Subtract sample run by empty can

Author: jl-wynen

src/ess/dream/io/geant4.py

@@ -8,6 +8,7 @@
 from scippneutron.metadata import ESS_SOURCE
 
 from ess.powder.types import (
+    BackgroundRun,
     Beamline,
     CalibratedBeamline,
     CalibratedDetector,
@@ -320,7 +321,7 @@ def LoadGeant4Workflow() -> sciline.Pipeline:
     Workflow for loading NeXus data.
     """
     wf = GenericTofWorkflow(
-        run_types=[SampleRun, VanadiumRun], monitor_types=[CaveMonitor]
+        run_types=[SampleRun, VanadiumRun, BackgroundRun], monitor_types=[CaveMonitor]
     )
     wf.insert(extract_geant4_detector)
     wf.insert(load_geant4_csv)

src/ess/dream/workflow.py

@@ -19,6 +19,7 @@
 )
 from ess.powder.types import (
     AccumulatedProtonCharge,
+    BackgroundRun,
     CaveMonitorPosition,  # Should this be a DREAM-only parameter?
     MonitorType,
     PixelMaskFilename,
@@ -75,10 +76,13 @@ def default_parameters() -> dict:
     return {
         Position[snx.NXsample, SampleRun]: sample_position,
         Position[snx.NXsample, VanadiumRun]: sample_position,
+        Position[snx.NXsample, BackgroundRun]: sample_position,
         Position[snx.NXsource, SampleRun]: source_position,
         Position[snx.NXsource, VanadiumRun]: source_position,
+        Position[snx.NXsource, BackgroundRun]: source_position,
         AccumulatedProtonCharge[SampleRun]: charge,
         AccumulatedProtonCharge[VanadiumRun]: charge,
+        AccumulatedProtonCharge[BackgroundRun]: charge,
         TofMask: None,
         WavelengthMask: None,
         TwoThetaMask: None,

src/ess/powder/correction.py

@@ -12,6 +12,9 @@
 from ._util import event_or_outer_coord
 from .types import (
     AccumulatedProtonCharge,
+    BackgroundRun,
+    BackgroundSubtractedData,
+    BackgroundSubtractedDataTwoTheta,
     CaveMonitor,
     DataWithScatteringCoordinates,
     FocussedDataDspacing,
@@ -155,7 +158,7 @@ def _normalize_by_vanadium(
 
 
 def normalize_by_vanadium_dspacing(
-    data: FocussedDataDspacing[SampleRun],
+    data: BackgroundSubtractedData[SampleRun],
     vanadium: FocussedDataDspacing[VanadiumRun],
     uncertainty_broadcast_mode: UncertaintyBroadcastMode,
 ) -> IofDspacing:
@@ -185,7 +188,7 @@ def normalize_by_vanadium_dspacing(
 
 
 def normalize_by_vanadium_dspacing_and_two_theta(
-    data: FocussedDataDspacingTwoTheta[SampleRun],
+    data: BackgroundSubtractedDataTwoTheta[SampleRun],
     vanadium: FocussedDataDspacingTwoTheta[VanadiumRun],
     uncertainty_broadcast_mode: UncertaintyBroadcastMode,
 ) -> IofDspacingTwoTheta:
@@ -335,6 +338,22 @@ def _shallow_copy(da: sc.DataArray) -> sc.DataArray:
     return out
 
 
+def subtract_background(
+    data: FocussedDataDspacing[SampleRun],
+    background: FocussedDataDspacing[BackgroundRun],
+) -> BackgroundSubtractedData[SampleRun]:
+    return BackgroundSubtractedData[SampleRun](data.bins.concatenate(-background))
+
+
+def subtract_background_two_theta(
+    data: FocussedDataDspacingTwoTheta[SampleRun],
+    background: FocussedDataDspacingTwoTheta[BackgroundRun],
+) -> BackgroundSubtractedDataTwoTheta[SampleRun]:
+    return BackgroundSubtractedDataTwoTheta[SampleRun](
+        data.bins.concatenate(-background)
+    )
+
+
 class RunNormalization(enum.Enum):
     """Type of normalization applied to each run."""
 
@@ -357,6 +376,8 @@ def insert_run_normalization(
 
 
 providers = (
+    subtract_background,
+    subtract_background_two_theta,
     normalize_by_proton_charge,
     normalize_by_vanadium_dspacing,
     normalize_by_vanadium_dspacing_and_two_theta,

src/ess/powder/types.py

@@ -58,7 +58,7 @@
 TimeOfFlightLookupTableFilename = tof_t.TimeOfFlightLookupTableFilename
 SimulationResults = tof_t.SimulationResults
 
-RunType = TypeVar("RunType", SampleRun, VanadiumRun)
+RunType = TypeVar("RunType", SampleRun, VanadiumRun, BackgroundRun)
 MonitorType = TypeVar("MonitorType", CaveMonitor, BunkerMonitor)
 
 
@@ -175,6 +175,16 @@ class NormalizedRunData(sciline.Scope[RunType, sc.DataArray], sc.DataArray):
     """Data that has been normalized by proton charge."""
 
 
+class BackgroundSubtractedData(sciline.Scope[RunType, sc.DataArray], sc.DataArray):
+    """Data where background has been subtracted."""
+
+
+class BackgroundSubtractedDataTwoTheta(
+    sciline.Scope[RunType, sc.DataArray], sc.DataArray
+):
+    """Data with 2theta bins where background has been subtracted."""
+
+
 PixelMaskFilename = NewType("PixelMaskFilename", str)
 """Filename of a pixel mask."""