Improving the Fermilab Booster Notching Efficiency, Beam Losses and Radiation Levels

TL;DR

This paper proposes a new horizontal notching system at Fermilab Booster that significantly improves removal efficiency of unwanted bunches, reduces beam losses, and lowers radiation levels through advanced simulations and a dedicated beam dump.

Contribution

Introduction of a horizontal kicker system and beam dump to enhance notching efficiency and decrease radiation exposure in the Fermilab Booster.

Findings

Notching efficiency increased to 99% with horizontal kickers.

Beam loss on magnets and collimators reduced by over 80%.

Radiation levels decreased by a factor of ten.

Abstract

Currently a fast vertical 1.08-m long kicker (notcher) located in the Fermilab Booster Long-5 straight section is used to remove 3 out of 84 circulating bunches after injection to generate an abort gap. With magnetic field of 72.5 Gauss it removes only 87% of the 3-bunch intensity at 400 MeV, with 75% loss on pole tips of the focusing Booster magnets, 11% on the Long-6 collimators, and 1% in the rest of the ring. We propose to improve the notching efficiency and reduce beam loss in the Booster by using two horizontal kickers in the Long-12 section. The STRUCT calculations show that using such horizontal notchers, one can remove up to 99% of the 3-bunch intensity at 400-700 MeV, directing 96% of it to a new beam dump at the Long-13 section. This fully decouples notching and collimation. The beam dump absorbs most of the impinging proton energy in its jaws. The latter are encapsulated into an appropriate radiation shielding that reduces impact on the machine components, personnel and environment to the tolerable levels. The MARS simulations show that corresponding prompt and residual radiation levels can be reduced ten times compared to the current ones.