Nanoparticle enhanced laser induced plasma signal technology
It has also become a trend to realize charged detection of vacuum switch vacuum based on la-ser-induced breakdown spectroscopy,which can achieve a detection capability of 10-3 Pa.However,in the laser-induced breakdown spectroscopy(LIBS)technique there exist problems such as high detection limit and low sensitivity,so an enhancement technique was proposed based on metal nanoparticles to im-prove the precision of charged detection of vacuum switch vacuum.By coating a silver nanoparticle layer on the sample surface,the laser breakdown threshold is lowered and the signal spectral line intensity is enhanced.The variation rule of laser-induced plasma signal with delay time and reagent concentration un-der different air pressure was investigated,and the results show that silver nanoparticles can enhance the signal up to 1-2 orders of magnitude under normal air pressure,and the higher the concentration,the better the enhancement effect.Under low air pressure,the signal enhancement of silver nanoparticles rea-ches 1-2 times,and as the air pressure decreases,the enhancement times first increase and then de-crease,and the plasma is excited earlier than under atmospheric pressure.Silver nanoparticles have no significant effect on the background noise radiation intensity,so the use of silver nanoparticles can effec-tively improve the signal-to-noise ratio of the plasma signal,and play a certain optimization role in the vacuum switch vacuum charged detection.