Detection of mercury and thorium in aerosol particles with enhanced laser induced airbreakdown spectrum

Laser induced breakdown spectroscopy (LIBS) has a potential to detect the trace element in environment without sampling and pretreatment process. The typical detection limit for LIBS is close to PPM. It can only measure the elements with the content above milligram per cubic meter in aerosol. This limit has been improved to PPB level (i. e. μg/m³) with an enhanced plasma spark collector. A prototype called Aero-LIPS has been set up and successfully identified several heavy elements from sand-dusted air, such as Lead, Mercury, Thorium and Uranium. It shows the P-line intensities of Thorium at 698.966 nm and 576.055 nm had grown up 50 times compared with good quality air. The dependence of the thorium P-line intensity on the contents of particle matter in aerosols demonstrates the potential application of enhanced laser induced air plasma spectroscopy for the monitor of U/Th emission around the nuclear facilities. (authors)