I must say that Wilson had come to Pittsburgh for other purposes and the cyclotron visit was an afterthought.

Leo Szilard visited shortly after the massive concrete shield was assembled. He shook his head and said, "Creutz, you have built the tomb of science." But perhaps phoenix-like, after our unfortunate loss of Seitz and his principal co-workers in solid-state physics, there arose a new era of nuclear physics in Pittsburgh.
Saxonburg is the site where the Roebling brothers assembled the cables for the Brooklyn Bridge. The main street was originally a rope walk where strands of rope or steel were laid out and twisted by machine to make heavy cables.

Saxonburg was known for a product that, in its own way was almost as potent as the cyclotron. This was grown by the owner of the Saxonburg Hotel and was his own special brand of horseradish. I once had a dinner meeting with some non-physics Carnegie Tech staff at the hotel before we visited the cyclotron. Their memories later were filled at least as much by the Saxonburg horseradish as by the Saxonburg protons.

You have noticed that I mentioned several people by name tonight. Many other people who made truly significant contributions to the cyclotron program I have not mentioned. Please don't think that your work was not appreciated.

The true monument to all of you and to the loved ones who have left us is the work you did together, and not just the few things you have heard about today. Thank you all for being part of it.

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