Merge pull request #594 from scipp/fix-beer-geometry

[ESSDIFFRACTION] Fix beer geometry

Author: MridulS

packages/essdiffraction/src/ess/beer/io.py

@@ -209,7 +209,7 @@ def _load_beer_mcstas(f, *, north_or_south=None, number=None, detector_sizes):
         positions['MCC'],
     )
     data = (
-        next(_find_all_h5(data_dir, f'.*{north_or_south}{number}'))
+        next(_find_all_h5(data_dir, f'.*{north_or_south}{number}_events'))
         if north_or_south is not None and number is not None
         else next(_find_all_h5(data_dir, f'.*{north_or_south}'))
         if north_or_south is not None
@@ -222,7 +222,7 @@ def _load_beer_mcstas(f, *, north_or_south=None, number=None, detector_sizes):
     ]
     detector_rotation = _find_h5(
         f['/entry1/instrument/components'],
-        f'.*nD_Mantid_?{north_or_south}_{number}.*'
+        f'.*nD_Mantid_?{north_or_south}_{number}$'
         if north_or_south is not None and number is not None
         else f'.*nD_Mantid_?{north_or_south}.*'
         if north_or_south is not None

packages/essdiffraction/tests/beer/mcstas_reduction_test.py

@@ -105,6 +105,9 @@ def test_can_load_3d_detector():
         mcstas_few_neutrons_3d_detector_example(), DetectorBank.south, sizes
     )
     assert 'panel' in da.dims
+    # Detector position.x is monotone in panel dimension.
+    panel_x_diff = np.diff(da.coords['detector_position'].fields.x.values)
+    assert (panel_x_diff > 0).all() or (panel_x_diff < 0).all()
 
 
 def test_can_load_monitor():