RHIC Spin Flipper Status M Bai T Roser

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

RHIC spin flipper layout -167. 493 o 208. 03 o IP 10 30 o Spin rotator -15 o Spin rotator • Ac dipole x 2: • maximum field amplitude: 100 Gauss-m • frequency sweep range: ± 400 Hz • DC Spin rotator x 4: DC dipole with vertical field • 2 in the center • integrated field strength: 0. 45 Tesla-m • dipole deflection: • 100 Ge. V: 1. 35 mrad • 250 Ge. V: 0. 55 mrad

RHIC spin flipper layout

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

Assembled ac dipole

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.

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 Ge. V run and have it available for the 200 Ge. V run if it happens.

Simulation results p p Single particle with spin tune = 0. 5 Spin flipper: n n n Amplitude: 20 Gauss-m Tune: 0. 49 -> 0. 51 Sweep in half million turns

Spin tune meter p 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 p The beam spin tune can be calculated by measuring the turn by turn horizontal and vertical asymmetry

Cost Estimate