Spin tracking of polarized protons in the Main Injector at Fermilab

TL;DR

This paper investigates the feasibility of maintaining polarized proton beams in Fermilab's Main Injector by using detailed spin tracking simulations, considering real-world imperfections to identify depolarizing resonances and tolerances.

Contribution

It provides the first comprehensive spin tracking analysis for polarized protons in the Fermilab Main Injector, including realistic lattice imperfections and their impact on polarization.

Findings

Depolarizing resonances identified for ideal and imperfect lattices

Tolerances for magnet errors and misalignments quantified

Feasibility of polarization preservation assessed

Abstract

The Main Injector (MI) at Fermilab currently produces high-intensity beams of protons at energies of 120 GeV for a variety of physics experiments. Acceleration of polarized protons in the MI would provide opportunities for a rich spin physics program at Fermilab. To achieve polarized proton beams in the Fermilab accelerator complex, detailed spin tracking simulations with realistic parameters based on the existing facility are required. This report presents studies at the MI using a single 4-twist Siberian snake to determine the depolarizing spin resonances for the relevant synchrotrons. Results will be presented first for a perfect MI lattice, followed by a lattice that includes the real MI imperfections, such as the measured magnet field errors and quadrupole misalignments. The tolerances of each of these factors in maintaining polarization in the Main Injector will be discussed.