Implement and test updated opacity definition #27
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| ) -> bool: | ||
| return (data.variances is None) or all( | ||
| data.sizes.get(dim) == size for dim, size in sizes.items() | ||
| ) |
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I feel i cannot give feedback to this part without getting explained what exactly its doing. Maybe you could explain it in our next meeting?
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Yes, this file was actually just copier from esssans, so it is has been reviewed by someone previously.
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| def intensity(wavelength: sc.Variable, opacity0: sc.Variable) -> sc.Variable: | ||
| opacity = OpacityFunction(opacity0) | ||
| return transmission_empty_glass * sc.exp(-opacity(wavelength)) |
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It seems here that transmission_empty_glass is assumed to be a constant? (unless I misread).
However, in the documentation notebook it says that it could be wavelength dependent. Do we need to factor that in now, or are we leaving it for a later stage?
If the latter, should we include a TODO?
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As far as I remember, it was said "it is in principle not constant, but no one ever measured that". As it would complicate #24, I would like to keep this as it is, until we have clear evidence that this is not sufficient.
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Yes that was exactly the status, so I agree on keeping it as it is!
| return He3Opacity[Cell](0.07733 * pressure * cell_length * wavelength) | ||
| from scipp.constants import Boltzmann as k_B | ||
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| he3_neutron_absorption_cross_section_at_1_angstrom = 2966.0e-24 * sc.Unit( |
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Can we add a reference to an article or database where the 2966.0e-24 came from?
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We are already tracking this in #28. In particular, I think this should have error bars.
This should replace #20 and #21. This is based on my understanding looking at the docs added in #26.
@astellhorn Please check if this is correct.
Can you answer the TODO about the units?