• S.V. Kutsaev, R.O. Bolgov, M. Gusarova, D.S. Kamenshikov, K.I. Nikolskiy, A.Yu. Smirnov, N.P. Sobenin, S.E. Toporkov
  MEPhI, Moscow

This paper presents the results of a research that analyzed the possibility of using a magnetic coupled disk-loaded structure (DLS-M) as an accelerating structure. DLS-M seems to have decent advantages comparing to the classical electrical coupled structure (DLS). The electrodynamics parameters of such a structure at various modes in C-band for a wide range of phase velocities as a function of aperture radii and coupling slot sizes are presented. Both forward and backward travelling wave regimes are considered. The essential parameters are compared to those of classical DLS. The design of an input coupler to the accelerator consisting of this type structure cells is also presented.

• A. Palmieri, F. Grespan, A. Pisent
  INFN/LNL, Legnaro (PD)
• F. Scantamburlo
  INFN- Sez. di Padova, Padova

In order to attain the stringent goals that assure the required performances of the IFMIF-EVEDA RFQ in terms of field uniformity, Q-value and RF-induced heat removal capability, the study of the 3D details of the cavity is particularly important. In this paper the main issues regarding the design of the slug tuners, cavity ends and vacuum grids are addressed, as well as the related optimization procedure.

• S.A. Kondrashev, A. Barcikowski, A. Levand, P.N. Ostroumov, R.C. Pardo, G. Savard, R.H. Scott, T. Sun, R.C. Vondrasek, G.P. Zinkann
  ANL, Argonne

An emittance meter based on a pepper-pot coupled to a CsI (Tl) scintillator has been developed over the last several years [1] at Argonne National Laboratory. A compact version of such a probe for on-line emittance measurements has been designed, built and installed into the low energy beam transport (LEBT) line of the Argonne Tandem Linac Accelerator System (ATLAS) and also downstream of the gas catcher of the recently commissioned Californium Rare Isotope Breeder Upgrade (CARIBU). The probe has demonstrated the capability to measure emittance of ion beams with a current density as low as 10 nA/cm². Systematic emittance measurements in the ATLAS LEBT for different ion species have been done and results will be presented. The probe, based on a pepper-pot coupled to an MCP viewing system, has been designed and built to measure the emittance of low intensity (10²-106 ions/s) radioactive CARIBU ion beams.

[1] S. Kondrashev et al. Development of a pepper-pot emittance probe and its application for ECR ion beam studies. Nuclear Instruments and Methods in Physics Research A 606, 2009, pp. 296-304.

• Z. Li, L. Ge, K. Ko
  SLAC, Menlo Park, California
• W. Hartung, J.P. Holzbauer, J. Popielarski
  NSCL, East Lansing, Michigan

In the driver linac of the Facility for Rare Isotope Beams (FRIB), multipacting is an issue of concern for the superconducting resonators, which must accelerate the ion beams from 0.3 MeV per nucleon to 200 MeV per nucleon. While most of the multipacting bands can be conditioned and eliminated with RF, hard multipacting barriers may prevent the resonators from reaching the design voltage. Using the ACE3P code suite, multipacting bands can be computed and analysed with the Track3P module to identify potential problems in the resonator design. This paper will present simulation results for multipacting in half-wave and quarter-wave resonators for the FRIB driver linac and compare the simulations with RF measurements on the resonators.