• Y.-N. Rao, R.A. Baartman
  TRIUMF, Vancouver
• G. Goh
  SFU, Burnaby, BC
• I. Tashev
  UBC, Vancouver, B.C.

Funding: TRIUMF receives funding via a contribution agreement through the National Research Council of Canada.

For ISAC at TRIUMF, radioactive isotopes are generated with a 500MeV proton beam. The beam power is up to 40kW and can easily melt the delicate target if too tightly focused. We protect this target by closely monitoring the distribution of the incident proton beam. There is a 3-wire scanner monitor installed near the target; these give the vertical profile and the +45 and -45 degree profiles. Our objective is to use these 3 measured projections to find the 2-D density distribution. By implementing the maximum entropy (MENT) algorithm, we have developed a computer program to realize tomographic reconstruction of the beam density distribution. Of particular concern is to make the calculation sufficiently efficient that an operator can obtain the distribution within a few seconds of the scan. As well, we have developed the technique to perform phase space reconstruction, using many wire scans and the calculated transfer matrices between them. In this paper we present details of the computer code and the techniques used to improve noise tolerance and compute efficiency.

• F. Yan, Y.-C. Chao, R.E. Laxdal, M. Marchetto
  TRIUMF, Vancouver
• S. Dechoudhury, V. Naik
  DAE/VECC, Calcutta
• G. Goh
  SFU, Burnaby, BC
• B. Mustapha
  ANL, Argonne

The TRIUMF ARIEL Project plans to build a 50MeV electron linac at 10mA to produce radioactive ion beams through photofission. Beam dynamics studies of the accelerator are on-going. The TRACK code originally written to simulate proton and heavy ion linacs has been used in e-linac modeling studies. This paper will summarize the TRACK simulation studies and the simulation results will be compared with other codes like PARMELA and ASTRA.

• M. Marchetto, R.A. Baartman, Y.-C. Chao, G. Goh, S.R. Koscielniak, R.E. Laxdal, F. Yan
  TRIUMF, Vancouver
• S. Dechoudhury, N. Vaishali
  DAE/VECC, Calcutta

TRIUMF proposes a 1/2 MW electron linac (e-linac) for radioactive ion beam production via photofission. The e-linac is to operate CW using 1.3 GHz superconducting (SC) technology. The accelerator layout consists of a 100 keV thermionic gun, a normal conducting buncher, an injector module, and main linac modules accelerating to a final energy of 50 MeV. The design beam current is 10 mA. The beam dynamics of the injector, where electrons make the transition to the fully relativistic state, has been identified as the most critical part of the design and is the subject of simulations (starting at the gun cathode) using realistic EM fields in PARMELA and TRACK. CW operation demands the novel choice of adopting an SC capture section. A preliminary design of the injector foresees a capture section composed either of two independent or two coupled single-cell cavities, beta <1, that increase the energy to about 500 keV, followed by one nine-cell cavity that boosts the energy up to 10 MeV. The design parameters are subjected to a global optimization program. In this paper we present results from the beam dynamics study as well as details and final outcome of the optimization process.