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Author: Subject: Medical Laser
Rogeryermaw
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[*] posted on 8-10-2010 at 05:24


if night vision can help you with the beam forget the thousands. http://www.qvc.com/qic/qvcapp.aspx/view.2/app.detail/params.... this is just one of hundreds of possibilities that can get you rudimentary N/V for dirt cheap. i actually bought an older version of this and modified it to put the camera on my rifle scope. works like a charm!



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[*] posted on 8-10-2010 at 05:59


Quote: Originally posted by Rogeryermaw  
if night vision can help you with the beam forget the thousands. http://www.qvc.com/qic/qvcapp.aspx/view.2/app.detail/params.... this is just one of hundreds of possibilities that can get you rudimentary N/V for dirt cheap. i actually bought an older version of this and modified it to put the camera on my rifle scope. works like a charm!


Now only if you could shoot straight! :P:P:P




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[*] posted on 8-10-2010 at 06:21


test me any day bro! bet you'd rather have me on your side;)



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[*] posted on 8-10-2010 at 08:36


Entropy is correct about the reflections. Those lasers are usually crystals pumped with a flash light. They fire very short pulses, but with pretty darn high energies. As such, the reflections from things that would normally be fine with a torch or laser pen can be enough to damage your eyes.

Your eyes don't actually have many nerves in their surface. If they get blasted, you may not even feel it and only notice it later. Welders get that quite often, "sandy eye", where UV from someone else at work has hit their cornea from sides. It's easy to assume that not looking directly at the arc won't be so bad, but the cornea sticks out quite a lot and does soak it up. The result is, sun burnt eyes that start itching like crazy hours later. It can also cause the cornea to become opaque, like a cataract.

You could try removing the hand piece for a start, as the beam may already be suitable from the fibre, or there may be culminating optics inside the laser unit it's self to get the beam into the fibre. Obviously, it's diffused out at the exit to spread it better on the skin, and avoid burning holes in people when it dwells too long in one place; even the pattern out.

As far as uses go;

Start your own beauty salon? As I'm aware of things in the UK, it doesn't actually need a whole lot of paperwork to start shooting people with laZers. :D

Sintering?

Precision cutting / welding in a bell jar?

Frequency double it up to green?

Use it to burn tape / light matches and add to the already vast numbers of videos on youtube all about igniting matches with $400 laser pens? :P

Range finder?

Try to make a 3D scanner? There are some incredible ones of those from Leica and the others. It fires the beam and records the return as per a range finder, but then scans the beam using an X/Y mirror array and records one for each point. The result is a scanner that costs tens of thousands, but that can be setup, switched on and then produce a beautiful 3D scan of things as big as cathedrals, accurate down to the millimeter. There are scans from the inside of tombs in Egypt, for instance.

Lots of options.

@12AX7

Have you seen Audionote's site? There's one in the UK and one for Japan. The company was originally Japanese I think.

They are both hard for silver. Seriously hard, with it being a slightly better conductor than copper and there being a lot of talk about there possibly being other conduction differences at work that make the music sound 'better'.

The higher end models make use of things like pure silver capacitors and windings.

And the prices are out of this world. I mean, hundreds of thousands, for a single channel power amp. Then add on, the preamp, diamond / silver cartridges / silver speaker horns, silver drivers and crossovers. Millions for a full stereo setup.

Want!


Nice


[Edited on 8-10-2010 by peach]




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12AX7
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[*] posted on 9-10-2010 at 21:47


Quote: Originally posted by peach  

@12AX7

Have you seen Audionote's site? There's one in the UK and one for Japan. The company was originally Japanese I think.

They are both hard for silver. Seriously hard, with it being a slightly better conductor than copper and there being a lot of talk about there possibly being other conduction differences at work that make the music sound 'better'.


It's still more bizarre than that.

Lots of people think silver is "too conductive", that it brings out the harshness of some recordings! These people settle for copper, but it has to be oxygen free, single crystal, I don't know what else, material, naturally.

Tim




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peach
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[*] posted on 9-10-2010 at 23:41


Interesting, as I've also heard them going on about it being sweeter and smoother, like a fine wine or high class escort girl of coarse. :D

And going on about the crystal structure, conduction bands, electron pools, phase and harmonic distortion in silver versus copper.

I can understand their interest, but not their way of thinking. For instance, strapping $15k's worth of interconnect to a system not worth a whole lot more.

One of the magazines or online blog things did a test where they had 30 audiophile sat in a room, listening to different cables under a double blind setup. There was no statistical confirmation that they could tell the difference. Still, not to let a bit of simple, practical scientific evidence get in the way of discussing the science you agree with or want to sell right?!

Then there's also the real world other side of that cable. That a lot of musicians, while they're bothered about the instruments, don't spend a decade obsessing over wire selection. Quite a lot of them will just pick something up in the shop, think... yeah... that's good, mush it with tone controls, mutes, packing, hang fluffy toys and cigarettes off it, then beat the crap out of it over a few years. Lots of Marshalls come complete with at least a little bit of sick or beer ingrained in the tolex, or burn holes from people putting joints out on them. Case in point, Jimi didn't really care, he just played the mother. There are a lot of people with the same gear as him, and far better, but no one who can recreate what he could imagine up, in his early twenties.

Soooooo, I don't really get the point of trying to eek out details that have been statistically shown, by their own review, to not be detectable in the first place.

There is a point between shit and "SHITTING HELL! That's expensive!", that produces a practical, measurable by your brain, gain. I think Morgan Jones is well onto that idea. His book, Valve Amplifiers, is a killer read, as he's not afraid to blend valve with solid state when he thinks one will do the others job better. A definite read for anyone wanting to learn about analog circuits for audio.




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[*] posted on 12-10-2010 at 19:22


Well the mica capacitors are not silver, the foil dissolves in caustic to form a grey solution, however it also dissolves in conc HCl leaving behind a significant amount of black preicipate/unreacted material. My metalurgy sucks, better get out those underrad texts again. Reading about mica caps (notice the use of electronics vernacular, i'm so radio shack savy now) it appears they are largely either Pt or Pd or some alloy of both.
Anyone got a decent trick for dissolving the difficult to dissolve mica, without needing HF? Peeling it carefully away takes far to long given the brick is like 3000 layers thick.
Just got this baby!!!!! Fucking awesome!! Dork christmas has come early. Its a zeiss em10, however sans the ccd, only $1500.00! Ah how technology devalues. Reading through the documentation however it would appear that intense electron beams can be dangerous, must read more. Perchance does anyone use (or have used) one of these regularily?

zeiss_s.jpg - 61kB

The drawer on the right is a slide out dessicator, so german, i've bought it primarily for the vac pump array (not shown) and the cooling water setup (also not shown), however it seems sad to tear it up for parts so i might leave it intact as a monument.




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[*] posted on 12-10-2010 at 21:18


Mica dissolves readily in fluxes, if you don't mind fusing it...

Tim




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Panache
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[*] posted on 12-10-2010 at 21:42


Quote: Originally posted by 12AX7  
Mica dissolves readily in fluxes, if you don't mind fusing it...

Tim

i have some of this



Attachment: Flux Paste.pdf (369kB)
This file has been downloaded 638 times

so what i just mix the two together and heat like crazy?, what happens after that? lol waggh i'm a baby and need to be spoonfed, and i'm lazy.




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[*] posted on 13-10-2010 at 00:21


Daaaaaaamn panache!

It certainly would be a shame to tear it to bits. If the worse comes to the worse, you could use it to grill your sausages for a vacuum degassed, fat free breakfast.

{edit}I wonder if the gun can already, or be modified, to weld? Whatever it's welding, it's going to be small and probably thin (foils?), and take a while, but it could be fun to try. And you could offer SM's first in house electron beam welding service. That's how they do all the high end electronics welding and things for satellites; but probably with much, much higher power electron guns to speed it up. When TIG and gas shrouds just won't cut the lumpy mustard.

[Edited on 13-10-2010 by peach]




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[*] posted on 13-10-2010 at 07:52


I've seen EBW units before, as in, walked past them... didn't get a look inside or anything.

The trouble is getting enough power. A microscope has to use the least power possible to avoid burning the sample. With voltages around 100kV, it's probably nA-uA. Assuming the same power as a CO2 cutting laser, i.e. maybe 100W in a similarly sized spot, you need 100kV at 1mA. That's a pretty big beam, something most CRTs hardly even do (and they're projecting a bright image over a huge screen!).

100keV also means bremmstrahlung radiation (x-ray) hazard.

Tim




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[*] posted on 17-10-2010 at 01:45


well. i spent a day at the hospital yesterday taking the microscope apart, well that was the intention, however i only got to the 'unhard wiring it from the wall' part. Being a hospital i was concerned, as was the hierarchy regarding the integrity of their power supply. Four 3 core 240V supply leads came into an electrical box containing some sort of relay and a 240-24V transformer. As the room was right next to the blood freezers in the pathology research section it was of considerable importance that i was to remove the microscope without interrupting the supply.
That didn't happen i think, however as it was a saturday at least i didn't have anyone screaming at me. Turns out (perhaps, this my best guess), that the four supply leads coming in were perhaps part of some tricky lock relay for the microscope (it hasn't been used since 1993 and no-one who ever used it is still working there), as the first active lead i removed killed the lights in the room (strange).
Anyone i rather intelligently and cleverly circumvented the system by deciding i didn't really need any of that stuff in the box and just removed the 24V feed (a strange plug) into the instrument.
The instrument is quite epic and taking it apart (it was assembled in the room) is going to be arduous.
Thats a long and completely irrelevant intro to a short question. How does one happily discharge any capacitance within the system so i can safely go about unplugging things without fear of a zap and without the need of wearing rubber gumboots and rubber gloves. Is there a way to test it?




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[*] posted on 17-10-2010 at 10:46


I'm surprised they'd let anyone in there, particularly you. :P

I think the only way to be sure that's empty and safe would be to bridge it with a high ohm value resistor.

The old favourite, a screwdriver over the terminals, could be a bad idea given the amount of current that'll try to get through it if it's charged up to tens or hundreds of thousands.

Once it's done, leave the resistor in place (bolted or soldered on) so it can't charge up again. A lower ohm value will help avoid any building up, once it's electrically dead.

Some of the high voltage capacitors will build up quite a lot of voltage just sitting around, as they scoop it up from the static in the air. A wonky connection on there will make you think it's still safe after it's been sat around Panachest Villa for six months, but could allow it to give yars a nasty zap due to the assumption that the connection has kept it discharged - making it potentially more dangerous than not having it there and expecting it to be part charged.

Long of the short. Screw it on when done!

The typical method for handling high voltages minus the multi-million pound test gear and clothes is to use a chicken stick. Put the thing you're bridge it with on the end of a 100% none conductive pole and jab randomly at the terminals.



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Panache
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[*] posted on 17-10-2010 at 20:45


Thats the most disturbing thing i've ever seen, why was he like 80's dancing beforehand though?



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[*] posted on 18-10-2010 at 00:17


{edit}He's lowering the breaker into place by cranking a handle. Looks like the juice was still on.

This may be a demonstration of why lockout switches with personalized, multiple, colour coded keys are useful when dealing with things that powerful and your staff stood in front of them. That door creates a perfect surface for all the flames and toasty hot plasma to reflect off, into his face. I bet that other guy shit his pants when he saw that happening a few feet from him, I would. The victim probably did have time for that.

[Edited on 18-10-2010 by peach]




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