Hooray for Bob Reite!
Regarding Richard's most recent post, I am not one to shy away from arguments about semantic minutiae. So had to look up "neutron flux".
It would appear that Richard is right.
Yup, when the subject is free neutrons, they use the word "flux"
where most other disciplines say "flux density".
http://www.nrc.gov/reading-rm/basic-ref ... -flux.html
of neutrons is contrary to flux of, say, a magnetic field. Magnetic flux
(in webers or maxwells) is the total amount of lines of force emerging from a pole, or passing through an aperture. When divided by the transverse area, you get magnetic flux density
, measurable (in teslas or gausses) with a sensor at some point in space.
Another example is in photometry.
, measured in lumens, can be the total output of a light bulb. A detector at a distance can measure luminous flux density
, in candelas (lm/m^2). Also known as illuminance.
Uh oh, maybe it's not so clear cut after all.
seems to usually be a per-unit-area quantity, with units like Btu/h/ft^2, and watts/m^2. Wikipedia is unsurprisingly sloppy and inconsistent about it.
Lesson to take home: sometimes flux
is a per-area term and sometimes not. (I think more often not.)