photon density

(redirected from Number density)
Also found in: Encyclopedia, Wikipedia.

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
References in periodicals archive ?
To obtain the number density of particles, [N.sub.p] ([L.sup.-1]), and the average number of radicals, n, the following balance Equations are set.
These effects would nucleate a higher number density of cavities leading to reduction in creep ductility in Grade 91 material where Sn was present.
Rain-rate measured by both PMCS and OTT is higher than rain-rate measured by Gauge, the relative deviations are 4.5% and 15.0%, in which absolute deviation between PMCS and Gauge is higher than that between OTT and Gauge, the possible reason is that the sampling efficiency is affected by capture probability of PMCS, and the number density of large raindrops has an unsteady step-down variance.
where [n.sub.s] is the number density of species s (s represents [N.sub.2], [O.sub.2], N, O, and NO), [kappa] = 138 x [10.sup.-23] is the Boltzmann constant, and CTes is the collision cross section between electron and species s.
The quantity [n.sub.sp], i.e., the bulk-flow slow jet proton number density of ejected particles, is the dynamically important.
When compared with measurements on the soot number density and volume fraction, KM2 also shows much better predictions than ABF.
The more exactly the position of particle is updated, the less number density is disturbed.
2005) in order to predict microphysical cirrus properties such as size and number density (Luebke et al.
The shape of dust particles is assumed to be spherical with uniform size and constant number density. Considering these physical assumptions, along with the boundary layer approximations, the governing equations for the flow of dusty fluid together with the boundary conditions are given as (see [14])
Also, plasma parameters, temperature, and electron number density for plasma created by C[O.sub.2] and Nd:YAG laser pulses were evaluated and compared.
Calculating the MC Number Density at the APs in the Skin and for the Background.
The number density and composition of radiation-induced precipitates were determined by means of atom probe tomography using Cameca LEAP-4000 HR atom probe in voltage pulse mode.