High Intensity Beam Extraction and Transport for SuSI -- the Superconducting Source for Ions at NSCL/MSU

The ion beam produced with an ECR ion source (ECRIS) with an extraction voltage of 30 kV may be additionally accelerated using a negative voltage of -30 kV applied to the third electrode of the accel-decel extraction system connected to the vacuum pipe of the beamline. The total kinetic energy of the beam may be increased up to 60 keV per unit charge. The influence of the space charge on the ion beam may be decreased more than two times and it is possible to remove the focusing elements from the analyzing part of the beamline with the simultaneous shortening of the distance between the ECRIS and the analyzing magnet. The voltage at the vacuum pipe of the beamline must be kept constant from ECRIS till the point of the full separation of the beam charge states placed near the focal plane of the analyzing magnet. At this point the vacuum pipe break is provided for increasing of the voltage up to ground value. The kinetic energy of the beam is decreasing down to about 30 keV per unit charge just after this point. For decreasing of the beam divergence the focusing solenoid is installed behind the break point. The simulation of the argon beam transportation in the proposed beam line is performed in this work.