Talk:Fluence

Physical confusion
This note aims to be a radical criticism of the merge of "fluence" with "Radiant exposure", because fluence is a physical quantity and the estimation of radiant exposure as performed is far from the elementary fluence concept, as defined by Maurice Antony Biot (http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.210.3273&rep=rep1&type=pdf p.21-70). The physical meaning of fluence relates only to the number of particles, which crosses a reference surface (i.e. spherical for acoustic and radiation diffusion from a point source, or planar for laser beams or solar radiation). Hence fluence is completely independent of the physical magnitudes of particles that are transported by the particles. Hence, it allows describing any kind of transport phenomenon because by considering the particles as boxes containing physical properties (mass, kinetic energy, thermal energy, internal energy, etc.) it allows describing the flux of whatever property or magnitude is transported by the particles. Fluence concept by knowing the amount of energy of a photon and its mass allows determining both the solar radiation incoming to the hearth and the mass flow of the photons impacting the hearth system such as doing the same for laser beams. Limiting fluence to the transport of radiative particles is then a limiting and confusing model, which is really far from the real physical concept of fluence.

A
A pair of inscrutable mathematical formulae as the main body of the article isn't really approriaet for a general knowledge encyclopedia. This needs somebody to translate it into plainer English. -- Whpq 21:04, 4 December 2006 (UTC)

I would like to see a statement of whether the "two definitions" (rate of particles per surface area and sum of path lengths per volume) are equivalent or distinct. --67.249.58.190 (talk) 21:26, 14 July 2009 (UTC)

Definition?
So is it number per square meter or joules per square meter? There's a big difference when you're talking about radiation fields. HEL (talk) 20:07, 6 December 2007 (UTC)

It's number per square meter, or m^-2 --95.235.215.214 (talk) 17:35, 30 March 2010 (UTC)


 * If you look here you will see that there are two different types of fluence - particle fluence and energy fluence. It appears that this article has merged the two into one and become horribly inconsistent.  Particle fluence has the dimensions m–2 and energy fluence has the dimensions of J/m2.Martinvl (talk) 19:45, 30 March 2010 (UTC)

Medical Article?
I don't see where this article should contain medical information. Of course fluence is important in radiooncology as well as in many other fields ... I would suggest to remove the medical tag until information specifically related to medicine is added. Donik (talk) 14:43, 29 May 2008 (UTC)
 * That would be fine with me; alternatively, I've tagged it as low-importance to WPMED. WhatamIdoing (talk) 18:30, 16 September 2008 (UTC)

rewrite completely
The medical tag should be removed, that's pure physics. Also, the first sentence is wrong, since it is not "... per interval of time interest". It always is energy per area. A particle can be assigned a certain energy (hν for a photon, kinetic energy for an electron), hence, number of particles per area can be transformed to energy per area by multiplying it with energy per particle. I wouldn't relate it to the flux, that's confusing and most people would have to look up flux then (also in electromagnetics, the flux is called intensity). One can mention later that flux/intensity is the derivative of fluence with respect to time.

An exact and official definition could be found here: "Journal of the ICRU (2011) 11(1)" but this costs actual money. Suggestion for a start (and to remove the wrong sentence): In physics, fluence F is the amount of energy E traversing a certain area A, F=E/A. The term fluence can also be applied to particles, then it is a certain number of particles N traversing a certain area A, F=N/A. However in the latter case, the correct term would be particle fluence.

Fruehling42 (talk) 23:02, 13 February 2012 (UTC)