AGS PERFORMANCE AND UPGRADES A Possible Proton Driver for a Muon Collider

After the successfull completion of the AGS Booster and several upgrades of the AGS, a new intensity record of 6:3 10 13 protons per pulse accelerated to 24 GeV was achieved. Futher intensity upgrades are being discussed that could increase the average delivered beam intensity by up to a factor of six. The total beam power then reaches almost 1 M W and the AGS can then be considered as a proton driver for a muon collider. The proton beam intensity in the AGS has increased steadily over the 35 year existence of the AGS, but the most dramatic increase occurred over the last few years with the addition of the new AGS Boosterr1]. In Fig. 1 the history of the AGS intensity improvements is shown and the major upgrades are indicated. The AGS Booster has one quarter the circumference of the AGS and therefore allows four Booster beam pulses to be stacked in the AGS at an injection energy of 1:5 GeV. At this energy space charge forces are much reduced and this in turn allowed for the dramatic increase in the AGS beam intensity. The beam intensity in the Booster surpassed the design goal of 1:5 10 13 protons per pulse already to reach a peak value of 2:210 13 protons per pulse. This was achieved by very carefully correcting all the important nonlinear orbit resonances especially at the injection energy of 200 MeV , where the space charge tune shift reaches about 0.4, and also by using the extra set of rf cavities, that were installed for heavy ion operation, as a second harmonic rf system. A second harmonic system allows for the creation of a attened rf bucket which gives longer bunches with lower space charge forces. The AGS itself also had to be upgraded to be able to cope with the higher beam intensity. During beam injection from the Booster, the AGS needs to store the already transferred beam bunches. During this time the beam is