• K. Seiya, T. Berenc, B. Chase, J.E. Dey, I. Kourbanis, J.A. MacLachlan, K.G. Meisner, R.J. Pasquinelli, J. Reid, C.H. Rivetta, J. Steimel
  Fermilab, Batavia, Illinois

In order to increase proton intensity on anti proton production cycle of the Main Injector we are going to use the technique of 'slip stacking' and doing machine studies. In slip stacking, one bunch train is injected at slightly lower energy and second train is at slightly higher energy. Afterwards they are aligned longitudinally and captured with one rf bucket. This longitudinal stacking process is expected to double the bunch intensity. The required intensity for anti proton production is 8·10¹² protons in 84 bunches. Beam studies of the slip stacking process have started and we have already established that the stacking procedure works as expected for a low beam intensity. In order to make this stacking process usable for higher intensity beam in standard mode of operation, we are working on high intensity beam and the development of the feedback and feed forward system is under way.

• C.M. Bhat, D. Capista, B. Chase, J.E. Dey, I. Kourbanis, K. Seiya, V. Wu
  Fermilab, Batavia, Illinois

Recently, we have adopted a scheme called "Mixed pbar Source Operation" to transfer 2.5 MHz pbar bunches from the Recycler and the Accumulator to the Fermilab Main Injector (MI). In this scheme, 2.5MHz pbar bunches are captured adiabatically in 53 MHz buckets at 8 GeV in the MI and accelerated to 150 GeV before bunch coalescing and transfer to the Tevatron collider stores. A special magnet ramp was needed in the MI to allow for pbar beam of slightly different 8 GeV energies from the Recycler and the Accumulator. Here we present the details of the scheme and its advantage over the method used for past several years.

• J.E. Dey, I. Kourbanis
  Fermilab, Batavia, Illinois

Recently In-Phase and Quadrature (I&Q) was added to both the 53 MHz Feedback and Feedforward Beam Loading Compensation for Slip Stacking in the Fermilab Main Injector. With 53 MHz Feedback, we can now turn the 18 Radio Frequency (RF) Stations off down to below 100 V. In using I&Q on Feedforward, beam loading compensation to the beam on both the upper and lower frequencies of Slip Stacking can be applied as we slip the beam. I&Q theory will be discussed.

• V. Wu, C.M. Bhat, B. Chase, J.E. Dey, K.G. Meisner
  Fermilab, Batavia, Illinois

In an effort to provide higher intensity and lower emittance antiproton beam to the Tevatron collider for high luminosity operation, a new Main Injector (MI) antiproton acceleration scheme has been developed [1-4].* In this scheme, beam is accelerated from 8 to 27 GeV using the 2.5 MHz rf system and from 27 to 150 GeV using the 53 MHz rf system. This paper reports the experimental results of beam study. Simulation results are reported in a different PAC'05 paper [5]. Experiments are conducted with proton beam from the Booster. Acceleration efficiency, emittance growth and beam harmonic transfer between 2.5 MHz (h=28) and 53 MHz (h=588) buckets have been studied. Beam study shows that one can achieve an overall acceleration efficiency of about 100%, longitudinal emittance growth less than 20% and negligible transverse emittance growth.

*G. P. Jackson, The Fermilab Recycler Ring Technical Design Report, FERMILAB-TM-1991, November 1996.