Ostroumov, P.N.

Paper	Title	Page
MOP01	Beam Intensity Adjustment in the RIA Driver Linac	33
	P.N. Ostroumov, J.A. Nolen, I. Sharamentov ANL/Phys, Argonne, Illinois A.V. Novikov-Borodin RAS/INR, Moscow
	The Rare Isotope Accelerator Facility currently being designed in the U.S. will use both heavy ion and light ion beams to produce radionuclides via the fragmentation and spallation reactions, respectively. Driver beam power of up to 400 kW will be available so that beam sharing between target stations is a viable option to increase the number of simultaneous users. Using a combination of rf-sweepers and DC magnets the driver beams can be delivered to up to four targets simultaneously. With simultaneous beam delivery to more than one target independent adjustment of the relative beam intensities is essential. To enable such intensity adjustment we propose to use a fast chopper in the Medium Energy Beam Transport (MEBT) section. Several options of fast chopper design are discussed. The MEBT beam optics is being designed to accommodate and match the chopper technical specifications. Possible solutions and performance with the fast chopper are proposed.
MOP71	Advanced Beam-Dynamics Simulation Tools for RIA	186
	T.P. Wangler, R. Garnett LANL, Los Alamos, New Mexico N. Aseev, P.N. Ostroumov ANL/Phys, Argonne, Illinois R. Crandall TechSource, Santa Fe, NM D. Gorelov, R.C. York NSCL, East Lansing, Michigan J. Qiang, R. Ryne LBNL, Berkeley, California
	Understanding beam losses is important for the high-intensity RIA driver linac. Small fractional beam losses can produce radioactivation of the beamline components that can prevent or hinder hands-on maintenance, reducing facility availability. Operational and alignment errors in the RIA driver linac can lead to beam losses caused by irreversible beam-emittance growth and halo formation. We are developing multiparticle beam-dynamics simulation codes for RIA driver-linac simulations extending from the low-energy beam transport (LEBT) line to the end of the linac. These codes run on the NERSC parallel supercomputing platforms at LBNL, which allow us to run simulations with large numbers of macroparticles for the beam-loss calculations. The codes have the physics capabilities needed for RIA, including transport and acceleration of multiple-charge-state beams, and beam-line elements such as high-voltage platforms within the linac, interdigital accelerating structures, charge-stripper foils, and capabilities for handling the effects of machine errors and other off-normal conditions. We will present the status of the work, including examples showing some initial beam-dynamics simulations.
TUP26	Alternating Phase Focusing in Low-Velocity Heavy-Ion Superconducting Linac	348
	P.N. Ostroumov, K.W. Shepard ANL/Phys, Argonne, Illinois A. Kolomiets ITEP, Moscow E.S. Masunov MEPhI, Moscow
	The low-charge-state injector linac of the RIA post-accelerator is based on ~60 independently phased SC resonators providing total ~70 MV accelerating potential. The low charge-state beams, however, require stronger transverse focusing, particularly at low velocities, than is used in existing SC ion linacs. For the charge-to-mass ratios considered here (q/A = 1/66) the proper focusing can be reached by the help of strong SC solenoid lenses with the field up to 15 T. Magnetic field of the solenoids can be reduced to 9 T applying an Alternating Phase Focusing (APF). A method to set the rf field phases has been developed and studied both analytically and by the help of the three-dimensional ray tracing code. The paper discusses the results of these studies.
TH204	End-to-End Beam Dynamics Simulations for the ANL-RIA Driver Linac	584
	P.N. Ostroumov ANL/Phys, Argonne, Illinois
	The proposed Rare Isotope Accelerator (RIA) Facility consists of a superconducting (SC) 1.4 GV driver linac capable of producing 400 kW beams of any ion from hydrogen to uranium. The driver is configured as an array of ~350 SC cavities, each with independently controllable rf phase. For the end-to-end beam dynamics design and simulation we use a dedicated code, TRACK. The code integrates ion motion through the three-dimensional fields of all elements of the driver linac beginning from the exit of the electron cyclotron resonance (ECR) ion source to the production targets. TRACK has been parallelized and is able to track large number of particles in randomly seeded accelerators with misalignments and a comprehensive set of errors. The simulation starts with multi-component dc ion beams extracted from the ECR. Beam losses are obtained by tracking up to million particles in hundreds of randomly seeded accelerators. To control beam losses a set of collimators is applied in designated areas. The end-to-end simulations with the TRACK code have been extremely useful for studies of different options of the driver linac design with respect to beam quality, beam losses and sensitivity of beam parameters to various types of errors.
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