One more correction:
For example, if you see an average pixel value of 20 photons on a
Pilatus 6M, then that is P=120e6 photons. If that was a t=0.1 s
exposure from a sample 100 microns thick, then the beamline flux was
about 1e12 photons/s. Note that this is the flux after any attenuation,
Ah! I did that last formula wrong. Never do algebra in your head
without checking. It should be:
The equation then becomes:
f = P/t/L/1.2e-5
Where 1.2e-5 = 0.2 cm^2/g * 1.2 g/cm^3 * 1e-4 cm/micron * 50%, f=flux
and t=exposure (as above).
For example, if you see an average pixel value of
In general? No.
I believe a few places put "flux" into the header, but as Andreas just
mentioned that is only one of the bits of information you need to
calculate dose. If all you want is a rough estimate, then the numbers
you need are:
f = flux (photons/s)
t = exposure time (s)
w =
Dear Murpholino,
all diffraction patterns contain information on absorbed dose in the form
of radiation damage.
You might be more interested in a quantitative description of dose. For
this, you need information on the size and shape of your crystal; the
sequence of your protein + cofactors,
