Is this 7000 watt xenon arc tube an HID?

That link seems to be a revolving breaking news link for Yahoo News. As of this posting, it pulls up a pic related to the 9/11 attacks - nothing about flashlights.

BTW, do you still have have your 19 LED "blaster"?
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Just curious.
 
I think he meant this baby!!!
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"The memorial, "Tribute in Light," powered by 88 of these 7,000 watt xenon arc tubes, will be lit on the six-month annivesary of the attack on the World Trade Center, Monday, March 11, 2002 ."
 
I can't tell off the picture what kind of lamps fire these lights. HIDs (metal halide arc discharge lamps) seem to have become the standard light source for such applications. They offer white light with (relatively) good color rendition (very good in the special case of HMI / MSR type metal halide lamps as used for film shooting), and high efficiency, up to about 100 lumen per watt.
Xenons arc discharge lamps, such as the one shown above by LEDagent, have lower efficiency "only" about 40 lumen per watt, and are quite dangerous (I wouldn't touch them the way the guy on the photo does!) as the xenon gas inside the bubble is under high pressure, and if you drop or otherwise crack the bubble, it explodes like a bomb. Bulb manufacturers therefore recommend to use special protective wear when replacing xenon bulbs. they operate on low DC voltage (25 to 30V), resulting in extremely high currents for the higher wattages (around 230A for the 7000W model) and very expensive ballasts. The advantage of xenon arc lamps is that they offer the highest initial light density, as all the light really comes from one spall spot on one of the electrodes. This is the ideal prerequisite to concentrate the light into a narrow beam, and that's why they are used (primarily) in movie projectors and the like.
 
The light that is pictured above is very similar to the lamps we use in our follow spots. I know our lamps cost about $1400 each. We wear welding gloves and face shields whenever we are working on the lamp or near them with out the cover over it. We run them at 28 volts at about 85 amps. As I have said before they are the brightest lights I have seen in person, you can literally see the bones in your hand if you hold it in front of the light (if you don't go blind or burn you hand). Our lights are labeled "Xenon arc lamps" The gap is about 3/4 of an inch if I remember correctly.
 
HID stands for High Intensity Discharge- and refers not only to Metal Halide, but also low and high pressure Sodium, Mercury, that kind of thing. I`m not sure if those Xenon arc lamps count- possibly. Light is emmited by passing a current through a vapor, but there`s no metals or minerals involved so I`ll have to check. Neon lighting isn`t HID lighting, neither are Xenon flash tubes, so the possibility is that it`s not. The term "xenon arc lamp" is correct though.


And you have no idea how much I`d love to add one of those beauties to my "bulb museum" collection here. Sure, it`ll never happen, but I can dream......

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<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by wus:
(I wouldn't touch them the way the guy on the photo does!) as the xenon gas inside the bubble is under high pressure, and if you drop or otherwise crack the bubble, it explodes like a bomb. Bulb manufacturers therefore recommend to use special protective wear when replacing xenon bulbs. <HR></BLOCKQUOTE>

I'm betting that the bulb in the photograph has been "pre-popped" and is not under pressure; this would allow media and other people to handle it and have their photograph taken with it without the need for the ballistic suit. Drop that one and it's no worse than dropping a vase or a pitcher.
 
This is very interesting stuff! What kind of explosion would you get if you dropped one? Also, the Twin Tower project would consist of 88 of these kind of bulbs. Are we talkin' a huge amount of power to run these to the point where it is rediculous? Or are there other things out there that consume more energy that this?

There is a lot of contraversy about the design of the memorial, but i for one think it is a nice idea - and yes it does have a ghostly cast to it. I just hope that this place will be protected from vandalism. Can you imagine someone who hated this memorial throwing a rock into this grid of 88 bulbs and actually hitting one and staring a chain reaction of explosions? My oh my that would be bad - and not to mention ironic.
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Either way, what ever they do to that site I just hope it will help all generations remember what had happened that day.
 
This gets comfusing because both types of lamps have xenon gas and use an arc, but I believe that the primary difference between an "arc" lamp and an "HID" lamp is that the arc in the HID lamp is used to "excite" the gas in the bulb - as the electrons in the gas atoms fall back to their normal state they give up energy as photons of a specific wavelength. Different gas mixtures=different mixures of wavelengths, but the spectrum is still "chunky" due to the mechanism used. A simple "arc" lamp, on the other hand, makes light the old-fashioned way, like the sun - it's just really, really hot. So you get a full continuous spectrum. The Maxa beam is a true arc lamp, the Surefire beast is an HID. Because the arc lamp works by getting hot, a lot of the energy is radiated in the infrared where it doesn't do any good (unless you have NVGs) - this is why the arc lamps have poor efficencies compared to HID. On the plus side, color rendition is true to sunlight, and the arc is more of a point source than a glowing gas tube, so it can be focused tighter. This is why the main uses for the arc lamps are theatrical lighting, microscope illuminators, and searchlights. If you can get away with a little less perfect color or a slightly larger source, the HID is more efficient.

-BCK
 
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