Charge exchange injection and diagnostics with H- in LEAR

The new 50 MeV H- beam1 from Linac I has been employed for first machine tests at the end of 1984. The H- can be injected in the normal sense (''clockwise'') to test the ring in antiproton polarity. In this mode, the lifetime of a beam of 8 x 108 H- has been determined to be about 7 s. The H- can also be stripped in the injection line to inject protons for machine studies without changing the ion source. Using a new injection line2 and a foil stripper in the centre of the straight section SL4, protons can be injected anticlockwise into LEAR by stripping injection. By multiturn injection, intense beams of protons for the collider option can be produced. Secondly, by using the normal injection kicker, protons can be ejected to test the antiproton injection line up to the PS with antiproton polarity. First results of the injection tests and the diagnostics based on fast and slow electrons from the stripper foil are reported