ABSTRACT

This source utilizes an ion gun emitting beam of ions (e.g., Bi+, Ga+, and Au+) or ion clusters (e.g., C and Bi60 3

+ +) toward the analyzed surface. Ions, treated with the ion gun, and desorbed from the surface are traveling to the time-of-ight (TOF) analyzer, where their m/z are determined [5,6]. The main advantage of this ion source is its high spatial resolution. For routine analyses, the pixel resolution of the nal image is usually better than 10 × 10 μm, sometimes reaching the value of 1 × 1 μm or less, providing the ion beam can be precisely focused on the area of interest [7]. This parameter corresponds to the image resolution in a range from 2500 to 25,000 dpi. However, the ion beam carries a high quantity of energy, which results in the pronounced and unwanted fragmentation of the molecules in the source, especially those of higher MW. In conclusion, SIMS is mainly used for imaging of small objects (e.g., single cells, internal parts of the electronic components, metal ions, catalysts, pollutants, and others) where high resolution of the image is the most important factor. Additionally, MW range of the ionized molecules usually does not exceed 1000 Da, which signicantly limits the nature of the samples successfully undergoing analysis performed by this method.