The Design of the ISR Inflector

Protons with momenta up to 28 GeV/c will be ejected from the CERN Proton Synchrotron (CPS) transferred via two beam transfer channels, each about 500 m long and injected into each of the two Intersecting Storage Rings (ISR) which are being constructed at CERN. At 1/4 betatron wavelength downstream of the injection septum magnet a fast pulsed inflector deflects the beam over an angle of 2.5 mrad onto the injection orbit. This pulsed inflector consists of two delay-line type magnets each 1.5 m long, which operate in ultra high vacuum. The C-shaped ferrite magnets have a gap width of 44.5mm and a gap height of 20 mm. The useful magnetic field region is more than 40 mm wide. A prototype inflector has been constructed with all auxiliary electrical elements, one magnet and two UHV tanks. The 2.1 ??sec long magnetic pulses are generated by discharging a coaxial high voltage cable via a deuterium thyratron into the magnet and its matched terminating resistor of 14 ??. The droop on the magnetic field flat top is 1% and the transients on the flat top and at 1 ??sec after the pulse are within ?? 1%. The magnet has been tested at its maximum required operating voltage of 21.5 kV and, additionally, at 25 kV in a vacuum of 10-10 torr.