Highschool Nitrogen Laser Project

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DaemonStudent
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I don't know if this is the right place to post this but here goes. I'm a Highschool student building a nitrogen laser for an independent research project. I don't know much about lasers besides what I've read in physics textbooks and amateur laser pages. My and my mentor have already constructed the laser itself but we cannot get it to lase or arc in between the spark gap. We are using two aluminum plates for top plates, another aluminum plate for the common plate, polyethylene for the dielectric, a six turn copper inductor and a solid state transformer for the power supply. The power supply can arc by itself through a few cm's of air so we know that we are making enough voltage. When we connect the bottom and one of the top plates nothing happens except a high pitch noise from the power supply. Also no voltage is present in the plates when we probe it with a DMM. I'm pretty sure there aren't any shorts and my mentor has the slightest clue. Hopefully there are some laser experts...
 
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  • Black ETP Model ID-3005ST solid-state induction coil power supply with labeled positive and negative electrode rods, a DANGER HIGH VOLTAGE warning, a power dial, polarity switch and on/off toggle.
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  • Photo of a homemade spark gap apparatus on a workbench: an aluminum base plate with two wooden blocks holding clamped metal electrodes, a central aluminum strip and copper coil pieces, held down by red clamps.
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  • Wooden clamps hold two wooden blocks on a metal plate, with a central aluminum strip and a six-turn copper coil above it, forming a spark gap test setup.
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The power supply probably does not supply much current. Any leakage would probably effectively short the supply.

Wood is not a very good insulator if it is damp. High humidity might be enough. It appears that the C-clamps are only insulated by a piece of electrical tape. One or two pieces of electrical tape would likely short out at that voltage. A short though a hole in electrical tape would not necessarily be noticed at low currents. Can you operate it without the C-clamps at least for testing? Try using something other then wood and tape for insulation under the C-clamps. Replace the wood and tape with polyethylene sheet. Or, use a stack of plastic strips (4-5) cut from a soda bottle (PET is durable and a good insulator) under all of the C-clamps. The high voltage current will tend to "leak" on surfaces, so have the path between two high voltage points be a couple of inches.

This appears to be similar to a Scientific American Amateur Scientist article quite awhile ago. Might be good reading.
 
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