The Design of an 860 KeV Pre-Accelerator for the New SIN High Current Injector Cyclotron

The new injector for the SIN 590 MeV ring cyclotron will deliver a continuous 72 MeV proton beam of more than 1 mA. The pre-accelerator for this injector is of the Cockcroft-Walton type and will incorporate some unconventional features. A 40 keV 30 mA source is decoupled from the acceleration tube by a 4 m long beam transport system. The beam line consists of two 45° bends which filter out the parasitic H2+ and H3+ beams and is dispersionless for tie remaining clean beam of protons. The acceleration tube is of a simple constant gradient type with a large aperture. Solenoids and quadrupoles are able to match the 40 keV beam to the acceptance of the tube for a wide range of intensities. A low power chopper and a 50 MHz buncher will be installed inside the dome. A 300 keV test stand with a 40 keV ion source, associated beam line and a 260 keV prototype accelerating tube is under construction.