- #1
Mr Boom
- 30
- 0
Hello. I was hoping someone could help me understand some units. In several papers, I have seen the two photon LIF signal written as:
S = n*(Ω/4π)*T*G*σ*(E/hv)^2*η*a
where the units are
n (density of measured atom): #/cm3
Ω/4π (solid angle fraction): unitless
T (optical transmission fraction): unitless
G (statistical factor): unitless
E/hv (total photons): photons2 to photons4
η (detector conversion): unitless
So that leaves σ, which I've only seen defined in cm4*s. However, that leaves cm on top as well as square photons, which doesn't make sense. What am I not getting?
S = n*(Ω/4π)*T*G*σ*(E/hv)^2*η*a
where the units are
n (density of measured atom): #/cm3
Ω/4π (solid angle fraction): unitless
T (optical transmission fraction): unitless
G (statistical factor): unitless
E/hv (total photons): photons2 to photons4
η (detector conversion): unitless
So that leaves σ, which I've only seen defined in cm4*s. However, that leaves cm on top as well as square photons, which doesn't make sense. What am I not getting?