AUTOMATED LASER-ABLATION SAMPLING (ALAS) FOR ICP-MS

A computer program has been developed to perform automated laser ablat ion ICP-MS measurements. Up to 500 points can be selected on one sampl e and analyzed automatically. For each point, all the laser parameters (laser pulse mode, laser energy, Q-switch delay, frequency, and numbe r of shots per point) can be selected individually. All of these param eters are stored together with the coordinates of the selected points in a log file. Due to the degree of automation offered by the program, measuring distribution patterns or doing fundamental studies on laser ablation by systematically varying the laser parameters becomes much less time-consuming. Homogeneity testing is possible by selecting an a rea on the sample and specifying a number of sample sites, which will be randomly distributed within this area. Stored patterns can be re-us ed offering the possibilities of repetitive sampling or depth profilin g. The performance of the program is shown by doing a homogeneity anal ysis of a steel sample. Furthermore, some hardware changes were made i n order to simplify the location of the laser spot on the sample and t o illuminate the sample not only from the top or the side, but also fr om the bottom of the sample.