photon density


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pho·ton den·si·ty

the number of counted events recorded in scintigraphy per square centimeter or per square inch of imaged area.
Synonym(s): count density
Farlex Partner Medical Dictionary © Farlex 2012
References in periodicals archive ?
[G.sub.em]([r.sub.d],r) denotes the photon density for emission at the position of detector [r.sub.d] when a point source is located at position r.
When a planar source is implemented, the distribution of the photon density for excitation [[PHI].sub.e]x is not a Green's function solution to the diffusion equation anymore but a convolution of Green's function and the distribution function of the source.
Nonlinear processes are excited at high photon density. In cells, two-photon fluorescence (TPF), second and even third harmonic generation (SHG, THG) have been quite widely used in multiphoton microscopy with a photon density of around 1010 ~ 1011 W/cm2.
If the photon density is even higher, more than [10.sup.12] W/[cm.sup.2], molecules will be ionized by several different mechanisms.
Now notice that arguing that photons possess "which way" information implies that the photon density matrix at detectors is that of a mixed type.
The high photon density, or brightness, of the x-ray beam is what makes Nilsson's experiments possible, according to Joachim Stohr, a researcher from IBM's Almaden Research Center, San Jose, Calif., and Beam Line 8's participating research team spokes-person.
A light beam of low photon density can merely be regarded as a stream of non-interacting photons.