Originally Posted by heroic
Heroic, there are three schemes. insulating Be0 tubes at 5x the thermal conductivity of Aluminum, Tungsten disk in quartz, and you radiate the heat into the water as IR, and metal disk, where you have a two inch diameter alumina tube, filled with copper disks, that have tungsten or silicon carbide disks with the bore hole in them. A typical bore is .56 to .65 mm in diameter, and dissipation is 300 to 700 watts per CM of length depending on what your lasing and if your going for UV or not. AR is is actually ar++, doubly ionized argon, and for the UV lines, its AR+++ , or triply ionized argon. You need 1000 gauss of magnetic field to contain the plasma on a watercooled, so the cooling fluid flows between the tube and the magnet.
A rule is 1.1 kilowatts per watt on a large frame, plus about 2 kilowatts of threshold.
So I typically am using a meter to two meter long arc .65 mm diameter in 125 to 300 millitorr of gas, drop across the arc is 106 for a decent aircooled, to as much as 570V for a large frame. At currents anywhere from 6 to 10 amps for a small aircooled to as much as 60 amps for a UV largeframe. Add another 250-500 watts for the magnet if used.
You can get air cooled to roughly 2-3 watts CW, 7 watts short pulse.
yes .001% effiecient , and the tube has a negitive slope if its a aircooled or is barely positive if its a large frame, so you have a current regulated power supply running into a negitive resistance load. They will run away to destruction if allowed. A big 171 measures out at -7 ohms when running full blast.
PSUs are FEt or IGBT buck regulator or a linear passbank, or a combination of both. And they work into what might as well be a dead short that likes to oscillate if yournot careful.
My 2 watt tube has 16 water cooled 2N6259s in series with it.
Steve
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Well maybe thats is not the word but I have been feeling bumbed lately myself about how easy its been getting...
