RHIC Spin Flipper Commissioning Plan• Phase I

– Spin tune measurement using spin flipper• How: use the spin flipper to induce large coherent spin precession

and measure the projection of the spin vector in the horizontal plane• Challenge: use CNI to measure the turn by turn coherent spin

precession• This is the key for successfully commissioning the spin flipper• This also is critical for optimizing the snake settings for machine

operation

• Phase II– Measure spin tune spread using spin flipper

• Approach I: – use the spin flipper to induce a large coherent spin precession by

sweeping its frequency and shuts off at the spin tune– Measure the total polarizaton of the beam. The total polarization should

be preserved if the tune spread is zero

• Approach II– Map the vertical beam polarization with different spin flipper frequency

from below the spin tune to above the spin tune. The width of the vertical beam polarization as a function of the flipper tune around the spin tune is proportional to the spread of the spin tune

RHIC Spin Flipper Commissioning Plan

• Phase III– Commissioning spin flipper

• Evaulate the specs of the spin flipper– The strength of the magnet– The range that the frequency of the spin flipper is required to sweep for

full spin flip

• scan the spin flipping efficiency with– Different strength but the same frequency sweeping range– Different frequency sweep range but fixed strength