History of linacs - page 4

      In addition, in 1975 after the highly successful completion of the 800 MeV proton linac at Los Alamos (the Los Alamos Meson Physics Facility-LAMPF), scientists at that laboratory began a program sponsored by the National Cancer Institute to vastly reduce the size of such conventional accelerators to make it possible to use proton linacs in a hospital-based facility for pion therapy. While the PIGMI (Pion Generator for Medical Irradiation) program did not result in the construction of such a system before it was terminated in 1981, it did have a significant impact on modern commercial ion linacs. Besides the testing of the first RFQ linac, the use of a higher frequency (425 MHz) to make the drift tube linac smaller in size and shorter in length was demonstrated, along with the use of rare-earth permanent magnet quadrupoles that could fit in the much smaller drift tubes found in such a system. In fact, many of the innovations of modern proton linacs proven during that program at Los Alamos are incorporated in the linac products available from AccSys today.

      No other type of accelerator is able to combine the functions of bunching and accelerating charged particles in such a compact size (an RFQ is typically 3-10 feet long and 1-3 feet in diameter). Use of the RFQ as the first stage for conventional ion linacs that go to much higher ion energies permits these larger machines to be greatly reduced in size and length, making the invention of the RFQ a milestone in the evolution of ion accelerators.

      Proclaimed as the "missing link" in linear accelerator technology by D.A. Swenson, who was the leader of the Los Alamos group that built the proof-of-principle RFQ and currently at Linac Systems, this unique class of particle accelerator has dramatically expanded the use of particle beams in both scientific research and commercial applications. Its small size, inherent flexibility, and considerable capability has resulted in many new applications for the ion linacs available from AccSys.

      For a more in depth discussion of RFQ accelerator technology and history, please see our reproduction of    "The Missing Link Accelerator" (PDF format, 1.61 MB), an article originally run in The World & I magazine.