Active control of the ablation plume for laser ablation atomic fluorescence spectroscopy

We have developed an extreme sensitive trace element detection technique that has been labeled Laser ablation atomic fluorescence (LAAF) spectroscopy, and applied to a nanometer-scale solid surface analysis. The absolute weight of the detection limit of 870 ag (10^-18g) and high depth resolution of 3.6 nm had been demonstrated in trace sodium detection of polymethylmethacrylate. As a laser ablation was used in the LAAF spectroscopy, the behavior of the ablation plume is a very important factor for high sensitivity. So, we tried to control the plume by a buffer gas and an assist mask for more sensitive analysis. The diffusion velocity of the ablated particles was modified in collision with the gas molecules. Furthermore, it was found that the form of the plume was changed by the mask. Thus, improvement of the detection sensitivity of the LAAF is expected using this approach.