[en] We present a steering algorithm which, with the aid of a model, allows the user to specify beam behavior throughout a beamline, rather than just at specified beam position monitor (BPM) locations. The model is used primarily to compute the values of the beam phase vectors from BPM measurements, and to define cost functions that describe the steering objectives. The steering problem is formulated as constrained optimization problem; however, by applying optimal control theory we can reduce it to an unconstrained optimization whose dimension is the number of control signals.

[en] We consider halo formation in continuous beams oscillating at natural modes by inspecting particle trajectories. Trajectory equations containing field nonlinearities are derived from a weighted polynomial expansion. We then use perturbational techniques to further analyze particle motion

No abstract available

[en] Progress was made during the past decade towards a better understanding of halo formation caused by beam mismatch in high-intensity beams. To test these ideas an experiment was carried out at Los Alamos with proton beams in a 52-quadrupole focusing channel. Rms emittances and beam widths were obtained from measured beam profiles for comparison with the maximum emittance-growth predictions of a free-energy model and the maximum halo-amplitude predictions of a particle-core model. The experimental results are also compared with multiparticle simulations. In this paper we will present the experimental results and discuss the implications with respect to the validity of both the models and the simulations

No abstract available

[en] A simple, novel electrostatic quadrupole (ESQ) lens system has been developed to transport and focus an intense, high-brightness (normalized beam brightness ∼ 10¹¹ A/m² rad²) H^- beam. The physics of emittance growth in the ESQ transport system is studied in detail by computer simulation of beam dynamics, when the influence of various factors, e.g., input beam parameters, aberrations, misalignments, etc. has been examined. Possible methods to control the emittance growth have been suggested

[en] A moment method technique for solving Laplace's equation is presented. The technique is then extended to Poisson's equation to include space charge. The procedure is implemented on a PC and applied to the cases of an electrostatic quadrupole (ESQ) lens and an ellipsoidal bunch in a grounded pipe

[en] An experiment is designed to transport a round and diverging H^- beam, with beam current of 30 mA and voltage of 35 kV, over a length of about 30 cm with the aim to match it to an RFQ with a modest emittance growth. The low energy beam transport system consists of six electrostatic quadrupole (ESQ) lenses. A linear KV code, in conjunction with a 3-D Laplace solver, is used to configure the electrode geometry. Fringe field integrals from the Laplace solver are given as input to a modified PARMILA code to evaluate the influence of the nonlinear forces and calculate the emittance growth. The ESQ system is designed with a mechanical tolerance of < 1 mil; the critical issue of alignment of the apparatus with respect to the beam is addressed. Details on the design and construction of the ESQ system and some preliminary experimental results are presented

[en] We analyze the image effects of a cylindrical pipe on continuous beams with elliptical symmetry. Differential equations involving the second-order spatial moments of a particle distribution are given. From the moment equations, a set of Kapchinskij-Vladimirskij-type equations is developed, which include the image effects of a cylindrical beam pipe. These equations are used to analyze the image effects for focusing, drift, defocusing, drift channels, sheet beams, and a magnetic quadrupole matching section. copyright 1996 The American Physical Society

[en] A low-energy beam transport system is designed with the aim of transporting a 30 mA, 35 kV H^- beam from a volume source and focusing it into an RFQ. The characteristics of the beam from the source are determined analyzing the emittance data. The behavior of the beam through the LEBT is studied using simulation codes. The system parameters are optimized so that the LEBT has a very modest contribution to the emittance growth (here a factor of about 1.5) and the emittance budget of the linac section is maintained