Some ways to calculate the radiation dose that a crystal has absorbed: Difference between revisions

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-James Holton
-James Holton
MAD Scientist
MAD Scientist
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and he posted two corrections, the first at Thu, 7 May 2020 09:06:29 -0700:
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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 20 photons on a
Pilatus 6M, then that is P=12e6 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, not before.
Oh, and if you want a reference for that 2000 ph/um^2 = 1 Gy rule, it is
here:
https://doi.org/10.1107/S0909049509004361
And, of course, if you are lucky enough to have accurate flux, size and
shape information for the beam and sample, plus chemical composition the
most accurate dose you'll get from raddose-3D: https://www.raddo.se/
-James Holton
MAD Scientist
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and at Thu, 7 May 2020 09:33:03 -0700
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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,
not before.
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