Secondary ion mass spectrometry (SIMS) is used for chemical and isotopic analysis of micrometer-scale volumes of material. Dynamic SIMS continuously sputters a sample, modifying the sample surface chemistry with the primary implanted species, to achieve trace element sensitivity down to nmol/mol (parts per billion) or isotope fractionation determinations down to one part in one thousand or better. Both large- and small-geometry dynamic SIMS instruments are available at NIST. Current projects include improving and standardizing actinide particle analyses, quantifying solar wind ion implants in collector materials from NASA's Genesis Discovery Mission, and developing new measurement paradigms (e.g., new primary ion species, sample flooding species, and multicollection schemes).