Low Energy RHIC Electron Cooling LERe C RHIC

Low Energy RHIC Electron Cooling (LERe. C) RHIC Time Meeting March 12, 2019

LERe. C progress/updates for March 5 -11 • High-current CW running to injection Dump and ripple measurements. Did not observe large Gun voltage ripple at around 10 k. Hz measured last year. • Re-established CW running through full LERe. C beamline to High-Power beam dump • Worked on beam optics for various bunch charges • Established good energy spread of electron beam • Timed electron and ion bunches at 3. 85 Ge. V ion beam energy • Worked on orbit alignment of electron and ion beams in yellow cooling section • Observed focusing effect of ion on electrons

Energy spread of electron bunch no slit with the slit

Timing of electron and ion bunches at 3. 85 Ge. V 20 electron bunches Ion bunches

Orbit of ions in yellow cooling section LERe. C BPMs RHIC BPMs

Transverse electron beam profile in Blue cooling section No ion beam in Yellow With ion beam in Yellow

LERe. C status and plans • • • New RF Timing system commissioned with beam Started to use LERe. C dedicated time at 3. 85 Ge. V Synchronized electrons and ions at 3. 85 Ge. V Observed focusing effect of ions on electrons Need to implement and commission new 76 k. Hz CW mode Need to commission Recombination and new Schottky monitor. Work on ion dispersion lattice at 3. 85 Ge. V continues. • To be followed by energy calibration and energy matching between electron and ion beam