Booster 6-GeV Study
  Since a wider aperture has been obtained along the Booster beam line, this opens the opportunity for Booster running a higher intensity beam than ever before. Sooner or later, the available RF accelerating voltage will become a new limit for the beam intensity. Either by increasing the RFSUM or by reducing the accelerating rate can achieve the similar goal. The motivation for the 6-GeV study is to gain the relative accelerating voltage via a slower acceleration. 
Xi Yang, Charles M. Ankenbrandt, William A. Pellico, James Lackey,   Rene Padilla, and J. Norem