Provenance of this laser before Bob got it:
This laser was originally bought by Borg-Warner for Holographic Non-Destructive Testing at their research center in the northwest suburbs of Chicago. It had done a fine job for them, but B-W was shutting down their research center, and we at Lake Forest College got wind of it, and bought it for a dime on the dollar, only $200! Plus a Coherent CR-2 and an early vintage Newport Table of the 3-legged era.
We set it up at the college and got some decent burn patterns, but then its power supply stopped working. Even though I had the prints, I needed someone with more experience than I in the way of high voltage power supplies, so I tapped Ed Bennett, electronics technician supreme at the School of the Art Institute of Chicago to help me get the thing running.
I had tuned the two mirrors to be parallel to each other with a He-Ne, and he got the cap’s charging and discharging, but no action at the burn paper! Plus it was making an unfamiliar noise, like a clunk.
We were staring at the target with our Laser-Grad goggles, not at the laser itself, so we did on the next shot. The clunk was from the laser rail bucking like a bronco! And you could see paint fly off the pumping cavity at the crease of the bubble on the top of the casting as the cooling H20 boiled from the injection of a few kiloVolts into it from as you have guessed, a cracked flashlamp!
These old Apollos and even Korads had the flashlamp cathode underwater! They left this end of the helical tube free to flex, as the high voltage zapping through the glass spiral would try to straighten it out; if it were constrained like the anode end in a well isolated O-ringed well the tube would crack after a few shots.
Legend has it that a broken flashlamp in a Korad could cause the pumping chamber housing to explode; here we see how much safer the very thick Apollo casting was!
I know what I want and I know how to get it
I want to destroy passersby! - Sex Pistols