Speaker
Description
The vertically polarized electron beam will undergo spin rotation in a solenoidal magnetic field. In low-energy, high–space-charge regions, i.e. electron source, quads or solenoids with clockwise/counter-clockwise windings are typically used to maintain a vertical spin orientation. In the EIC preinjector, two Wien filters are employed as the spin rotators. Between them, the spin vector is oriented at 45 degrees in the vertical plane, making it highly sensitive to solenoidal field error, which can distort the intended spin direction. A triplet is the baseline solution for beam focusing in this region, but it requires large longitudinal space, limiting the space for diagnostics. To address this, we propose a compact solenoidal focusing system composed of multiple permanent magnets that preserves the vertical spin orientation while providing the required focusing. A permanent-magnet solenoid naturally yields a zero net longitudinal magnetic field integral, ensuring negligible spin rotation. This proceeding presents the design of a compact focusing solenoid assembled from permanent bar magnets for use in the low-energy section of a spin-polarized electron injector. The design offers a compact, power-free, and non-coupling alternative to conventional quadrupole triplets. We also developed a method for tuning the focusing strength by adjusting the spacing between two permanent-magnet solenoids. With optimal solenoid, the concept can be extended to higher-energy polarized beams.
| In which format do you inted to submit your paper? | Word |
|---|---|
| Preprint marking on your proceeding paper | I wish my paper to be marked as preprint. |
| I no longer wish to present this contribution, please withdraw it. | Keep my contribution |