UV lines of mercury spectra
Physikfan, Sun Jan 28 2018, 12:22AMThe spectra are photos of Hg spectra with increasing exposure time from top to bottom, light source is a Hg high-pressure lamp, the entrance slit is imaged with a quartz lens via a reflection grating on a screen, to detect the UV lines, the right part of an ultraviolet screen:
Only in the first two spectra do the colors correspond to the visual impression with unarmed eyes.
The blue line on the far left in the last spectrum is a ghost.
Further experiments with quartz glass prism and zinc sulphide screen are in preparation.
Re: UV lines of mercury spectra
klugesmith, Sun Jan 28 2018, 02:59PM
Spectacular work there, Physikfan. Thanks for sharing. That's a great idea, visualizing the invisible lines with a fluorescent screen. Some 17th century scientist discovered infrared in sunlight after placing a thermometer in a projected spectrum, and trying places out past the red end.
I bet the brightest UV bands are 254 and 365 nm. Have you made a wavelength scale for the pictures? One way to start is with an XY chart of known wavelengths vs. horizontal position in the picture. Would you like to share a picture of your setup?
If the Hg lamp's arc tube is made of quartz, for thermal engineering reasons, it would let out most of the 185 nm. Then if you ran it without the outer bulb, you would have an ozone generator. Does anyone know the attenuation length in air for that part of the "vacuum UV" band? Maybe it would be much greater in dry nitrogen or argon.
When us old guys were young, visible & UV wavelengths were four-digit numbers given in Angstrom units. Nanometers seem to have taken over in all but a few disciplines, just as pF now serves in place of MMF. And GHz replaced kilomegacycles. Any guesses about how soon 1048786 bytes will mostly be called a mebibyte?
klugesmith, Sun Jan 28 2018, 02:59PM
Spectacular work there, Physikfan. Thanks for sharing. That's a great idea, visualizing the invisible lines with a fluorescent screen. Some 17th century scientist discovered infrared in sunlight after placing a thermometer in a projected spectrum, and trying places out past the red end.
I bet the brightest UV bands are 254 and 365 nm. Have you made a wavelength scale for the pictures? One way to start is with an XY chart of known wavelengths vs. horizontal position in the picture. Would you like to share a picture of your setup?
If the Hg lamp's arc tube is made of quartz, for thermal engineering reasons, it would let out most of the 185 nm. Then if you ran it without the outer bulb, you would have an ozone generator. Does anyone know the attenuation length in air for that part of the "vacuum UV" band? Maybe it would be much greater in dry nitrogen or argon.
When us old guys were young, visible & UV wavelengths were four-digit numbers given in Angstrom units. Nanometers seem to have taken over in all but a few disciplines, just as pF now serves in place of MMF. And GHz replaced kilomegacycles. Any guesses about how soon 1048786 bytes will mostly be called a mebibyte?
Re: UV lines of mercury spectra
Physikfan, Fri Feb 23 2018, 03:07PM
Applied experimental setup:
Physikfan, Fri Feb 23 2018, 03:07PM
Applied experimental setup:
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