# Krypton, Xenon bulbs – How are they different?



## Darkstream (Sep 15, 2005)

What is the difference between krypton and xenon bulbs?

Is one brighter than the other?

Is one more efficient than the other, using less power?

How do they work?

Or is there some article somewhere you can link me to?


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## Lurveleven (Sep 15, 2005)

According to this web page at CarleyLamps you get 15% more lumens per watt with Xenon than Krypton.

Sigbjoern


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## bfg9000 (Sep 15, 2005)

They are both noble gases (which are for the most part nonreactive) which work by repelling tungsten particles that are vaporized off of the filament, keeping them off the glass. Xenon apparently works better at hotter temperatures than krypton, so the filaments in xenon filled bulbs may be made thinner to burn hotter; this results in greater efficiency. That is subsequently the reason why xenon bulbs generally cannot take as much overvoltage as krypton bulbs.

This property also helps keep arc-discharge lamps like HID from blackening their bulbs. Most people actually think of HID when xenon is mentioned, but it is also used as fill in plain old incandescent bulbs too.

Halogen gases work differently, by actually reacting with the tungsten and redepositing it on the filament if the temperature is hot enough to maintain this halogen cycle.


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## js (Sep 15, 2005)

OK, guys, this has been covered extensively in other threads, but the short of it is this:

xenon and krypton, as mentioned, are noble gasses and suppress (but do not eliminate) the tungsten atoms from vaporizing off of the filament. This suppression allows the filament to be run at a higher temperature, very close to the melting point in fact, and still not blacken the glass too quickly. Xenon works better for this because the atoms have a higher Z and work better at suppressing vaporization of the tungsten filament. The figure I have seen in an Osram publication is a *ten percent* increase in either efficiency or lifetime (take your pick).

However, neither xenon nor krypton will prevent blackening of the glass over time, because they do not remove tungsten from the glass wall. All they do, as mentioned by bfg9000, is slow this process down.

Enter the *halogen lamp*.

A halogen is from column VII of the periodic table, and includes such elements as F, Cl, Br, and I. When a trace amount of a halogen is added to the fill gas (bromine or iodine seem to be the ones used, but this is often proprietary information. All I know for sure is that Fluourine is NOT used, as it would corrode the filament even when cold) then an amazing thing happens: the halogen cycle. The halogen atoms bond with tungsten atoms at the colder glass envelope and float away in the fill gas. When they happen to float close to the filament, the higher temperature causes the reaction to reverse and the atoms are re-deposited back onto the filament. But not in the same place from which they left. In fact, the thin spots tend to get thinner until eventually --poof-- you blow the filament. Usually at turn on.

Now, you will notice that a *halogen* lamp must of necessity also have a noble gas fill gas. It need not be xenon, but on the other hand, in my experience, no company goes to the expense of using xenon without also adding a trace of a halogen.

Non-halogen krypton or argon/nitrogen lamps blacken over time and thus their output falls off with time. The stock mini-mag lamps are a prime example.

Halogen lamps do NOT blacken over time, or not significantly anyway, and thus their output stays more or less constant over their life span. All the SureFire incans are halogens.


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## Lurveleven (Sep 16, 2005)

js said:


> no company goes to the expense of using xenon without also adding a trace of a halogen.



I cannot see that this statement is correct. CarleyLamps makes both pure Xenon lamps (without halogen) and Halogen+Xenon lamps.
My CA1499 bulbs show signs of blackening after short runtime.

Sigbjoern


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## LightObsession (Sep 16, 2005)

js said:


> Halogen lamps do NOT blacken over time, or not significantly anyway, and thus their output stays more or less constant over their life span. All the SureFire incans are halogens.



Finally, an explanation of why the higher cost of the Surfire lamps may be better than less expensive lamps. Are the Brinkman Maxfire lamps halogen too?

Parden my ignorance, but other than slightly better beam, nobody has explained to me why Surfire lamps are worth the extra $10 to $12 each as compared to the Brinkman Maxfire replacement lamps.


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## js (Sep 19, 2005)

Lurveleven,

You left out the first part of my sentence: "In my experience, no company goes . . ." I think that's a rather important qualification, don't you?

I don't have any experience with the 1499, although I do have one sitting on my shelf. All I can say is that considering the cost of a 1499, it seems unacceptable and strange that it is not a halogen.

LightObsession,

Yes, but that's not the only reason why SF lamps are more expensive. The other is that they are potted into holders that exactly position their filaments relative to the reflectors, either via a spring like the P60,61,90,91, or via a tube and collar with double coil springs on the end, like the M3, M3T, M4, and M6 lamps. Plus, the double coil spring setup itself is also an extra expense, but allows the shock isolated head setup to electrically connect to the rest of the body and the batteries.

Plus, no question, you are paying something just for the SureFire name, BUT, you also get something for this name (it is to be hoped): good customer service. I know I have had good CS from them. They replaced my M6 Head and MN20 lamp for free when my MN20 lamp exploded inside.

In the last analysis, it is my opinion that you get what you pay for when it comes to SureFire products.


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## Lurveleven (Sep 21, 2005)

js said:


> Lurveleven,
> 
> You left out the first part of my sentence: "In my experience, no company goes . . ." I think that's a rather important qualification, don't you?



Sorry, I overlooked that part. But I must say I'm not very fond of such qualifications since it doesn't say anything about your experience on the subject, so people will have to guess how close the statement is to the truth. 
IMO one should always be careful when using absolute statements, even with qualifications. 



js said:


> I don't have any experience with the 1499, although I do have one sitting on my shelf. All I can say is that considering the cost of a 1499, it seems unacceptable and strange that it is not a halogen.



I don't understand it either and find it strange that most of the Carley bulbs are Xenon without Halogen. I just sent them an email asking them why.

Pila is also using Xenon without Halogen in their LAs. The bulb in my GL2 became so black that it was unusable after just 1 hour use 
Does anybody know of a replacement from another manufacturer that uses Halogen bulbs?

Sigbjoern


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## js (Sep 21, 2005)

Lurveleven said:


> But I must say I'm not very fond of such qualifications since it doesn't say anything about your experience on the subject, so people will have to guess how close the statement is to the truth.
> IMO one should always be careful when using absolute statements, even with qualifications.



I should think that people in this community generally know something about my experience on the subject of incandescent technology, and this would inform their guess as to how close to the truth my various statements are.

Depending on your working definition, an absolute statement (probably) _by definition_ lacks any qualifying statements. But in any case, I'd rather not be chastised for the style in which I choose to form my sentences, ill considered or not. I prefer to try to be as definite and informative as possible, while adding qualifications and while being happy to receive correction (and thus increase my knowledge) rather than live in fear of making an incorrect statement or misinforming people. I do the best I can, like anyone else, and I'm sure that most everyone here on CPF knows that no post should be considered an infallible and perfect statement of absolute Truth. So spare me the lecture on style, please.


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## Unicorn (Sep 22, 2005)

*Re: Krypton, Xenon bulbs – How are they different?*

Ok, children play nicely. 

Anyway, for the halogen cycle to take place the bulb needs to burn for a certain period of time correct? Or the bulb will blacken and the output will dim? Does the bulb actually blacken if a halogen bulb is used for only short intervals, say 30 seconds to a minute?


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## js (Sep 22, 2005)

*Re: Krypton, Xenon bulbs – How are they different?*

According to what I've read in the Osram publication "Low Voltage Tungsten Halogen Photo Optics" most if not all modern halogen lamps will handle being pulsed like this for a large number of cycles before building up any kind of tungsten deposition. In other words, none of us is likely to run into this problem, but it is a possibility if you always run your lights in 15 to 30 second bursts over many sets of batteries. (Who would do that? Special Ops military people maybe?)


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## gadget_lover (Sep 22, 2005)

It's my understanding that the halogen does no good if the bulb temperature falls below a certain point. I don't know if it decreases the efficiency.

The only reason I can imagine for a xenon without halogen is dimming applications, where the light will be run at partial brightness (and therefore lower temp) most of the time.

I could, of course, be all wet here.

Daniel


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## Unicorn (Sep 22, 2005)

*Re: Krypton, Xenon bulbs – How are they different?*



js said:


> According to what I've read in the Osram publication "Low Voltage Tungsten Halogen Photo Optics" most if not all modern halogen lamps will handle being pulsed like this for a large number of cycles before building up any kind of tungsten deposition. In other words, none of us is likely to run into this problem, but it is a possibility if you always run your lights in 15 to 30 second bursts over many sets of batteries. (Who would do that? Special Ops military people maybe?)



I did while in the desert on gate duty when searching cars. The Stinger HP's that were there had the fast chargers, but my MagCharger and later 9N had the slow charger so I had the light turned on only when actually looking at something. It was probably more than that though. Looking under the dash, then under the seat. The wheel well were pretty quick though, and if there was no place to hide anything because the under dash area was totally open (my God there are some pieces of crap in the Middle East, even in the rich countries, but mostly the foreign workers) it went quicker.


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## nemul (Sep 22, 2005)

:duck: :whoopin:

:grouphug:


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## Lurveleven (Sep 23, 2005)

*Re: Krypton, Xenon bulbs – How are they different?*

I'm doing SAR. These days I use two lights (not including headlamp and EDC/backup), one for close/medium range searching that stays on for most of the time (depending on the terrain, it may be used in burst mode in difficult terrain). The other is much brighter and is used for long range searching and is usually used in 3 to 10 seconds burst. I do a burst, walk a little, do a new burst and so on.

Sigbjoern


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## js (Sep 23, 2005)

Lurveleven said:


> I'm doing SAR. These days I use two lights (not including headlamp and EDC/backup), one for close/medium range searching that stays on for most of the time (depending on the terrain, it may be used in burst mode in difficult terrain). The other is much brighter and is used for long range searching and is usually used in 3 to 10 seconds burst. I do a burst, walk a little, do a new burst and so on.
> 
> Sigbjoern



So, Sigbjoern, have you noticed blackening in the brighter, long range light?


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## Lurveleven (Sep 23, 2005)

No blackening at all. But I have not used it that much yet. I will report back if I see any blackening before the bulb is worn-out. Btw, it is a WA1318 bulb.

Sigbjoern


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## mykall (Sep 23, 2005)

So where does Halogen fit into the brightness picture?
I always thought that in ascending order of brightness they
went like this.

1. Halogen
2. Krypton
3. Xenon

I also always thought that SF's incans like the E2e etc were
Xenon. Now I'm confus-ED.

MB


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## bwaites (Sep 23, 2005)

All of Surefires bulbs are Xenon/Halogen to my knowledge.

I'm surprised that any lamp manufacturer would go to the expense of making Xenon lamps without putting a halogen gas in them, but Carley apparently does.

So far as I can see, the halogen gas plays no part in tint or brightness, only in aiding in the redeposition of tungsten back to the filament.

Carleylamps.com has a nice little tutorial about the differences if you are interested.

Bill


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## winny (Sep 23, 2005)

js said:


> OK, guys, this has been covered extensively in other threads, but the short of it is this:
> 
> xenon and krypton, as mentioned, are noble gasses and suppress (but do not eliminate) the tungsten atoms from vaporizing off of the filament... and such



I'm a bit late into the discussion, but may I say, js, what an excellent explanation! I could not have said it better myself.

gadget_lover, 
yes, you are right. Reading from Philips OEM guide for halogen lamps:

"To contain the higher gas pressure of the Halogen lamps, the bulbs
must be considerably stronger than those of GLS lamps. In addition,
the Halogen cycle will only function if the bulb wall temperature is
kept between 250° C and 950° C during operation (in comparison
the GLS lamp operates at a bulb temperature of about 100° C)."

(A little bit off-topic)
If we are discussing the best incandescent lamp you use, efficiency-wise, halogen lamps with IR-reflection should be considered. About 4 times as expensive and 40% more efficient. I couldn't find anything that said whether they where xenon filled or not, so I leave that question unrequited.


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## Unicorn (Sep 24, 2005)

*Re: Krypton, Xenon bulbs – How are they different?*

At work last night I realised that I'm doing it there too. I'm a security guard working the graveyard shift. I light up an area of the woods behind or beside the building for a few seconds turn it off, then repeat a different patch. This is the same MC that I used overseas, and I haven't noticed any blackening so I guess that it's long enough for it to prevent the buildup.


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