diff --git a/src/pg_rad/detector/builder.py b/src/pg_rad/detector/builder.py
index cf5a6e8..940a2f9 100644
--- a/src/pg_rad/detector/builder.py
+++ b/src/pg_rad/detector/builder.py
@@ -14,7 +14,7 @@ class DetectorBuilder:
         if self.detector_spec.is_isotropic:
             return IsotropicDetector(
                 self.detector_spec.name,
-                self.detector_spec.eff
+                self.detector_spec.efficiency
             )
         else:
             raise NotImplementedError("Angular detector not supported yet.")
diff --git a/src/pg_rad/detector/detectors.py b/src/pg_rad/detector/detectors.py
index cb4ec1f..439ee56 100644
--- a/src/pg_rad/detector/detectors.py
+++ b/src/pg_rad/detector/detectors.py
@@ -5,10 +5,10 @@ class BaseDetector(ABC):
     def __init__(
         self,
         name: str,
-        eff: float
+        efficiency: float
     ):
         self.name = name
-        self.eff = eff
+        self.efficiency = efficiency
 
     def get_efficiency(self):
         pass
@@ -18,21 +18,21 @@ class IsotropicDetector(BaseDetector):
     def __init__(
         self,
         name: str,
-        eff: float | None = None
+        efficiency: float,
     ):
-        super().__init__(name, eff)
+        super().__init__(name, efficiency)
 
     def get_efficiency(self, energy):
-        return self.eff
+        return self.efficiency
 
 
 class AngularDetector(BaseDetector):
     def __init__(
         self,
         name: str,
-        eff: float | None = None
+        efficiency: float
     ):
-        super().__init__(name, eff)
+        super().__init__(name, efficiency)
 
     def get_efficiency(self, angle, energy):
         pass