invention the assembly generally includes one or more driver units 12 with a pressure gage 12a the drivers containing a gas at a predetermined temperature and pressure as may be needed to generate the shockwave in the form illustrated the driver may be a generally cylindrical container containing a gas such as air or nitrogen gas although other inert and non toxic gases may be used as seen the oneend of the driver is open as at 14 but is sealed by a diaphragm assembly 15 the diaphragm assembly may include one or more diaphragms 16 and 17 spacedfrom each other to form a chamber 15a therebetween a vent valve 18 may beconnected to the chamber 15a while a pressure by pass line 19 and pressure regulating valve 20 interconnects the driver and the chamber 15a to pressurize the chamber at approximately 50 of the driver pressure because the driver is pressurized to a relatively high pressure with a heated gas e g 2 250 psi at 700 degrees f for example the diaphragm 17 normally would have to be rather thick to withstand such pressure whenthe diaphragm bursts the petals formed must bend a full 90 degrees to fully open and the amount of metal strain at the bend of a thick plate will probably exceed the allowable causing cracks and rupture at the bendline thus when fired it is possible that fragments of the thick diaphragm may be propelled supersonically down the shocktube to reduce the tendency of such high velocity relatively large projectiles from the fragmented diaphragm the by pass system operates to.