REO Ohmeda Raman Particle Counter

[SoulFeast]

Hmm..If I have time tonight, I will. Just got in a load of parts, and have 2 pretty big projects to finish up and get sent out, so that might have to wait until tomorrow night.

[The_Doctor]

As for common HeNes, there are many to be found at very affordable prices on eBay. Most HeNes have that pure TEM00 low divergence beam one expects from a real laser.

In the UK. For a person who quit PayPal over two years ago defying their excessive policy restrictions and dodgy tax habits. Trust me, this really limits the field. I'll set up a watch list entry though.

PS. Got to like your use of 'semi-infinitely'. Put like that I totally agree. What would be weirdly cool is a HeNe managing to put out two sharp TEM00 lines, one red, one green, of equal apparent brightness, at same time. There could be all manner of ways to make a gorgeous bit of artwork out of that.

[Jem]

Hey Doc, if you need a HeNe give me a shout. I've got a fair few kicking around the place of varying powers and wavelengths

[SoulFeast]

*cough* If he doesn't want them, I am interested in anything 30mW+ 632.8nm, 3mW+ 543nm, 612nm, and 604nm

[The_Doctor]

Hey Doc, if you need a HeNe give me a shout. I've got a fair few kicking around the place of varying powers and wavelengths

I think you're on! Any chance you have pictures and a shortlist of specs and prices for each? I ought to pick at least one, but I reckon SoulFeast will not be disappointed. I have a PSU that ought to power a medium sized tube, too. And a few spare carbon resistors in case I need to change its current limit.

Re those scanners, I'll have to hold on that whole thing for now. No sign of interest in WideMoves to prompt me to set up a pitch, and what money I have stashed is already getting into other things like finishing my 1KW solar power project. But a nice HeNe might be the kind of inspiration I could use best during the coming months.

[SoulFeast]

Saw this...removing it didn't help the spot size, but still.

[krazer]

That is quite an impressive laser you have there! I found a nice dual-brewster tube (SP 120) that I hope to try and get a few other lines out of at some point, but getting that many lines out of a tube at once is pretty impressive.

Also, I found this reference you guys may be interested in (attached)

[SoulFeast]

I'm not sure what I'm looking at here..

My next HeNe project involves a 633nm 1B tube, a rail setup with mirror mounts, and a dozen or so variously coated OCs and HRs. Going to see what I can lase with these, even plan to combine 2-3 extra mirrors. Theory is simple, but ludicrous at the same time (but can work). Say your HeNe lases 633 exclusively. I can use an OC for the orange lines with a 99.5% reflectivity or so, then another mirror coated with 99.95% or so for 594, and see if I can't get 4 lines at once. I would try to get 543, but the gas mixture is going to be an unavoidable obstacle. Unfortunately, getting green from red isn't totally feasible, the opposite is possible though.

Let me know if you ever want to part with your SP 120, I'd love to run some tests on it.

[krazer]

That is a list of the plasma lines from a 'typical' HeNe tube, sadly it doesn't go down to the yellow/orange lines. In theory there is a tiny bit of radiation at each of those lines coming out of your tube, but of course only a few of them will have enough gain to start lasing. It would take a bit of head scratching to figure out which ones you should expect to see, but it might help you sort out what you have there.

As per the 120, I would like to play with it a bit myself first but I will let you know if I am considering getting rid of it.

[SoulFeast]

Well there are hundreds of lines, but you can only lase a handful of them. They need to remain in that excited state and stabilize in order to be visible laser lines.