Conserving Polarization of Protons in the Nuclotron/JINR up to 3.5 GeV/c Using Correction Dipoles and a Weak Solenoid

In Nuclotron, there are no intrinsic spin resonances for protons up to 3.5 GeV/c, and in this momentum range beam depolarization is associated with the crossing of integer spin resonances. Correction dipoles are used to deliberately increase the resonance strength due to controlled deflection of the closed synchrotron orbit. When the closed orbit is deflected up to 10 mm and the field ramp rate in arch dipoles is 0.6 T/s, almost all integer resonances will cross adiabatically without loss of polarization, with the exception of the first two resonances at energies of 108 and 631 MeV. Adiabatic crossing of these resonances can be provided by introducing a weak longitudinal field with an integral of 50 mT m. Conserving polarization by the proposed method will allow the injection of protons into the NICA collider up to 3.5 GeV/c, as well as experiments on external targets.