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Science Forum Index » Optics Forum » krypton lamps
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| ratman |
 Posted: Sun Jan 06, 2008 10:19 pm |
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Does anyone know of good sources for krypton instrumentation
lamps? We now use Gilway 188-1 s, but the price keeps going up and
their quality control has never been better than mediocre. |
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| Don Klipstein |
| Posted: Sun Jan 06, 2008 10:19 pm |
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In article <vr23o3144q80nrgkn5bpihagi2rrevi1lj@4ax.com>, ratman wrote:
Quote: Does anyone know of good sources for krypton instrumentation
lamps? We now use Gilway 188-1 s, but the price keeps going up and
their quality control has never been better than mediocre.
Krypton generally gives only incrementally minor to sometimes modest
improvement in combination of energy efficiency and life expectancy in
comparison to cheaper alternatives (argon, or vacuum should lamp current
or wattage be so low for a filament designed for vacuum to outperform one
designed for argon due to heat conduction losses).
In general, krypton flashlight lamps have much of their increased light
output over cheaper ones by also being higher current and higher power
ones, and after that taking advantages of "economies of scale" that hinder
efficiency and/or life expectancy of lower current and lower wattage
incandescent lamps.
I would check into non-krypton alternatives. I expect the compromise in
performance to be minor, fair chance tolerable.
After that, I would check into LEDs. However, please keep in mind that
there is some data indicating that low power white LEDs can fade from
phosphor deterioration at a rate allowing only as low as 6,000 or 10,000
hour life expectancy at "full current" (or maybe even the
"characterization current" of typically 20 mA). Use only as much current
as you need - the latest white through-hole LEDs by Nichia with D revision
letter late in the part number may be plenty bright at 2-6 mA!
Otherwise, if you push about 30-50 mA through a heatsinkable white LED
designed for at least 350 mA (Lumileds "Luxeon", Cree "XLamp", Seoul
Semiconductor "P4" using Cree dice, Nichia high power white LEDs), I see
low chance of need for a heatsink. These should have efficiency maximized
as a function of current by current being in/near the 50-100 mA ballpark,
so I expect good results of going a little lower to not heat them up too
much. Expect extremely long lifetimes, since Lumileds Luxeons nowadays
have good expectations of lasting 50,000 hours at 350 mA.
Just know that the Lumileds "Luxeon Rebel" is a smaller size part that
needs heatsinking at some range of currents where other Lumileds "Luxeon
Emitters" can get away without a heatsink (I suspect roughly 50 mA
ballpark).
- Don Klipstein (don@misty.com) |
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