diff --git a/src/ess/reduce/nexus/generic_types.py b/src/ess/reduce/nexus/generic_types.py
index e35275f5..8dcab03e 100644
--- a/src/ess/reduce/nexus/generic_types.py
+++ b/src/ess/reduce/nexus/generic_types.py
@@ -23,11 +23,14 @@
 """
 SampleRun = NewType('SampleRun', int)
 """Sample run."""
+VanadiumRun = NewType('VanadiumRun', int)
+"""Vanadium run."""
 
 ScatteringRunType = TypeVar(
     'ScatteringRunType',
-    SampleRun,
     BackgroundRun,
+    SampleRun,
+    VanadiumRun,
 )
 
 
@@ -48,6 +51,7 @@ class TransmissionRun(Generic[ScatteringRunType]):
     # Note that mypy does not seem to like this nesting, may need to find a workaround
     TransmissionRun[SampleRun],
     TransmissionRun[BackgroundRun],
+    VanadiumRun,
 )
 """TypeVar used for specifying BackgroundRun, EmptyBeamRun or SampleRun"""
 
diff --git a/src/ess/reduce/nexus/workflow.py b/src/ess/reduce/nexus/workflow.py
index 8cca2660..92f39261 100644
--- a/src/ess/reduce/nexus/workflow.py
+++ b/src/ess/reduce/nexus/workflow.py
@@ -334,7 +334,7 @@ def get_calibrated_detector(
     # the detector array from the raw loader NeXus group, to prevent a source of bugs.
     return AnyRunCalibratedDetector(
         da.assign_coords(
-            position=da.coords['position'] + offset,
+            position=da.coords['position'] + offset.to(unit=da.coords['position'].unit),
             source_position=source_position,
             sample_position=sample_position,
             gravity=gravity,
@@ -389,7 +389,7 @@ def get_calibrated_monitor(
     """
     return AnyRunAnyCalibratedMonitor(
         nexus.extract_monitor_data(monitor).assign_coords(
-            position=monitor['position'] + offset,
+            position=monitor['position'] + offset.to(unit=monitor['position'].unit),
             source_position=source_position,
         )
     )