diff --git a/core/ArchiveExtractor.py b/core/ArchiveExtractor.py
index 2f862dba703f39f71992047cfdcdfe8d83547c7c..6da1dd91c2087eeebf3c2c95204b2dddc47b0aa5 100755
--- a/core/ArchiveExtractor.py
+++ b/core/ArchiveExtractor.py
@@ -5,6 +5,7 @@ import logging
 import datetime
 import numpy as np
 import PyTango as tango
+import pandas as pd
 
 __version__ = "1.0.1"
 
@@ -238,6 +239,7 @@ class ArchiveExtractor:
                 return None
 
             # Transform to datetime - value arrays
+            # NOTE: it is faster than using pandas.to_datetime()
             _value = np.asarray(_value, dtype=float)
             if len(_date) > 0:
                 _date = ArrayTimeStampToDatetime(_date/1000.0)
@@ -251,7 +253,7 @@ class ArchiveExtractor:
 
 
         self.logger.debug("Extraction done for %s."%attribute)
-        return [date, value]
+        return pd.Series(index=date, data=value)