CO2 lasers and PSU's

Hey guys, its been a while...

So I have a CO2 laser cutting machine, currently using a 1.2m long CO2 tube, apparently rated for 40W.

The laser tube has seen the light at the end of the tunnel and is dead. I'm wanting to replace it, but the cheap 40W laser tubes are all 700mm long. A good 500mm shorter than the one in my laser cutter.

If the output power rating is the same, I'm wondering if I can use my current PSU with a new 700mm tube without any issues.....

Has anyone tried this / know if that will work.

Cheers boys and girls
-Adrian