| Paper | Title | Page |
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| TUPP002 | Commissioning of the 72 MHz Quarter-Wave Cavity Cryomodule at ATLAS | 440 |
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Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under contract number DE-AC02-06CH11357. A cryomodule of seven 72 MHz SC quarter-wave cavities optimized for ions with v/c=0.077 has been commissioned in the ATLAS heavy-ion accelerator at Argonne. ATLAS has a new capability for increased beam currents with low beam losses for nuclear physics experiments using stable or rare isotope beams or neutron rich beams from the Californium Rare Isotope Breeder. The main goal for the cryomodule, to provide an accelerating voltage of 17.5 MV (2.5 MV/cavity), with no detectable beam losses has been met within the first month of commissioning. Thus far, cavities and primary subsystems including high-power couplers and pneumatic tuners are operating as designed with full availability. For present levels there is practically no field emission (EPEAK=40 MV/m) and RF losses of ~5 Watts/cavity are only half of that planned. Cavity fields will continue to be gradually increased, with the limits due to cavity quench measured at VACC=3.75 MV. Due to a combination of rf design and cavity processing, effective voltages are now 2 ½ times those for any other operational cavities for this v/c. We report here on the recent online test results and technical features of the present design. |
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