Now from reading wiki i understand there are Pin-bar and non pin-bar, non pin-bar is what people have moved to today with the spark gap. but i read that "These first 'Pin-Bar' TEA lasers, operating at around one pulse per second, were easy and cheap to construct. By operating at atmospheric pressure, complex vacuum and gas-handling systems could be avoided. They could produce MW peak powers of a few 100 ns duration". I also read that Pin-bar was more of an early model, and that in the pin bar laser one electrode took the form of a plain bar, and another a series of pins. I dont know if that will help you answering this but i want to construct one of these pin-bar lasers but cant seem to find anything anywhere. I see CO2 TEA lasers with spark gaps but i think thats non pin bar?