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Lasers, Radiance vs Irradiance
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- Subject: Lasers, Radiance vs Irradiance
- From: "RICHARD W. EDWARDS" <SHEA132@KGV2.bems.boeing.com>
- Date: Fri, 01 Sep 1995 08:51:27 -0700 (PDT)
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I talked to our laser safety specialist about the units used. He refered me to
ANSI Z136.1-1993, and then added his personal perspective.
The ANSI standard has a rather lengthy series of definitions, measurement
guides and figures that relate to this--it certainly confused me. The laser
jock simplified it this way. Watts per centimeter squared is used to measure
irradiance-how much radiant flux strikes a surface. Watts per steradian per
centimeter squared is used to measure radiance-how much radiant flux is
scattered back from a diffuse surface. The standard defines how this is to be
measured and what solid angle or circular area is to be used in calculating
the radiance.
(By the way, I thought the top two reasons for being a CHP were:
2) It's easy to spell.
1) It's safer than being a postal worker.)
This reflects my opinions only, not the opinions of my employer.
Thanks,
Richard W. Edwards, Analyst The Boeing Company
Phone: (206) 393-1999 P.O. Box 3707, M/S 6Y-38
Fax: (206) 393-3060 Seattle, WA 98124-2207