• N. Vinogradov, V.N. Aseev, M.R.L. Kern, P.N. Ostroumov, R.C. Pardo, R.H. Scott
  ANL, Argonne, Illinois

The Rare Isotope Accelerator (RIA) facility utilizes the concept of simultaneous acceleration of two charge states from the ion source. We are building a prototype two charge-state (2Q) injector of the RIA Driver Linac, which includes an ECR ion source originally built by Berkeley Ion Equipment Corporation, a LEBT and one-segment of the prototype RFQ. The reassembly and commissioning of the ECR source has been completed. During the commissioning process we modified and replaced several major components of the BIE-100 to increase the source performance. A new diagnostic station has been designed and built for accurate measurements of the output beam emittance. The paper will discuss detailed beam dynamics studies together with extensive emittance measurements of various ion beams. The status of the design and fabrication of 100 kV high voltage platform, achromatic bending system, multi-harmonic buncher, and a full power 57.5 MHz RFQ segment will be presented.

• B. Mustapha, V.N. Aseev, E.S. Lessner, P.N. Ostroumov
  ANL, Argonne, Illinois

The new ray-tracing code TRACK was developed* to fulfill the special requirements of the RIA accelerator systems. The RIA lattice includes an ECR ion source, a LEBT containing a MHB and a RFQ followed by three SC linac sections separated by two stripping stations with appropriate magnetic transport systems. No available beam dynamics code meet all the necessary requirements for an end-to-end simulation of the RIA driver linac. The latest version of TRACK was used for end-to-end simulations of the RIA driver including errors and beam loss analysis.** In addition to the standard capabilities, the code includes the following new features: i) multiple charge states ii) realistic stripper model; ii) static and dynamic errors iii) automatic steering to correct for misalignments iv) detailed beam-loss analysis; v) parallel computing to perform large scale simulations. Although primarily developed for simulations of the RIA machine, TRACK is a general beam dynamics code. Currently it is being used for the design and simulation of future proton and heavy-ion linacs at TRIUMF, Fermilab, JLAB and LBL.

*P.N. Ostroumov and K.W. Shepard. Phys. Rev. ST. Accel. Beams 11, 030101 (2001). **P.N. Ostroumov, V. N. Aseev, B. Mustapha. Phys. Rev. ST. Accel. Beams, Volume 7, 090101 (2004).

• B. Mustapha, V.N. Aseev, P.N. Ostroumov
  ANL, Argonne, Illinois
• J. Qiang, R.D. Ryne
  LBNL, Berkeley, California

In order to benchmark the newly developed beam dynamics code TRACK we have performed comparisons with well established existing codes. During code development, codes like TRANSPORT, COSY, GIOS and RAYTRACE were used to check TRACK's implementation of the different beam line elements. To benchmark the end-to-end simulation of the RIA driver linac, the simulation of the low-energy part (from the ion source to the entrance of the SC linac) was compared with PARMTEQ and found to agree well. For the simulation of the SC linac the code IMPACT is used. Prior to these simulations, the code IMPACT had to be updated to meet the special requirements of the RIA driver linac. Features such as multiple charge state acceleration, stripper simulation and beam collimation were added to the code. IMPACT was also modified to support new types of rf cavities and to include fringe fields for all the elements. This paper will present a comparison of the beam dynamics simulation in the RIA driver linac between the codes TRACK and IMPACT. A very good agreement was obtained which represents another validation of both codes.

• P.N. Ostroumov, V.N. Aseev
  ANL, Argonne, Illinois
• A. Kolomiets
  ITEP, Moscow

The RIB linac includes two strippers for the heaviest ions and three main sections: a room temperature injector up to an energy of ~100 keV/u, a superconducting (SC) linac for ions with charge-to-mass ratio 1/66 or more up to an energy of ~1 MeV and a higher energy SC linac to produce 10 MeV/u beams up to the mass of uranium. The RIA post-accelerator is a complex system designed for acceleration singly-charged ions before the stripper and includes many different accelerating and focusing structures operating both at room and cryogenic temperatures. Extensive accelerator design studies and end-to-end beam dynamics simulations have been performed to minimize the cost of the linac while providing high-quality and high-intensity radioactive beams. Specifically, we have found that cost-effective acceleration can be provided by several hybrid RFQs in the front end. The hybrid RFQs have been proposed and developed for acceleration of low-velocity heavy ions.* For the beam focusing in the second section it is appropriate to use electrostatic lenses and SC quadrupoles inside common cryostats with the resonators. The electrostatic lenses are most effective in the first cryostat of the SC linac.

*P.N. Ostroumov and A.A. Kolomiets. Proc. of the PAC-2001, Chicago, IL, June 18-22, 2001, p. 4077.