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Type of presentation requested : Poster Classification : [D05] Code Developments and Simulation Techniques 1044  Beam Tracking Study for the Large Aperture Bump System M. Shirakata, H. Fujimori, Y. Irie, KEK, Ibarakiken Generally, the magnet aperture tends to be large with respect to the core length for the high intensity accelerators. The effect of the fringe fields on beam may cause the unexpected interferences when the magnet aperture is very large. In joint project of JAERI and KEK, the compact beam bump system is required for the beam injection of the 3 GeV booster ring. The eight magnets bump system is under consideration, here. The core length of bump magnets cannot be so long and the strong fringe fields are expected. Because the distance between the adjacent bump magnets is also close, the fringe fields enhance or override each other and the magnet effective lengths change dinamically. The beam tracking study is discussed of the large aperture bump system with the crossing fringe fields from the closely aligned bump magnets. Type of presentation requested : Poster Classification : [D05] Code Developments and Simulation Techniques 1495  An Analysis Tool for RF Control for Superconducting Cavities S.N. Simrock, DESY, Hamburg; V. Ayvazyan, A. Vardanyan, Yerevan Physics Institute, Yerevan The rf control analysis tool consists of a set of library blocks to be used with SIMULINK. The tool allows to study the performance of a given rf control design. The library blocks include models for the superconducting cavities, the rf power source, the beam, and the rf feedback system. The rf control relevant electrical and mechanical characteristics of the cavity are described in form of timevarying state space models. Included are perturbations from Lorentz force detuning and microphonics with the appropriate parameters for several mechanical resonances. The power source is calibrated in terms of actual power and includes saturation characteristics and noise. An arbitrary time structure can be imposed on the beam current to reflect a macropulse structure and bunch charge fluctuations. For rf feedback several schemes can be selected: Generator driven system or selfexcited loop, traditional amplitude and phase control or I/Q control. The choices for the feedback controller include analog or digital approaches and various choices of filters for the gain stages. Feed forward can be added to further suppress repetitive errors. The results of a performance analysis of the TTF Linac rf system using these tools are presented. Type of presentation requested : Poster Classification : [D05] Code Developments and Simulation Techniques 141  Resonance Strengthening and Damping of Synchrotron Oscillations A. Taratine, JINR, Dubna, Moscow Region Resonance strengthening and damping of synchrotron oscillations of collider bunch halo particles was studied by simulation. Additional longitudinal kicks are applied in resonance with the synchrotron oscillations of the particles. It was shown that the strengthening of particle synchrotron oscillations can be high efficient. The resonance damping of particle synchrotron oscillations is only possible when the inverse population of the accelerated bunch halo is realized. Resonance method of synchrotron oscillation strengthening can be used for the extraction of beam halo particles with a bent crystal to improve the background conditions for colliding beam experiments and to fulfill simultaneously some fixed target experiments. Possibility to use this method for high intensity beams is also discussed. Type of presentation requested : Poster Classification : [D05] Code Developments and Simulation Techniques 215  BRICTEST: a Code for Charge Breeding Simulations V. Variale, INFNBari, Bari; T. Clauser, A. Raino', Universita' di Bari e INFNBari, Bari; M. Claudione, Universita' di Bari, Bari In the framework of the SPES project [1], already funded by INFN at the LNL (Padua) in Italy, for Radioactive Ion Beam (RIB) production, an experiment of a charge breeder device, BRIC, is in progress at Bari INFN section [2]. BRIC is an EBIS type ion charge state breeder in which a quadrupolar rf field is added at the trapped ion region to introduce a selective containment with the aim to increase the wanted ion containment efficiency. A code that study the ion charge state evolution in the trap region, which allows of choosing the rf quadrupole parameters to optimise the ion charge breeding efficiency, has been recently developed in Bari. In this paper the main feature of the code, named BRICTEST, and the simulation test will be presented and discussed. [1]"SPES Project Study", LNLINFN (REP), 145/99 [2]G. Brautti,T. Clauser,A. Raino',V. Stagno, V. Variale,"BRIC: An EBIS Design for Charge State Breeding in RIB. Type of presentation requested : Poster Classification : [D05] Code Developments and Simulation Techniques 955  High Current Beam Simulation using Templates* L. Vorobiev, R.C. York, NSCL, East Lansing Charged particle beam dynamics including space charge and image forces was simulated in both two and three dimensions with a newly developed code. The formalism for this new code is based on the template potential techique and can be employed for calculational approaches ranging from envelope equations to particleincell (PIC) models in either two or threedimensional geometries. The selfconsistency of the method is not complete for all cases but is appropriate for a large class of beam distributions and conducting boundary configurations. The calculational speed is high and memory demands are moderate in comparison with conventional PIC algorithms. *Work supported by the U.S. Department of Energy Contract No. DEFG0299ER41118 Type of presentation requested : Poster Classification : [D05] Code Developments and Simulation Techniques 1473  Aberration Coefficients of High Order Optics for Beam Transport Channels I. Yudin, JINR, Dubna, Moscow Region In this paper the nonlinear high order beam optics is built for a wide list of different elements of the charge particle transport channels. The optical elements are a drift space, a bending magnet, a quadrupole, a sextupole, an octupole, a solenoid, a toroidal ("orange" type) magnetic lens, an accelerating tube. The motion equations are written. The solution techniques is the Green' function method (GFM). Polarization effects and selfcoordinate space charge analysis are performed to integrate it into the proposed model. The programme realization of our model is presented. Some results of the investigation are demonstrated. Type of presentation requested : Poster Classification : [D05] Code Developments and Simulation Techniques 694  A Conformal Scheme for Wake Field Calculation* I. Zagorodnov, T. Weiland, TUDarmstadt, Darmstadt The existing computer codes experience problems in wake field calculations for long smooth structures. To overcome them a new staircase free scheme for rotationally symmetric case is developed. It allows to calculate wake potentials for ultra short bunches in long arbitrary shaped perfectly conducting geometries. Unlike previous conformal approaches the scheme has a second order convergence without the need to reduce the maximal stable time step of conventional staircase method. Several numerical examples are presented and the algorithm is compared to other approaches. * Work supported in part by the Deutsche Forschungsgemeinschaft, Graduiertenkolleg Physik und Technik von Beschleunigern Type of presentation requested : Poster Classification : [D05] Code Developments and Simulation Techniques 1519  Computation of RFProperties of Long and Complex Structures* U. van Rienen, H. Glock, D. Hecht, K. Rothemund, Universität Rostock, Rostock Numerical calculation of RFproperties of accelerating structures are normally done by numerical field solving codes such as MAFIA or Microwave Studio(TM). But if a certain amount of details has to be considered in long structures, e.g. the TESLA accelerating channel, the numerical effort grows to a level where the computational resources reach the limit of todays computer hardware. Therefore we have been developing a method called Coupled SParameter Calculation (CSC) which is based on a scattering parameter description. It allows the splitting of large structures into several components and results in the entire structure´s scattering properties, or, if all external ports are closed, in the eigenfrequencies and modes of the structure. The Sparameters of the components are computed by customary field solving codes. Exploiting all possible symmetries and repetitions can reduce the computational expense, especially if certain components are of rotational symmetry which allows for 2Dcalculation. Additional a frequency range can be specified concentrating on the frequency band of interest, hence neglecting lower frequencies, which is not possible for the majority of eigenmode solvers. The authors want to demonstrate the capabilities of CSC reporting results on the effect of different HOMcoupler geometries in the TESLA channel and compare the effects of different cavitiy and coupler arrangements. * work supported by DESY, Hamburg Type of presentation requested : Poster Classification : [D05] Code Developments and Simulation Techniques / 