AN ION-SOURCE FOR ELECTRICAL PULSE INDUCED DESORPTION

Ions may be formed by different mechanisms (lasers, ion beams etc.), u sing fast dissipation of energy at a solid surface, causing a non-equi librium phase transition of the surface material. Some years ago a tec hnique was proposed using very short high-current electrical pulses th rough a thin wire for transferring sufficient energy to desorb materia l from the wire surface. The authors have modified this technique to e liminate the most severe problems connected with the original ion sour ce. The improved ion source consists of a thin aluminium film on a pla nar substrate. The generation of ions from an active area of the alumi nium film, which can be coated with a sample substance, can be simply actuated by a short electrical pulse with significantly less energy co mpared with the original ion source. Some first investigations of the characteristics of the ion source are presented, using both a time-of- flight and a Fourier transform ion cyclotron resonance mass spectromet er. (C) 1997 Elsevier Science B.V.