Particle accelerators use high field quality magnets to steer and focus beams. Normal conducting magnets commonly use soft iron for the yoke, which is subject to hysteresis effects. It is common practice to use an initialization procedure to accomplish a defined state of the magnet for which its hysteresis behavior must be known. In this article, a variation of the scalar Jiles-Atherton model with an improved physical basis called the Extended Jiles-Atherton (EJA) model is employed to predict the B-H trajectories in a Rapid Cycling Synchrotron (RCS) magnet. Simulations are conducted using COMSOL Multiphysics using the external material feature to integrate EJA model with the Finite Element Method (FEM). Results from the experimental studies conducted on a magnet prototype are also presented. Finally, potential improvements in the model and extension to the case of a two-dimensional anisotropic material are discussed.

Brookhaven National Laboratory (BNL) was recently chosen to host the Electron Ion Collider (EIC), which will collide high energy and highly polarized hadron and electron beams with a center of mass energy up to 140 GeV and a luminosity of up to 1e+34 1/cm^2/s. Part of the accelerator complex is a Rapid Cycling Synchrotron (RCS), which is planned to accelerate electrons from 400 MeV to 18 GeV. Due to the large energy range and the given circumference of the ring, the magnetic fields of the RCS magnets at injection are very low (~mT). A test dipole magnet was constructed to study differences in field quality from 5-50 mT. The paper discusses the design of the test magnet and first measurement results.

The Chiral Belle project is a proposed project which aims to expand the capabilities of SuperKEKB and the physics goals of Belle II by injection polarized electrons into the High Energy Ring. Before the full implementation of spin rotator magnets near the interaction point, we propose to demonstrate the injection and transport of polarized electrons in the SuperKEKB Main Ring. By measuring the effect of differing polarization states on the Touschek lifetime, we aim to show the preservation of polarized spin vectors around the main ring without the need for the full apparatus of Compton polarimetry and spin rotator magnets which will be required for the full Chiral Belle project.