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- เผยแพร่เมื่อ 2 ก.ค. 2024
- Episode 32
#laser
#electronicscreators
#optics
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I bought a couple of MNL-100 Nitrogen lasers that were listed as "Pulled form a working environment" but we ll know that means "Pulled from a Dumpster"!
These are of course non working, and in very poor physical condition, so I do a very in depth tear down on one, right down to the guts.
Later I rebuild it, and hack on a good old fashioned Spark Gap switch to see if I can get some output.
This will be a two part video. Later I will build my own control electronics, and graft in a triggered spark gap. Stay Tuned!
www.ltb-berlin.de/en/products...
Link to Manuals: www.ltb-berlin.de/en/company/d...
Relevant patent:
patentimages.storage.googleap...
**Video Contents**
00:00 - Intro
00:18 - Nitrogen Laser overview
00:52 - Teardown
01:57 - Control Board description
05:54 - High Voltage Power Supply
07:30 - Pre-Ionizer board
08:45 - High Voltage IGBT switch
13:39 - Laser Energy Sensor
16:53 - Laser Tube
23:33 - Preionizer powerd up
24:28 - Oscilloscope Measurement
26:14 - High voltage power supply hacked
29:01 - Replacing the IGBT switch with a spark gap
31:13 - First Light! Powering up the Laser!
32:00 - Measurement of RF Noise
32:35 - Further improvements for the Laser. Commercial spark gaps and control electronics.
33:20 - Outro
#Laser
#Teardown
#SparkGap
#Dumpsterhack
#electreonics
#optics - วิทยาศาสตร์และเทคโนโลยี
I wish one of my students in the lab had that much passion for lasers.
Finding a student with a passion for the thing you have a grant for, or a worker who has a passion for the thing you have a contract for, is the hardest thing in the world...
What kind of students they are ! Even kids loves Lasers
Very nice, I love the construction of expensive gear, where you don't need to make sure to save every penny.
The ceramic parts are really beautiful, they are very fascinating to me.
Looking forward to part 2 :)
Thanks! Yeah, this is really something! All the metalwork (apart from the cover) is all milled aluminum, including the rear box. They must have disposed of about a pound of shavings. Beautiful right down to the last bolt.
Awesome ! I'm looking forward to part 2 and it would be nice to build the HV supply from scratch....cheers.
Hell yeah this is awesome!!
The switch is very much similar to what I made for a Xenon tube switch working at 1500 V with a selector for various time delays. Those were made by different combinations L And C..I used HV thyristors as switches and inductive triggers
Thanks so much for putting these professional videos together Les, I'm learning so much from your vast knowledge.
Thanks! You are very welcome!
Great Stuff Les as always! looking forward to part 2 ;-)
Cheers! Just ironing out one or two bugs, but it is coming together nicely!
I wish you explained more of what you're seeing. Why are those capacitors on a flexible board? Why are they wrapped around the tube? Why are those wires arranged in such a strange way around that semiconductor gate? Why do they use fiber optics to communicate between boards? What are these lasers typically used for and what specifications is their design driven by? Why do they use a semiconductor gate instead of a spark gap?
I was gifted with two nitrogen lasers, one of which worked. No fancy uControllers, just a simple external trigger, and a rep-rate auto trigger circuit. The main item of note was that it used a Hydrogen Thyratron as the primary switch. I investigated replacements, rather $pendy devices. :(
Cool! Yeah, Sometimes, just trigger in is all you need :-)
I have been looking for Thyratrons for a while, and yes, many $$$ even second hand.
I suppose if you need kHz repetition rates, or precision timing, but a spark gap will do for most purposes, and of course a triggered gap is better.
@@LesLaboratory Back in the day, when I was experimenting with optically pumping cuvettes full of coumarin and rhodamine dye trying to achieve *super radiance*, I had made a coaxially triggered spark gap to drive the bejesus out of a poor little flash lamp. :D
Never achieved *super radiance* but it sure made one hell of a rep-rate sun-tan machine.
You can make a spark gap with a literal spark plug screwed into two thick plates of aluminum or copper. Presurize it with a mixture of gases to get the desired hold off and fast switching, usualy a 70/30 mix of SF6 to argon. The SF6 provides hold off and argon provides the comutation.
Hi, Les. This is just outstanding!
Thanks! There is a lot to be learned yet as well. I wonder for example if it possible to preionize a TEA Laser in a similar fashion. Granted this laser is likely to be less than atmospheric, and buffered with He, but if the rise time of the preionizer can be made fast enough.. They really improve shot to shot stability, and by the looks of it , output energy as well.
Looks like a cool project
11:00 looks like you’re opening a Wonka bar
Those are pulls from MALDI machine, never seen them designed with naked HV components like that. IME the nitrogen plasma tube is usually OK, but the little spark gap switch tends to go pop. All it needs to work is 20to 30kv for the HV and a 10kv pulse to fire the spark gap switch.
I think the filter not only blocks other wavelengths but it also must attenuate the light, because the pulse is in the tens of kW's in power, that might saturate the diode or put it in a non linear state so the filter could help avoid that.
Those are scrs they are triggered all at once and share equally the high voltage
Is used for nano pulse generation
Never saw it other than in parents
Thanks for the video
Great stuff, very interesting too and I can't wait for the next episode. One day I'll build my own N2 laser but for the moment I've got to get my 40W FAP power supply built and hooked up to my CNC machine (which also needs building lol). A lathe sounds like a great idea and I wish I had room for one, instead I'll just keep watching in awe at your builds which are just fantastic!!
Cool! I'm actually thinking about buying one of the infamous Mini Lathe's, as I am stuck for room and on a tight budget. From what I understand (See: This Old Tony on TH-cam) if you are prepared to spend time time modifying them, they can be a half decent tool.
@@LesLaboratory I love tot's channel, great minds think alike on the lathe which will be my next big purchase, eventually!!
@@danriches7328 yep! There comes a point where the junk box runs dry, and you have to make your own parts.
HV IGBTs are actually fairly cheap! You can find them as low as ~$1.3-1.6 a piece for the 1200V flavor. Not sure about the pulsed current though - most of them are only rated to around 20-60A peak, but seems reasonable enough to try building a trigger device with.
Oh, and beware - the gas fill isn't just low pressure nitrogen. It's a specific mix of helium and nitrogen, I believe around 3-15%He. And of course, you need at least 4-5N gas purity to maintain a long life.
It's the pulse current rating that counts for these. You need to be able to conduct Kilo-Amps at KiloVolts in just a few tens of nanoseconds. I was looking at IXYS IXYX50N170C, erring on the side of caution, and they run 18 bucks each.
Yes it will have He:N2 mix. All sealed designs I have seen use this. He ionizes easily, but also helps conduct heat from the gas to the walls of the tube.
@@LesLaboratory The IXYS part is nice, but it's not that far ahead in terms of ratings compared to the cheaper ones. It might be worth a try to use the cheap ones. Perhaps even in parallel, to reduce inductance and increase capacity.
LOve these videos man.
Can we see close ups please? Macro's that is.
Is a flat surface mount cap parallel with each 12, switch/chips on the 12.5kv potted card?
That's awesome! I am a bit surprized at the solid state switches being so small considering how much peak current they must have to supply. The pre ionization pulses looked really pretty down that bore. I worked with a lot of ion lasers and solid state diode and OPSL stuff but never had a chance to use any Nitrogen lasers. I did get hold of an old CO2 medical laser but never found the time to get it working. It did have two huge triodes to control the HV current, yeah, it was pretty old. Nice video, very informative, thank you.
I'd say that there might be some issues with preionization, because it is probably supposed to be from both sides.
Yes I thought that as well, but the other one behaves in exactly the same way. Perhaps worthy of some investigation. I have already reverse engineered the output stage of the Pre-Ioniser. When I get time, I will diagram out the tube as well.
Thanks! Yeah, some IGBT's are rated for this kind of work. I suppose if you are dealing with very short pulses, you can get away with pushing though some quite high currents. I imagine they are very fragile though.
Cool! I love the old Tube/Valve stuff :-)
Wow the ones i tore apart had an Argon/SF6 spark gap to fire the tub, which i imagine would be much cheaper. That switch has to clamp in less than 4 nanoseconds which is no easy feat. Not normal IGBTs to be sure, probably SiC. If they are fast enough to fire a nitrogen laser and fast enough transition nit to blow up, they could be used for a nuclear weapon firing set! 😲
Just as you fired that up, my connection failed and the video froze - I had to check it wasn't a problem with your recording from the RF inteference!
Regarding a lathe, it's an excellent investement. My advice is go for something bigger than you expect to need, provided you have the space for it. I graduated from an ancient 3" lathe to a Myford ML7, and now I have a Colchester Bantam 5 5/8" lathe and I still occasionally find jobs that are too big for it.
Ha! There is that much radiated RF, it probably could :-D
Indeed, I have had my eyes on one for a while now, but budget and space are both limited. I reckon I can get away with a small hobby Lathe, at least for immediate projects, but I suspect, it will become yet another tool addiction...
The fiber cables are to electrically and thermo isolate the hv/hf group in case there is a failure you want the shutdown to still be able to detect it and do its job. I'm sure you know this just Mentioning for others interested in rolling their own controller
Yep! It is something I have used for real noisy stuff like Tesla coils and such. A game-changer for stuff like that!
Excellent. I've just bought Quantronix Integra-HE from the ebay at the same condition for ~30000$ including all the taxes. Hopefully I'll be lucky enough to bring it back to life.
That's an expensive eBay purchase! Academic budget? :P
@@Spirit532 not exactly, me and a few other scientists chipped in to buy it from our own money. If we will make it work, we will be able to get that money back. Just a very expencive bet in laser casino xD
Awesome stuff, and a bargain for sure, but waaaay out of my budget sadly!
@@LesLaboratory well, we needed four guys to make this happen. Just all four need some new equipment to make some progress in each other research, and since the new one still costs 0.3M$ such things are becoming the only options. Esp. in Russia where academic budgets are tenfold less than in Germany or USA :(
24v mains, field portable to only 500 watt. This is has extreme step-up hardware and losses too.
Even better than a spark gap use the electronic switching less electronic NOISE
It is possible to reduce the noise to acceptable levels with a spark gap. I though about using semiconductors, however at these voltages and speed is gets expensive fast!(see part2: th-cam.com/video/ngs9zPdI_t0/w-d-xo.html)
i was just wondering do you have a discord group or something? thanks for the awesome vids btw!
Hi.and thanks! Unfortunately no, but I am happy to field questions via e-mail if you like.
@@LesLaboratory I did email you, to ask what you thought of my diy chiepo spectrometer. I would love your input
You can done this laser to work at 220v or with an adaptor? I dont know if is a good idea but i want to buy one of nitrogen laser repaired by you.
You can tell me a price if you want.I dont know how much costs the travel from america to romania.I cant buy things from ebay because it need to give personal data and im not agree.It need more time get the money.And your latests clips are awesome in special this clip.
Thanks! Unfortunately not at the moment, there are still things I want to do with them.
They run off of 24v DC, which seems to be common for a lot of N2 Lasers from various manufacturers.
The good news though is they are showing up surplus lately, and even if you get one in non-working condition, chances are it can be repaired ;-)
I wonder if part of the front end to the optical input to the energy monitor is something acts like a fluorescent down-converter. Pin diodes have low sensitivity at at the UV end of the spectrum. It's hard to tell from the vid but that photo sensor appears to be in a plastic case. I'm not aware of any plastic that passes UV. :/
Yeah, it looks like a plastic case photodiode, and there appears to be UV damage to it as well. Almost everything is fluorescent to some degree, so maybe they do, though I suspect UV photons will penetrate such a thin layer. Some plastics will pass UV (You can get disposable UV plastic Cuvettes for Spectrometers).
@@LesLaboratory Interesting. Back when I was trying to do what (what you have done in another video) I was using plastic cuvettes. I dont' recall but I just assumed no UV was getting in them. Maybe it was what I saw from the data sheet. I had'nt even considered versions that were uv transparent. I assumed I needed quartz cuvettes, which I did *not* have money for. :/
This was back in the 90's.
Ive seen both types, the power sampler uses either a florescent converter or a silicon carbide photodiode. 🤓
Les, could one use a flash from a deposable camera as a triggered spark gap?
Not the flashtube itself (well at least for this application), but the trigger circuit itself might trigger the triggered park gap. I have actually rolled my own trigger circuit, to ensure consistent repeatable results, and I have built a very large version for another upcoming project....
@@LesLaboratory fantastic Les! I'm looking forward to the video. But tell me, how does a flash lamp and a triggered spark gap differ? This is probably a silly question, I have not much knowledge on spark gaps. Triggered or not...
@@Robertwclarke Great! A triggered flash-lamp is designed to convert as much of the energy into light as possible. They are comparatively low voltage devices with voltages ranging from a few hundred volts, though very large ones exist that require KiloVolts. Generally the discharge is quite long, and lasts from microseconds to milliseconds
Spark gaps on the other hand are designed to switch as efficiently as possible and not dissipate the energy in the form of light and heat. They can switch from hundreds of volts to thousands of volts at thousands of amps. The discharge is very short (Just a few millimetres) so they can switch quickly (10's to 100's of nanoseconds)
@@LesLaboratory Wow! Thanks for that super explanation. It makes sense now. It makes me wonder about short arc HID lamps(like in video projectors). They are high pressure, short distance. Is it just the gas mix which is the difference here? What else is different?
I rescued a marking laser that my work was throwing out. It is supposedly a 30w unit, has Windows PC control and all. I couldn't find much info on it, although it is a name brand Markem Imaje unit. Would love to find information on it. Any ideas where I could start?
Interesting, physically it looks like the Domino head I have on another video. Is there a model number on the case?
@LesLaboratory Markem Image 7011, I cannot find anything online. Only the Smartlase.
Not 100% sure about that exact model but many of the industrial ones use a PATLITE . That’s a set of lights which interestingly also serve as a fuse if one light is blown. Color’s are usually red yellow green like traffic lights but in a tube form. If one of the lights are blown the system will not work as a safety measure since they alert if bright red is on that something is wrong and can pose a danger. So if one of those lights are blown you may bang your head thinking it’s the laser when it’s the light that needs replacing and then the board works fine. Just sharing what I learned. One guy running a nitro cutter was banging his head trying to look up cumpter codes and testing wires and it was a single blown bulb not allowing the system to kick on so when in doubt check the schematics . If it has the warning system as part of the whole and it will not run you may need to just look for a cheap Chinese one and adapt it to the board. The onboard SOC will not let it run if it is that.
@@carlospenalver8721 I'll have to check that out, I think there is a little stacklight on it...
Is it also Tea ! Than why its design is in cylindrical shape ? Can we copy this in Diy Version if it's Tea laser !?
It is convenient and from an engineering standpoint, sensible, to manufacture anything that contains gas at high or low pressure in a cylinder. Have a look around my channel, I designed a TEA Laser they outperforms this in terms of power.
@@LesLaboratory I already watched that video long before and also just before .
But I still wanna Know , it tea laser and nitrogen laser is exactly same setup and thing ?
Nice mod, you never failed to amazed me :-)....I'm just wondering, would you be interested to sell me one of your micro nitrogen laser you shown in this video mate? What type of power supply you need to run it? Thanks & keep the great vids coming.
Thanks! Unfortunately not at the moment, there are still things I want to do with them.
They run off of 24v DC, which seems to be common for a lot of N2 Lasers from various manufacturers.
The good news though is they are showing up surplus lately, and even if you get one in non-working condition, chances are it can be repaired ;-)
I will keep you posted though if I decide to punt one!
@@LesLaboratory I think you misunderstood me my friend. I was referring to your homemade N2 laser, not the ebay ones.
I realize you know what you're doin and all but the bare finger willy nilly around the HV caps thing is nerve racking.
Hi Les, can you give some details about the air pressure spark gap? Distance between electrodes, shape, material(brass?)?And what is the pressure inside the laser tube. Many thanks! Cristian
The distance in the gap is about 2mm. the material is brass. The two electrodes are simply a brass acorn nut (M8) and the head of a brass bolt with the corners rounded off. Both are polished. inside this laser tube, my best guess is atmospheric pressure, with Helium as a buffer gas. My home made N2 lasers all run at atmospheric pressure.
@@LesLaboratory Many thanks man...you're awsome!
You're giving me anxiety every time you put a finger on the HV parts. I'm sure you discharge these things first, but still better to not teach bad practices.