A CESIUM SPUTTER NEGATIVE-ION SOURCE USING A MULTI-LAMINATE WIRE MESHIONIZER

A new ventilated surface ionizer has been developed for a 860A cesium sputter negative ion source operated at BNU. The new ionizer consists of a multi-laminate nickel wire mesh and a spiral heater, and is spher ical in shape. Low pressure cesium vapour diffuses through the wire me sh to the extraction side of the ionizer, meanwhile the neutral cesium can be ionized. The ionizer is capable of producing a positive ion cu rrent up to milliampere range. The negative ion current is 50 mu A for P- and more than 150 mu A for 0(-) and Si-.