• N. Solyak, E. Gianfelice-Wendt, I.G. Gonin, S. Kazakov, V.A. Lebedev, S. Nagaitsev, J.-F. Ostiguy, N. Perunov, G.V. Romanov, V.P. Yakovlev
  Fermilab, Batavia

The concept design of the 2.5 GeV superconducting CW linac of the Project X is discussed. The linac structure and break points for different cavity families are described. The results of the RF system optimization are presented as well as the lattice design and beam dynamics analysis.

• N. Solyak, I.G. Gonin, J.-F. Ostiguy, V.P. Yakovlev
  Fermilab, Batavia
• N. Perunov
  MIPT, Dolgoprudniy, Moscow Region

In this paper, we discuss beam dynamics optimization for a proposed continuous wave (CW) Project-X superconducting (SC) linac. This 2.6 GeV linac has an average current (over few microseconds) of 1 mA, with a pulsed current of up to 5-10 mA. The beam power is 2.6 MW. The CW linac consists of a low-energy 325 MHz section (2.5 MeV - 470 MeV) containing three families of SC single-spoke resonators and one family of triple-spoke resonators followed by a high-energy 1.3 GHz SC section (470 MeV - 2.6 GeV) containing squeezed elliptical (β=0.81) and ILC-type (β=1) cavities. Transverse and longitudinal dynamics in the CW linac are modeled assuming a peak current 10 mA. Different options for focusing structures are considered: solenoidal, doublet, and triplet focusing in the low-energy section; FODO and doublet focusing in the high energy section.

• T. Sen, C.M. Bhat, H.J. Kim, J.-F. Ostiguy
  Fermilab, Batavia

We investigate the dynamics of longitudinally flat bunches created with a second harmonic cavity in a high energy collider. We study Landau damping in a second harmonic cavity with analytical and numerical methods. The latter include particle tracking and evolution of the phase space density. The results are interpreted in the context of possible application to the LHC.