Hollow Cathode Ion Source for IMA

This paper describes a hollow cathode duoplasmatron which has been developed for the use as primary ion source in the ion micro prove analyzer(IMA). Design parameters have been given for construction and operation of the ion source. Ion beams of O+2, O-, A+r of 10 keV energy were obtainable with the beam intensities of 1.7×10-5 -1.8×10-4Ampere having an initial energy of less than 25 eV at full width at half maximum. The stability of the ion beam current was within±1% fluctuation range under optimum gas pressure in the discharge chamber. The constituents of the ion beam was mass-analyzed by means of a Wien filter. A technique for measuring the beam emittance was developed and results are discribed. The normarized maximum brightness and the normarized minimum emittance of the ion source were 3×1010A/m2·rad2and 1.7×10-8 m ·rad respectively. Finally, the ion source was incorporated to the Hitach model IMA-2 ion micro probe analyzer for the examination of the focusing properties .The specimen current of 25 μA and minimum spot size of about 2μm diameter were obtained. By apply ing Oxygen+primary ion with oxygen gas introduction technique and specimen tilting method, the secondary ion current intensity of F+e increased to approximately 200 times larger than that obtained by applying Argon ion and without applying above mentioned technique.