Interstellar dust laser explorer (IDLE): A new instrument for submicron analyses of stardust-quantification of laser SNMS

摘要

We have constructed a TOFSIMS instrument based upon the BIOTOF design. SIMS mapping of mass resolved secondary ions and molecules with an intrinsic mass resolving power of 3700 has been achieved with an estimated spatial resolution of 250 run. We have conducted studies of non-resonant laser post-ionization of sputtered neutrals in order to improve the ionization efficiency over SIMS and avoid matrix effects for more precise quantification of element abundances. The laser used is a GAM F-2 excimer laser producing up to 4.5 mJ per pulse at 750 Hz at a wavelength of 157 nm. With a photon energy of 7.9 eV, around 60% of the elements of the periodic table may be non-resonantly photo ionized by single photon ionization. SNMS laser post ionization improves detection sensitivity especially for elements with mid-range first ionization potentials up to the single photon energy of 7.9 eV. We are currently quantifying the highest sensitivities obtainable using this technique for a range of elements. (c) 2006 Elsevier B.V. All rights reserved.