I've used some 2x squares of dead life to cool everything, and it works remarkably well for most everything but for when the laser gets a taste of it's own medicine right down it's own barrel. It appears as though it's so hot that it actually heats up the dead life to several hundred degrees, and melts the PSCN and NCSN! So I guess the only way to finally make this thing completely protected would to add something to the end of it that allows photons out but not in. Using filter and diamond seems to work well to fix this, but is also reflects some of the photons coming out right back in, making the laser less... Dense? Not sure how to put it, but it's no longer a nice-looking straight line of photons, it's rather inconsistent. I appreciate all of your help on the matter, and hope you can help me solve this one last, minor problem. I've already learned a lot from you :)

EDIT: I managed to figure it out! I put some 2x2 dead life squares down the barrel before it gets to the heating section, so now light coming back down the barrel is cooled back down. It works perfectly now.