• B. Mustapha, P.N. Ostroumov, J. Xu
  ANL, Argonne
• J.-P. Carneiro
  Fermilab, Batavia

Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.

The latest version of PTRACK*, the parallel version of the beam dynamics code TRACK, is capable of simulating a very large number of particles (a billion or more). In the case of the Fermilab 8-GeV H-minus linac, it is possible to simulate the actual number of particles in the bunch. Taking advantage of this capability we are revisiting our original beam loss studies**, but this time with larger statistics and including a new process of beam loss which is the stripping of H^- ions. TRACK has recently been updated*** with the possibility of stripping H^- by three different processes, namely black body radiation, Lorentz force stripping and residual gas interactions. Results of ideal end-to-end simulations (no errors) with the actual number of particles in a beam bunch (860M) as well as error simulations for different sets of errors with 10M and eventually 100M particles per seed will be presented and discussed. These simulations are being performed on Argonne's new petascale computing facility "BG/P".

* J. Xu et al, Proceedings of HB-2008.
** P. Ostroumov, B. Mustapha and V.A. Aseev, Proceedings of Linac-06.
*** J.-P. Carneiro, B. Mustapha and P. Ostroumov, submitted to PRST-AB.

• J.-P. Carneiro, I.G. Gonin, N. Solyak, V.P. Yakovlev
  Fermilab, Batavia
• W. Hartung
  NSCL, East Lansing, Michigan
• B. Mustapha, P.N. Ostroumov
  ANL, Argonne

A superconducting cavity has been designed for acceleration of particles traveling at 81% the speed of light (beta = 0.81). The application of interest is an 8 GeV proton linac proposed for a Fermilab upgrade; at present, the cavity is to be used from 420 MeV to 1.3 GeV. The cavity is similar to the 805 MHz high-beta cavity developed for the SNS Linac, but the resonant frequency (1.3 GHz) and beam tube diameter (78 mm) are the same as for the beta = 1 cavities developed for the TESLA Test Facility. Four single-cell prototype cavities have been fabricated and tested. Two multi-cell prototypes have also been fabricated, but they have not yet been tested. The original concept was for an 8-cell cavity, but the final design and prototyping was done for 7 cells. An 11-cell cavity was proposed recently to allow the cryomodules for the beta = 0.81 cavity and downstream 9-cell beta = 1 cavities to be identical. The choice of number of cells per cavity affects the linac design in several ways. The impact of the number of cells in the 8 GeV linac design will be explored in this paper. Beam dynamics simulations from the ANL code TRACK will be presented.