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This update provides information on the current status of RHIC, including the setup of beams at 9.8GeV and 3.85GeV energies, successful mode switching tests, and important upgrades for improved performance. Plans for physics at different energies and upcoming tasks are also outlined.
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RHIC status Chuyu Liu Machine/Experiment meeting 02/26/2019
Where we are now • Providing collisions for STAR at 9.8GeV beam energy starting from the evening of 02/22/19 (last Friday). • Beams at 3.85GeV have been set up in both rings. • Beam at 7.3GeV has been set up in the Blue ring. • Mode switching has been tested multiple times.
Issues • None
What’s new this year • Wiggle (demagnetization) ramp for RHIC superconducting magnets to reduce persistent current effects. • New betatron working point at 0.09/0.08. • Upgrade of corrector control from 12 to 16 bit. • 9 MHz cavities for 3.85 and 4.55 GeV, much improved lifetime. • To be tested: flat orbit in LEReC cooling section with g1-tvx separation bump.
Mode-switching and wiggles • Benefits: quickly switch between energies, zero wait time for persistent currents to settle down. 9.8GeV 7.3GeV 9.8GeV 9.8GeV 3.85GeV 7.3GeV
Improved orbit with corrector controller upgrade Last year in blue This year in black
To-do list for physics at 9.8GeV • Gap cleaning fine tuning. • Increase bunch intensity incrementally. • Squeeze beta star from 3 to 2 m.--scheduled as a beam development on Thursday. • As decided in the 9 am meeting today, beam scrubbing in RHIC is scheduled 4am Wednesday for 3 hours, with full intensity from AGS and quad pumping.
To-do list for 3.85GeV • Establish lattice for physics with 4m beta star and required optics functions in cooling section. • Establish lattice (so called dispersion lattice) for LEReC cooling demonstration. • Recombination monitor testing for detecting Au78+ produced by cooling. • Setup new Schottky detector for detecting cooling effects.
Summary • No concerns for operation in 2019. • Plans are in place to get RHIC ready for LEReC cooling commissioning.