不同气压下银纳米粒子增强激光诱导等离子体信号

It has also become a trend to realize charged detection of vacuum switch vacuum based on laser-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 improve 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 under 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 reaches 1 - 2 times, and as the air pressure decreases, the enhancement times first increase and then decrease, 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 effectively improve the signal-to-noise ratio of the plasma signal, and play a certain optimization role in the vacuum switch vacuum charged detection.