Crossing a Coupling Spin Resonance with an RF Dipole

Technical Report · Thu Feb 01 04:00:00 EST 2001

DOI:https://doi.org/10.2172/1061632· OSTI ID:1061632

Bai, M. ^[1]; Roser, T. ^[1]

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1. Brookhaven National Laboratory (BNL), Upton, NY (United States). Relativistic Heavy Ion Collider (RHIC)

In accelerators, due to quadrupole roll errors and solenoid fields, the polarized proton acceleration often encounters coupling spin resonances at the horizontal betatron tune. In the Brookhaven AGS, the coupling effect comes from the solenoid partial snake which is used to overcome imperfection resonances. The coupling spin resonance strength is proportional to the amount of coupling as well as the strength of the corresponding intrinsic spin resonance. Generally in accelerators, the betatron tunes in the horizontal and vertical planes are separated to reduce the coupling strength and therefore the depolarization due to the coupling spin resonance. However, the coupling resonance can still cause substantial beam polarization loss if its corresponding intrinsic spin resonance is very strong. A new method of using an horizontal rf dipole to induce a full spin ip crossing both the intrinsic and its coupling spin resonances is studied in the Brookhaven's AGS. In this method, both the horizontal and vertical unperturbed betatron tunes are set to be equal, and the coupling resonance is as strong as the intrinsic resonance. Numerical simulations show that a full spin ip can be induced after crossing the two resonances by using a horizontal rf dipole to induce a large vertical coherent oscillation.

• Research Organization: Brookhaven National Laboratory (BNL), Upton, NY (United States). Relativistic Heavy Ion Collider (RHIC)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 1061632
• Report Number(s): BNL--99191-2013-IR; C-A/AP/37; KB0202011
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
Relativistic Heavy Ion Collider