safety of quartz bulbs / WAS Re: GB 4000 MOPA

[Guest guest]

Hi Glen,

Here are some links about how the different types of glass transmit (allow passage of) UV. The largest concern has to do with the area around 260 nanometers (nm) wavelength, because that area will damage DNA easily. Other longer UV wavelengths may also be of concern, and some folks are more sensitive than others. Quartz will allow about 85% of a 260 nm wavelength through, see the transmittance chart at http://www.almazoptics.com/KV.htm.

Pyrex will allow about 8-10% of a similar emission through. To see a similar transmission chart for pyrex, go to:

http://catalog2.corning.com/Lifesciences/en-US/TDL/techInfo.aspx?categoryname=General%20Labware%20and%20Equipment|Glassware

Then go to the "technical reports" chart at the lower part of that page, and click on the pdf titled: "Properties of PYREX, PYREXPLUS and Low Actinic PYREX Code 7740 Glasses";

At the bottom of page 2, there is a chart for transmittance of common pyrex glass, similar to the one for quartz above.

Leaded glass is the safest in this regard. It allows virtually no emissions through at the 260 nm wavelength region. In fact, thick leaded glass only allows 1% through at 347 nm (the transmission percentage will vary with the thickness of the glass). That data can be found in the CRC Handbook of Chemistry and Physics.

That text also gives information about the various wavelengths emitted by ionized gases. From that data, I would personally want to avoid the use of ionized neon and/or argon (and certainly mercury!), with a quartz bulb.

Best wishes,

Charlene Boehm

Member New York Academy of Sciences

Member Bioelectromagnetics Society

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Hi Charlene,

Thank you for your offer - I would very much appreciate any information you could offer.

[snip]

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Hi Glen,

Good question. Leaded and pyrex glass plasma tubes will not pass damaging UV. Quartz however, is capable of transmitting damaging UV wavelengths. If you would like more information about this, please reply and I will dig up some posts and references I've made in years past.

Best wishes,Charlene Boehm