The Superconducting Heavy-Ion Linac at Argonne

Abstract

The design, statuB, and performance of the first operating superconducting heavy-Ion accelerator, ft llnac used to boost the energies of beams from a 9-KV tandea, 1* summarized. When completed In 1901, the linac will consist of 26 Independently-phased splitting niobium resonators operating ac 97 MHz. This llnac Is dealgned to provide 29 MV of acceleration. Because of the modular character of the system, the llnac has been operable and useful since nld-1976, when a beam was accelerated through 2 units and the first nuclear-physics experiments were performed. How, 16 resonators are In use, and a beam has been accelerated for i 6000 hr. Resonator performance has been remarkably stable. In spite of vacuum accidents, and the llnac as a whole operates reliably without opera' tors In attendance during nights and weekends. The ease and speed with which the beam energy can be changed is proving to be unexpectedly valuable to users. I• IntroductionThe Superconducting Llxiac Project at Argonne was undertaken with three major objectives In mind; (1) to develop a new technology, (2) to build a prototype accelerator that cm serve as a guide for others, and (3) Co build a heavy-Ion accelerator that Is immediatedly useful as a Teaear.cn tool. This paper is concerned largely with objectives (2) and (3).For our needs at Argonne, the linac must be an energy booster for heavy lone from an existing tandem *Work performed under the auBpicee of the U.S. Department of Energy, IrUKI MEAl electrostatic accelerator, and the compound system must provide, «t minimum cost, the beams required for precision nuclear-structure research. That Is, it must have easy energy variability, excellent bean quality, and overall flexibility. In short, It should hf>ue tandem-like characteristics, but provide a much higher bean energy than Is obtainable from most tandems. Figure 1 shows the tandem-linac accelerator system* that has been developed both to test the accelerator concept and Co meet our research requirements. II. The Accelerator System

SRF acceleration for heavy ions: ATLAS decadal operation and evolution

“…Thus in making design choices for new resonators at ATLAS the frequencies allowed must be multiples of 12.125 MHz. After the initial demonstration of the overall concept in 1978-1979 [6], during the next six years additional cryostats were constructed, installed and operated. In 1985, the ATLAS facility was completed, commissioned, and identified as a National User Facility for Low-Energy Nuclear Physics Research.…”