AGS performance and upgrades a possible proton driver for a muon collider

Abstract

After the successfull completion of the AGS Booster and several upgrades of the AGS, a new intensity record of 6.3 x 1013 protons per pulse accelerated to 24GeV 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. Recent AGS High Intensity PerformanceThe 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 Booster [l]. 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 x 1013 protons per pulse already to reach a peak value of 2.2 x 1013 protons per pulse. This was achieved by very carefully correcting all the important nonlinear orbit resonances especially at the injection energy of 200MeV, 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 harmo&c system allows for the creation of a flattened 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 Work performed under the auspices of the U.S. Department of Energy

Muon Colliders

“…2. In the examples, the µ-source driver is a high-intensity (2.5 × 10 13 protons per pulse) 30 GeV proton synchrotron. The preferred cycling rate would be 15 Hz, but for the demonstration using the AGS [8], the repetition rate is limited to 2.5 Hz and to 24 GeV. For the lower energy machines, 2 final bunches are employed (one to make µ − 's and the other to make µ + 's).…”

Muon collider: Introduction and status

“…The probability for such interactions is reduced, and the overall production rate increased (by about 60 %) if the target and proton beam are set at an angle (10)(11)(12)(13)(14)(15) o ) with respect to the field axis [17,18].…”

Muon collider design

“…In the examples, it is a high-intensity (2.5×10 13 protons per pulse) 30 GeV proton synchrotron. The preferred cycling rate would be 15 Hz, but for a demonstration machine using the AGS [8], the repetition rate would be limited to 2.5 Hz and to 24 GeV. For the lower energy machines, 2 final bunches are employed (one to make µ − 's and the other to make µ + 's).…”