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  • The Beginning Under the Lonely Hill

    by E. M. Rowe

    "Old men forget; yet all shall be forgot, But he'll remember, with advantages, What feats he did that day..." Shakespeare, King Henry V

        In 1965, two events took place that were to have far reaching effects on the then infant field of Synchrotron Radiation Research. They were the formation of a subcommittee of the Solid State Panel of The National Academy of Sciences charged with evaluating the utility of synchrotron radiation for condensed matter research, and the beginning at the laboratory of the Midwestern Universities Research Association (MURA) of a project that resulted in the construction of a small (240 MeV) electron storage ring that became known as Tantalus.

    At the time, the groups participating in these events were totally unaware of each other. The MURA group, after the failure in early 1964 of its hopes to build a very high current (30 uA, time average), 12.5 GeV proton accelerator, was still interested in pursuing fundamental studies of particle accelerators. The unexpected phenomena observed at other laboratories that had built electron storage rings at that time, plus the possession of a suitable injector made the construction of an electron-positron storage ring for such studies an attractive and exciting prospect. The Solid State Panel Subcommittee, on the other hand, was interested, initially, only in the possible uses of synchrotron radiation, not in possible sources.


    Ed Rowe and the Tantalus storage ring
    Ed Rowe and the Tantalus storage ring (click for larger image)


        In late 1965, the late Professor P. Gerald Kruger of the University of Illinois, who was a member of the Subcommittee and who also had been the first director of the MURA laboratory, learned of the Tantalus project. He brought this to the attention of the Subcommittee, in particular to the chairman, Professor Frederick C. Brown, also of the University of Illinois. Professor Brown then contacted me, since I was the Tantalus project leader, for information. I was aware that synchrotron radiation had been used previously at the Cambridge Electron Accelerator (CEA) to measure the out gassing rates of various materials that were being considered for use in the vacuum chambers of a number of electron accelerators being planned at that time, so the possible use of the radiation from Tantalus for other condensed matter researches did not come as a great surprise. Thus, a dialog between the members of the two groups was begun.

        In March, 1966, the Subcommittee completed its report, giving a somewhat qualified endorsement to the notion that synchrotron radiation would be a useful research tool, and submitted it to the Panel. However, in the meantime, Fred Brown's interest in the possibility of access to the synchrotron radiation from Tantalus had become more than academic. He asked if it might be possible to connect an "experimental" beam line to the machine when it became operational. After a short discussion, I agreed, and, with the enthusiastic blessings of Dr. Frederick E. Mills, then the MURA laboratory director, we made the necessary modification to the ring vacuum chamber. This consisted of obtaining a straight through valve, at a cost of $750, and mounting it on an already existing beam viewing port on the vacuum chamber. Things were much simpler in those days. The worst problem we had was to find the $750!

        Word of Fred Brown's plans got around, and soon there were inquiries from other members of the condensed matter community, notably Professors Hellmut Fritzsche of the University of Chicago and David Lynch of Iowa State University, as to the possibility of access to the ring. Again, after brief negotiations (we who were building the ring still thought we would be the principal users of it), Hellmut and David started to prepare their experiments and I started to look for another $750 for a valve for the only other beam viewing port on the ring. Things were getting a bit tight with three users but only two ports, but we thought that they would make only a minor perturbation in the planned use of the ring. After all, these users would only do a few experiments from time to time so they wouldn't interfere with our plans, would they?

        Completion of the ring was scheduled for mid 1967, which was also the expected time for the final disbanding of the MURA organization and the end of AEC support for the Tantalus construction program. The construction program was delayed, but the end of MURA was not. In June 1967, The University of Wisconsin, a member of the MURA organization, acquired the MURA laboratory and hired as many of the staff as wished to stay on to form the nucleus of a new entity: The Physical Sciences Laboratory of The University of Wisconsin, Madison. This Laboratory was to be a service organization for the Madison campus of the University with the mandates to provide scientific and engineering services to all research programs on campus and to be self supporting. The High Energy Physics Division of the AEC, which had funded Tantalus, had made it clear that in the future, research on particle accelerators would be carried out only at AEC national laboratories. We had a nearly complete machine, but no funds to complete it, and no prospects of support for the particle accelerator research for which it was intended. At this point, we named the machine Tantalus, and our interest in synchrotron radiation became far more than academic, as well.

        By this time, Fred Brown, Dave Lynch, and Hellmut Fritzsche had made quite substantial commitments to the development of their experimental systems and programs to be carried out at Tantalus, hence, they had a strong interest in the completion of the machine. After Fred Mills, who had become the first PSL director, had approached the Solid State Physics Division of the AEC for support of the project and been turned down, with regrets, they suggested that the Air Force Office of Scientific Research (AFOSR) be contacted. This was done, and, because of the strong support of Fred Brown and his colleagues, the appeal was successful. With interim funding from the Defense Advanced Research Projects Agency (DARPA) before AFOSR funding could begin, we completed Tantalus in January 1968 and began the commissioning process. The first stored am at 240 MeV was achieved early in the following March.

        With the first operation of Tantalus, the three pioneer users pushed ahead with their preparations and were scheduled to begin to use the beam in May of 1968. They were delayed, of course, but by July both Hellmut's and Fred's equipment was on site and installation had begun. Fred might well have been the first to see photons through his monochromator, but his post doc, Hiizu Fujita, had an unfortunate accident while unloading their equipment, and they were further delayed.

        At 10:40 AM, August 7, 1968 the first modern synchrotron radiation facility, that is, the first dedicated, electron storage ring based synchrotron radiation facility, produced its first data when Dr. Ulrich Gerhardt, then working with Hellmut Fritzsche, carried out a simultaneous reflection and absorption measurement on CdS over the wavelength range of 1100 A to 2700 A. The circulating beam current was 1.4 mA! This event did not, however, receive much attention in the leading scientific journals.