• V.V. Paramonov, L.V. Kravchuk
  RAS/INR, Moscow

The hybrid HE11 mode in the cylindrical disk loaded deflectors is twice degenerated. To ensure operational performance and stabilize the position for the plane of deflection, the dispersion curve for modes with perpendicular field polarization must be shifted in frequency with respect to the curve for modes with operating polarization. A lot of decisions, based on the deterioration of the axial symmetry of the structure, are known for this purpose. The resonant method of stabilization is proposed. Resonant elements ' slots, coupled only with modes of perpendicular polarization, are placed in the disks. Two created branches of dispersion curve for composed slot - structure modes are generated and placed symmetrically with respect to the non perturbed dispersion curve for operating modes. In the plane stabilization it provides qualitative advantage with respect a simple frequency shift, because cancels, in the first order, the influence of modes with perpendicular field polarization on the plane of deflection. The criteria for the slots definition are presented. The example of application for the traveling wave S-band deflector is described as well.

• D. Raparia, J.G. Alessi, B. Briscoe, J.M. Fite, O. Gould, V. LoDestro, M. Okamura, J. Ritter, A. Zelenski
  BNL, Upton, Long Island, New York

BNL 200 MeV linac has been under operation since 1970 and gone through several changes during its 40 year lifetime. The latest reconfiguration in low and medium energy (35 and 750 keV) beam transport lines results in about a factor of 2 reduction in the transverse emittance for the accelerated polarized proton beam, and for the unpolarized high current H^- beam a several fold reduction in the radiation levels due to beam losses throughout the linac and isotope production facility complex with more beam current on the isotope production target. These improvements are achieved by proper matching into the linac in longitudinal as well as transverse phase space. This paper will emphasize how longitudinal matching resulted in lower emittance and beam losses.