Bucket Shaking Stops Bunch Oscillations In The Tevatron

TL;DR

This paper demonstrates that applying a specific bunch distribution change in the Tevatron can effectively stop longitudinal oscillations, known as 'dancing bunches', without the need for a damper, supported by experimental evidence.

Contribution

It provides experimental validation that a targeted bunch distribution modification can suppress bunch oscillations in the Tevatron, offering an alternative to damping systems.

Findings

Bunch oscillations can be stopped by distribution changes.

Experimental results support theoretical predictions.

Method reduces reliance on damping systems.

Abstract

Bunches in the Tevatron are known to exhibit longitudinal oscillations which persist indefinitely. These oscillations are colloquially called "dancing bunches". Although the dancing bunches do not cause single bunch emittance growth or beam loss at injection, it leads to bunch lengthening at collisions. In operations, a longitudinal damper has been built which stops this dance and damps out coupled bunch modes. Recent theoretical work predicts that the dance can also be stopped by an appropriate change in the bunch distribution. This paper shows the Tevatron experiments which support this theory.