Enable user defined sample and container geometry for abs correction

Framework/PythonInterface/mantid/utils/absorptioncorrutils.py

@@ -8,6 +8,7 @@
 from mantid.kernel import Logger, Property, PropertyManager
 from mantid.simpleapi import (
     AbsorptionCorrection,
+    DefineGaugeVolume,
     DeleteWorkspace,
     Divide,
     Load,
@@ -24,6 +25,7 @@
 import numpy as np
 import os
 from functools import wraps
+import xml.etree.ElementTree as ET
 
 VAN_SAMPLE_DENSITY = 0.0721
 _EXTENSIONS_NXS = ["_event.nxs", ".nxs.h5"]
@@ -284,6 +286,11 @@ def calculate_absorption_correction(
     sample_formula,
     mass_density,
     sample_geometry={},
+    can_geometry={},
+    can_material={},
+    gauge_vol="",
+    container_gauge_vol="",
+    beam_height=Property.EMPTY_DBL,
     number_density=Property.EMPTY_DBL,
     container_shape="PAC06",
     num_wl_bins=1000,
@@ -323,6 +330,11 @@ def calculate_absorption_correction(
     :param sample_formula: Sample formula to specify the Material for absorption correction
     :param mass_density: Mass density of the sample to specify the Material for absorption correction
     :param sample_geometry: Dictionary to specify the sample geometry for absorption correction
+    :param can_geometry: Dictionary to specify the container geometry for absorption correction
+    :param can_material: Dictionary to specify the container material for absorption correction
+    :param gauge_vol: String in XML form to define the volume of the sample visible to the beam
+    :param container_gauge_vol: String in XML form to define the volume of the container visible to the beam
+    :param beam_height: Optional beam height to use for absorption correction
     :param number_density: Optional number density of sample to be added to the Material for absorption correction
     :param container_shape: Shape definition of container, such as PAC06.
     :param num_wl_bins: Number of bins for calculating wavelength
@@ -344,12 +356,26 @@ def calculate_absorption_correction(
         material["SampleNumberDensity"] = number_density
 
     environment = {}
-    if container_shape:
+    find_env = True
+    if container_shape or (can_geometry and can_material):
         environment["Name"] = "InAir"
-        environment["Container"] = container_shape
+        find_env = False
+        if not (can_geometry and can_material):
+            environment["Container"] = container_shape
 
     donorWS = create_absorption_input(
-        filename, props, num_wl_bins, material=material, geometry=sample_geometry, environment=environment, metaws=metaws
+        filename,
+        props,
+        num_wl_bins,
+        material=material,
+        geometry=sample_geometry,
+        can_geometry=can_geometry,
+        can_material=can_material,
+        gauge_vol=gauge_vol,
+        beam_height=beam_height,
+        environment=environment,
+        find_environment=find_env,
+        metaws=metaws,
     )
 
     # NOTE: Ideally we want to separate cache related task from calculation,
@@ -381,6 +407,8 @@ def calculate_absorption_correction(
         donorWS,
         abs_method,
         element_size,
+        container_gauge_vol=container_gauge_vol,
+        beam_height=beam_height,
         prefix_name=absName,
         cache_dirs=cache_dirs,
         ms_method=ms_method,
@@ -392,6 +420,8 @@ def calc_absorption_corr_using_wksp(
     donor_wksp,
     abs_method,
     element_size=1,
+    container_gauge_vol="",
+    beam_height=Property.EMPTY_DBL,
     prefix_name="",
     cache_dirs=[],
     ms_method="",
@@ -401,7 +431,7 @@ def calc_absorption_corr_using_wksp(
     if cache_dirs:
         log.warning("Empty cache dir found.")
     # 1. calculate first order absorption correction
-    abs_s, abs_c = calc_1st_absorption_corr_using_wksp(donor_wksp, abs_method, element_size, prefix_name)
+    abs_s, abs_c = calc_1st_absorption_corr_using_wksp(donor_wksp, abs_method, element_size, container_gauge_vol, beam_height, prefix_name)
     # 2. calculate 2nd order absorption correction
     if ms_method in ["", None, "None"]:
         log.information("Skip multiple scattering correction as instructed.")
@@ -452,6 +482,8 @@ def calc_1st_absorption_corr_using_wksp(
     donor_wksp,
     abs_method,
     element_size=1,
+    container_gauge_vol="",
+    beam_height=Property.EMPTY_DBL,
     prefix_name="",
 ):
     """
@@ -461,6 +493,8 @@ def calc_1st_absorption_corr_using_wksp(
     :param donor_wksp: Input workspace to compute absorption correction on
     :param abs_method: Type of absorption correction: None, SampleOnly, SampleAndContainer, FullPaalmanPings
     :param element_size: Size of one side of the integration element cube in mm
+    :param container_gauge_vol: String in XML form to define the volume of container visible to the beam
+    :param beam_height: Beam height for defining the gauge volume for container visible to the beam
     :param prefix_name: Optional prefix of the output workspaces, default is the donor_wksp name.
 
     :return: Two workspaces (A_s, A_c), the first for the sample and the second for the container
@@ -473,6 +507,13 @@ def calc_1st_absorption_corr_using_wksp(
             raise RuntimeError("Specified donor workspace not found in the ADS")
         donor_wksp = mtd[donor_wksp]
 
+    def is_valid_xml(xml_string):
+        try:
+            ET.fromstring(xml_string)
+            return True
+        except ET.ParseError:
+            return False
+
     absName = donor_wksp.name()
     if prefix_name != "":
         absName = prefix_name
@@ -482,6 +523,25 @@ def calc_1st_absorption_corr_using_wksp(
         return absName + "_ass", ""
     elif abs_method == "SampleAndContainer":
         AbsorptionCorrection(donor_wksp, OutputWorkspace=absName + "_ass", ScatterFrom="Sample", ElementSize=element_size)
+        if container_gauge_vol and is_valid_xml(container_gauge_vol):
+            DefineGaugeVolume(donor_wksp, container_gauge_vol)
+        elif container_gauge_vol and beam_height != Property.EMPTY_DBL:
+            gauge_vol = """<hollow-cylinder id="container_gauge">
+                <centre-of-bottom-base r="{0:4.2F}" t="90.0" p="270.0" />
+                <axis x="0.0" y="0.2" z="0" />
+                <inner-radius val="{1:7.5F}" />
+                <outer-radius val="{2:7.5F}" />
+                <height val="{3:4.2F}" />
+              </hollow-cylinder>
+            """
+            gauge_vol = gauge_vol.format(
+                beam_height / 200.0,
+                float(container_gauge_vol.split()[0]) / 100.0,
+                float(container_gauge_vol.split()[1]) / 100.0,
+                beam_height / 100.0,
+            )
+            DefineGaugeVolume(donor_wksp, gauge_vol)
+
         AbsorptionCorrection(donor_wksp, OutputWorkspace=absName + "_acc", ScatterFrom="Container", ElementSize=element_size)
         return absName + "_ass", absName + "_acc"
     elif abs_method == "FullPaalmanPings":
@@ -499,6 +559,10 @@ def create_absorption_input(
     num_wl_bins=1000,
     material={},
     geometry={},
+    can_geometry={},
+    can_material={},
+    gauge_vol="",
+    beam_height=Property.EMPTY_DBL,
     environment={},
     find_environment=True,
     opt_wl_min=0,
@@ -513,6 +577,10 @@ def create_absorption_input(
     :param num_wl_bins: The number of wavelength bins used for absorption correction
     :param material: Optional material to use in SetSample
     :param geometry: Optional geometry to use in SetSample
+    :param can_geometry: Optional container geometry to use in SetSample
+    :param can_material: Optional container material to use in SetSample
+    :param gauge_vol: Optional gauge volume definition, i.e., sample portion visible to the beam.
+    :param beam_height: Optional beam height to define gauge volume
     :param environment: Optional environment to use in SetSample
     :param find_environment: Optional find_environment to control whether to figure out environment automatically.
     :param opt_wl_min: Optional minimum wavelength. If specified, this is used instead of from the props
@@ -611,7 +679,31 @@ def confirmProps(props):
     # Make sure one is set before calling SetSample
     if material or geometry or environment:
         mantid.simpleapi.SetSampleFromLogs(
-            InputWorkspace=absName, Material=material, Geometry=geometry, Environment=environment, FindEnvironment=find_environment
+            InputWorkspace=absName,
+            Material=material,
+            Geometry=geometry,
+            ContainerGeometry=can_geometry,
+            ContainerMaterial=can_material,
+            Environment=environment,
+            FindEnvironment=find_environment,
         )
 
+    if beam_height != Property.EMPTY_DBL and not gauge_vol:
+        # If the gauge volume is not defined, use the beam height to define it,
+        # and we will be assuming a cylinder shape of the sample.
+        gauge_vol = """<cylinder id="shape">
+            <centre-of-bottom-base r="{0:4.2F}" t="90.0" p="270.0" />
+            <axis x="0.0" y="0.2" z="0.0" />
+            <radius val="{1:7.5F}" />
+            <height val="{2:4.2F}" />
+            </cylinder>"""
+        if isinstance(geometry["Radius"], float):
+            sam_rad = geometry["Radius"]
+        else:
+            sam_rad = geometry["Radius"].value
+        gauge_vol = gauge_vol.format(beam_height / 200.0, sam_rad / 100.0, beam_height / 100.0)
+
+    if gauge_vol:
+        DefineGaugeVolume(absName, gauge_vol)
+
     return absName

Framework/PythonInterface/plugins/algorithms/SNSPowderReduction.py

@@ -291,6 +291,19 @@ def PyInit(self):
         )
         self.declareProperty("SampleFormula", "", doc="Chemical formula of the sample")
         self.declareProperty("SampleGeometry", {}, doc="A dictionary of geometry parameters for the sample.")
+        self.declareProperty("ContainerGeometry", {}, doc="A dictionary of geometry parameters for the container.")
+        self.declareProperty("ContainerMaterial", {}, doc="A dictionary of material parameters for the container.")
+        self.declareProperty(
+            "GaugeVolume", "", "A string in XML form for gauge volume definition indicating sample portion visible to the beam."
+        )
+        self.declareProperty(
+            "ContainerGaugeVolume", "", "A string in XML form for gauge volume definition indicating container portion visible to the beam."
+        )
+        self.declareProperty(
+            "BeamHeight",
+            defaultValue=Property.EMPTY_DBL,
+            doc="Height of the neutron beam cross section in cm",
+        )
         self.declareProperty(
             "MeasuredMassDensity",
             defaultValue=0.1,
@@ -423,6 +436,11 @@ def PyExec(self):  # noqa
         self._absMethod = self.getProperty("TypeOfCorrection").value
         self._sampleFormula = self.getProperty("SampleFormula").value
         self._sampleGeometry = self.getProperty("SampleGeometry").value
+        self._containerGeometry = self.getProperty("ContainerGeometry").value
+        self._containerMaterial = self.getProperty("ContainerMaterial").value
+        self._gaugeVolume = self.getProperty("GaugeVolume").value
+        self._containerGaugeVolume = self.getProperty("ContainerGaugeVolume").value
+        self._beamHeight = self.getProperty("BeamHeight").value
         self._massDensity = self.getProperty("MeasuredMassDensity").value
         self._numberDensity = self.getProperty("SampleNumberDensity").value
         self._containerShape = self.getProperty("ContainerShape").value
@@ -524,6 +542,11 @@ def PyExec(self):  # noqa
             self._sampleFormula,  # Material for absorption correction
             self._massDensity,  # Mass density of the sample
             self._sampleGeometry,  # Geometry parameters for the sample
+            self._containerGeometry,  # Geometry parameters for the container
+            self._containerMaterial,  # Material parameters for the container
+            self._gaugeVolume,  # Gauge volume definition for sample
+            self._containerGaugeVolume,  # Gauge volume definition for container
+            self._beamHeight,  # Height of the neutron beam cross section in cm
             self._numberDensity,  # Optional number density of sample to be added
             self._containerShape,  # Shape definition of container
             self._num_wl_bins,  # Number of bins: len(ws.readX(0))-1
@@ -1515,6 +1538,7 @@ def _process_vanadium_runs(self, van_run_number_list, samRunIndex, **dummy_focus
                 self._num_wl_bins,
                 material={"ChemicalFormula": "V", "SampleNumberDensity": absorptioncorrutils.VAN_SAMPLE_DENSITY},
                 geometry={"Shape": "Cylinder", "Height": 7.0, "Radius": self._vanRadius, "Center": [0.0, 0.0, 0.0]},
+                beam_height=self._beamHeight,
                 find_environment=False,
                 opt_wl_min=self._wavelengthMin,
                 opt_wl_max=self._wavelengthMax,
@@ -1543,6 +1567,9 @@ def _process_vanadium_runs(self, van_run_number_list, samRunIndex, **dummy_focus
             )
             api.RenameWorkspace(abs_v_wsn, "__V_corr_abs")
 
+            # Here, we are using a combo of absorption correction with the numerical integration approach and multiple
+            # scattering correction with the Carpenter approach - `Absorption` param set to `False` below, making sure
+            # only `__V_corr_ms` will be created without overwriting the already calculated `__V_corr_abs`.
             api.CalculateCarpenterSampleCorrection(
                 InputWorkspace=absWksp, OutputWorkspaceBaseName="__V_corr", CylinderSampleRadius=self._vanRadius, Absorption=False
             )

docs/source/release/v6.13.0/Diffraction/Powder/New_features/38887.rst

@@ -0,0 +1 @@
+- Enable user defined sample and container geometry together with the definition of gauge volume to account for the beam size. Implementation made in :ref:`SNSPowderReduction <algm-SNSPowderReduction>` and ``mantid.utils.absorptioncorrutils``.