RHIC Spin Flipper Status

1
RHIC Spin Flipper Status

• M. Bai, T. Roser, A. Luccio, Y. Makdisi, I.
  Marneris, W. Meng, P. Oddo, C. Pai, C. Pearson,
  P. Pile, T. Russo,
• J. Sandberg, J. Tuozzolo, P. Rosas

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RHIC spin flipper layout
-167.493o
208.03o
IP10
30o Spin rotator
-15o Spin rotator

• Ac dipole x2
• maximum field amplitude 100 Gauss-m
• frequency sweep range 400 Hz
• DC Spin rotator x4 DC dipole with vertical
  field
• 2 in the center
• integrated field strength 0.45 Tesla-m
• dipole deflection
• 100 GeV 1.35 mrad
• 250 GeV 0.55mrad

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RHIC spin flipper layout
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Status

• 4 DC dipoles were measured and installed
• in the tunnel
• the 500 A power supply for the 4 DC dipoles was
• ready and are now in the Bldg 1010 high bay
  area
• 2 ceramic pipes were made and coated with TiN
• coils of the 2 ac dipoles were made and
  assembled
• and are in process of being measured
• supports for ac dipoles are made and installed
• in the tunnel
• vacuum group is working on installing beam pipes
• including the ceramic ones.

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Assembled ac dipole
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Status

• installation of cable trays in the tunnel is
  working
• progress. Cabling starts as soon as the trays
  are
• ready. Goal is to have it done before RHIC
  starts
• AC dipole power supply
• capacitors for the ac dipoles, cabinets and
  other
• parts were ordered and expect to be
  delivered at
• the end of January
• Dynamic tuning for the ac dipole is under tuning
• and the ados for the ac dipole control are
  also
• under development
• Expect ac dipoles are ready by the end of Feb.

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Plan Goal

• Without beam
• measure the ac dipole frequency response on the
  bench
• With beam
• calibrate the 4 DC dipoles
• Measure the local bump size
• this can be done during the machine setup period
  as long
• there is an opportunity
• no polarization is needed
• calibrate the ac dipole strength
• in early March
• no polarization is needed
• commissioning spin flipping
• at store
• dedicated time either during APEX session or MD
  session
• operational as soon as the commissioning is
  done. So, the goal is to commission it during 500
  GeV run and have it available for the 200 GeV run
  if it happens.

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Simulation results

• Single particle with spin tune 0.5
• Spin flipper
• Amplitude 20 Gauss-m
• Tune 0.49 -gt 0.51
• Sweep in half million turns

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Spin tune meter

• Instead of sweeping the spin flipper tune across
  the beam spin precession tune, one can also keep
  the spin flipper tune fixed nearby the beam spin
  tune. In this case, the stable spin direction is
  given by
• The beam spin tune can be calculated by measuring
  the turn by turn horizontal and vertical asymmetry

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Cost Estimate