Rayleigh scattering is the elastic scattering of
electromagnetic radiation by particles much smaller than the wavelength of the
radiation. Example: light scattering off individual atoms or molecules. Rayleigh scattering is a function of the electric polarizibility of the
Raman scattering is the inelastic scattering of electromagnetic radiation by particles much smaller than the wavelength of the radiation
Famous experiments, frame transformation
Propagation of uncorrelated errors
P = ε2/R, dP/P = 2dε/R - dr/R, ΔP = P ((4dε/R)2
The uncertainties are added quaratically.
ΔP = uncertainty in P
Properties of diodes
Read a log-log scale
gain G = kω-2, log(G) = log(k) - 2log(ω).
The slope on the log-log plot in the region ω > 2*105 is -2.
The Gaussian distribution: The standard deviation of the Gaussian distribution is given by σ = Navg1/2. The standard deviation σ is a measure of the width of the distribution. Approximately 1/3 of the counts will lie outside the interval Navg - σ to Navg + σ.
Cross section σ
small beam, big target: (# of particles scattered per second
= [(# of beam particles)/s] * [(# of target particles)/area ] * σ
(# of target particles)/area = number per unit volume * thickness).
Also: only one answer is dimensionless.
Absorption of radiation is a random process. When
a photon travels through a material, we cannot predict exactly how far it will
penetrate and at which depth it will be absorbed, we can only predict the
probability that the photon will travel through a certain distance Δx of the material.
I(z) = I0exp(-kz), I(3d) = I0exp(-3kd) = I0exp(-kd)3 = (1/2)3 I0 = (1/8)I0.
If R is the rate of particles reaching the detector, r is the measured
count rate, and T is the dead time of the detector then r = R/(1 + RT).