Nd:YAG laser microprobe system for Fourier-transform ion cyclotron resonance mass spectrometry

An optical system has been interfaced to a commercial Fourier-transform ion cyclotron resonance mass spectrometer to facilitate laser microprobe mass spectrometry. The system allows a 266-nm laser beam to be focused and directed onto a specimen surface near an ICR trap plate. Reflected light is used to view the specimen in a reflected light microscope mode. Spatial resolution of the reflected light microscope, and laser microprobe spot diameter are 5–8 μm and are limited by the working distance of the objective lens. A novel specimen translation mechanism was constructed which overcomes difficulties associated with positioning a specimen in a high magnetic field. An interface system based on an IBM PC-AT was developed to coordinate experimental sequences between the ICR and laser.