“…Its utilization has been reported by a number of groups in recent years (Ferge et al, 2006;Fergenson et al, 2004;Gard et al, 1997;Johnston & Wexler, 1995;Kievit, Weiss, Verheijen, Marijnissen, & Scarlett, 1996;Nash, Baer, & Johnston, 2006;Suess & Prather, 1999;Tobias et al, 2005) and applied to fields ranging from atmospheric chemistry (Cziczo et al, 2004;Jost et al, 2004) to microbiology (Fergenson et al, 2004;Steele et al, 2003). Single particle detection for homeland security applications have also been investigated for explosives, chemical weapon agents, and drugs, at Lawrence Livermore National Laboratory (LLNL) (Martin, Farquar, Gard, Frank, & Fergenson, 2007a, 2007bMartin, Farquar, Jones, & Frank, 2007). Schematic of an SPAMS system.…”