Implement He3 polarization function and He3 transmission function #48
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SimonHeybrock
changed the title
| He3Transmission | ||
| He3OpacityFunction | ||
| He3PolarizationFunction | ||
| He3TransmissionFunction |
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(minor) I think it's better to not add the type of the quantity to the name. In this case ...Function. Just like we don't add ...Variable or ...DataArray to the names of domain types that are variables or data arrays. He3Opacity seems less noisy to me.
But this is maybe more of a personal preference.
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Especially for the functions where a fit has to be performed, I actually like the naming ...Function --> it is more clear (to me) what is the function and what is the result itself
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I also think having "function" here is important, since we initially thought we would return the evaluated function. The comparison to Variable and DataArray is not equivalent, I think.
src/ess/polarization/base.py
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| polarization -= 1.0 | ||
| else: | ||
| polarization += 1.0 | ||
| return self.transmission_empty_glass * sc.exp(opacity * polarization) |
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In the description (section "Spin-dependent transmission values") it looks like plus_minus = 'plus' implies that the expression in exp() should be
Seems to be two things different:
-
$\lambda$ does not occur in the final expression, is that because the notation in the description is different, and the wavelength is actually an argument to the opacity like it is in this function? - The sign of
$P$ seems to be wrong.
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Hm, we want for 'plus' : -OP-1, and for 'minus': +OP-O.
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But I have another question: is this used only for the TransmissionFunction for a polarized incoming beam? It is a bit unclear to me. It should NOT be used for transmission_incoming_unpolarized
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Good catch, should be fixed now, please have another look.
@astellhorn No, this is not used during the fit.
src/ess/polarization/base.py
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| ) -> He3Transmission[Cell]: | ||
| """ | ||
| Transmission for a given cell. | ||
| def direct_beam_ratio( |
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(minor) I still prefer the name transmission here, or maybe expected_transmission. The "ratio" here is (imo) the observed transmission.
Fixes #44.