They both perform the same task of dumping a huge stored charge to pulse your laser. A Hydrogen Thyratron requires a power supply, bias control and support circuitry. A triggered spark gap can handle higher power but the by-products of the discharge should be vented using nitrogen gas (quenching with nitrogen gas keeps the spark gap from building up high levels of internal atmospheric contamination caused by the discharge, IE Ozone etc...which will affect the spark gap oepration). You could also build a rotary spark gap which is popular with tesla coil builders. I have a new triggered spark gap designed for Lumonics Lasers for sale if you wish to purchase it, P.M. me.
Good luck
Rick
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