Laser Induced Breakdown Spectroscopy (LIBS) Detection of Heavy Metals Using a Cone Penetrometer: System Design and Field Investigation Results

摘要

U.S. Army Engineer Waterways Experiment station (WES) investigators hasve designed, fabricated and field tested a cone penetrometer sensor based on Laser Induced Breakdown Spectroscopy (LIBS). The patented LIBS penetrometer design presented here is a useful tool in the detection, identification and delineation of heavy metals in soils in teh vadose zone. The LIBS penetrometer is forced into the ground using a hydraulic ram system mounted within the Site Characterization and Analysis Penetrometer System (SCAPS) truck. The probe design relies on a recessed window geometry to avoid output window damage and a 80 millijoule Nd: YAG laser inside the probe to create the plasma. The probe design is discussed with particular emphasis on design tradeoffs, strengths and limitations of this design.