Add efficiency error

libra_toolbox/neutron_detection/activation_foils/calibration.py

@@ -103,6 +103,7 @@ class Reaction:
     reactant: Nuclide
     product: Nuclide
     cross_section: float
+    type: str = "(n,2n)"
     """
     Class to hold the information of a reaction.
     Attributes
@@ -113,6 +114,7 @@ class Reaction:
         The product of the reaction.
     cross_section :
         The cross section of the reaction in cm2.
+    type: The type of the reaction (default is "(n,2n)").
     """
 
 nb93_n2n = Reaction(
@@ -133,6 +135,7 @@ class CheckSource:
     nuclide: Nuclide
     activity_date: datetime.date
     activity: float
+    activity_error: float = 0.0
 
     """
     Class to hold the information of a check source.
@@ -175,6 +178,36 @@ def get_expected_activity(self, date: datetime.date) -> float:
         time = (date - activity_datetime).total_seconds()
         act_expec = self.activity * np.exp(-decay_constant * time)
         return act_expec
+
+    def get_expected_activity_error(self, date: datetime.date) -> float:
+        """Returns the expected activity error of the check source at a given date.
+        Time is assumed to have no error in its measurement.
+
+        Args:
+            date: the date to calculate the expected activity error for.
+
+        Returns:
+            the expected activity error of the check source in Bq
+        """
+
+        decay_constant = np.log(2) / self.nuclide.half_life
+
+        # Convert date to datetime if needed
+        if isinstance(self.activity_date, datetime.date) and not isinstance(
+            self.activity_date, datetime.datetime
+        ):
+
+            activity_datetime = datetime.datetime.combine(
+                self.activity_date, datetime.datetime.min.time()
+            )
+            # add a timezone
+            activity_datetime = activity_datetime.replace(tzinfo=date.tzinfo)
+        else:
+            activity_datetime = self.activity_date
+
+        time = (date - activity_datetime).total_seconds()
+        act_expec = self.activity_error * np.exp(-decay_constant * time)
+        return act_expec
 
 
 @dataclass