A pneumatic gun for ballistic delivery of microparticles to soft targets is
proposed and demonstrated. The particles are accelerated by a high speed flow
of Helium in a capillary tube. Vacuum suction applied to a concentric, larger
diameter tube is used to divert substantially all of the flow of Helium from
the gun nozzle, thereby preventing the gas from hitting and damaging the
target. Speed of ejection of micron-sized gold particles from the gun nozzle,
and their depth of penetration into agarose gels are reported.Comment: 7 pages, 3 figure