Gold ion collisions were expected by about the second week in June. On May 30, a hard ground was confirmed in the yellow ring buss in the 12 o'clock sector of the collider. As of this writing, repairs continue. Repairs are expected to take about two weeks. The plan is to bring RHIC immediately up to operation at last year's peak beam intensity and then try to raise beam intensity by a factor of about 5 to 10. Operation with peak ion energies of 100 GeV are also planned.
The current run is scheduled to continue through January 2001. What is different about this planned running period is that the Collider-Accelerator Department plans on running a high-intensity, high-energy proton program concurrent with RHIC operations. Changes in accelerator instrumentation now allow operation in the Alternating Synchrotron Gradient (AGS) booster and main rings with both protons and ions without having to swap out critical components. The process of filling RHIC with ions from the tandem requires only about 5 minutes, and each fill can last up to 12 hours. During those 12 hours protons will be injected into the booster ring from the 200-MeV linac and extracted from the main ring into the fixed target building for several high-energy physics experiments. The first test of this dual mode of accelerator operation is scheduled to occur in mid-July.
Meanwhile, construction of the Booster Accelerator Facility (BAF) continues full bore. The BAF will be a dedicated beam line off the booster ring for shielding, dosimetry, and dose response studies for NASA experimenters. It will be replete with its own target and support buildings. For the last 5 years, NASA experimenters have been using one of the AGS's low-intensity beam lines in the fixed target building for their dose response and shielding studies. BAF will allow them to take full advantage of the lower energy beam (less than 1 GeV/nucleon) directly from the booster ring to simulate specific portions of the space radiation environment. This is easier for the accelerator physicists who will not have to tune the main AGS ring for low-energy extraction. The NASA team is expected to operate BAF about 1500 hours per year. The safety assessment document has recently undergone final internal reviews, and construction is slated to be completed by late next spring, with commissioning planned for next summer.