One 4-Twist Helix Snake to Maintain Polarization in 8-120 GeV Proton Rings

TL;DR

This paper introduces a novel 4-twist helix snake design that effectively maintains proton beam polarization in rings from 8 to 120 GeV, overcoming limitations of traditional solenoid snakes at high energies.

Contribution

The paper proposes a new single Siberian snake design using a 4-twist helix and short dipoles, capable of preserving polarization in multi-GeV rings where previous methods failed.

Findings

The 4-twist helix snake maintains polarization in 8-120 GeV rings.

The design is practical for use in various high-energy accelerators.

It overcomes depolarizing resonances that limit existing solutions.

Abstract

Solenoid Siberian snakes have successfully maintained polarization in particle rings below 1 GeV, but never in multi-GeV rings because the Lorentz contraction of a solenoid's integral B dl would require impractically long high-field solenoids. High energy rings, such as Brookhaven's 255 GeV Relativistic Heavy Ion Collider (RHIC), use only odd multiples of pairs of transverse B-field Siberian snakes directly opposite each other. When it became impractical to use a pair of Siberian Snakes in Fermilab's 120 GeV Main Injector, we searched for a new type of single Siberian snake, which should overcome all depolarizing resonances in the 8.9 - 120 GeV range. We found that one snake made of one 4-twist helix and 2 short dipoles could maintain the polarization. This snake design might also be used at other rings, such as Japan's 30 GeV J-PARC, the 12 - 24 GeV NICA proton-deuteron collider at JINR-Dubna, and perhaps RHIC's injector, the 25 GeV AGS.