Spin Flipping in the Presence of a Full Siberian Snake

RHIC Spin Flipper Commissioning

“…To achieve a 99.999% spin flip, the following condition has dg -e(l + Gy)$ x g(t), X -ym to be satisfied (1) (Y 5 0.131EK12 where s'is the spin vector in the particle rest frame, G is the 2 SPIN FLIPPING IN RHIC anomalous gyro-yagnetic g-factor and ymc2 is the moving particle energy. B(t) is the magnetic field of the ac dipole 2.1 RHIC spin setup B(t) = B,cos(27rj-,t + x) (2) where B, is the amplitude of the oscillating magnetic field, fm is the oscillation frequency and x is the arbitrary phase of the ac dipole oscillating magnetic field. In a perfect planar circular accelerator, the beam's spin vector precesses around vertical direction.…”

“…With two full snakes, the spin vector completes one full precession around the vertical direction in two revolutions, and the spin depolarization resonances due to the machine imperfections and betatron oscillations are eliminated. Since the spin flipper provides an oscillating horizontal dipole field, a "spin resonance" can occur if the spin flipper frequency is placed in the neighborhood of the spin precession frequency [ 1,2,3]. By slowly sweeping the spin flipper frequency across the spin precession frequency, a full spin flip can be achieved.…”

Achieving 99.9% Proton Spin-Flip Efficiency At Higher Energy With A Small rf Dipole

“…Many polarized scattering experiments require frequent spin-direction reversals (spin flips), while the polarized beam is stored, to reduce their systematic errors. Spin resonances [9,10] induced by either an rf solenoid or rf dipole can produce these spin flips in a well controlled way [11][12][13][14][15][16][17][18][19][20][21].An rf dipole was earlier used [19] to spin flip 120 MeV (490 MeV=c) polarized protons stored in the IUCF Cooler Ring with a 99:93 0:02% spin-flip efficiency. At very high energy, the spin-flip efficiency with an rf dipole should become almost independent of energy, mostly due to the Lorentz invariance of a magnet's transverse R Bdl [22]; this invariance is quite important for very high energy polarized proton rings [23].…”

“…The vertical polarization can be perturbed by an rf dipole's horizontal rf magnetic field. This perturbation can induce an rf depolarizing resonance, which can flip the spin direction of the stored polarized protons [11][12][13][14][15][16][17][18][19][20][21]; the resonance's frequency iswhere f c is the protons's circulation frequency and k is an integer. Adiabatically ramping the rf magnet's frequency through f r can flip each proton's spin.…”

“…Many polarized scattering experiments require frequent spin-direction reversals (spin flips), while the polarized beam is stored, to reduce their systematic errors. Spin resonances [9,10] induced by either an rf solenoid or rf dipole can produce these spin flips in a well controlled way [11][12][13][14][15][16][17][18][19][20][21].…”