[[sigma].sub.ai]: neutron absorption cross section
of FP i ([cm.sup.2]).
The largest absorption cross section
at 767 nm of 3 at.% Tm, 3 at.% Y:Ca[F.sub.2] improves to 0.45 x [10.sup.-20] [cm.sup.-2], much larger than that reported in .
[[sigma].sub.ij] and [[[tau]].sub.ij] are the absorption cross section
and lifetime between the two adjacent energy levels, respectively.
Although the absorption cross section
luminescence efficiency of lanthanides can be improved using organic ligands and energy transfer (antenna effect), the chelate molecules luminescence is quenched by PMMA nonradiative transitions and efficient luminescence can be observed only for triplet state europium ([Eu.sup.3+]) and terbium ([Tb.sup.3+]) complexes [19-26].
Cao et al., "Light scattering and extinction measurements combined with laser-induced incandescence for the real-time determination of soot mass absorption cross section
," Analytical Chemistry, vol.
Zirconium alloys are used for fuel rod cladding in fission reactors owing to their small absorption cross section
In this case, the absorption cross section
per unit length of a cylinder is obtained
The ground-state absorption cross section
, [[sigma].sub.g], is calculated from [alpha]= [[sigma].sub.g]NC, where N is Avogadro's number and C is the concentration in mol [cm.sup.-3].
The cladding material should have good oxidation resistance, proper delay of the ballooning and burst , stress resistance, and small thermal neutron absorption cross section
For nanoparticles in the Rayleigh regime with appreciable absorption cross section
, damping of resonant absorption yields a strong photothermal response influenced by incident intensity, NP morphology [39, 40], and host media [41-43].
This behavior of [m with photon energy may be attributed to the photoelectric absorption cross section
which is relative to [E.sup.3.5].
Much effort has been made to improve the detection sensitivity, such as changing the scattering and absorption cross section
via chemical approach  or a local electromagnetic field enhancement mechanism [6,7].