Effects Of Laser Target Materials For Performance Of The Laser Triggered Vacuum Switch

High power switch is an important research content in pulsed power technology.Thecharacteristic of the Laser trigger vacuum switch is the short closed time,stable performance,small triggering jitter and low pre-breakdown probability.Laser trigger is an effective way to realize energy compression and transmission of pulsed power equipment.The use of trigger targets can effectively improve the laser trigger vacuum switch conduction performance.The work performance in the subject is conduction delay and conduction jitter.Trigger targets can reduce the trigger energy of the conduction required.In this experiment,solid Nd: YAG laser was used as the trigger source.The target are a mixture of potassium chloride(KCl)and titanium(Ti),graphite,titanium hydride(Ti H2)and Cu Cr50.First,the working principle of LTVS is analyzed,the mechanism of the initial plasma generation is discussed.Three major plasma generation mechanisms are introduced: 1 laser ablation,2 photoelectric effect,3 thermionic emission.Then I introduced the laser equipment and target parameters.Secondly,introduced the experimental system structures,including experimental platform structures,the basic switch structure and laser optical device parameters.By changing the main circuit capacitor voltage values of 500 V,1k V,2k V,3k V and 4k V respectively,to change the laser source laser energy at 20 m J,30 m J,40 m J,50 m J,and60 m J.get the performance of the laser trigger vacuum switch under different working voltage and laser energy.The use of target material seriously affects the practical life of laser-triggered vacuum switches.The direct interaction with the target is the laser and the arc.The relationship between laser excitation energy,laser focusing,triggering frequency and target relative position and target loss is analyzed by experiment.Experiments show that: arc ablation is the major factor in the destruction of the target,by placing the target slightly inside the contact can reduce the ablation and damage of the arc and does not affect the performance of the laser trigger vacuum switch.The microscopic microscopy and energy spectrum analysis were used to investigate the interaction between laser and target.The target debris was found on the surface of the contact.The target was sputtered onto the contact surface due to excessive laser energy.Laser energy is too large to increase the target loss,and pollution of the contact surface,reducing the laser trigger vacuum switch pressure level.In a certain voltage and laser energy range,the target can effectively improve the laser trigger vacuumswitch conduction performance,including conduction delay is shorter,more stable conduction(jitter small),the required trigger source laser energy smaller.