Single/Few Bunch Space Charge Effects at 8-GeV in the Fermilab Main Injector

TL;DR

This paper investigates the effects of increased space charge at 8-GeV in the Fermilab Main Injector, analyzing how higher intensity bunches affect beam transmission and tune shifts, with implications for Project X upgrades.

Contribution

It provides experimental data on high-intensity bunch transmission and tune shifts at 8-GeV, supporting theoretical predictions and aiding future high-intensity beam studies.

Findings

Transmission curves scale with intensity and bunch length increases

Incoherent tune shifts are consistent with theoretical expectations

Results inform future high-intensity beam operation strategies

Abstract

For Project X, it is planned to inject a beam of 3x10**11 particles per bunch into the Main Injector. Therefore, at 8-GeV, there will be increased space charge tune shifts and an increased incoherent tune spread. In preparation for these higher intensity bunches exploratory studies have commenced looking at the transmission of different intensity bunches at different tunes. An experiment is described with results for bunch intensities between 20 and 300 10**9 particles. To achieve the highest intensity bunches coalescing at 8-GeV is required, resulting in a longer bunch length. Comparisons show that similar transmission curves are obtained when the intensity and bunch length have increased by factors of 3.2 and 3.4 respectively, indicating the incoherent tune shifts are similar, as expected from theory. The results of these experiments will be used in conjugation with simulations to further study high intensity bunches in the Main Injector.