The Study Of Acceleration Of Polarized Beam At HIAF-BRing

The understanding of the forces among nucleons is fundamental to the whole of nuclear and hadronic physics.The nucleon-nucleon scattering is the ideal probe to study the nuclear forces.The complete description of thenucleon-nucleon interaction requires measurements with polarized experiments.Thus,in order toexplore the nucleon properties in details,it has been proposed that the polarized proton is used for some special experiments at HIAF project in Institute of Modern Physics,Chinese Academy of Sciences(IMPCAS).The acceleration of polarized beams in circular accelerator is complicated by the presence of numerous perturbed magnetic field.Because of those undesired magnetic field,the beams may be depolarized.The work,design a suitable scheme for the acceleration of polarized proton,is based on this requirement.A depolarizing resonance is crossed whenever the number of spin precessions per turn equals the frequency with which spin-perturbing magnetic fields are encountered.There are kinds of depolarizing resonances,such as imperfection resonance,intrinsic resonance,coupling resonance,synchrotron sideband resonance and snake resonance.For neglecting three high-order spin resonance,we only study the influence of the two main resonance,imperfection resonance and intrinsic resonance.The spin motion of a particle in circular accelerators is governed by the Thomas-BMT equation.We assume that the particle moves in the vicinity of a planar reference orbit and its characterized by Frenet-Serret curvilinear coordinates.And how to calculate the strength of those depolarizing resonance is also presented.Polarized protons will be accelerated to 9.3GeV/u in the Booster Ring(BRing),in which depolarizing resonances will reduce on the beam's polarization,and it's necessary to suppress those resonances during the acceleration.According to our work above,the code DEPOL is used to simulate the depolarizing resonances process in the Bring.The evolution of polarization is governed by Froissart-Storaequation,which can be used to study the influence of the main depolarizing resonance.It can be findthat the beam's polarization has been destroyed completely by the depolarizing resonances in the acceleration.There are some scheme to overcome depolarizing resonance,spin rotator,orbit correction,tune jump and Siberian snake.Because the frequency of vertical betatron oscillationnear a half integer.Thus,a full Siberiansnakemagnetic system is chosen to preserve the beam's polarization during the acceleration.X-Y beam coupling introduced by solenoid is compensated locally,and the strength and location of those quadrupoles for decoupling are also presented.