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Polverone
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Production of ultraviolet in 300-315 nm range?
I'm interested in producing ultraviolet radiation down to 300 nm or so. It's imperative that I be able to effectively filter out radiation below 297
nm (cut-off at a slightly longer wavelength would be acceptable too) and it'd be desirable, though not as crucial, that I filter out UV radiation
longer than 315 nm. The link that not_important gave in the chlorine thread recently indicates that mercury vapor lamps may have a spectral peak in the area that I'm
interested in, but peak location is highly dependent on pressure.
Do any consumer or standard industrial (not expensive specialty) mercury lamps emit significantly in the range I'm interested in, at least within the
inner envelope? I could imagine removing the safety glass from a lamp to permit UV emission. It doesn't have to be a mercury lamp if there is some
other sort of lamp that will do what I want and it's under (say) $500.
Is there any readily purchased or made material that is preferentially transparent in the 300 to 315 nm range that I could use as a filter? Barring
that, is there at least a material that rapidly attenuates radiation shorter than 300 nm but is mostly transparent to longer wavelengths?
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vulture
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Well, forget standard mercury vapor lamps. Their main output is at 254nm with minor peaks in the 300-400 region, IIRC, as most of them are being used
as UV-C lamps. You might consider UV-LEDs, they usually don't get to short wavelengths and are fairly monochromatic.
Why do you want such a specific region anyway?
One shouldn't accept or resort to the mutilation of science to appease the mentally impaired.
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Nick F
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What about using a standard mercury lamp, or anything that has a peak in the right area, and getting a quartz prism to select the bit you want?
Although a source that emits just at 300-315nm would be neater...
What's it for? Sounds intriguing...
Edit: I just had a little look for UV LED's on Google, I thought they stopped at about 390nm but it seems that they can now go right down to 240nm
(for a price!). What sort of power do you need?
[Edited on 1-1-2008 by Nick F]
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Polverone
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I'm interested in that range because it's the effective phototherapy range for psoriasis. I have a friend who has that condition and can't get enough
natural sunlight exposure in the winter to control it. Tanning salons are ineffective because their lamps emit longer UV radiation. There are
medically licensed phototherapy lamps but they cost thousands of dollars and require a prescription, and he doesn't have insurance coverage. I was
hoping that it might be possible to construct a DIY alternative for a few hundred dollars instead of a few thousand. LEDs for those short wavelengths
don't appear to exist (at least not readily, commercially).
I suppose I'll try looking at patents and medical books to see if I can find out what the light source is in the commercial devices and how it's
filtered.
[Edited on 1-1-2008 by Polverone]
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Rosco Bodine
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http://www.polmanminerals.com/html/ultralum__inc_.html
You will have to use filters to get as narrow as you are wanting , or use LED's which are specific to the wavelength .
BTW , IIRC that is the " D vitamin wavelength "
so ...maybe have your friend also try vitamin D supplement .
[Edited on 1-1-2008 by Rosco Bodine]
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Xenoid
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All the UV - LEDs I've seen for sale, peak in the 395-405 nm region, and have very narrow bandwidths of about +/- 15 nm.
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Rosco Bodine
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Really what Polverone is looking for is something using
medical approved phototherapy narrow band UVB tubes like Philips TL01 . Probably just the tubes in a 4 bulb panel
are a couple of hundred bucks .
http://www.natbiocorp.com/panosol-II.htm
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not_important
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Damn, you mean I did something useful? Can't have that, so don't look here
http://www.hilltech.com/uvlamps.html
http://www.msscientific.de/hpk125wlamp.htm
http://www.uvguide.co.uk/zoolamps.htm
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Rosco Bodine
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Probably for a medical use it would be best to stay with something already made for human use .
Anyway , one six foot 100W bulb is a bit over $200 .
Have no idea what is the ballast requirement .
http://www.donsbulbs.com/cgi-bin/r/b.pl/tl%7C100w%7C01~phili...
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-jeffB
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Polverone, a friend of mine came across a box of UV-B bulbs in the effects of a woman who had SEVERE hoarding disorder. Here's a Google Groups link
to the sci.electronics thread where I asked for info on them:
http://groups.google.com/group/sci.electronics/browse_thread...
I'm at a loss as to how one ships 48-inch fluorescent tubes cross-country without breakage, but I'm willing to work with you if you think they'd do
the trick.
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tentacles
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Let us know what you figure out, and if it works, my MIL has psoriasis as well.
[Edited on 1-1-2008 by tentacles]
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Polverone
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Not_important, those links were very helpful, particularly the last two. It looks like the reptile bulbs have a peak around 313 nm which would be
almost perfect. To reduce side effects, it would be best if I could filter out UVA and the shorter UVB while permitting the ~313 nm radiation to pass.
I don't suppose anyone's mental storehouse of knowledge has materials to suggest for those purposes? I will try to do some searching of my own if
nothing immediately comes to mind.
-jeffB, those bulbs look like they would be just about perfect if I can figure out some filtering as mentioned above. Do these bulbs go in standard
fluorescent fixtures with standard ballasts?
I found out that the state of the art in drug-free psoriasis phototherapy is narrowband UVB. This is treatment using special tubes that have a narrow
spectral peak around 311 or 312 nm. The tubes are fairly expensive and you have to shop around a bit to find any place that will sell them without a
prescription. I haven't yet determined if the electrical connections and ballast requirements are different for these tubes. The dedicated medical
units that accept them range from fairly expensive to extremely expensive, but I don't know how much (if any) of that cost is related to specialized
electrical requirements.
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Rosco Bodine
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Found a 2 foot 20W tube with standard bi-pin ends
Philips TL20W/01 , that would probably work in a standard fluorescent fixture . It's $95 . And a prescription is needed .
http://www.solarcsystems.com/us_phototherapy_bulbs.html
Your friend may have to mug an iguana for a bargain 
http://www.reptileuv.com/megaray-sb-100-watt-self-ballasted-...
Looks like they may require a UVB meter purchase also .
[Edited on 2-1-2008 by Rosco Bodine]
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-jeffB
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| Quote: | Originally posted by Polverone
-jeffB, those bulbs look like they would be just about perfect if I can figure out some filtering as mentioned above. Do these bulbs go in standard
fluorescent fixtures with standard ballasts? |
As far as I can tell, yes. They lit up in a standard fixture, not terribly bright in the visible, but I don't remember any flickering, banding, or
persistent filament glow from the ends. Then again, I didn't look at them very closely, or for very long. They did make my clothing fluoresce (from
laundry detergent brightener).
I should be home Friday or Saturday, and I'll try to find them then and verify that they still work.
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Polverone
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| Quote: | Originally posted by -jeffB
| Quote: | Originally posted by Polverone
-jeffB, those bulbs look like they would be just about perfect if I can figure out some filtering as mentioned above. Do these bulbs go in standard
fluorescent fixtures with standard ballasts? |
As far as I can tell, yes. They lit up in a standard fixture, not terribly bright in the visible, but I don't remember any flickering, banding, or
persistent filament glow from the ends. Then again, I didn't look at them very closely, or for very long. They did make my clothing fluoresce (from
laundry detergent brightener).
I should be home Friday or Saturday, and I'll try to find them then and verify that they still work. |
I appreciate you looking. On a second reading of the thread, I realize that nobody actually verified that those are the markings of the reptile-type
tubes, only that similar tubes are used for reptiles. I would probably need to find more information about the specific output of those tubes (either
manufacturer information or some specific way of measuring) before I'd suggest deliberate skin exposure.
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JohnWW
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Laundry brighteners consist of Prussian blue (ferric ferrocyanide), which absorbs near-UV light, especially that in sunlight, and re-emits the energy
in a wide band of visible wavelengths. I once had a shirt made of expensive fabric that spectacularly fluoresced under a UV lamp in a university
chemistry lab - it must have had this or some similar brightener either permanently bonded to the fabric or embedded in its (polyester I think) fiber.
BTW I wonder if anyone here can actually SEE near-UV light of 300-315 nm wavelength? I am sure that at least some people can see violet light somewhat
shorter than 400 nm. Bees and other insects are supposed to be able to see well into the UV.
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12AX7
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Stilbene. Quite common in "ultra-white" detergents, etc.
I can just barely maybe kinda see the...fourth? visible spectral hydrogen line. That's around 410 nm. The third is a nearby 434 nm, suggesting a
steep rolloff of visual response. (In contrast, it's supposed that you can see as low as 800nm or so, if it's *really* bright. Not something good to
test directly, as too bright and you won't see anything ever again!)
Tim
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-jeffB
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| Quote: | Originally posted by JohnWW
BTW I wonder if anyone here can actually SEE near-UV light of 300-315 nm wavelength? I am sure that at least some people can see violet light somewhat
shorter than 400 nm. Bees and other insects are supposed to be able to see well into the UV. |
I read some years ago that artificial replacement lenses used in cataract surgery were UV-transparent, and that people who had undergone that surgery
were actually used in some military operations, since they could see UV signals that were otherwise invisible. I don't know whether the story was
true. I'd like to think that materials science has advanced enough to give us UV-blocking replacement lenses, but I don't know that, either.
Even if your retina is sensitive to UV light, though, the resolution would be terrible. Even blue and violet light doesn't get focused very well by
the human eye, and UV would presumably be focused even more poorly.
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tentacles
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That reptileuv place sells a UVB meter for $179. Says it measures from 280-320nm. They also mention their bulbs peak at 295nm. I have seen some
reptile bulbs that sell based on the percentage of UVB they output, 3% or 5%. Not sure if this is percentage of the bulbs lumens, % of daylight UV
equivalent, or what. The solution may be to replace the regular light bulbs in the house with CF reptile bulbs, lol.
"Solartech's Solarmeter model 6.2 is the most accurate hand held ultraviolet radiometer (UVB meter) on the market. And although it's a 'broad band'
meter, meaning it is measuring the complete UVB range (280 nanometers to 320 nanometers) it's peak sensitivity is at 295nm. This is the prime
wavelength of UVB needed to induce Vitamin D3 synthesis, making the 6.2 meter the perfect instrument to use to check your UVB reptile lamps."
ZooMed makes flourescent and mercury vapor UVA/UVB lamps. They also seem to have a UVB meter. You may be able to find a spectral chart for the MV lamp
somewhere.
[Edited on 3-1-2008 by tentacles]
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UnclearReactor
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Most moderately priced midwave UV lamps should provide the 300nm light. They normally use a Mercury discharge lamp (254nm peak) and a special phosphor
fluoresces, producing the midwave. Each lamp manufacturer has their own proprietary formula) Typically, they use a Hoya U-325C filter to block out
visible light (since they can also use a bare lamp for producing UV-C), and that filter is a significant part of the lamp's cost. From Hoya's website,
http://www.hoyaoptics.com/color_filter/uv_transmitting.htm it looks like you could replace it with a U-330 filter and remove the emission line, if
any should get past the phosphor or the lamp glass. This would still leave UV-A, and I'm not sure what side effects this would cause. It's the same as
exposure to garden variety "black lights". For lamps, try http://www.fluorescents.com/uv.html , or search for midwave uv.
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AceMile
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Quote: Originally posted by Polverone  | I'm interested in that range because it's the effective phototherapy range for psoriasis. I have a friend who has that condition and can't get enough
natural sunlight exposure in the winter to control it. Tanning salons are ineffective because their lamps emit longer UV radiation. There are
medically licensed phototherapy lamps but they cost thousands of dollars and require a prescription, and he doesn't have insurance coverage. I was
hoping that it might be possible to construct a DIY alternative for a few hundred dollars instead of a few thousand. LEDs for those short wavelengths
don't appear to exist (at least not readily, commercially).
I suppose I'll try looking at patents and medical books to see if I can find out what the light source is in the commercial devices and how it's
filtered.
[Edited on 1-1-2008 by Polverone] |
Yes I absolutely agree with you that tanning lamps is not effective in this case. The best way is looking forward to with the alternatives which is
better. We conduct more experiment and feasibility in order to give the result.
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tentacles
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Here might be some useful information as to repurposing reptile bulbs:
http://www.uvguide.co.uk/phototherapyphosphor-discussion.htm
Sorry, much more useful link:
http://www.uvguide.co.uk/phototherapyphosphor-tests.htm#spec...
Scroll down a bit for the chart that lists the lamps that don't produce significant sub 300nm radiation.
Okay, last edit, farther down they have UV index-distance charts for those lamps, which should be a pretty good indicator of distance/exposure.
[Edited on 14-4-2010 by tentacles]
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densest
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This report http://www.ncbi.nlm.nih.gov/pubmed/20302573 has a clinical trial of UVB LEDs for psoriasis. http://www.s-et.com is the manufacturer of some (all?) of the deep (UVB-edge of UVC) LEDs.
This auction http://cgi.ebay.com/Vitiligo-Psoriasis-UVB-Narrowband-lamp-H... on EBay has a unit for about $US 300 - mercury vapor lamp with a Philips box in
the picture. There are 220V models for about $100 from Israel. http://cgi.ebay.com/Psoriasis-Medical-Lamp-UVB-Narrowband-31... which they say will not work with a 110-220 transformer. Unless there is circuitry
in the lamp specifically rejecting 60Hz mains, I don't understand. Maybe there are grounding issues or they just don't want to tangle with the FDA.
Who knows?
Hope this helps.
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tentacles
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I'd bet if you can get ahold of a copy of that trial report, it will describe the kind of dosage applied to be an effective treatment.. IE uW/cm2
etc. With the reptile bulbs, be sure to watch out for the ones that have below 300nm spectrum without some sort of filter or at least reasonable
distance from the bulb. Ultimately, probably better to use a type that doesn' t output the sub-300 stuff, though a longer application or a reflector
may be appropriate.
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unionised
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| Quote: Originally posted by AceMile | | Quote: Originally posted by Polverone | I'm interested in that range because it's the effective phototherapy range for psoriasis. I have a friend who has that condition and can't get enough
natural sunlight exposure in the winter to control it. Tanning salons are ineffective because their lamps emit longer UV radiation. There are
medically licensed phototherapy lamps but they cost thousands of dollars and require a prescription, and he doesn't have insurance coverage. I was
hoping that it might be possible to construct a DIY alternative for a few hundred dollars instead of a few thousand. LEDs for those short wavelengths
don't appear to exist (at least not readily, commercially).
I suppose I'll try looking at patents and medical books to see if I can find out what the light source is in the commercial devices and how it's
filtered.
[Edited on 1-1-2008 by Polverone] |
Yes I absolutely agree with you that tanning lamps is not effective in this case. The best way is looking forward to with the alternatives which is
better. We conduct more experiment and feasibility in order to give the result. |
AceMile, did you see the date of the post you were replying to?
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