Polarization correction

docs/user-guide/estia/index.md

@@ -41,4 +41,5 @@ hidden:
 
 estia-mcstas-reduction
 estia-advanced-mcstas-reduction
+simulated-spin-flip-sample
 ```

pyproject.toml

@@ -40,6 +40,8 @@ dependencies = [
   "scippneutron>=24.10.0",
   "scippnexus>=24.9.1",
   "essreduce>=25.11.0",
+  "esspolarization>=25.7.0",
+  "essreduce>=25.4.0",
   "pandas>=2.1.2",
 ]
 

requirements/base.in

@@ -12,4 +12,6 @@ scipp>=24.09.1
 scippneutron>=24.10.0
 scippnexus>=24.9.1
 essreduce>=25.11.0
+esspolarization>=25.7.0
+essreduce>=25.4.0
 pandas>=2.1.2

requirements/base.txt

@@ -1,4 +1,4 @@
-# SHA1:ac5d5ed5d7ed7425eb3b92f0cfa128fe6db146b4
+# SHA1:7d24e61b002964358637133b46eac8bab3600eae
 #
 # This file was generated by pip-compile-multi.
 # To update, run:
@@ -17,20 +17,28 @@ cyclebane==24.10.0
     # via sciline
 cycler==0.12.1
     # via matplotlib
-dask==2025.10.0
-    # via -r base.in
+dask==2025.11.0
+    # via
+    #   -r base.in
+    #   esspolarization
 dnspython==2.8.0
     # via email-validator
 email-validator==2.3.0
     # via scippneutron
-essreduce==25.11.0
+esspolarization==25.10.0
     # via -r base.in
+essreduce==25.11.1
+    # via
+    #   -r base.in
+    #   esspolarization
 fonttools==4.60.1
     # via matplotlib
 fsspec==2025.10.0
     # via dask
 graphviz==0.21
-    # via -r base.in
+    # via
+    #   -r base.in
+    #   esspolarization
 h5py==3.15.1
     # via
     #   scippneutron
@@ -81,9 +89,9 @@ plopp==25.10.0
     # via
     #   -r base.in
     #   scippneutron
-pydantic==2.12.3
+pydantic==2.12.4
     # via scippneutron
-pydantic-core==2.41.4
+pydantic-core==2.41.5
     # via pydantic
 pyparsing==3.2.5
     # via matplotlib
@@ -93,7 +101,6 @@ python-dateutil==2.9.0.post0
     #   matplotlib
     #   pandas
     #   scippneutron
-    #   scippnexus
 pytz==2025.2
     # via pandas
 pyyaml==6.0.3
@@ -103,24 +110,27 @@ pyyaml==6.0.3
 sciline==25.11.1
     # via
     #   -r base.in
+    #   esspolarization
     #   essreduce
-scipp==25.8.0
+scipp==25.11.0
     # via
     #   -r base.in
+    #   esspolarization
     #   essreduce
     #   scippneutron
     #   scippnexus
 scippneutron==25.7.0
     # via
     #   -r base.in
     #   essreduce
-scippnexus==25.6.0
+scippnexus==25.11.0
     # via
     #   -r base.in
     #   essreduce
     #   scippneutron
 scipy==1.16.3
     # via
+    #   esspolarization
     #   scippneutron
     #   scippnexus
 six==1.17.0

requirements/basetest.txt

@@ -5,7 +5,7 @@
 #
 #    requirements upgrade
 #
-certifi==2025.10.5
+certifi==2025.11.12
     # via requests
 charset-normalizer==3.4.4
     # via requests
@@ -25,7 +25,7 @@ pooch==1.8.2
     # via -r basetest.in
 pygments==2.19.2
     # via pytest
-pytest==8.4.2
+pytest==9.0.0
     # via -r basetest.in
 requests==2.32.5
     # via pooch

requirements/ci.txt

@@ -7,7 +7,7 @@
 #
 cachetools==6.2.1
     # via tox
-certifi==2025.10.5
+certifi==2025.11.12
     # via requests
 chardet==5.2.0
     # via tox

requirements/dev.in

@@ -6,6 +6,6 @@
 -r test.in
 -r wheels.in
 copier
-jupyterlab
+jupyterlab>=4.4.3
 pip-compile-multi
 pre-commit

requirements/dev.txt

@@ -1,4 +1,4 @@
-# SHA1:efd19a3a98c69fc3d6d6233ed855de7e4a208f74
+# SHA1:d4ffe53db30990b73c1af821d46399aafea47d77
 #
 # This file was generated by pip-compile-multi.
 # To update, run:

requirements/docs.txt

@@ -30,7 +30,7 @@ bleach[css]==6.3.0
     # via nbconvert
 bqplot==0.12.45
     # via ipydatagrid
-certifi==2025.10.5
+certifi==2025.11.12
     # via requests
 charset-normalizer==3.4.4
     # via requests
@@ -66,7 +66,7 @@ ipykernel==7.1.0
     # via -r docs.in
 ipympl==0.9.8
     # via -r docs.in
-ipython==9.6.0
+ipython==9.7.0
     # via
     #   -r docs.in
     #   ipykernel
@@ -173,7 +173,7 @@ pybtex==0.25.1
     #   sphinxcontrib-bibtex
 pybtex-docutils==1.0.3
     # via sphinxcontrib-bibtex
-pydantic-settings==2.11.0
+pydantic-settings==2.12.0
     # via autodoc-pydantic
 pydata-sphinx-theme==0.16.1
     # via -r docs.in

requirements/nightly.in

@@ -6,6 +6,8 @@ python-dateutil
 graphviz
 orsopy>=1.2
 essreduce>=25.11.0
+esspolarization>=25.7.0
+essreduce>=25.4.0
 pandas>=2.1.2
 pytest>=7.0
 pooch>=1.5

requirements/nightly.txt

@@ -1,4 +1,4 @@
-# SHA1:1e183c3e9d303722f2579385b8d7861f9200b810
+# SHA1:ccf027ae6c53853baac5291a4a5faf53045d0292
 #
 # This file was generated by pip-compile-multi.
 # To update, run:
@@ -10,7 +10,7 @@
 
 annotated-types==0.7.0
     # via pydantic
-certifi==2025.10.5
+certifi==2025.11.12
     # via requests
 charset-normalizer==3.4.4
     # via requests
@@ -24,20 +24,28 @@ cyclebane==24.10.0
     # via sciline
 cycler==0.12.1
     # via matplotlib
-dask==2025.10.0
-    # via -r nightly.in
+dask==2025.11.0
+    # via
+    #   -r nightly.in
+    #   esspolarization
 dnspython==2.8.0
     # via email-validator
 email-validator==2.3.0
     # via scippneutron
-essreduce==25.11.0
+esspolarization==25.10.0
     # via -r nightly.in
+essreduce==25.11.1
+    # via
+    #   -r nightly.in
+    #   esspolarization
 fonttools==4.60.1
     # via matplotlib
 fsspec==2025.10.0
     # via dask
 graphviz==0.21
-    # via -r nightly.in
+    # via
+    #   -r nightly.in
+    #   esspolarization
 h5py==3.15.1
     # via
     #   scippneutron
@@ -64,7 +72,7 @@ matplotlib==3.10.7
     #   plopp
 mpltoolbox==25.10.0
     # via scippneutron
-networkx==3.5
+networkx==3.6rc0
     # via cyclebane
 numpy==2.3.4
     # via
@@ -100,15 +108,15 @@ pluggy==1.6.0
     # via pytest
 pooch==1.8.2
     # via -r nightly.in
-pydantic==2.12.3
+pydantic==2.12.4
     # via scippneutron
-pydantic-core==2.41.4
+pydantic-core==2.41.5
     # via pydantic
 pygments==2.19.2
     # via pytest
 pyparsing==3.3.0a1
     # via matplotlib
-pytest==8.4.2
+pytest==9.0.0
     # via -r nightly.in
 python-dateutil==2.9.0.post0
     # via
@@ -127,10 +135,12 @@ requests==2.32.5
 sciline @ git+https://github.com/scipp/sciline@main
     # via
     #   -r nightly.in
+    #   esspolarization
     #   essreduce
 scipp==100.0.0.dev0
     # via
     #   -r nightly.in
+    #   esspolarization
     #   essreduce
     #   scippneutron
     #   scippnexus
@@ -145,6 +155,7 @@ scippnexus @ git+https://github.com/scipp/scippnexus@main
     #   scippneutron
 scipy==1.16.3
     # via
+    #   esspolarization
     #   scippneutron
     #   scippnexus
 six==1.17.0

requirements/static.txt

@@ -17,7 +17,7 @@ nodeenv==1.9.1
     # via pre-commit
 platformdirs==4.5.0
     # via virtualenv
-pre-commit==4.3.0
+pre-commit==4.4.0
     # via -r static.in
 pyyaml==6.0.3
     # via pre-commit

src/ess/amor/normalization.py

@@ -85,6 +85,10 @@ def evaluate_reference_at_sample_coords(
     ref.coords["sample_size"] = sample.coords["sample_size"]
     ref.coords["detector_spatial_resolution"] = detector_spatial_resolution
     ref.coords["wavelength"] = sc.midpoints(ref.coords["wavelength"])
+
+    if "theta" in ref.coords:
+        ref.coords.pop("theta")
+
     ref = ref.transform_coords(
         (
             "Q",

src/ess/estia/calibration.py

@@ -0,0 +1,80 @@
+from dataclasses import dataclass
+from typing import Self
+
+import scipp as sc
+
+
+@dataclass
+class PolarizationCalibrationParameters:
+    I0: sc.DataArray
+    '''Reference intensity.'''
+    Pp: sc.DataArray
+    '''Effective polarization of polarizer when polarizer flipper is off.'''
+    Pa: sc.DataArray
+    '''Effective polarization of polarizer when polarizer flipper is on.'''
+    Ap: sc.DataArray
+    '''Effective polarization of analyzer when analyzer flipper if on.'''
+    Aa: sc.DataArray
+    '''Effective polarization of analyzer when analyzer flipper is off.'''
+    Rspp: sc.DataArray
+    '''Magnetic supermirror reflectivity for neutrons with
+    spin parallel to instrument polarization.'''
+    Rsaa: sc.DataArray
+    '''Magnetic supermirror reflectivity for neutrons with
+    spin anti-parallel to instrument polarization.'''
+
+    @classmethod
+    def from_reference_measurements(
+        cls: type[Self],
+        Io: tuple[sc.DataArray, sc.DataArray, sc.DataArray, sc.DataArray],
+        Is: tuple[sc.DataArray, sc.DataArray, sc.DataArray, sc.DataArray],
+    ) -> Self:
+        """
+        Solves for the calibration parameters given the reference
+        measurements.
+
+        See https://doi.org/10.1016/S0921-4526(00)00823-1.
+
+        Parameters
+        ------------
+        Io:
+            Intensity from measurements with perfect
+            non-magnetic supermirror.
+        Is:
+            Intensity from measurements with
+            magnetic supermirror.
+
+        Returns
+        ----------
+        :
+            Polarization calibration parameters
+        """
+        Iopp, Iopa, Ioap, Ioaa = Io
+        Ipp, Ipa, Iap, Iaa = Is
+
+        I0 = 2 * (Iopp * Ioaa - Iopa * Ioap) / (Iopp + Ioaa - Iopa - Ioap)
+        rho = (Ioaa - Ioap) / (Iopp - Iopa)
+        alp = (Ioaa - Iopa) / (Iopp - Ioap)
+
+        num_base = rho * alp * Ipp + Iaa + rho * Ipa + alp * Iap
+        den_base = Ipp + Iaa - Ipa - Iap
+        term_rho = rho * (Ipp - Ipa) - Iaa + Iap
+        term_alp = alp * (Ipp - Iap) - Iaa + Ipa
+
+        Rspp_plus_Rsaa = 4 * num_base / ((1 + rho) * (1 + alp) * I0)
+
+        Pp = sc.sqrt(den_base * term_alp / (num_base * term_rho))
+        Ap = sc.sqrt(den_base * term_rho / (num_base * term_alp))
+        Rs = sc.sqrt(term_alp * term_rho / (num_base * den_base))
+
+        Pa = -rho * Pp
+        Aa = -alp * Ap
+
+        Rspp_minus_Rsaa = Rs * Rspp_plus_Rsaa
+        Rspp = (Rspp_plus_Rsaa + Rspp_minus_Rsaa) / 2
+        Rsaa = Rspp_plus_Rsaa - Rspp
+
+        return cls(I0, Pp, Pa, Ap, Aa, Rspp, Rsaa)
+
+
+providers = ()