Sodium band in mercury free xenon MH lamps still have only one wing at the red « on: July 13, 2019, 03:44:53 AM » Author: dor123
Yesterday, I watched a spectrum of automotive HID headlamps that had mercury free xenon MH lamps, through my CD-R, at the parking lot of Azrieli Haifa mall. Despite the absence of mercury lines, the sodium band still had only one wing at the red, and not two wings like in a HPS lamp. Why this is happening?
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	Re: Sodium band in mercury free xenon MH lamps still have only one wing at the red « Reply #1 on: July 13, 2019, 06:44:26 AM » Author: halofosfaatti
Are you sure that the other red wing is not coming from mercury? Mercury does also have red-yellow emission lines, but to my knowledge, they are not very prominent on low pressure lamps. Lamp pressure and other conditions can also affect emission spectrum.
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	Re: Sodium band in mercury free xenon MH lamps still have only one wing at the red « Reply #2 on: July 13, 2019, 09:52:32 AM » Author: dor123
Low pressure sodium lamp don't have mercury. HPS lamps getting redder during life because of the increasing pressure of mercury, which push the sodium band more to the red and less to the green. The sodium band in MH lamps have only red wing because of the mercury. But I've seen a spectrum of mercury free xenon MH lamps of an automotive HID headlight of a car at Thursday 11.Jul.2019, and the mercury lines wasn't existed in the spectrum, but the sodium band still had only one wing at the red.
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I"m don't speak English well, and rely on online translating to write in this site.
Please forgive me if my choice of my words looks like offensive, while that isn't my intention.

I only working with the international date format (dd.mm.yyyy).

I lives in Israel, which is a 220-240V, 50hz country.

	Re: Sodium band in mercury free xenon MH lamps still have only one wing at the red « Reply #3 on: July 15, 2019, 02:35:17 AM » Author: Medved
The thing is, what mechanism exactly is causing the "yellow" wing of the sodium to disappear with the presence of mercury. It could be other components (like Xenon) do the same effect...
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	Re: Sodium band in mercury free xenon MH lamps still have only one wing at the red « Reply #4 on: July 15, 2019, 04:13:21 PM » Author: halofosfaatti
HPS lamps often have mercury with sodium, but there is also low mercury and mercury free HPS lamps. I meant is it possible that the yellow "wing" is coming from mercury discharge and not from sodium. Mercury has some yellow and red lines, that are prominent on high pressure lamps. Maybe I understood it wrong. Some other mechanism can also cause it. Maybe some fill component of the lamp ionizes at lower energy and "steals" the energy from sodium. Same phenomenon happens inside fluorescent lamps: the buffer gas is not producing light (in reality it may ionize little). Edit: Probably you meant it this way: HPS doesn't have the other wing because of mercury. Normal MH doesn't have it because of mercury, but even some mercury free MHs doesn't have it, and you want to know the reason. But does mercury free HPS and LPS have both wings? LPS has two narrow bands to my knowledge, very near each other.
« Last Edit: July 15, 2019, 04:42:38 PM by halofosfaatti »		Logged

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	Re: Sodium band in mercury free xenon MH lamps still have only one wing at the red « Reply #5 on: July 16, 2019, 03:25:55 AM » Author: Medved
Quote from: halofosfaatti on July 15, 2019, 04:13:21 PM But does mercury free HPS and LPS have both wings? LPS has two narrow bands to my knowledge, very near each other. Well, obviously LPS has no wings at all, it has just the (double) line. Because the wings come from the Doppler effect (the heated atoms are moving, that then shifts the frequency of the radiated wave), that means it is rather symmetrical in the frequency domain (the atoms are moving the same speeds in all directions). But in the wavelength domain, how these things use to be displayed, it causes quite significant asymetry: The wing towards shorter wavelengths becomes way narrower than the longer wavelength side, making it seemingly way smaller.
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	Re: Sodium band in mercury free xenon MH lamps still have only one wing at the red « Reply #6 on: July 16, 2019, 06:46:16 AM » Author: halofosfaatti
Ok. That is interesting. But why mercury causes the other wing to disappear?
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Too many things are secret. Only open information can really preserve old technology.

I like fluorescent and other conventional lighting and old electronic equipment. Today's things are not made to last.